Progesterone receptor loss identifies Luminal B breast cancer subgroups at higher risk of relapse

BackgroundThe immunohistochemical (IHC) evaluation of estrogen receptor (ER), progesterone receptor (PgR), Ki-67 and HER2 is considered a surrogate means for identifying the molecular subtypes of breast cancer with different prognosis.Patients and methodsWe explored patterns of recurrence in 4837 women with breast cancer defined as Luminal B (ER-positive and/or PgR-positive, HER2 positive and/or Ki-67≥14%) by IHC classification. We evaluated four subgroups within the Luminal B subtype according to HER2 expression and PgR status.ResultsPatients within the ER+/PgR+/HER2- subgroup presented a 5-year breast cancer-related survival (BCS) of 97% (95% confidence interval (CI), 96–97) and overall survival (OS) of 95% [95% CI, 95–96], the best survivals of the Luminal B subgroups. In the multivariate analysis, the ER+/PgR-/HER2- subgroup was associated with a reduced BCS (HR 1.71; 95%CI, 1.25–2.35) and OS (HR 1.47; 95%CI, 1.10–1.96) when compared with the ER+/PgR+/HER2- subgroup. Also patients within the ER+/PgR-/HER2+ subgroup had a reduced BCS (HR 1.93; 95%CI, 1.32–2.83) and OS (HR 1.62; 95%CI, 1.14–2.30) when compared with ER+/PgR+/HER2- subgroup. On the other hand, no statistically significant differences were found with regard to BCS and OS among patients with ER+/PgR+/HER2+ and patients with ER+/PgR+/HER2- disease.ConclusionsPgR loss identifies Luminal B breast cancer subgroups at higher risk of relapse and death, both with HER-2-positive and HER-2-negative disease.     

Anastrozole alone or in combination with tamoxifen versus tamoxifen alone for adjuvant treatment of postmenopausal women with early-stage breast cancer: results of the ATAC (Arimidex, Tamoxifen Alone or in Combination) trial efficacy and safety update analyses

BACKGROUND: The first analysis of the ATAC (Arimidex, Tamoxifen Alone or in Combination) trial (median follow-up, 33 months) demonstrated that in adjuvant endocrine therapy for postmenopausal patients with early-stage breast cancer, anastrozole was superior to tamoxifen in terms of disease-free survival (DFS), time to recurrence (TTR), and incidence of contralateral breast cancer (CLBC). In the current article, the results of the first efficacy update, based on a median follow-up period of 47 months, are reported along with the results of an updated safety analysis, performed 7 months after the first analysis (median duration of treatment, 36.9 months). METHODS: DFS, TTR, CLBC incidence, and safety were assessed in the same patient group as in the first analysis of the ATAC trial. RESULTS: DFS estimates at 4 years remained significantly more favorable (86.9% vs. 84.5%, respectively) for patients receiving anastrozole compared with those receiving tamoxifen (hazard ratio [HR], 0.86; 95% confidence interval [CI], 0.76-0.99; P = 0.03). The benefit generated by anastrozole in terms of DFS was even greater in patients with hormone receptor-positive tumors (HR, 0.82; 95% CI, 0.70-0.96; P = 0.014). The HR for TTR also indicated a significant benefit for patients receiving anastrozole compared with those receiving tamoxifen (HR, 0.83; 95% CI, 0.71-0.96; P = 0.015), with additional benefit for patients with hormone receptor-positive tumors (HR, 0.78; 95% CI, 0.65-0.93; P = 0.007). CLBC incidence data also continued to favor anastrozole (odds ratio [OR], 0.62; 95% CI, 0.38-1.02; P = 0.062), and statistical significance was achieved in the hormone receptor-positive subgroup (OR, 0.56; 95% CI, 0.32-0.98; P = 0.042). The updated safety analysis also confirmed the findings of the first analysis, in that endometrial cancer (P = 0.007), vaginal bleeding and discharge (P < 0.001 for both), cerebrovascular events (P < 0.001), venous thromboembolic events (P < 0.001), and hot flashes (P < 0.001) all occurred less frequently in the anastrozole group, whereas musculoskeletal disorders and fractures (P < 0.001 for both) continued to occur less frequently in the tamoxifen group. These results indicated that the safety profile of anastrozole remained consistent. CONCLUSIONS: After an additional follow-up period, anastrozole continues to show superior efficacy, which is most apparent in the clinically relevant hormone receptor-positive population. Furthermore, anastrozole has numerous noteworthy advantages in terms of tolerability compared with tamoxifen. These findings suggest that the benefits of anastrozole are likely to be maintained in the long term and provide further support for the status of anastrozole as a valid treatment option for postmenopausal women with hormone-sensitive early-stage breast cancer.     

Anastrozole (Arimidex) versus tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: survival analysis and updated safety results

We present an initial survival analysis and an update of the safety data of the North American and Tamoxifen or Arimidex Randomized Group Efficacy and Tolerability (TARGET) double-blind, randomised, multicentre studies which compared anastrozole with tamoxifen as first-line treatment in postmenopausal patients with oestrogen receptor and/or progesterone receptor-positive (ER+/PR+) or receptor-unknown advanced breast cancer (ABC). At a median follow-up of 43.7 months, 56.0% of patients in the anastrozole group and 56.1% of patients in the tamoxifen group had died. The proportion of patients dead at 2 years was 31.1 and 32.0% in the anastrozole and tamoxifen groups, respectively. In the ER+/PR+ subgroup, 55.1 and 55.9% of patients had died and median time to deaths (TTD) were 40.8 and 41.3 months in the anastrozole and tamoxifen groups, respectively. Both agents remained well tolerated, with fewer reports of vaginal bleeding (anastrozole versus tamoxifen, 1.0% versus 2.5%) and thromboembolic events (anastrozole versus tamoxifen, 5.3% versus 9.0%) in the anastrozole group versus the tamoxifen group. Hot flushes and vaginal dryness were reported marginally less in the tamoxifen group compared with the Anastrozole group. Although no improvement in survival was observed, the favourable profile of anastrozole with respect to efficacy (TTP) and tolerability [Cancer 92 (2001) 2247] support the use of anastrozole in advance of tamoxifen as the first-line therapy choice in postmenopausal women with ABC.     

Comparison of fulvestrant versus tamoxifen for the treatment of advanced breast cancer in postmenopausal women previously untreated with endocrine therapy: a multinational, double-blind, randomized trial.

PURPOSE: To evaluate the efficacy and tolerability of fulvestrant (Faslodex; AstraZeneca Pharmaceuticals LP, Wilmington, DE), a new estrogen receptor (ER) antagonist that downregulates ER and has no agonist effects, versus tamoxifen, an antiestrogen with agonist and antagonist effects, for the treatment of advanced breast cancer in postmenopausal women. PATIENTS AND METHODS: In this multicenter, double-blind, randomized trial, patients with metastatic/locally advanced breast cancer previously untreated for advanced disease were randomly assigned to receive either fulvestrant (250 mg, via intramuscular injection, once monthly; n = 313) or tamoxifen (20 mg, orally, once daily; n = 274). Patients' tumors were positive for ER (ER+) and/or progesterone receptor (PgR+), or had an unknown receptor status. RESULTS: At a median follow-up of 14.5 months, there was no significant difference between fulvestrant and tamoxifen for the primary end point of time to progression (TTP; median TTP, 6.8 months and 8.3 months, respectively; hazard ratio, 1.18; 95% CI, 0.98 to 1.44; P =.088). In a prospectively planned subset analysis of patients with known ER+ and/or PgR+ tumors ( approximately 78%), median TTP was 8.2 months for fulvestrant and 8.3 months for tamoxifen (hazard ratio, 1.10; 95% CI, 0.89 to 1.36; P =.39). The objective response rate for the overall population was 31.6% with fulvestrant and 33.9% with tamoxifen, and 33.2% and 31.1%, respectively, in the known hormone receptor-positive subgroup. Both treatments were well tolerated. CONCLUSION: In the overall population, between-group differences in efficacy end points favored tamoxifen, and statistical noninferiority of fulvestrant could not be demonstrated. However, in patients with hormone receptor-positive tumors, fulvestrant had similar efficacy to tamoxifen and was well tolerated.     

Activation of Akt, mTOR, and the estrogen receptor as a signature to predict tamoxifen treatment benefit

The frequent alterations of the PI3K/Akt/mTOR-growth signaling pathway are proposed mechanisms for resistance to endocrine therapy in breast cancer, partly through regulation of estrogen receptor α (ER) activity. Reliable biomarkers for treatment prediction are required for improved individualized treatment. We performed a retrospective immunohistochemical analysis of primary tumors from 912 postmenopausal patients with node-negative breast cancer, randomized to either tamoxifen or no adjuvant treatment. Phosphorylated (p) Akt-serine (s) 473, p-mTOR-s2448, and ER phosphorylations-s167 and -s305 were evaluated as potential biomarkers of prognosis and tamoxifen treatment efficacy. High expression of p-mTOR indicated a reduced response to tamoxifen, most pronounced in the ER+/progesterone receptor (PgR) + subgroup (tamoxifen vs. no tamoxifen: hazard ratio (HR), 0.86; 95 % confidence interval (CI), 0.31–2.38; P = 0.78), whereas low p-mTOR expression predicted tamoxifen benefit (HR, 0.29; 95 % CI, 0.18–0.49; P = 0.000002). In addition, nuclear p-Akt-s473 as well as p-ER at -s167 and/or -s305 showed interaction with tamoxifen efficacy with borderline statistical significance. A combination score of positive pathway markers including p-Akt, p-mTOR, and p-ER showed significant association with tamoxifen benefit (test for interaction; P = 0.029). Cross-talk between growth signaling pathways and ER-signaling has been proposed to affect tamoxifen response in hormone receptor-positive breast cancer. The results support this hypothesis, as an overactive pathway was significantly associated with reduced response to tamoxifen. A clinical pre-treatment test for cross-talk markers would be a step toward individualized adjuvant endocrine treatment with or without the addition of PI3K/Akt/mTOR pathway inhibitors.     

Progesterone receptor loss identifies luminal-type local advanced breast cancer with poor survival in patients who fail to achieve a pathological complete response to neoadjuvant chemotherapy

The aim of this study was to investigate the potential of progesterone receptor (PgR) as a biomarker for differentiating estrogen receptor (ER)-positive patients who fail to achieve a pathological complete response to neoadjuvant chemotherapy (NCT) with different prognoses. A total of 327 consecutive, locally advanced breast cancer patients with ER-positive disease were included in this study. According to their HER-2 and Ki-67 status, the patients were classified into the Luminal-A or Luminal-B subtype. We evaluated the clinical and pathological response to NCT and relapse or death occurring during follow-up according to PgR status in the different luminal subtypes. In the Luminal-B subtype, patients with PgR- tumors had a relatively higher pathological complete response (pCR) rate (29.5% vs. 4.7% pCR, P < 0.001) and Miller-Payne grades (45.5% vs. 23.5% of grade 4-5, P = 0033) compared to PgR+ tumors. In Luminal-B patients with residual tumor after NCT, PgR loss was also independently correlated with poor relapse-free survival (P = 0.017; HR = 0.430; PgR- as a reference) and overall survival (P = 0.013; HR = 0.355; PgR- as a reference). However, in the Luminal-A subtype, there were no statistically significant differences between PgR+ and PgR- disease in response to NCT or survival. Our findings have demonstrated the prognostic value of PgR loss in the neoadjuvant setting, indicating that ER+/PgR- Luminal-B tumors warrant further attention due to their high risk of relapse after primary treatment.     

Low-dose tamoxifen in the treatment of breast ductal intraepithelial neoplasia: results of a large observational study

Background: Tamoxifen's cost–benefit ratio for breast ductal intraepithelial neoplasia (DIN) is unclear. Since low-dose tamoxifen showed a favorable modulation of breast cancer biomarkers in phase II trials, a monoinstitutional cohort of women with DIN treated with low-dose tamoxifen or no systemic treatment was analyzed.Patients and methods: A total of 309 patients with DIN received low-dose tamoxifen as part of institutional guidelines and were compared with 371 patients with DIN who received no systemic treatment after surgery.Results: Women with estrogen receptor (ER)/progesterone receptor (PgR) >50% DIN who were not treated had a higher incidence of breast events than women on tamoxifen [hazard ratio (HR) 1.76; 95% confidence interval (CI) 1.00–3.12] or women with ER/PgR <50% DIN (HR 1.72; 95% CI 1.14–2.58). Among untreated patients with ER >50% DIN, recurrence was higher in PgR ≥50% DIN than in PgR <50% DIN, whereas it was similar among low PgR (<50%) DIN against which tamoxifen had no effect. No difference in endometrial cancer incidence was noted.Conclusions: High ER and especially high PgR expression is a significant adverse prognostic indicator of DIN, and low-dose tamoxifen appears to be an active treatment. Women with low-expression ER or PgR DIN do not seem to benefit from tamoxifen. A definitive clinical trial is warranted.     

Fulvestrant is an effective and well-tolerated endocrine therapy for postmenopausal women with advanced breast cancer: results from clinical trials

Fulvestrant ('Faslodex') is a new type of endocrine treatment--an oestrogen receptor (ER) antagonist that downregulates the ER and has no agonist effects. Early efficacy data from phase I/II trials have demonstrated fulvestrant to be effective and well tolerated. Two randomised phase III trials have compared the efficacy of fulvestrant and the aromatase inhibitor, anastrozole, in postmenopausal women with advanced breast cancer progressing on prior endocrine therapy. Fulvestrant (intramuscular injection 250 mg month(-1)) was found to be at least as effective as anastrozole (orally 1 mg day(-1)) for time to progression (5.5 vs 4.1 months, respectively (hazard ratio (HR): 0.95; 95.14% confidence interval (CI), 0.82-1.10; P=0.48)) and objective response 19.2 vs 16.5%, respectively; treatment difference 2.75%; 95.14% CI, -2.27 to 9.05%; P=0.31). More recently, fulvestrant has also been shown to be noninferior to anastrozole in terms of overall survival, with median time to death being 26.4 months in fulvestrant-treated patients and 24.2 months in those treated with anastrozole (HR: 0.97; 95% CI, 0.78-1.21; P=0.82). In a further randomised phase III trial, fulvestrant was compared with tamoxifen as first-line therapy for advanced disease in postmenopausal women. In the overall population, efficacy differences favoured tamoxifen and noninferiority of fulvestrant could not be ruled out. In the prospectively defined subset of patients with ER-positive and/or progesterone receptor-positive disease, there was no statistically significant difference between fulvestrant and tamoxifen. This paper reviews the efficacy and tolerability results from these trials.     

Anastrozole is superior to tamoxifen as first-line therapy for advanced breast cancer in postmenopausal women: results of a North American multicenter randomized trial. Arimidex Study Group.

PURPOSE: The efficacy and tolerability of anastrozole (Arimidex; AstraZeneca, Wilmington, DE, and Macclesfield, United Kingdom) and tamoxifen were compared as first-line therapy for advanced breast cancer in 353 postmenopausal women. PATIENTS AND METHODS: The randomized, double-blind, multicenter study was designed to evaluate anastrozole 1 mg once daily relative to tamoxifen 20 mg once daily in patients with hormone receptor-positive tumors or tumors of unknown receptor status who were eligible for endocrine therapy. Primary end points were objective response (OR), defined as complete (CR) or partial (PR) response, time to progression (TTP), and tolerability. RESULTS: Anastrozole was as effective as tamoxifen in terms of OR (21% v 17% of patients, respectively), with clinical benefit (CR + PR + stabilization > or = 24 weeks) observed in 59% of patients on anastrozole and 46% on tamoxifen (two-sided P =.0098, retrospective analysis). Anastrozole had a significant advantage over tamoxifen in terms of TTP (median TTP of 11.1 and 5.6 months for anastrozole and tamoxifen, respectively; two-sided P =.005). The tamoxifen:anastrozole hazards ratio was 1.44 (lower one-sided 95% confidence limit, 1.16). Both treatments were well tolerated. However, thromboembolic events and vaginal bleeding were reported in fewer patients who received anastrozole compared with those who received tamoxifen (4.1% v 8.2% [thromboembolic events] and 1.2% v 3.8% [vaginal bleeding], respectively). CONCLUSION: Anastrozole satisfied the predefined criteria for equivalence to tamoxifen. Furthermore, we observed both a significant increase in TTP and a lower incidence of thromboembolic events and vaginal bleeding with anastrozole. These findings indicate that anastrozole should be considered as first-line therapy for postmenopausal women with advanced breast cancer.     

Switching to anastrozole versus continued tamoxifen treatment of early breast cancer: preliminary results of the Italian Tamoxifen Anastrozole Trial.

PURPOSE: Tamoxifen, which is actually the gold standard adjuvant treatment in estrogen receptor-positive early breast cancer, is associated with an increased risk of endometrial cancer and other life-threatening events. Moreover, many women relapse during or after tamoxifen therapy because of the development of resistance. Therefore new approaches are required. PATIENTS AND METHODS: We conducted a prospective randomized trial to test the efficacy of switching postmenopausal patients who were already receiving tamoxifen to the aromatase inhibitor anastrozole. After 2 to 3 years of tamoxifen treatment, patients were randomly assigned either to receive anastrozole 1 mg/d or to continue receiving tamoxifen 20 mg/d, for a total duration of treatment of 5 years. Disease-free survival was the primary end point. Event-free survival, overall survival, and safety were secondary end points. RESULTS: Four hundred forty-eight patients were enrolled. All women had node-positive, estrogen receptor-positive tumors. At a median follow-up time of 36 months, 45 events had been reported in the tamoxifen group compared with 17 events in the anastrozole group (P = .0002). Disease-free and local recurrence-free survival were also significantly longer in the anastrozole group (hazard ratio [HR] = 0.35; 95% CI, 0.18 to 0.68; P = .001 and HR = 0.15; 95% CI, 0.03 to 0.65; P = .003, respectively). Overall, more adverse events were recorded in the anastrozole group compared with the tamoxifen group (203 v 150, respectively; P = .04). However, more events were life threatening or required hospitalization in the tamoxifen group than in the anastrozole group (33 of 150 events v 28 of 203 events, P = .04). CONCLUSION: Switching to anastrozole after the first 2 to 3 years of treatment is well tolerated and significantly improves event-free and recurrence-free survival in postmenopausal patients with early breast cancer.     

Anastrozole versus tamoxifen as first-line therapy for advanced breast cancer in 668 postmenopausal women: results of the Tamoxifen or Arimidex Randomized Group Efficacy and Tolerability study.

PURPOSE: To compare the efficacy and tolerability of anastrozole (Arimidex; AstraZeneca, Wilmington, DE, and Macclesfield, United Kingdom) with that of tamoxifen as first-line therapy for advanced breast cancer (ABC) in postmenopausal women. PATIENTS AND METHODS: This randomized, double-blind, multicenter study evaluated the efficacy of anastrozole 1 mg once daily relative to tamoxifen 20 mg once daily in patients with tumors that were hormone receptor-positive or of unknown receptor status who were eligible for endocrine therapy. The primary end points were time to progression (TTP), objective response (OR), and tolerability. RESULTS: A total of 668 patients (340 in the anastrozole arm and 328 in the tamoxifen arm) were randomized to treatment and followed-up for a median of 19 months. Median TTP was similar for both treatments (8.2 months in patients who received anastrozole and 8.3 months in patients who received tamoxifen). The tamoxifen:anastrozole hazards ratio was 0.99 (lower one-sided 95% confidence limit, 0.86), demonstrating that anastrozole was at least equivalent to tamoxifen. Anastrozole was also as effective as tamoxifen in terms of OR (32.9% of anastrozole and 32.6% of tamoxifen patients achieved a complete response [CR] or partial response [PR]). Clinical benefit (CR + PR + stabilization of > or = 24 weeks) rates were 56.2% and 55.5% for patients receiving anastrozole and tamoxifen, respectively. Both treatments were well tolerated. However, incidences of thromboembolic events and vaginal bleeding were reported in fewer patients treated with anastrozole than with tamoxifen (4.8% v 7.3% [thromboembolic events] and 1.2% v 2.4% [vaginal bleeding], respectively). CONCLUSION: Anastrozole satisfied the predefined criteria for equivalence to tamoxifen. Together with the lower observed incidence of thromboembolic events and vaginal bleeding, these findings indicate that anastrozole should be considered as first-line therapy for postmenopausal women with ABC.     

Steroid hormone receptors and response to high-dose medroxyprogesterone acetate in advanced breast cancer

Forty-six patients with advanced breast cancer were treated with oral high-dose medroxyprogesterone acetate (MPA) as a second line endocrine treatment, with a 28% 13/46) response rate. There was a significant difference in response to MPA between patients with estrogen (ER)- or progesterone (PgR)-receptors and those with negative receptors assayed just before the treatment (ER+, 7/10, ER-, 0/9 of response rates, p = 0.007, PgR+, 4/4: PgR-, 3/15, p = 0.02). The combination of ER and PgR was observed to be best in predicting the response (p = 0.02). The ER status as well as the combination of ER and PgR, but not PgR alone detected in the primary tumors, correlated well with the response (ER+, 10/23: ER-, 0/15, p = 0.0094, PgR+: PgR-, p = 0.13, ER+PgR+, ER+PgR-, ER-PgR-:p = 0.024). The correlation between steroid hormone receptors and response to MPA in advanced breast cancer was established from the literature. Response rate to MPA was shown to be 42% (69/169) in ER+ cancer patients, and 10% (9/90) in ER- cancer patients (p = 0.00004). There was no correlation between PgR status and the response. Changes of receptors were studied in relation to the response. When ER+ or PgR+ tumors retained their positivity until MPA treatment, a good response was obtained, while there were almost no responders if one or both receptors changed from positive to negative, or remained negative. In conclusion, the response to MPA can be predicted by the steroid hormone receptors.     

Systematic review of aromatase inhibitors in the first-line treatment for hormone sensitive advanced or metastatic breast cancer

To undertake a systematic review of three first-line treatments (letrozole, anastrozole and exemestane) for hormone sensitive advanced or metastatic breast cancer (MBC) in post-menopausal women. We searched six databases from inception up to January 2009 for relevant trials regardless of language or publication status. Randomised controlled clinical trials assessing the safety and efficacy of first-line AIs for post-menopausal women with hormone receptor-positive (HR+, i.e. ER+ and/or PgR+) with or without ErbB2 (HER2)-positive MBC, who have not received prior therapy for advanced or metastatic disease were included. Where meta-analysis using direct or indirect comparisons was considered unsuitable for some or all of the data, we employed a narrative synthesis method. Four studies (25 papers) met the inclusion criteria. From the available evidence, it was possible to directly compare the three AIs with tamoxifen. In addition, by using a network meta-analysis it was possible to compare the three AIs with each other. Based on direct evidence, letrozole seemed to be significantly better than tamoxifen in terms of time-to-progression (TTP) (HR = 0.70 (95% CI: 0.60, 0.82)), objective response rate (RR = 0.65 (95% CI: 0.52, 0.82)) and quality-adjusted time without symptoms or toxicity (Q-Twist difference = 1.5; P < 0.001). Exemestane seemed significantly superior to tamoxifen in terms of objective response rate (RR = 0.68 (95% CI: 0.53, 0.89)). Anastrozole seemed significantly superior to tamoxifen in terms of TTP in one trial (HR = 1.42 (95% CI: 1.15, NR)), but not in the other (HR = 1.01 (95% CI: 0.87, NR)). In terms of adverse events, no significant differences were found between letrozole and tamoxifen. Tamoxifen was associated with significantly more serious adverse events in comparison with exemestane (OR = 0.61 (95% CI: 0.38, 0.97)); while exemestane was associated with significantly more arthralgia in comparison with tamoxifen (OR = 2.33 (95% CI: 1.07, 5.11)). Anastrozole was associated with significantly more total adverse events (OR = 1.04 (95% CI: 1.00, 1.09)) and hot flushes (OR = 1.39 (95% CI: 1.03, 1.89)) in comparison with tamoxifen in one trial; however, the other trial showed no significant differences in adverse events between anastrozole and tamoxifen. The indirect comparison of AIs with each other in women with post-menopausal, hormone sensitive advanced or MBC showed that letrozole and exemestane were better in terms of objective response rate than anastrozole; while the more clinically relevant outcomes overall survival (OS) and progression-free survival (PFS) showed no significant differences between AIs. OS and PFS showed no significant differences between AIs and hence based on these results a class effect for all AIs is possible. However, these results are based on indirect comparisons and a network analysis for which the basic assumptions of homogeneity, similarity and consistency were not fulfilled. Therefore, despite the fact that these are the best available data, the results need to be interpreted with appropriate caution. Head-to-head comparisons between letrozole, anastrozole and exemestane in the first-line MBC setting are warranted.     

Outcomes of Japanese breast cancer patients treated with pre-operative and post-operative anastrozole or tamoxifen

The present study examined long-term efficacy outcomes in a subgroup of postmenopausal, estrogen receptor-positive Japanese breast cancer patients from the Pre-Operative "Arimidex" Compared with Tamoxifen trial, following pre-operative (3 months) and post-operative (5 years) adjuvant treatment with either anastrozole or tamoxifen. Patients with large, potentially operable, locally-advanced breast cancer were randomized to receive anastrozole (1 mg/day) plus tamoxifen placebo or tamoxifen (20 mg/day) plus anastrozole placebo pre-operatively. After surgery at 3 months, patients continued on the same study medication as adjuvant therapy for up to 5 years or until recurrence, intolerable toxicity or withdrawal of patient consent. Recurrence-free survival and overall survival were measured from the date of randomization to the date of recurrence or death, whichever occurred first. Patients were monitored for adverse events throughout the study period and up to 30 days following administration of the last study medication. During post-operative adjuvant therapy, 4/48 (8%) anastrozole and 25/49 (51%) tamoxifen patients experienced recurrence. There was a significant difference in recurrence-free survival between the two groups (hazard ratio 0.14; 95% confidence interval 0.05-0.41; P = 0.0003). There was a significant increase in overall survival with anastrozole (0.21; 0.05-0.96; P = 0.0436) and there were 2/48 (4%) and 10/49 (20%) deaths with anastrozole and tamoxifen, respectively. Most patients responding to pre-operative therapy remained recurrence-free. Sequential pre-operative/post-operative treatment with anastrozole resulted in lower recurrence and death rates, compared with tamoxifen.     

Comparison of anastrozole versus tamoxifen as preoperative therapy in postmenopausal women with hormone receptor-positive breast cancer: the Pre-Operative "Arimidex" Compared to Tamoxifen (PROACT) trial

BACKGROUND: The Pre-Operative "Arimidex" Compared to Tamoxifen (PROACT) study was a randomized, multicenter study comparing anastrozole with tamoxifen as a preoperative treatment of postmenopausal women with large, operable (T2/3, N0-2, M0), or potentially operable (T4b, N0-2, M0) breast cancer. The effect of preoperative endocrine therapy in patients scheduled for mastectomy or with inoperable tumors at baseline was also investigated. METHODS: Patients with hormone receptor-positive breast cancer received anastrozole (n = 228) or tamoxifen (n = 223) with or without chemotherapy for 12 weeks before primary surgery. RESULTS: Objective responses for anastrozole and tamoxifen occurred in 39.5% and 35.4% of patients, respectively (ultrasound measurements), and 50.0% and 46.2% of patients, respectively (caliper measurements). In hormonal therapy-only patients (n = 314), feasible surgery at baseline improved after 3 months in 43.0% of patients receiving anastrozole and 30.8% receiving tamoxifen (P = .04). In the intent-to-treat population, improvement in feasible surgery at baseline to actual surgery at 3 months was found to be numerically higher in the anastrozole group compared with the tamoxifen group, although this difference did not reach significance. Drug-related adverse events were reported in 20.2% and 18.1% of patients, respectively, in the anastrozole and tamoxifen groups. CONCLUSIONS: Anastrozole is an effective and well-tolerated preoperative therapy, producing clinically beneficial tumor downstaging and reductions in tumor volume. These effects enable more minimal surgical interventions in patients scheduled for mastectomy, and mastectomy in patients with previously inoperable tumors. Anastrozole appears to be at least as effective as tamoxifen in this setting, and more effective than tamoxifen in certain clinically relevant subgroups. Cancer 2006. (c) 2006 American Cancer Society.     

Cost-effectiveness analysis of anastrozole vs tamoxifen in adjuvant therapy for early stage breast cancer in the United Kingdom: the 5-year completed treatment analysis of the ATAC ('Arimidex', Tamoxifen alone or in combination) trial

Results from the completed treatment analysis of the ATAC (Arimidex, Tamoxifen alone or in combination) trial indicated that anastrozole was significantly superior to tamoxifen in terms of efficacy and safety in the adjuvant treatment of postmenopausal women with hormone receptor-positive (HR+) early breast cancer. On the basis of these results, this study estimated the cost-effectiveness of anastrozole vs tamoxifen, from the perspective of the UK National Health Service (NHS). A Markov model was developed using the 5-year completed treatment analysis from the ATAC trial (ISRCTN18233230), as well as data obtained from published literature and expert opinion. Resource utilisation data and associated costs (2003-4 UK pound) were compiled from standard sources and expert opinion. Utility scores for a number of health states were obtained from a cross-sectional study of 26 representative patients using the standard gamble technique. The utility scores were then inserted into the model to obtain cost per quality adjusted life-year (QALY) gained. Costs and benefits were discounted at recommended annual rates of the UK Treasury (3.5%). Modelled for 25 years, anastrozole, relative to generic tamoxifen, was estimated to result in 0.244 QALYs gained per patient at an additional cost of pound4315 per patient). The estimated incremental cost-effectiveness of anastrozole compared with tamoxifen was pound17 656 per QALY gained. There was a greater than 90% probability that the cost-effectiveness of anastrozole was below pound30 000 per QALY gained and of the order of 65% that it was below pound20 000 per QALY gained. The results were robust to all parameters tested in sensitivity analysis. Compared with commonly accepted thresholds, anastrozole is a cost-effective alternative to generic tamoxifen in adjuvant treatment of postmenopausal women with HR+ early breast cancer from the UK NHS perspective.     

Effect of low-dose tamoxifen after surgical excision of ductal intraepithelial neoplasia: results of a large retrospective monoinstitutional cohort study

BackgroundPostsurgical treatment of ductal intraepithelial neoplasia (DIN) with standard doses of tamoxifen has not reached a consensus yet. Given positive results of low-dose tamoxifen on breast cancer biomarkers modulation, we analyzed a large cohort of DIN patients treated with low-dose tamoxifen or no treatment as per institutional guidelines.Patients and methodsAll consecutive women operated on at the European Institute of Oncology for estrogen receptor (ER)-positive DIN (474 treated with low-dose tamoxifen and 509 untreated patients) were followed up for a median of 7 years.ResultsCompared with untreated patients, a significant 30% reduction in breast cancer risk was observed on low-dose tamoxifen with an adjusted hazard ratio (HR) = 0.70 [95% confidence interval (CI) 0.51–0.94], with a greater benefit in postmenopausal (HR = 0.57; 95% CI 0.34–0.94) than in premenopausal women (HR = 0.79; 95% CI 0.54–1.17). Treated patients with ER and progesterone receptor (PgR) >50% DIN had a lower incidence of breast events than untreated ones (HR = 0.61; 95% CI 0.40–0.94), whereas no protective effect has been observed in patients with ER or PgR <50% DIN. Drug discontinuation resulted in a doubled risk of recurrence in premenopausal women only (HR = 1.95; 95% CI 0.98–3.89). No excess of endometrial cancer occurred.ConclusionsLow-dose tamoxifen is a promising and safe strategy for highly endocrine responsive DIN. Treatment adherence is crucial in premenopausal women. A definitive trial is ongoing.     

Emerging role of aromatase inhibitors in the adjuvant setting

Aromatase inhibitors (AIs) have been approved as second-line treatment for estrogen receptor-positive (ER+) metastatic breast cancer after first-line treatment with the selective estrogen receptor modulator (SERM) tamoxifen. Anastrozole and letrozole have also recently been widely approved as first-line endocrine therapy for postmenopausal women with hormone receptor-positive metastatic breast cancer. The three third-generation selective oral AIs approved for use in the United States include two nonsteroidal agents, anastrozole (Arimidex) and letrozole (Femara), and the irreversible steroidal inhibitor exemestane (Aromasin). Several major ongoing clinical trials with a variety of treatment regimens are comparing the relative efficacy of tamoxifen with the steroidal and nonsteroidal AIs in the adjuvant setting. The first strategy compares an AI against tamoxifen directly. Among these are the ATAC (Arimidex, Tamoxifen Alone or in Combination) trial (anastrozole), the BIG FEMTA (Femara-Tamoxifen Breast International Group) trial (letrozole), and the EXEM and TEAM (exemestane) trials. A second strategy is examining the use of an AI as an extension after the initial 5 years of tamoxifen. Examples of this trial design are the MA-17 (letrozole) and the National Surgical Adjuvant Breast and Bowel Project (NSABP B-33, exemestane) trials. A third approach is the use of these agents in sequence with tamoxifen as therapy within the initial 5 postoperative years. Examples of this approach are the International Collaboration Cancer Group trial (tamoxifen for 2-3 years followed by either tamoxifen or exemestane for the remainder of the 5-year period), the BIG FEMTA trial (patients are crossed over from tamoxifen to Ietrozole or letrozole to tamoxifen), and the Arimidex-Nolvadex (ARNO) trial (patients receiving tamoxifen are randomized either to continue with tamoxifen or to switch to anastrozole). A single trial is comparing tamoxifen and anastrozole as initial 5-year therapy, or a combination of the two. The study addressing this design is the ATAC trial. Finally, a small trial in Norway is comparing 2 years of an AI versus a placebo in very low-risk patients with receptor-positive breast tumors. Most adjuvant trials have companion studies associated with the main protocol. These are to determine the end-organ effects of the inhibitors and include measurements of quality of life, bone and lipid metabolism, and endometrial effects. This review addresses the clinical implications of these studies of AIs.     

Prognostic value of estrogen and progesterone receptors in primary breast cancer

Estradiol receptor alone or estradiol and progesterone receptors (ER, PgR) have been measured in tumors from 307 women who were treated for primary breast adenocarcinoma. Patients received adjuvant therapy in relation to tumor stage independently of receptor status. Over a relatively short follow-up, more recurrences are recorded in patients with ER+ tumors, but at 7 years the same proportion of recurrences are registered in both groups of patients whose tumors were ER+ or ER-. Patients whose tumors were processed for both ER and PgR (148 cases) have now been evaluated after 5 years follow-up. Among 56 patients with PgR+ tumors 5 recurred, versus 22/92 in the PgR- group. 21/87 patients who had 1 to 4 invaded nodes at the time of surgery relapsed: 17/54 had PgR- tumors versus 4/33 PgR+. 6 recurrences were recorded in the 61 patients with negative nodes: 5 of them occurred in patients with PgR- tumors. In addition, recurrences observed in patients with negative receptor status occurred after a shorter disease-free interval. Analysis of the incidence of recurrences in relation to the combined ER/PgR status in patients who did not receive adjuvant therapy suggests that tumor PgR content is a more significant criterion than ER for long-term prognosis.     

Potential predictive value of Bcl-2 for response to tamoxifen in the adjuvant setting of node-positive breast cancer

Approximately 50% of patients with estrogen receptor (ER)-positive breast cancer (BC) and 70%-80% of patients with ER-positive and progesterone receptor (PgR)-positive BC respond to hormonal therapy. Additional predictive markers are needed. A group of 287 patients with ER- and/or PgR-positive tumors was selected from 804 patients previously enrolled in a multicenter phase III trial. Bcl-2 expression was evaluated and correlated with response to adjuvant tamoxifen and survival. Estrogen receptor and PgR were determined by biochemical means and Bcl-2 by immunohistochemistry. With a median follow-up of 76 months (95 relapses and 60 deaths), of the 287 patients with, 187 (65%) had Bcl-2-positive tumors and 78 of these patients received tamoxifen. Of the 100 patients with Bcl-2-negative disease, 51 received tamoxifen and 49 regular follow-up. Using patients treated with tamoxifen as a reference, a univariate analysis of disease-free interval for patients who did not receive tamoxifen showed a hazard ratio (HR) of 1.42 (95% CI, 0.82-2.44; P = 0.21) for patients with Bcl-2-positive disease and a HR of 1.05 (95% CI, 0.55-1.99; P = 0.89) for patients with Bcl-2-negative disease (P = 0.48). After adjusting for number of positive lymph nodes, degree of receptor and PgR positivity, and type of surgery, the HRs were 1.54 (95% CI, 0.87-2.73; P = 0.14) for Bcl-2-positive disease and 1.05 (95% CI, 0.52-2.11; P = 0.88) for Bcl-2-negative disease. Despite its being a retrospective nonrandomized study with a relatively low number of patients, our results suggest that Bcl-2 deserves further evaluation as a predictive factor of sensitivity to tamoxifen.