Biologic markers as predictors of clinical outcome from systemic therapy for primary operable breast cancer.

PURPOSE: To determine whether pretreatment clinical features and molecular markers, together with changes in these factors, can predict treatment response and survival in patients with primary operable breast cancer who receive neoadjuvant therapy. PATIENTS AND METHODS: Mitoxantrone, methotrexate (with or without mitomycin), and tamoxifen chemoendocrine therapy was administered to 158 patients before surgery. Clinical response was assessed after four cycles of treatment. Fine-needle aspiration cytology for estrogen receptor (ER), progesterone receptor (PgR), c-erbB-2, p53, bcl-2, Ki67, S-phase fraction (SPF), and ploidy were performed pretreatment and repeated on day 10 or day 21 after the first cycle of treatment. RESULTS: Good clinical response (GCR, defined as complete response or minimal residual disease) was achieved in 31% of patients (49 of 158). Tumor size, nodal disease, response, ER, PgR, c-erbB-2, p53, bcl-2, Ki67, SPF, and ploidy were analyzed as predictors of survival. By univariate analysis, node-positive disease (P =.05), lack of ER (P <.05) and PgR (P <.05), and failure to attain GCR (P =.008) were associated with a significantly increased risk of relapse. A significantly increased risk of death was associated with node-positive disease (P =.02), lack of ER expression (P =.04), and failure to attain GCR. By multivariate analysis, GCR was an independent predictor for survival (P =.05). ER expression (P =.03), absence of c-erbB-2 (P =.03), and a decrease in Ki67 on day 10 or day 21 of the first cycle (P <.05) significantly predicted for subsequent GCR. CONCLUSION: Molecular markers may be used to predict the likelihood of achieving GCR, which seems to be a valid surrogate marker for survival.     

Changes in hormone receptors and proliferation markers in tamoxifen treated breast cancer patients and the relationship with response

Aim: To determine the effects of tamoxifen on the levels of hormone receptors and proliferation markers in the early phase of treatment and the relationship of the changes with tumor response in patients with primary breast cancer. Methods: Twenty-one women with primary, operable breast carcinomas were treated with tamoxifen 20 mg daily. Fine needle aspiration (FNA) was used to obtain samples prior to the start and at 14 days and 8-weeks post-treatment. From these samples estrogen receptor (ER), progesterone receptor (PgR), and Ki67 levels were determined using immunocytochemistry and ploidy and S-phase fraction (SPF) using flow cytometry. Tumor response was measured clinically according to UICC criteria. Results: There were 12 responders (2 CR, 10 PR) and 9 non-responders (2 NC, 7 PD). Responders were more likely to be ER + (p=0.002), PgR + (p=0.006), and low SPF (p=0.06). At 14 days post-tamoxifen, the median decrease in Ki67 (% cells staining) for responders was – 4.8 and for non-responders – 0.15 (p=0.005). This decrease was seen predominantly in ER + tumours. The difference in SPF was not significant. A decrease in ER was seen in 3/15 patients all of whom were responders. A rise in PgR was seen in 7/17 patients and all but one were responders. Similar changes for ER and PgR were seen at 8-weeks post-tamoxifen, although the reductions in Ki67 and SPF at that time point were not related to response. Conclusion: We have observed a decrease in Ki67 and ER and a rise in PgR after 14 days of treatment with tamoxifen that was related to subsequent response. This is the first study in which an early decrease in a proliferation marker has been shown to relate to subsequent clinical response.     

Letrozole inhibits tumor proliferation more effectively than tamoxifen independent of HER1/2 expression status

BACKGROUND: The biological basis for the superior efficacy of neoadjuvant letrozole versus tamoxifen for postmenopausal women with estrogen receptor (ER)-positive locally advanced breast cancer was investigated by analyzing tumor proliferation and expression of estrogen-regulated genes before and after the initiation of therapy. METHODS: Tumor samples were obtained at baseline and at the end of treatment from 185 patients participating in a double blind randomized Phase III study of neoadjuvant endocrine therapy. These paired specimens were simultaneously analyzed for Ki67, ER, progesterone receptor (PgR), trefoil factor 1 (PS2), HER1 (epidermal growth factor receptor), and HER2 (ErbB2 or neu) by semiquantitative immunohistochemistry. RESULTS: The treatment-induced reduction in geometric mean Ki67 was significantly greater with letrozole (87%) than tamoxifen (75%; analysis of covariance P = 0.0009). Differences in the average Ki67 reduction were particularly marked for ER-positive tumors that overexpressed HER1 and/or HER2 (88 versus 45%, respectively; P = 0.0018). Twenty-three of 92 tumors (25%) on tamoxifen and 14 of 93 on letrozole (15%) showed a paradoxical increase in Ki67 with treatment, and the majority of these cases was HER1/2 negative. Letrozole, but not tamoxifen, significantly reduced expression of the estrogen-regulated proteins PgR and trefoil factor 1, regardless of HER1/2 status (P < 0.0001). ER down-regulation occurred with both agents, although levels decreased more with tamoxifen (P < 0.0001). CONCLUSION: Letrozole inhibited tumor proliferation to a greater extent than tamoxifen. The molecular basis for this advantage appears complex but includes possible tamoxifen agonist effects on the cell cycle in both HER1/2+ and HER1/2- tumors. A pattern of continued proliferation despite appropriate down-regulation of PgR expression with estrogen deprivation or tamoxifen was also documented. This observation suggests the estrogenic regulation of proliferation and PgR expression may be dissociated in endocrine therapy resistant cells.     

Analysis of Ki‐67 expression with neoadjuvant anastrozole or tamoxifen in patients receiving goserelin for premenopausal breast cancer

BACKGROUND:

The increasing costs associated with large‐scale adjuvant trials mean that the prognostic value of biologic markers is increasingly important. The expression of nuclear antigen Ki‐67, a marker of cell proliferation, has been correlated with treatment efficacy and is being investigated for its value as a predictive marker of therapeutic response. In the current study, the authors explored correlations between Ki‐67 expression and tumor response, estrogen receptor (ER) status, progesterone receptor (PgR) status, and histopathologic response from the STAGE study (S_ tudy of T_ amoxifen or A_ rimidex, combined with G_ oserelin acetate to compare E_ fficacy and safety).

METHODS:

In a phase 3, double‐blind, randomized trial (National Clinical Trials identifier NCT00605267), premenopausal women with ER‐positive, early stage breast cancer received either anastrozole plus goserelin or tamoxifen plus goserelin for 24 weeks before surgery. The Ki‐67 index, hormone receptor (ER and PgR) status, and histopathologic responses were determined from histopathologic samples that were obtained from core‐needle biopsies at baseline and at surgery. Tumor response was determined by using magnetic resonance imaging or computed tomography.

RESULTS:

In total, 197 patients were randomized to receive either anastrozole plus goserelin (n = 98) or tamoxifen plus goserelin (n = 99). The best overall tumor response was better for the anastrozole group compared with the tamoxifen group both among patients who had a baseline Ki‐67 index ≥20% and among those who had a baseline Ki‐67 index <20%. There was no apparent correlation between baseline ER status and the Ki‐67 index in either group. Positive PgR status was reduced from baseline to week 24 in the anastrozole group.

CONCLUSIONS:

In premenopausal women with ER‐positive breast cancer, anastrozole produced a greater best overall tumor response compared with tamoxifen regardless of the baseline Ki‐67 index. Cancer 2013. © 2012 American Cancer Society.     

Relationship between estrogen receptor,progesterone receptor,HER-2 and Ki67 expression and efficacy of aromatase inhibitors in advanced breast cancer

BackgroundSurprisingly few data are published on the relevance of even commonly used biomarkers of response to aromatase inhibitors (AIs) in advanced breast cancer. Here, we aim to determine the effectiveness of AIs in that setting according to quantitative levels of estrogen receptor (ER), progesterone receptor (PgR) and Ki67 or human epithelial growth factor receptor-2 (HER-2) status.Patients and methodsER, PgR, HER-2 and Ki67 protein expressions were centrally assessed in 177 archival formalin-fixed paraffin-embedded primary or locally recurrent breast tumours from women who subsequently received AI treatment of advanced disease.ResultsAmong ER-positive patients (n = 146), higher PgR, but not ER, levels were associated with increased time to AI treatment failure (TTF). Higher Ki67 staining was associated with decreased TTF. ER-positive/HER-2-positive patients showed a non-significant trend for decreased TTF compared with ER-positive/HER-2-negative patients. PgR level, but not Ki67, remained a significant predictor of TTF in multivariate analysis of ER-positive patients.ConclusionsHigher PgR and Ki67 levels are significantly associated with increased and decreased TTF, respectively, in ER-positive patients receiving AI treatment of advanced disease. The higher proliferation seen in PgR-negative tumours does not explain the poorer clinical responsiveness of this subgroup.     

Relationship between tumour shrinkage and reduction in Ki67 expression after primary chemotherapy in human breast cancer.

The association between tumour shrinkage and reduction in kinetic cell activity after primary chemotherapy in human breast cancer is still a matter of investigation. 157 patients with T2-4, N0-1, M0 breast cancer received primary chemotherapy consisting of either the CMF regimen + tamoxifen (the first consecutive 76 cases) or the single agent epirubicin (the subsequent 81). Ki67, p53, bcl2, c-erbB2 and steroid hormone receptors were evaluated immunohistochemically in tumour specimens obtained before chemotherapy and at surgery. Tumour shrinkage of >50% occurred in 72.4% of patients. Ki67 expression significantly decreased after chemotherapy; the reduction correlated with tumour response in both univariate (P < 0.005) and multivariate analysis (P = 0.02). p53, bcl-2, steroid hormone receptor and c-erbB2 immunostaining were scarcely affected. Baseline bcl2 (P = 0.04) and c-erbB2 (P = 0.02) were directly and inversely associated with the reduction in Ki67 immunostaining, respectively. Baseline p53 expression (P < 0.01) was directly related with Ki67 expression at residual tumour, whereas oestrogen receptor expression (P < 0.001) was inversely related. Ki67 at residual tumour was a better predictor for relapse-free survival (RFS) than baseline Ki67. Clinical response (P < 0.03), but not reduction in Ki67, was a significant independent predictor for disease recurrence. Chemotherapy was found to induce tumour shrinkage and to reduce the number of cells in the cell cycle, but its effect on tumour biology/aggressiveness was minimal. Reduction in Ki67 immunostaining correlated with clinical response but failed to be related to RFS. Ki67 expression at surgery rather than at baseline appears to be a better predictor for disease relapse.     

Comparison of the short-term biological effects of 7alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)-nonyl]estra-1,3,5, (10)-triene-3,17beta-diol (Faslodex) versus tamoxifen in postmenopausal women with primary breast cancer

7Alpha-[9-(4,4,5,5,5-pentafluoropentylsulfinyl)-nonyl]estra-1,3,5, (10)-triene-3,17beta-diol (ICI 182,780; Faslodex) is a novel steroidal antiestrogen. This partially blind, randomized, multicenter study compared the effects of single doses of long-acting ICI 182,780 with tamoxifen or placebo on estrogen receptor (ERalpha) and progesterone receptor (PgR) content, Ki67 proliferation-associated antigen labeling index (Ki67LI), and the apoptotic index in the primary breast tumors of postmenopausal women. Previously untreated patients (stages T(1)-T(3); ER-positive or -unknown) were randomized and received a single i.m. dose of ICI 182,780 50 mg (n = 39), ICI 182,780 125 mg (n = 38), or ICI 182,780 250 mg (n = 44) or oral tamoxifen 20 mg daily (n = 36) or matching tamoxifen placebo (n = 43) for 14-21 days before tumor resection surgery with curative intent. The ER and PgR H-scores, together with the Ki67LI were determined immunohistochemically in the matched pretreatment biopsy and the posttreatment surgical specimens. The apoptotic index was determined by terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling on the same samples. The effects of treatment on each of these parameters were compared using analysis of covariance. ICI 182,780 produced dose-dependent reductions in ER and PgR H-scores and in the Ki67LI. The reductions in ER expression were statistically significant at all doses of ICI 182,780 compared with placebo (ICI 182,780 50 mg, P = 0.026; 125 mg, P = 0.006; 250 mg, P = 0.0001), and for ICI 182,780 250 mg compared with tamoxifen (P = 0.024). For PgR H-score, there were statistically significant reductions after treatment with ICI 182,780 125 mg (P = 0.003) and 250 mg (P = 0.0002) compared with placebo. In contrast, tamoxifen produced a significant increase in the PgR H-score relative to placebo, and consequently, all doses of ICI 182,780 produced PgR values that were significantly lower than those in the tamoxifen-treated group. All doses of ICI 182,780 significantly reduced Ki67LI values compared with placebo (ICI 182,780 50 mg, P = 0.046; 125 mg, P = 0.001; 250 mg, P = 0.0002), but there were no significant differences between any doses of ICI 182,780 and tamoxifen. ICI 182,780 did not alter the apoptotic index when compared with either placebo or tamoxifen. Short-term exposure to ICI 182,780 reduces the ERalpha in breast tumor cells in a dose-dependent manner by down-regulating ER protein concentration. The reductions in tumor PgR content by ICI 182,780 demonstrate that ICI 182,780, unlike tamoxifen, is devoid of estrogen-agonist activity. Reductions in tumor cell proliferative activity (as indicated by Ki67LI) show that ICI 182,780 is likely to have antitumor activity in the clinical setting.     

Proliferation, steroid receptors and clinical/pathological response in breast cancer treated with letrozole

Sixty-three postmenopausal women with large primary breast cancers were treated with neoadjuvant letrozole (2.5 mg daily) for 3 months. Tumour samples were taken at diagnosis and after 10-14 days and 3 months treatment. Immunohistochemical staining for Ki67, oestrogen receptor (ER) and progesterone receptor (PgR) was performed and related to clinical (ClinR) and pathological responses (PathR) after 3 months treatment. ClinR was observed in 48 of 63 cases (76.2%) and PathR in 47 of 62 (75.8%). Pretreatment Ki67 scores were similar in responders (R) and non-responders (NR). Highly significant Ki67 decreases occurred in all tumour subgroups at 10-14 days (P<0.005). A significant difference in Ki67 scores at 10-14 days (P<0.007) was found between PathR and PathNR but not between ClinR and ClinNR. At 3 months, decreases from pretreatment Ki67 scores were highly significant in all tumour subgroups irrespective of response status. However, whereas Ki67 scores were significantly different between pathological R and NR (P = 0.009), the corresponding comparison of ClinR status was not. Significant decreases between 10-14 days and 3 months were found only in ClinR and PathR (P = 0.02 and 0.045, respectively). Treatment significantly reduced PgR expression at 14 days and 3 months (both P<0.0001), but the level of changes was not different between response status groups. In summary, letrozole produces rapid and profound decreases in expression of Ki67 and PgR but changes do not always correlate with clinical and pathological responses.     

Ki67 index changes, pathological response and clinical benefits in primary breast cancer patients treated with 24 weeks of aromatase inhibition

Aromatase inhibitor shows efficacy for hormone receptor positive postmenopausal breast cancer. We evaluated the activity of 24 weeks of aromatase inhibition with exemestane for primary breast cancer in a neoadjuvant setting. Patients with stage II/IIIA invasive breast cancer with estrogen receptor (ER) and/or progesterone receptor (PgR)-positive status were eligible. Primary endpoints were objective response rate (ORR) and safety. A steroidal aromatase inhibitor exemestane of 25 mg/day was administered for 16 weeks with an 8-week extension. Secondary endpoints were rates of breast-conserving surgery (BCS), and change of Ki67 index and ER/PgR expression in central laboratory analyses. Between March 2006 and December 2007, 116 patients were enrolled. Among those, 102 patients completed 24 weeks of administration. The ORR was 47% (55/116) at Week 16 and 51% (59/116) at Week 24, respectively. No serious toxicity was seen. ORR was associated with ER Allred scores but not with PgR scores. The significant reduction in Ki67 index was confirmed. No progression was experienced in tumors with less than 15% Ki67 index. Pathological response was observed in 28 (30%) of 94 evaluated cases. No statistical correlation between pre-treatment Ki67 index and pathological response was detected; however, a trend of correlation was found between the post-treatment preoperative endocrine prognostic index (PEPI), a prognostic score and the pathological response. At diagnosis, 59 patients (51%) would have required mastectomy but 40 patients were converted to BCS, showing an increase in the rate of BCS (77%). The 24-week aromatase inhibition provided preferable clinical benefits with significant reduction in Ki67 index. More precise mechanisms of the response need to be investigated.     

HER-2 amplification impedes the antiproliferative effects of hormone therapy in estrogen receptor-positive primary breast cancer.

In experimental models, human epidermal growth factor receptor-2 (HER-2) amplification leads to estrogen independence and tamoxifen resistance in estrogen receptor (ER)-positive human breast cancer cells. Some but not all reports suggest an association between HER-2 positivity and hormone independence in breast cancer patients. This study aimed to evaluate the antiproliferative effects of endocrine therapy in HER-2-positive/ER-positive primary human breast cancer. The effect on proliferation (Ki67) of hormone therapy was assessed at 2 weeks and/or 12 weeks in biopsies from 115 primary breast cancers with ER-positive tumors. The patients took part in one of 3 neoadjuvant trials of hormonal therapy with a SERM (tamoxifen or idoxifene) or an aromatase inhibitor (anastrozole or vorozole). HER-2 status was assessed by immunocytochemistry and fluorescence in situ hybridization (FISH). Fifteen patients were defined as HER-2 positive by both immunohistochemistry and FISH, with the remaining 100 patients HER-2 negative. Geometric mean Ki67 levels were substantially higher in HER-2-positive than HER-2-negative tumors (27.7% versus 11.5%, respectively; P = 0.003). In HER-2-negative patients, Ki67 was reduced by 62 and 71% at 2 and 12 weeks, respectively (P < 0.0001 for both), but HER-2-positive patients showed no significant fall. The proportional change in Ki67 was significantly different between HER-2-positive and -negative patients (P = 0.014 at 2 weeks; P = 0.047 at 12 weeks). Mean ER levels were lower in the HER-2-positive patients (P = 0.06) but the change in Ki67 was impeded even in those with high ER. Apoptotic index was reduced by 30% at 2 weeks in the HER-2-negative group. However, there were no statistically significant differences in apoptotic index between the groups. It is concluded that ER-positive/HER-2-positive primary breast carcinomas show an impeded antiproliferative response to endocrine therapy that nonetheless may vary between individual treatments. This together with high baseline proliferation is likely to translate to poor clinical response.     

Effect of tamoxifen on Ki67 labelling index in human breast tumours and its relationship to oestrogen and progesterone receptor status.

This study aimed to investigate the effect of tamoxifen on breast tumour levels of oestrogen and progesterone receptor (ER and PR) and proliferation as defined by the Ki67 antibody. A group of primary breast cancer patients was randomised to receive either tamoxifen (n = 59) or placebo (n = 44) treatment in the interval between clinic and surgery (median 21 days). Frozen sections of breast tumour biopsies obtained before and after treatment were stained immunocytochemically to obtain the percentage of nuclei containing ER and PR, and a Ki67 labelling index (LI). Tamoxifen-treated patients had a median Ki67 LI of 5.6% in the first biopsy falling to 3.0% in the second biopsy (P < 0.001 by Wilcoxon''s matched pairs test), whereas placebo-treated patients had a median Ki67 LI of 5.4% in the first biopsy and 5.75% in the second (no significant difference). No significant differences were observed when the median %ER or %PR staining before and after treatment were compared. The Ki67 LI tended to increase with increasing histological grade and was greater in tumours that were ER - ve compared to those that were ER + ve (> 5% nuclei stained), median 7.8% and 4.3% respectively (P = 0.011 by Mann-Whitney U-test). However, the decline in tumour Ki67 LI following anti-oestrogen treatment failed to correlate with ER and PR status or to predict recurrence over a short follow-up period. To our knowledge, this is the first time that tamoxifen treatment has been shown to reduce the Ki67 LI in human breast tumours in vivo. These data indicate that staining with the Ki67 antibody may be useful in monitoring response to anti-oestrogen therapy.     

Results of two or five years of adjuvant tamoxifen correlated to steroid receptor and S-phase levels

A Swedish cooperative trial demonstrated that 5 years of adjuvant tamoxifen was more beneficial than 2 years of tamoxifen in the treatment of postmenopausal women with estrogen receptor (ER) positive, early stage, invasive breast cancer. The main aim of the present study was to investigate the importance of progesterone receptor (PgR) and ER concentration levels for patients participating in the trial and still distant recurrence free two years after the primary operation. Subgroup analyses revealed that only patients with ER positive and PgR positive breast cancer had improved distant recurrence free survival (DRFS) by prolonged tamoxifen therapy (p=0.0016). Patients with ER negative and PgR negative as well as ER positive and PgR negative tumors showed no significant effect of prolonged tamoxifen (p=0.53 and p=0.80, respectively). The percentage of ER negative and PgR positive breast cancers was too small (2.2%) for any meaningful subgroup analysis. There was a significant positive trend that the concentration level of PgR (high positive vs. low positive vs. negative) decreased the recurrence rate for those with prolonged therapy. No corresponding pattern was found for the ER content. S-phase fraction did not correlate to the recurrence rate of PgR positive breast cancers. Patients recurring during tamoxifen therapy had receptor negative tumors to a greater extent than those recurring after tamoxifen treatment.In conclusion, prolonged tamoxifen therapy for 5 years instead of 2 years was found to be beneficial for patients with ER positive and PgR positive breast cancer, whereas three extra years of tamoxifen had little or no effect for patients with ER positive but PgR negative tumors as well as for steroid receptor negative patients.     

Letrozole is more effective neoadjuvant endocrine therapy than tamoxifen for ErbB-1- and/or ErbB-2-positive, estrogen receptor-positive primary breast cancer: evidence from a phase III randomized trial.

PURPOSE: Expression of ErbB-1 and ErbB-2 (epidermal growth factor receptor and HER2/neu) in breast cancer may cause tamoxifen resistance, but not all studies concur. Additionally, the relationship between ErbB-1 and ErbB-2 expression and response to selective aromatase inhibitors is unknown. A neoadjuvant study for primary breast cancer that randomized treatment between letrozole and tamoxifen provided a context within which these issues could be addressed prospectively. PATIENTS AND METHODS: Postmenopausal patients with estrogen- and/or progesterone receptor-positive (ER+ and/or PgR+) primary breast cancer ineligible for breast-conserving surgery were randomly assigned to 4 months of neoadjuvant letrozole 2.5 mg daily or tamoxifen 20 mg daily in a double-blinded study. Immunohistochemistry (IHC) for ER and PgR was conducted on pretreatment biopsies and assessed by the Allred score. ErbB-1 and ErbB-2 IHC were assessed by intensity and completeness of membranous staining according to published criteria. RESULTS: For study biopsy-confirmed ER+ and/or PgR+ cases that received letrozole, 60% responded and 48% underwent successful breast-conserving surgery. The response to tamoxifen was inferior (41%, P =.004), and fewer patients underwent breast conservation (36%, P =.036). Differences in response rates between letrozole and tamoxifen were most marked for tumors that were positive for ErbB-1 and/or ErbB-2 and ER (88% v 21%, P =.0004). CONCLUSION: ER+, ErbB-1+, and/or ErbB-2+ primary breast cancer responded well to letrozole, but responses to tamoxifen were infrequent. This suggests that ErbB-1 and ErbB-2 signaling through ER is ligand-dependent and that the growth-promoting effects of these receptor tyrosine kinases on ER+ breast cancer can be inhibited by potent estrogen deprivation therapy.     

Influence of the antioestrogen tamoxifen on normal breast tissue

Immunohistochemical assays have been employed to study the expression of ER, PgR, EGFR and Ki67 immunostaining in normal breast tissue (n = 76). The expression of ER and PgR was highly variable in both pre and postmenopausal women and was characterised by large numbers of apparently negative cells. This was most evident for ER-ICA staining in tissues removed from premenopausal women. PgR levels were highest in the ducts of premenopausal women, while EGFR expression was elevated in both ducts and lobules. Ki67 expression was observed in less than 10% of all normal cells and was suppressed by the menopause in lobular tissue. Tamoxifen therapy (40 mg d-1) did not influence the expression of PgR, EGFR or Ki67 immunostaining in cancer associated normal tissue (n = 17). A significant increase, however, was observed in the mean percentage ER positivity in ductal tissue. No effect of duration of tamoxifen therapy was observed on the expression of the antigens studied.     

Role of biologic markers in patient selection and application to disease prevention

Aromatase inhibitors (AIs) are now under investigation for the treatment of early stage breast cancer and for disease prevention as alternatives to standard treatment with tamoxifen. Currently identified genetic risk factors of breast cancer include BRCA-1/BRCA-2 mutations, ATM mutations, and history of high estrogen levels, as evidenced by plasma analyses and/or dense bones. To date, estrogen receptor (ER) and progesterone receptor (PgR) status has predictive value for determining response to therapy in patients with hormone receptor-positive breast cancer (ER+ and/or PgR+ tumors). Recent studies have shown AIs to be safer and more effective than tamoxifen in postmenopausal women with advanced disease. Some data suggest that letrozole may be a more effective treatment than tamoxifen for patients with ER+ and/or PgR+ early breast cancers expressing ErbB-1 and/or ErbB-2. Changes in cell proliferation markers (e.g., S-phase fraction and Ki67 antigen), plasma lipid levels, and the bone resorption marker C-terminal peptide are biomarkers that have been evaluated for preventive and prognostic value in breast cancer patients and normal volunteers. Results from biomarker screens can be used to define inclusion criteria for clinical trials and eventually to individualize treatment. Gene expression profiling (microarray analysis), i.e., genomic and proteomic studies, will probably advance the discovery of new biomarkers for breast cancer prevention and treatment.     

Preoperative treatment of postmenopausal breast cancer patients with letrozole: A randomized double-blind multicenter study

Background:A randomized, double-blind, multicenter studywas conducted to compare the anti-tumor activity of letrozole vs.tamoxifen in postmenopausal women with ER and/or PgR positive primaryuntreated breast cancer. Patients and methods:Threehundred thirty-seven postmenopausal women with ER and/or PgR positiveprimary untreated breast cancer were randomly assigned once dailytreatment with either letrozole 2.5 mg or tamoxifen 20 mg for fourmonths. At baseline none of the patients were considered to becandidates for breast-conserving surgery (BCS) and 14% ofthe patients were considered inoperable. The primary endpoint was tocompare overall objective response (CR + PR) determined by clinicalpalpation. Secondary endpoints included overall objective response onultrasound and mammography and the number of patients who qualified forBCS. Results:Overall objective response rate (clinicalpalpation) was statistically significantly superior in the letrozolegroup, 55% compared to tamoxifen, 36% (P<0.001). Secondary endpoints of ultrasound response, 35% vs.25% (P= 0.042), mammographic response, 34% vs.16% (P< 0.001), and BCS, 45% vs. 35%(P= 0.022) between the letrozole and tamoxifen groups,respectively, showed letrozole to be significantly superior. Bothtreatments were well tolerated. Conclusions:This studyshows that letrozole is more effective than tamoxifen as preoperativetherapy in postmenopausal patients with ER and/or PgR positive primaryuntreated breast cancer and is at least as well tolerated.     

One year of adjuvant tamoxifen compared with chemotherapy and tamoxifen in postmenopausal patients with stage II breast cancer

PurposeWe report the long-term results of a randomised trial comparing tamoxifen with tamoxifen plus cyclophosphamide, methotrexate and fluorouracil (CMF) in postmenopausal high-risk breast cancer patients. In addition, we analyse the prognostic and predictive value of centrally assessed subtypes.MethodsPostmenopausal patients with breast cancer and positive nodes, deep invasion or size exceeding 5 cm were randomly assigned to 1 year of tamoxifen, or cyclophosphamide 600 mg/m², methotrexate 40 mg/m² and fluorouracil 600 mg/m² intravenously on day 1 every 4 weeks for nine cycles plus tamoxifen (CMFT). Tissue microarrays were constructed retrospectively and oestrogen receptor (ER), progesterone receptor (PgR), human epidermal growth factor receptor 2 (HER2), and proliferation-related Ki-67 antigen (Ki67) status were assessed.ResultsFrom October 1982 through March 1990 we randomised 1445 patients and 969 (67%) were eligible for the biomarker analysis. At 10-years 936 women had suffered a disease-free survival (DFS) event (tamoxifen, 495 events in 686 patients; CMFT, 441 events in 642 patients). The addition of CMF to tamoxifen significantly improved DFS (adjusted hazard ratio 0.82; 95% confidence interval (CI) 0.71–0.93; P = 0.003) but not overall survival (adjusted hazard ratio 0.95; 95% CI 0.85–1.08; P = 0.44). DFS was superior in Luminal A tumours (ER or PgR positive, HER2 negative and Ki67 ?14%) when compared to Luminal B or non-luminal (ER and PgR negative) tumours. There was no statistical evidence of heterogeneity by subtype in the benefit from CMF (P_interaction = 0.45).ConclusionCMF added to 1 year of tamoxifen reduces the risk of a DFS event. The benefit from CMF was not significantly different in Luminal A and B subtypes.     

Relationship of PS2 with response to tamoxifen therapy in patients with recurrent breast cancer.

PS2, an oestrogen-inducible protein, was measured in the cytosol of 230 primary tumours from patients who were subjected to first-line tamoxifen therapy for advanced disease without prior adjuvant therapy with tamoxifen. PS2 correlated positively with oestrogen receptor (ER, P < 0.01) and progesterone receptor content (PgR, P < 0.001), and with the length of progression-free survival (PFS, P = 0.05). Although not statistically significant, higher levels of PS2 (> or = 10 ng mg-1 protein) were also associated with increased probability of response to tamoxifen treatment and a longer total post-relapse survival (PRS). ER, PgR, menopausal status, site of disease and prior adjuvant chemotherapy were all associated with response to tamoxifen therapy and with PFS. In multivariate analysis for PFS, low levels of ER and PgR, visceral metastasis, a disease-free interval of less than 1 year and prior adjuvant chemotherapy were all significantly associated with an increased probability of a rapid disease progression after start of tamoxifen therapy. In the subset of 83 tumours with intermediate levels of ER and PgR (both > or = 10, but not both > or = 75 fmol mg-1 protein), PS2 was positively related with the length of PFS (P < 0.01) and PRS (P < 0.05). PS2 remained the strongest factor in multivariate analysis for PFS (P < 0.01) in this ER/PgR intermediate subgroup, but was not of predictive value in univariate or multivariate analysis for both PFS and PRS in tumours classified as ER/PgR low or high (> or = 75 fmol mg-1 protein). It is concluded that PS2 status may be used as a parameter, additional to ER and PgR, for better refinement of prediction of response to tamoxifen treatment in advanced breast cancer patients especially with intermediate ER/PgR levels in their primary tumour.     

Effect of raloxifene on breast cancer cell Ki67 and apoptosis: a double-blind, placebo-controlled, randomized clinical trial in postmenopausal patients.

PURPOSE: Raloxifene is a selective estrogen receptor (ER) modulator approved for prevention and treatment of postmenopausal osteoporosis. This is an exploratory study of raloxifene in primary breast cancer patients. Experimental Design: Postmenopausal women (50-80 years of age), with histological or cytological diagnosis of stage I or II primary breast cancer, were randomly assigned to 14 days of placebo, 60 mg/day raloxifene, or 300 mg twice daily (600 mg/day) of raloxifene. A core biopsy of the primary tumor was obtained before therapy, and a representative sample of the excised tumor was obtained from the operative specimen after treatment. Paired baseline and endpoint biopsies from each patient were analyzed for Ki67, apoptosis, and estrogen and progesterone receptors. Treatment group differences in efficacy measurements were primarily evaluated for baseline-to-endpoint change and percentage change using a one-way ANOVA with treatment as the fixed effect. RESULTS: Of 167 enrolled patients, 143 had evaluable efficacy data. Most breast cancer cases were invasive (98.6%), stage I (76.6%), and ER-positive (83.2%). In patients with ER-positive tumors, Ki67 increased 7% from baseline on placebo and decreased by 21% on 60 mg/day raloxifene (P = 0.015 versus placebo) and by 14% on 600 mg/day raloxifene (P = 0.064 versus placebo). Raloxifene did not affect apoptosis. ER decreased significantly with 60 mg/day or 600 mg/day raloxifene compared with placebo (P < 0.01 for each comparison). Raloxifene had no statistically significant effects on Ki67 among patients with ER-negative tumors. There were no treatment differences in adverse events. CONCLUSION: In this exploratory trial, 60 mg/day raloxifene showed a significant antiproliferative effect in ER-positive breast cancer, demonstrated by the decrease in Ki67, with no effect in ER-negative cancer. This provides support for raloxifene having a breast cancer preventive effect in postmenopausal women.