Predictors of timing of adjuvant chemotherapy in older women with hormone receptor–negative,stages II–III breast cancer

Adherence to consensus guidelines for cancer care may vary widely across health care settings and contribute to differences in cancer outcomes. For some women with breast cancer, omission of adjuvant chemotherapy or delays in its initiation may contribute to differences in cancer recurrence and mortality. We studied adjuvant chemotherapy use among women with stage II or stage III, hormone receptor–negative breast cancer to understand health system and socio-demographic correlates of underuse and delayed adjuvant chemotherapy. We used Surveillance Epidemiology and End Results (SEER)-Medicare linked data to examine the patterns of care for 6,678 women aged 65 and older diagnosed with stage II or stage III hormone receptor–negative breast cancer in 1994–2002, with claims data through 2007. Age-stratified logistic regression was employed to examine the potential role of socio-demographic and structural/organizational health services characteristics in explaining differences in adjuvant chemotherapy initiation. Overall utilization of guideline-recommended adjuvant chemotherapy peaked at 43% in this population. Increasing age, higher co-morbidity burden, and low-income status were associated with lower odds of chemotherapy initiation within 4 months, whereas having positive lymph nodes, more advanced disease, and being married were associated with higher odds (P < 0.05). Health system–related structural/organizational characteristics and race/ethnicity offered little explanatory insight. Timely initiation of guideline-recommended adjuvant chemotherapy was low, with significant variation by age, income, and co-morbidity status. Based on these findings, future studies should seek to explore the more nuanced reasons why older women do not receive chemotherapy and why delays in care occur.     

Disparities in medical care among commercially insured patients with newly diagnosed breast cancer

BACKGROUND:

African‐American women have increased breast cancer mortality compared with white women. Diagnostic and treatment gaps may contribute to this disparity.

METHODS:

In this retrospective, longitudinal cohort study, Southern US health plan claims data and linked medical charts were used to identify racial disparities in the diagnoses, treatment, and mortality of commercially insured women with newly diagnosed breast cancer. White women (n = 476) and African‐American women (n = 99) with newly diagnosed breast cancer were identified by breast cancer claims codes (International Classification of Diseases, Ninth Revision, Clinical Modification codes 174, 233.0, 238.3, and 239.3) between January 2000 and December 2004. Race, diagnoses (breast cancer stage, estrogen/progesterone receptor [ER/PR]‐positive status), treatment (breast‐conserving surgery, antiestrogen therapy, and chemotherapy interruption or reduction), and all‐cause mortality were assessed from medical charts. Multivariate regression analyses were adjusted for age, geography, and socioeconomic status to test the association of race with diagnoses/treatment.

RESULTS:

White women were older (P < .001) and had higher rates of diagnosis at stage 0/I (55.2% vs 38.4%; P < .05) than African‐American women. More white women had positive ER/PR status (75% vs 56% African‐American; P = .001) and received antiestrogen therapy if they were positive (37.2% vs 27.3% African‐American; P < .001). White women received slightly more breast‐conserving surgery and chemotherapy dose modification than African‐American women (P value nonsignificant). African‐American women had a higher mortality rate (8.1%) than white women (3.6%; P = .06). In adjusted analyses, African‐American women were diagnosed at later stages (odds ratio, 1.71; P = .02), and white women received more antiestrogen therapy (odds ratio, 2.1; P = .03).

CONCLUSIONS:

Disparities in medical care among patients with newly diagnosed breast cancer were evident between African‐American women and white women despite health plan insurance coverage. Interventions that address the gaps identified are needed. Cancer 2010. © 2010 American Cancer Society.     

Patterns of toxicity in older patients with breast cancer receiving adjuvant chemotherapy

Summary Objective. To retrospectively determine the relationship of age to toxicity from adjuvant chemotherapy for breast cancer.Design and Methods We identified 1405 consecutive patients age 65 or older with primary invasive breast cancer who were seen at Memorial Sloan-Kettering Cancer Center from January 1998 to December 2000. Patients selected from this cohort for analysis were aged 65 or older at diagnosis; received their follow-up care at Memorial Sloan-Kettering Cancer Center; had stage I, II, or III breast cancer; and received adjuvant chemotherapy consisting of CMF (cyclophosphamide, methotrexate, and 5-fluorouracil), an anthracycline-based regimen (AC [doxorubicin and cyclophosphamide], or AC-T [AC and paclitaxel or docetaxel]). Exclusion criteria included prior chemotherapy or previous breast cancer. Results. One hundred thirty-two patients were included in this study, with a mean age of 70 (range 65–79). Comorbidity measured by the Charlson comorbidity index was low: score 0 (83%), 1 (12%), 2 (5%); with stages: I(18%), IIA (41%), IIB (27%), IIIA (8%), IIIB (6%), T1Nx (1%). Patients receiving an anthracycline-based regimen were more likely to experience grade 3 or 4 toxicity (p=0. 01), require hospitalization (p<0.001), and/or develop febrile neutropenia (p<0.001). Treatment delays due to myelosuppression occurred more frequently in patients receiving CMF (p<0.001). The type of chemotherapy regimen (anthracycline compared to CMF) was a better predictor for toxicity than increased age or comorbidity score. Conclusions. In this cohort of older patients with breast cancer, the risk for toxicity from adjuvant chemotherapy depended more on the type of regimen (anthracycline vs. CMF) than the patient’s chronological age.     

The effect of postoperative beam,implant, and combination radiation therapy on GI and bladder toxicities in female Medicare beneficiaries with stage I uterine cancer

ObjectiveThe objective of the current study is to determine the risk of late gastrointestinal (GI) and bladder toxicities in women treated for stage I uterine cancer with postoperative beam, implant, or combination radiation.Materials and methodsThe Surveillance, Epidemiology, and End Results (SEER) tumor registry and Medicare claims were used to estimate the risk of developing late GI and bladder toxicities by type of radiation received. Bladder and GI diagnoses were identified 6–60 months after cancer diagnosis. Cox-proportional hazard models were used to estimate risk of any late GI or bladder toxicity due to type of radiation received.ResultsA total of 3024 women with uterine cancer diagnosed from 1992 to 2005 were identified for analysis with a mean age of 73.9 (standard deviation (SD) ± 6.5). Bladder and GI toxicities occurred most frequently in the combination group, and least frequently in the implant group. After controlling for demographic characteristics, tumor grade, diagnosis year, SEER region, comorbidities, prior GI and bladder diagnosis, and chemotherapy, women receiving implant radiation had a 21% absolute decrease in GI toxicities compared to women receiving combination radiation (hazard ratio (HR) 0.79, 95% confidence interval (CI) 0.68–0.92). No differences were observed between those receiving beam and combination radiation in GI (HR 1.01 (0.89–1.14)) and bladder (HR 0.95 (0.80–1.11)) toxicities.ConclusionsOlder women receiving combined radiation had the highest rates of GI and bladder toxicities, while women receiving implant radiation alone had the lowest rates. When selecting the type of radiation for a patient, these toxicities should be considered. Counseling older women surviving cancer on late toxicities due to radiation must be a priority for physicians caring for them.     

Therapy related acute myeloid leukemia in breast cancer survivors,a population-based study

The aim of this study was to determine the association between age and stage at diagnosis of breast cancer with the subsequent development of acute myeloid leukemia (AML). The National Cancer Institute’s Surveillance, Epidemiology, and End Results program were analyzed for incidence of second malignancies by age and stage at diagnosis of breast cancer. 420,076 female patients were identified. There was an age dependent risk of a subsequent diagnosis of AML in women younger than 50 years old (RR 4.14; P < 0.001) and women 50–64 years old (RR 2.19; P < 0.001), but not those 65 and older (RR 1.19; P = 0.123) when compared with the expected incidence of AML. A similar age dependent pattern was observed for second breast and ovarian cancers. There was also a stage dependent increase in risk of subsequent AML in younger women with stage III disease when compared with stage I disease (RR 2.92; P = 0.004), and to a lesser extent in middle age women (RR 2.24; P = 0.029), but not in older women (RR 0.79; P = 0.80).Younger age and stage III disease at the time of breast cancer diagnosis are associated with increased risk of a subsequent diagnosis of AML. This association maybe explained by either greater chemotherapy exposure or an interaction between therapy and genetic predisposition.     

The impact of sociodemographic, treatment, and work support on missed work after breast cancer diagnosis

Work loss is a potential adverse consequence of cancer. There is limited research on patterns and correlates of paid work after diagnosis of breast cancer, especially among ethnic minorities. Women with non-metastatic breast cancer diagnosed from June 2005 to May 2006 who reported to the Los Angeles County SEER registry were identified and asked to complete the survey after initial treatment (median time from diagnosis = 8.9 months). Latina and African American women were over-sampled. Analyses were restricted to women working at the time of diagnosis, <65 years of age, and who had complete covariate information (N = 589). The outcome of the study was missed paid work (≤1 month, >1 month, stopped all together). Approximately 44, 24, and 32% of women missed ≤1 month, >1 month, or stopped working, respectively. African Americans and Latinas were more likely to stop working when compared with Whites [OR for stop working vs. missed ≤1 month: 3.0, 3.4, (P < 0.001), respectively]. Women receiving mastectomy and those receiving chemotherapy were also more likely to stop working, independent of sociodemographic and treatment factors [ORs for stopped working vs. missed ≤1 month: 4.2, P < 0.001; 7.9, P < 0.001, respectively]. Not having a flexible work schedule available through work was detrimental to working [ORs for stopped working 18.9, P < 0.001 after adjusting for sociodemographic and treatment factors]. Many women stop working altogether after a diagnosis of breast cancer, particularly if they are racial/ethnic minorities, receive chemotherapy, or those who are employed in an unsupportive work settings. Health care providers need to be aware of these adverse consequences of breast cancer diagnosis and initial treatment.     

Generalisability of survival estimates for patients with breast cancer--a comparison across two population-based series

The purpose of the study was to analyse the generalisability and geographic transportability of survival estimates produced by commonly used prognostic factors. We compared the influence of tumour size, histologic grade, axillary nodal status, oestrogen and progesterone receptor contents, age at diagnosis and two prognostication schemes (the Nottingham Prognostic Index and St. Gallen criteria) in two nationwide cohorts of patients diagnosed with breast cancer in 1991–2, the FinProg (n = 2923, Finland) and the SEER series (n = 43,249, the United States (US)). Eight-year estimates of breast cancer-specific (84% versus 80%), relative (86% versus 83%), and overall (70% versus 69%) survival were slightly more favourable in the SEER than in the FinProg series, respectively. Despite differences in demographic variables and the frequency of use of adjuvant therapies and mammography screening between the series, the prognostic factors examined produced close to overlapping survival curves with similar shapes. The results suggest that quantitative survival estimates based on frequently used prognostic factors and prognostication schemes are generalisable and transportable between large, unselected cohorts of breast cancer patients.     

Factors affecting the delivery of adjuvant/neoadjuvant chemotherapy in older women with breast cancer

BackgroundRecent studies suggest that older women derive similar benefits from adjuvant systemic chemotherapy (AST) as younger women. In older women, the ability to successfully complete chemotherapy may be complicated by other health conditions and performance status. We examined factors affecting the delivery of chemotherapy to older patients with breast cancer.MethodsWomen age ≥ 65 treated with adjuvant/neoadjuvant chemotherapy at Roswell Park Cancer Institute were identified from the RPCI database from 7/1997 to 4/2010. Endpoints were delay, hospitalization, dose reduction, relative dose intensity (RDI) < 85%, and incomplete administration of chemotherapy. Data recorded included medical comorbidities and the use of anthracycline-based chemotherapy. The Pearson chi-squared, Wilcoxon rank sum, logistic regression, Kaplan–Meier, and log-rank tests were used to analyze outcomes. A 0.05 nominal significance level was used in all testing.Results204 older women received AST. Median follow-up was 50.2 months. Seventy percent received anthracycline-based AST. In multivariate analysis, older age was a predictor for early termination of chemotherapy and RDI < 85%. Hypertension was correlated with delay and hospitalization. A Charlson comorbidity index ≥ 1 and anthracycline-based chemotherapy regimens were associated with chemotherapy delays. The successful completion of chemotherapy and the delivery of a RDI ≥ 85% of planned chemotherapy were associated with improved survival (p = 0.01, and p < 0.01 respectively). Significant toxicity resulting in a change in therapy or schedule occurred in 45% of cases.ConclusionSuccessful administration of planned chemotherapy to older women with breast cancer was associated with improved OS. However, delivery of chemotherapy was associated with increased toxicity and reduced tolerance. Models allowing physicians to better risk-stratify older patients with breast cancer are needed and under development.     

Increase of chemotherapy use in older women with breast carcinoma from 1991 to 1996

BACKGROUND: There is little population-based information available on the actual use of chemotherapy and how closely this use mirrors consensus recommendations. The authors hypothesized that given the relative stability of consensus conference recommendations on chemotherapy use during the period 1991-1996 the patterns of use would more closely approximate consensus recommendation over time. METHODS: The authors studied women who received a diagnosis of Stage I-IV (American Joint Committee on Cancer staging) breast carcinoma at age 65 years and older from 1991 through 1996, using the SEER cancer registry cases linked with Medicare claims. RESULTS: Overall, women whose disease was diagnosed in 1996 had a 30% higher chance of receiving chemotherapy than those in 1991, after controlling for changes in tumor size, stage, and other factors. The use of chemotherapy was strongly influenced by age, with women age 65-69 years more than twice as likely to receive it as were women 70 years and older. The increase over time in chemotherapy depended on both tumor stage and patient age. For Stage I tumor, there was no increase in chemotherapy for any age. For Stage II, the increase was limited to younger women, whereas for Stage III and IV it was observed in women age 70 years and older. CONCLUSIONS: There was a significant increase of chemotherapy use over time from 1991 to 1996 in women age 65 years and older with breast carcinoma. The increase was limited to younger women and those with advanced stage at diagnosis. Thus, consensus recommendations and community practice seemed to mirror each other over time.     

Febrile Neutropaenia and Chemotherapy Discontinuation in Women Aged 70 Years or Older Receiving Adjuvant Chemotherapy for Early Breast Cancer

AimsLow rates of adjuvant chemotherapy use are frequently reported in older women with early breast cancer. One of the reasons for this may be the risk of febrile neutropaenia or the perception that older patients will probably not complete the chemotherapy course prescribed. There are no data regarding these adverse outcomes in routine clinical practice.Patients and methodsWe identified 128 patients aged 70 years or over who received neoadjuvant or adjuvant chemotherapy for early breast cancer in seven UK cancer centres between 2006 and 2012. Data were collected regarding standard clinical and pathological variables and treatment toxicity and outcomes.ResultsTwenty-four patients (19%) had an episode of febrile neutropaenia. Overall, 27 patients (21%) did not complete their planned therapy. Chemotherapy discontinuation was more common in those patients with an episode of febrile neutropaenia (46% versus 16%, P = 0.004). Thirty patients (23%) were admitted with chemotherapy-related complications. There were no treatment-related deaths.ConclusionsThe rates of febrile neutropaenia and treatment discontinuation are high in women aged 70 years or over receiving adjuvant chemotherapy for breast cancer. Close attention should be paid to the choice or regimen and the use of supportive therapies in this patient population.     

Outcomes following adjuvant therapy for HER2-positive early breast cancer in the elderly

A third of breast cancer diagnoses are made in women aged 70 years or over. Historically, older women have been regarded as presenting with tumors that are low grade and hormone sensitive and that are likely to have a good prognosis. However, in those older women whose tumors overexpress the HER2 oncogene, the prognosis is likely to be worse. Under these circumstances, due consideration should be given to adjuvant systemic therapy, including chemotherapy and targeted treatments, in order to minimize risks of disease recurrence. In this article we discuss the evidence base for the role of adjuvant systemic therapy in older women with HER2-positive early breast cancer.     

Feasibility and toxicity of dose-dense adjuvant chemotherapy in older women with breast cancer

Introduction The objective of this study was to examine the feasibility and toxicity of adjuvant dose-dense chemotherapy in older women with breast cancer. Methods A search of the Memorial Sloan-Kettering Cancer Center (MSKCC) breast cancer database was performed to identify all patients age 60 and older who underwent an initial consultation with a breast medical oncologist between October 1, 2002 and June 28, 2005. Inclusion criteria were: (1) age ≥ 60, (2) follow-up care obtained at MSKCC, (3) intent to treat with adjuvant dose-dense AC-T (doxorubicin 60 mg/m² and cyclophosphamide 600 mg/m² every 2 weeks for 4 cycles followed by paclitaxel 175 mg/m² every 2 weeks for 4 cycles, with white blood cell growth factor support). Results One hundred sixty-two patients (mean age 66, range 60–76) with breast cancer, stages I (n = 5), II (n = 111), and III (n = 46) according to the sixth edition of the AJCC staging system, were included in this analysis. Forty-one percent (n = 67) experienced a grade 3 or 4 toxicity, 9% a grade 3 infection (n = 14), 6% grade 3 fatigue (n = 9), 5% neutropenic fever (n = 8), and 4% thromboembolic events (n = 7). Twenty-two percent (n = 36) did not complete the planned 8 cycles of treatment. There was no statistically significant association between age and either toxicity or treatment discontinuation. In multivariate analysis including age, pretreatment hemoglobin, and comorbidity, the presence of comorbidity (Charlson score ≥ 1) and a lower baseline hemoglobin score were associated with an increased risk of any grade 3 or 4 toxicity. Conclusions We found that the risk of toxicity depended more on comorbid medical conditions and baseline hemoglobin value than age in this cohort of older adults receiving dose-dense adjuvant chemotherapy.     

Mortality following bone metastasis and skeletal-related events among women with breast cancer: a population-based analysis of U.S. Medicare beneficiaries, 1999–2006

The aim of the study is to quantify the impact of bone metastasis and skeletal-related events (SREs) on mortality in older breast cancer patients. Using the linked Surveillance, Epidemiology and End Results-Medicare database, we identified women aged 65 years or older diagnosed with breast cancer between July 1, 1999 and December 31, 2005 and followed them to determine deaths occurring through December 31, 2006. We classified patients as having possible bone metastasis and SREs using discharge diagnoses from inpatient claims and diagnoses paired with procedure codes from outpatient claims. We used Cox regression to estimate mortality hazards ratios (HR) among women with bone metastasis with or without SRE, compared with women without bone metastasis. Among 98,260 women with breast cancer (median follow-up, 3.3 years), 7,189 (7.3%) had bone metastasis either at breast cancer diagnosis (1.5%) or during follow-up (5.8%). SREs occurred in 3,319 (46%) of women with bone metastasis. HRs for risk of death were 4.9 (95% CI 4.7–5.1) and 6.2 (95% CI 5.9–6.5), respectively, for women with bone metastasis but no SRE and for women with bone metastasis plus SRE, compared with women without bone metastasis. In analyses restricted to women with bone metastasis, the adjusted HR was 1.5 (95% CI 1.4–1.6) for women with bone metastasis plus SRE, compared with women with bone metastasis but without SRE. Having a bone metastasis, as indicated by Medicare claims, was associated strongly with mortality among women with breast cancer. This association was stronger for bone metastasis complicated by SRE than for bone metastasis without SRE.     

Association of time since last birth,age at first birth and parity with breast cancer survival among parous women: A register‐based study from Norway

Reproductive factors that have a well‐documented effect on breast cancer risk may also influence the prognosis of the disease, but previous studies on breast cancer survival have yielded conflicting results. We combined information from two population‐based registries and obtained information on 16,970 parous women with invasive breast cancer. Cox regression analysis was used to assess breast cancer survival in relation to age at diagnosis, age at first birth, time since last birth and parity. We stratified the analyses by age at diagnosis (<50 and ≥50 years) as an approximation for menopausal age. In women diagnosed before 50 years of age, breast cancer survival was reduced with younger age at diagnosis (p for trend <0.001), whereas in women diagnosed at 50 years or later, survival was reduced with older age at diagnosis (p for trend 0.011). For breast cancer diagnosed before 50 years, survival was poorer in women with four or more births compared to women with one or two births (hazard ratio 1.3, 95% confidence interval 1.1–1.6). A short time since last birth was associated with reduced survival (p for trend 0.05), but adjustment for stage and grade attenuated the association. Among women diagnosed at 50 years or later, we found no association with survival for any of the reproductive factors. In summary, reproductive factors were associated with survival from breast cancer diagnosed before but not after age 50 years. Young women had a particularly poor prognosis throughout the study period.     

Treatment choices for older women with primary operable breast cancer and cognitive impairment: Results from a prospective,multicentre cohort study

ObjectivesThe presence of dementia co-existing with a diagnosis of breast cancer may render management more challenging and have a substantial impact on oncological outcomes. The aim of this study was to examine the treatment and outcomes of older women with co-existing cognitive impairment and primary breast cancer.Materials and methodsA prospective, multicentre UK cohort study of women aged 70 years or over with primary operable breast cancer. Patients with and without cognitive impairment were compared to assess differences in treatment and survival outcomes.ResultsIn total, 3416 women were recruited between 2013 and 2018. Of these, 478 (14%) had a diagnosis of dementia or cognitive impairment, subcategorised as mild, moderate and severely impaired. Up to 85% of women with normal cognition underwent surgery compared to 74%, 61% and 40% with mild, moderate, and severe impairment (p = 0.001). Among women at higher risk of recurrence, the uptake of chemotherapy was 25% for cognitively normal women compared to 20%, 22% and 12% for mild, moderate and severe impairment groups (p = 0.222). Radiotherapy use was similar in the subgroups. Although patients with cognitive impairment had shorter overall survival (HR: 2.10, 95% CI: 1.77–2.50, p < 0.001), there were no statistically significant differences in breast cancer specific or progression-free survival.ConclusionCognitive impairment appears to play a significant part in deciding how to treat older women with breast cancer. Standard treatment may be over-treatment for some women with severe dementia and careful consideration must be given to a more tailored approach in these women.     

Bone mineral density loss during adjuvant chemotherapy in pre-menopausal women with early breast cancer: is it dependent on oestrogen deficiency?

Pre-menopausal women given adjuvant chemotherapy for breast cancer experience both premature ovarian failure and loss of bone mineral density (BMD), and this study was designed to see if these observations are causally linked. Chemotherapy was administered to 41 pre-menopausal women with early breast cancer enrolled prospectively in a study of ovarian function and BMD in such women given systemic therapy. After giving written informed consent, all patients underwent baseline and regular on-treatment measurements of BMD by dual-energy X-ray absorptiometry (DXA) scan, bone turnover and ovarian function by analysis of serum hormone levels and self-reported menstrual diaries. Baseline lumbar spine BMD in the 41 women given chemotherapy was higher than the normal population (Z score 0.28 ± 0.14 (mean ± SEM), P = 0.047), and fell significantly over the first 6 months from a mean of 1.05–1.01 g/m², P < 0.0001, and similar but smaller changes were demonstrated in hip BMD. This fall was independent of age at diagnosis, type of chemotherapy, development of amenorrhoea or either baseline or on-treatment estradiol concentration. During the 6 months after completion of adjuvant chemotherapy, BMD fell further only in those women with low estradiol or experiencing amenorrhoea during the first 6 months, although all groups showed evidence of increased bone turnover. This study demonstrates loss of both spine and hip BMD in pre-menopausal women during 6 months’ adjuvant systemic chemotherapy to be independent of changes in ovarian function. Ovarian function was, however, related to BMD changes after chemotherapy ceased.     

The Impact of Age and Adjuvant Chemotherapy Modifications on Survival Among Black Women With Breast Cancer

BackgroundBlack women receive less relative dose intensity with more dose reductions and early chemotherapy cessation compared with White women. Adding further risk, older patients with breast cancer are most at risk for treatment modifications; however, it is unclear if this remains true for Black patients. Furthermore, the clinical implications of treatment modifications and delays on survival is uncertain, particularly in Black patients.Patients and MethodsThe purpose was to investigate whether age was a moderator for the association between treatment modifications (dose held, dose delayed, and early cessation) and overall survival and disease-free survival (DFS) in Black women with breast cancer using a retrospective cohort study of patients with early stage breast cancer treated with adjuvant chemotherapy.ResultsAcross the entire sample (n = 115), 37.4% (n = 43) of patients experienced a treatment modification. There was a significant interaction between age group and held dose for DFS (P = .026). Specifically, those diagnosed at 55 years of age and older, who had doses of chemotherapy held, experienced worse DFS compared with those who did not (hazard ratio, 4.185; 95% confidence interval, 1.187-14.75). In contrast, there was no difference in DFS between those who did and did not have doses held in patients diagnosed below 55 years of age (hazard ratio, 0.626; 95% confidence interval, 0.177-2.218).ConclusionIn this study, Black women receiving adjuvant chemotherapy for treatment of early stage breast cancer had roughly equal treatment modifications across age groups. However, held doses of chemotherapy in older Black patients were associated with worse DFS. Age may impact clinical outcomes seen with adjuvant chemotherapy treatment modifications.     

Impact of treatment regimen on acute care use during and after adjuvant chemotherapy for early-stage breast cancer

Purpose

We studied elderly Medicare enrollees newly diagnosed with early-stage breast cancer to examine the association between adjuvant chemotherapy and acute kidney injury (AKI).

Methods

Using the linked Surveillance, Epidemiology, and End Results (SEER)-Medicare database, we conducted a retrospective cohort study including women diagnosed with stages I–III breast cancer at ages 66–89 years between 1992 and 2007. We performed one-to-one matching on time-dependent propensity score on the day of adjuvant chemotherapy initiation within 6 months after the first cancer-directed surgery based on the estimated probability of chemotherapy initiation at each day for each patient, using a Cox proportional hazards model. We estimated the cumulative incidence of AKI using Kaplan–Meier methods. We used Cox proportional hazards models to evaluate the association between chemotherapy and the risk of AKI, and compared the risk among major chemotherapy types.

Results

The study included 28,048 women. The 6-month cumulative incidence of AKI was 0.80% for chemotherapy-treated patients, compared with 0.30% for untreated patients (P < 0.001). Adjuvant chemotherapy was associated with a nearly threefold increased risk of AKI [hazard ratio (HR) 2.73; 95% CI 1.8–4.1]. Compared with anthracycline-based chemotherapy, the HRs (95% CIs) were 1.66 (0.94–2.91), 0.88 (0.53–1.47), and 1.15 (0.57–2.32) for taxane-based, CMF, and other chemotherapy, respectively.

Conclusion

Our findings showed that adjuvant chemotherapy was associated with increased risk of AKI in elderly women diagnosed with early-stage breast cancer. The risk seemed to vary by regimen type, but the differences were not statistically significant.