Abstract P5-10-23: Frequency and Cost of Chemotherapy-Related Serious Adverse Effects in a Canadian Population Sample of Women with Estrogen and/or Progesterone Receptor Positive Early Stage Breast Cancer

Abstract

Abstract Background: Chemotherapy-related serious adverse effects (CSAE) reported by clinical trials of chemotherapy and by population-based assessments of CSAE in breast cancer populations with different clinicopathological characteristics may not reflect the experiences of women with estrogen and/or progesterone receptor positive (ER+/PR+) early stage breast cancer (ESBC). We aimed to characterize the risks and economic impact of CSAE among women in the Canadian general population treated with chemotherapy for ER+/PR+ ESBC. Methods: We used the Manitoba Cancer Registry to identify all women (n=665) diagnosed with ER+/PR+ ESBC during the period from January 1, 2000 to December 31, 2002. One-year of follow-up information from diagnosis, including hospitalizations and emergency room visits for all adverse effects that are typically related to chemotherapy, were identified by linking with Manitoba Administrative Databases including the Hospital Discharge Database and the Physician Claims Database. 251 women received chemotherapy during the 12 months after the initial diagnosis with ESBC. Hospitalizations or emergency room visits for CSAE and health care expenditures were compared between women who did and did not receive chemotherapy. We assessed the effect of chemotherapy on rate of CSAE using logistic regression, adjusting for menopausal status, lymph node status, anthracycline-containing chemotherapy agents, and comorbid indices. All statistical tests were two-sided. Results: Women who received chemotherapy were more likely than those who did not to be hospitalized or visit an emergency room for CSAE (2.6% versus 9%, mean difference =6.4%, 95% CI=3.5% to 10%, p=0.01). In a logistic regression analysis, the rate of CSAE was found to be significantly greater for women with post-menopausal status (post-versus pre-menopausal, odds ratio 2.4; CI= 1.7 to 2.8) and 1-3 lymph node positive (LN+) (0 versus 1-3 LN+, odds ratio, 3.1; CI= 2.5 to 3.6). Chemotherapy recipients incurred large incremental expenditures for CSAE (pre-menopausal LN-: $1100 per person per year; post-menopausal LN-: $1600 per person per year; post-menopausal 1-3 LN+: $2200 per person per year). Conclusions: The impact and costs of CSAE among ER+/PR+ ESBC are larger than predicted from clinical data and vary significantly by lymph node and menopausal status. Our findings, when combined with recent population-based data suggesting that women with ER+/PR+ ESBC may not gain benefit from chemotherapy as much as reported in clinical trials, have important implications for quality of life and could affect decisions regarding the use of chemotherapy in these patients. Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P5-10-23.