Does life expectancy affect treatment of women aged 80 and older with early stage breast cancers?

Abstract

Background

Data are needed on how life expectancy affects treatment decisions among women ≥ 80 years with early stage breast cancer.

Methods

We used the linked Surveillance Epidemiology and End Results-Medicare claims dataset from 1992 to 2005 to identify women aged ≥ 80 newly diagnosed with lymph node negative, estrogen receptor positive tumors, ≤ 5 cm. To estimate life expectancy, we matched these women to women of similar age, region, and insurance, not diagnosed with breast cancer. We examined 5-year mortality of matched controls by illness burden (measured with the Charlson Comorbidity Index [CCI]) using Kaplan-Meier statistics. We examined treatments received by estimated life expectancy within CCI levels. We further examined factors associated with receipt of radiotherapy after breast conserving surgery (BCS).

Results

Of 9,932 women, 39.6% underwent mastectomy, 30.4% received BCS plus radiotherapy, and 30.0% received BCS alone. Estimated 5-year mortality was 72% for women with CCIs of 3+, yet 38.0% of these women underwent mastectomy and 22.9% received radiotherapy after BCS. Conversely, estimated 5-year mortality was 36% for women with CCIs of 0 and 26.6% received BCS alone. Age 80–84, urban residence, higher grade, recent diagnosis, mammography use, and low comorbidity, were factors associated with receiving radiotherapy after BCS. Among women with CCIs of 3 + treated with BCS, 36.9% underwent radiotherapy.

Conclusions

Many women aged ≥ 80 with limited life expectancies receive radiotherapy after BCS for treatment of early stage breast cancers while many in excellent health do not. More consideration needs to be given to patient life expectancy when considering breast cancer treatments.

Introduction

The benefits of radiotherapy after breast conserving surgery (BCS) among women aged ≥ 80 with early stage breast cancer are not well understood even though radiotherapy after BCS is standard treatment for most younger women.¹ No studies have demonstrated a mortality benefit of radiotherapy after BCS among women aged ≥ 80, although some studies suggest a small reduction in local recurrence.[1], [2], [3], [4] Most experts agree that older women in excellent health without comorbid disease limiting their life expectancy would be the most likely to benefit from radiotherapy after BCS.[2], [3], [4], [5]

A pooled analysis of data from several trials including women of all ages, (but few ≥ 70 years) found that radiotherapy after BCS resulted in 7% of women experiencing a local recurrence after 5 years compared to 26% of women who received BCS alone.⁶ This study also showed a 5.4% reduction in breast cancer mortality and a 5.3% reduction in overall mortality after 15 years among women who received radiotherapy after BCS. Breast cancer recurrence was less common among women aged ≥ 70 (3% among women who received radiotherapy after BCS compared to 13% among those who did not).⁶ Data were not presented on whether the mortality benefit of radiotherapy after BCS persisted among women ≥ 70 years. A randomized control trial (RCT) comparing mastectomy, BCS alone, and BCS plus radiotherapy including women of all ages after 20 years follow-up found that radiotherapy after BCS reduced rates of ipsilateral recurrence (39.2% to 14.3%).⁷ There were no significant differences in distant-disease free or overall survival in the three groups; however, radiotherapy after BCS was associated with a nearly significant increase in breast cancer survival.⁸ These studies suggest that radiotherapy after BCS for early stage breast cancer significantly reduces local recurrence and possibly reduces breast cancer mortality after 15–20 years follow-up, which is beyond the life expectancy of most women ≥ 80 years.⁸

Few studies examining radiotherapy after BCS have focused on older women. One RCT included 636 women aged ≥ 70 with stage I, estrogen receptor positive (ER +) breast cancer treated with BCS, and randomized women to treatment with tamoxifen plus radiotherapy or tamoxifen alone. After 5 years, the group that received radiotherapy experienced fewer local and regional recurrences (1% versus 4%, p < 0.001) but there were no significant differences in distant recurrence or survival.¹ An observational study that included women with similar characteristics found that radiotherapy after BCS reduced breast cancer recurrence from 5.1% to 1.1%.² Another RCT that included 769 women aged ≥ 50 (~ 40% ≥ 70 years) with node negative breast tumors, 5 centimeters (cm) or less, found that radiotherapy after BCS reduced local recurrence (7.7% to 0.6%, p < 0.001) but did not show significant differences in rates of distant relapse or overall survival after 5 years.³ A recent review recommended radiotherapy for all patients after BCS, except possibly women aged ≥ 70 with lymph node negative (LN–) tumors, 5 cm or less, being treated with hormonal therapy.⁹ Although not all investigators agree that elderly women with favorable tumor characteristics can forgo radiotherapy after BCS, nearly all concur that those with limited life expectancies are unlikely to benefit.[2], [6], [10], [11]

In this study, we examined initial treatment of women aged ≥ 80 with early stage breast cancers by life expectancy. We then examined characteristics associated with the use of radiotherapy after BCS among these women.