Age-related differences in breast cancer treatment

Abstract

Background: More than half of the cases of breast cancer treated in the United States occur in women over age 65. This study investigates age-related differences in breast cancer therapy.

Methods: A retrospective review of all women with primary operable invasive breast cancer treated at the University of Michigan Breast Care Center over a 30-month period showed a total of 77 older patients aged ⩾65 years (median, 71; oldest patient, 92) for whom full information was available regarding comorbidity, tumor stage and histology, and details of surgery, radiation, and chemohormonal therapy and complications. Fifty-one similar younger patients aged 55–64 years (median, 59) were identified for comparison. Patients were classified as either having received standard treatment or nonstandard treatment. Standard therapy was prospectively defined as follows: local/regional—lumpectomy and axillary lymph node dissection plus radiation therapy or modified radical mastectomy; systemic—chemotherapy and/or tamoxifen for stage II disease. A comorbidity score calculated for each patient assigned one point each for nursing home residence, nonambulatory status, recent surgery, and each medical problem requiring drug therapy.

Results: When overall treatment (local/regional plus systemic) was assessed, proportionately fewer older patients (55 of 77 versus 47 of 51;p<0.01) received standard treatment. Fewer older than younger patients (62 of 77 versus 50 of 51;p<0.01) received surgical therapy that included an axillary dissection. A smaller proportion of older patients received radiation therapy following lumpectomy and axillary lymph node dissection (26 of 29 versus 19 of 19; N.S.). Overall, only 59 of 77 older patients versus 50 of 51 younger patients (p<0.001) received standard local/regional care. Similar proportions of younger and older patients (19 of 22 and 24 of 30, respectively) received standard systemic therapy for stage II breast cancer, but older patients were less likely to receive chemotherapy than younger patients (7% versus 50%;p<0.001). Treatment-related complications were not age-related but were more frequent in patients receiving standard treatment than in patients receiving nonstandard treatment (45 of 102 versus two of 26;p<0.001). Comorbidity score correlated with the use of nonstandard therapy but not with age. The scores for both older and younger patients receiving overall standard treatment were 0.8 versus 1.5 and 1.4, respectively, in patients receiving nonstandard treatment. Interestingly, explanations for decisions to deviate from standard treatment guidelines were often not identified. Comorbidity was explicitly noted in only one of four younger patients who received nonstandard treatment therapy. In 22 older patients who received nonstandard treatment, comorbidity was cited in eight cases, patient age was cited in six cases, and patient choice was cited in four cases. Follow-up (median, 34 months) did not show that disease-free or overall survival differences were related to age or to treatment (standard versus nonstandard).

Conclusions: These data demonstrate age-related variations in breast cancer treatment in a multidisciplinary breast care unit. Lower complication rates and equivalent short-term outcomes in women who received nonstandard therapy suggest good clinical judgment may have played a role in these differences. Although age-related patient preferences and comorbidity are relevant, the age-related attitudes of caregivers must also be taken into account to fully explain these variations.