Patterns and correlates of adjuvant radiotherapy receipt after lumpectomy and after mastectomy for breast cancer

Abstract

Purpose: To use patient self-report to provide more valid estimates of whether radiotherapy (RT) is underutilized than possible with registry data, as well as to evaluate for disparities and the influence of preferences and provider interactions.

Methods: We considered 2,260 survey respondents who had nonmetastatic breast cancer, were age 20 to 79 years, were diagnosed between July 2005 and February 2007 in Detroit and Los Angeles, and reported to Surveillance, Epidemiology and End Results (SEER) registries (72% response rate). Survey responses were merged with SEER data. We assessed rates and correlates of RT receipt among all patients with invasive cancer receiving breast-conserving surgery (BCS) and among patients undergoing mastectomy with indications for RT (ie, positive lymph nodes or T3-4 tumors).

Results: Among 904 patients undergoing BCS with strong indications for RT, 95.4% received RT, and 77.6% received RT among the 135 patients undergoing mastectomy with strong indications (P < .001). Among 114 patients undergoing BCS with weaker indications (ie, elderly) for RT, 80.0% received treatment, and 47.5% received RT among the 164 patients undergoing mastectomy with weaker indications (T1N1, T2N1, or T3N0 disease; P < .001). On multivariate analysis, surgery type (P < .001), indication strength (P < .001), age (P = .005), comorbidity (P < .001), income (P = .03), patient desire to avoid RT (P < .001), level of surgeon involvement in decision to have radiation (P < .001), and SEER site (P < .001) were significantly associated with likelihood of RT receipt.

Conclusion: RT receipt was consistently high across sociodemographic subgroups after BCS but was lower after mastectomy, even among patients with strong indications for treatment, in whom clinical benefit is similar. Surgeon involvement had a strong influence on RT receipt.

Fig 1.

Rates of radiotherapy (RT) receipt by surgery type and indication strength. Higher proportions of patients receive RT after breast-conserving surgery (BCS) than after mastectomy, both among those with strong indications and among those with weaker indications. Twenty-three patients had missing information. Data adjusted for age, comorbidity, site, ethnicity, and education.

Fig 2.

Rates of radiotherapy (RT) receipt among patients (Pts) with strong indications, by surgery type, preference to avoid RT, and provider involvement level. Among patients with strong indications undergoing breast-conserving surgery (BCS), even those with a high desire to avoid RT and those reporting lower levels of surgeon involvement in radiation decisions were likely to receive RT. In contrast, among patients with strong indications for RT who underwent mastectomy, a substantial rate of lack of RT receipt was observed in certain subsets, particularly among those expressing high desire to avoid RT who reported lower levels of surgeon involvement in the decision process. Rates adjusted for age, comorbidity, site, ethnicity, and education. Forty-four patients had missing information.