Survival disadvantage among Medicaid-insured breast cancer patients treated with breast conserving surgery without radiation therapy

Bachground Clinical studies indicate that breast cancer patients treated with breast conserving surgery (BCS) without radiotherapy (RT) have a greater risk of recurrence and mortality compared to those receiving BCS plus RT. However, this relationship has been underdeveloped among low-income women in the community who may face barriers in accessing adjuvant treatment and post-treatment surveillance. It is possible that the prognostic significance of omission of RT in clinical trials underestimates the significance of risk in the community. Methods Using cancer registry, Medicaid claims, and the Social Security Master Death File, we evaluated receipt of RT in women with early stage breast cancer treated with BCS and mean 6-year overall and cancer-specific survival. Logistic regression was used to assess correlates of RT. The Kaplan-Meier method was used to determine survival by RT status and a multivariate Cox proportional hazards regression was used to evaluate the role of RT status on overall and cause-specific survival. Results A total of 65% of women received RT, and 82% of the sample survived the study period. Death rates of 16% and 51% were observed among those who did and did not receive RT, respectively (P < 0.001). One-third of women who died from cancer (8 of 24) received radiation. Use of RT was associated with a statistically significant decrease in all-cause (hazard ratio = 0.42, 95% CI 0.21-0.85) and cancer-specific mortality (hazard ratio = 0.22, 95% CI -0.09 to 0.57). Conclusions Adjuvant radiation following BCS was underused in this sample of poor breast cancer patients. Lack of adjuvant RT may be a proxy for inadequate access to care and poor cancer surveillance after treatment.