Postmastectomy Radiation in Breast Cancer Patients With Pathologically Positive Lymph Nodes After Neoadjuvant Chemotherapy: Usage Rates and Survival Trends.

PURPOSE: To analyze postmastectomy radiation therapy (PMRT) usage and its association with overall survival (OS) in breast cancer patients with pathologically positive lymph nodes after neoadjuvant chemotherapy (NAC). METHODS AND MATERIALS: Using the National Cancer Database, we identified women with nonmetastatic breast cancer diagnosed from 2004 to 2013 who had received NAC and undergone mastectomy with macroscopic pathologically positive lymph nodes. Joinpoint regression models were used to assess temporal trends in annual PMRT usage. Multivariable regression models were used to identify factors associated with PMRT use. A time-dependent Cox model was used to evaluate the predictors of mortality. RESULTS: The study included 29,270 patients, of whom 62.5% received PMRT. PMRT was markedly underused among all nodal subgroups, in particular, among ypN2 (68.4%) and ypN3 (67.0%) patients. Hispanic patients and those with Medicaid or Medicare insurance were less likely to receive PMRT than were non-Hispanics and patients with other insurance carriers. The adjusted 5-year OS rates were similar in ypN1 and ypN2 patients with or without PMRT but were significantly greater in ypN3 patients receiving PMRT (66% vs 63%; P=.042). On multivariable analysis, PMRT was associated with improved survival only among ypN3 patients after adjusting for patient, facility, and tumor variables (multivariable hazard ratio 0.85; 95% confidence interval 0.74-0.97). CONCLUSIONS: A considerable portion of breast cancer patients with advanced residual nodal disease after NAC did not receive appropriate adjuvant radiation. We also found socioeconomic disparities in national PMRT practice patterns. Patients with ypN3 disease might derive a survival benefit from PMRT.

Disparities in receipt of modern concurrent chemoradiotherapy in glioblastoma.

Temozolomide given concurrently with radiation after resection/biopsy improves survival in glioblastoma (GBM). The disparities in receipt of adjuvant single-agent chemotherapy and their association with outcome have not been well established. Observational study of a prospectively collected database, the National Cancer Database (NCDB), from 1998 to 2012 with median follow-up 12.4 months. Among the 114,979 patients in the NCDB with GBM, 44,531 patients were analyzed for disparities, and 28,279 patients were analyzed for overall survival (OS). Associations were assessed in a multivariable Cox proportional hazards regression model. Survival was estimated using the Kaplan-Meier method. Median age was 58 years. Chemotherapy use was associated with male gender, white race, younger age (≤50), higher performance status (≥70), more extensive surgery, insurance status, higher income/education, and treatment at academic centers (all p < 0.05). We found improved OS associated with type of insurance (private insurance HR 0.91, 95 % CI 0.85-0.96 and Medicare HR 1.24, 95 % CI 1.16-1.33, both p < 0.01 compared to uninsured) and treatment at academic programs (HR 0.86; p < 0.01). MGMT methylation status predicted improved OS (HR 0.54; 95 % CI 0.41-0.70, p < 0.01). 1-year OS for patients receiving chemotherapy was 55.9 % versus 35.3 % for those without (p < 0.0001). After adjustment for confounders, chemotherapy use remained associated with improved OS (HR 0.64, 95 % CI 0.63-0.66, p < 0.01). Chemotherapy utilization increased from 26.9 to 93.3 % during the study period. We have identified specific disparities in the use of chemotherapy that may be targeted to improve patient access to care. Widespread adoption of adjuvant chemoradiotherapy after resection or biopsy for GBM appears to improve OS.