Time to Adjuvant Radiotherapy in Breast Cancer Affects Survival: Implications for the American College of Surgeons Commission on Cancer Quality Metrics.

BACKGROUND

To optimize breast cancer care, the American College of Surgeons Commission on Cancer developed quality measures regarding receipt and timing of adjuvant radiotherapy (RT). Nationwide compliance with these measures and its impact on overall survival (OS) are evaluated herein.

PATIENTS AND METHODS

Patients (n = 285,291) diagnosed with invasive breast cancer from 2004 to 2012 were identified from the National Cancer Database. Compliance with RT administration within 365 days from diagnosis was determined for patients with stage III disease with ≥ 4 positive lymph nodes post mastectomy and stage I-III disease post breast-conserving surgery (BCS). Univariate and multivariate logistic regression and Cox proportional hazard models were used to assess factors associated with compliance and OS, respectively.

RESULTS

In the mastectomy cohort, 66.9% received timely RT, showing improved OS versus no RT patients (HR 0.70, 95% CI 0.67-0.73). Delayed RT patients (≥ 365 days) achieved equivalent OS to those receiving timely RT (HR 1.07, 95% CI 0.93-1.23) and superior OS to no RT patients (HR 0.74, 95% CI 0.65-0.85). In the BCS cohort, 89.4% received timely RT, showing improved OS versus no RT patients (HR 0.47, 95% CI 0.45-0.49). Delayed RT was associated with improved OS versus no RT (HR 0.64, 95% CI 0.56-0.74) and decreased OS versus timely RT (HR 1.37, 95% CI 1.19-1.58). Factors associated with noncompliance included insurance type and distance to hospital.

CONCLUSIONS

Quality measure compliance with adjuvant RT improves OS, regardless of timing after mastectomy. However, timeliness does impact OS after BCS. Focus on modifiable factors to improve compliance such as access to care may lead to improved compliance and OS.