Non-small-cell lung cancer after breast cancer: a population-based study of clinicopathologic characteristics and survival outcomes in 3529 women.

Introduction: Annually, 1.4 million women worldwide are diagnosed with breast cancer (BC) and are at risk for another common malignancy: non-small-cell lung cancer (NSCLC). No large population-based study has examined subsequent survival.

Methods: Women with histologically confirmed NSCLC after BC (BC-NSCLC, n = 3529) were identified in SEER-18 registries (1988-2009). Clinicopathologic characteristics and survival outcomes were compared among women with first primary NSCLC (NSCLC-1, n = 151,628). Cox regression analyses were adjusted for patient, BC, and NSCLC factors.

Results: BC-NSCLC was diagnosed at earlier stages (34% localized, 30% regional, 36% distant) than NSCLC-1 (22%, 28%, and 50%, respectively; p < 0.0001). For localized and regional BC-NSCLC, surgical resection rates were higher than NSCLC-1 (72% versus 69% [p < 0.01] and 56% versus 46% [p < 0.0001]), respectively). Radiotherapy was given less often for BC-NSCLC than NSCLC-1 (localized: 15% versus 18%, p < 0.004; regional: 38% versus 49%, p < 0.0001). Median overall survival (OS) after localized, regional, and distant BC-NSCLC was 5.1 years, 1.9 years, and 5.8 months, respectively. For NSCLC-1, median OS was 4.6 years, 1.5 years, and 4.6 months, respectively. BC history did not affect OS for localized NSCLC, and OS was modestly greater after regional (p = 0.016) and distant (p < 0.0001) BC-NSCLC compared with NSCLC-1. BC radiotherapy to the ipsilateral chest did not unfavorably influence OS.

Conclusions: BC survivors are more likely to be diagnosed with earlier stage NSCLC versus first primary NSCLC patients, perhaps reflecting heightened surveillance compared with the general population. In contrast to prior studies of NSCLC in survivors of lymphopoietic malignancies, BC history does not appear to adversely affect OS after NSCLC.