Breast Cancer Survivors and Risk for Primary Lung Cancer

By: Victoria Kuhr, MS
Posted: Tuesday, April 30, 2024

Chenxi Jiang,MPH, of the American Cancer Society, Atlanta, and colleagues observed that breast cancer survivors who received radiation therapy may be at increased risk for development of different subtypes of lung cancer. These findings, which were presented at the American Association for Cancer Research (AACR) Annual Meeting 2024 (Abstract LB151/18), show the need for evaluating risks and implementing surveillance for subsequent primary lung cancer in breast cancer survivors.

The study included female patients (aged 20–84) who were diagnosed with first primary breast cancer between 1992 and 2020. Patients were identified from 12 Surveillance, Epidemiology, and End Results (SEER) registries. Follow-up began at 2 months from breast cancer diagnosis and ended at subsequent lung cancer diagnosis, last known vital status, death, or December 2020. Standardized incidence ratios and excess absolute risks (per 10,000 women) were calculated for each histologic subtype of lung cancer using expected rates of each subtype in the SEER population. Subgroup analyses were conducted by treatment for breast cancer (radiotherapy yes or no/unknown) overall and stratified by the relative position (ipsilateral and contralateral) of the breast and subsequent primary lung cancer.

Of the 550,007 patients included in the study, 8,014 subsequent primary lung cancers were diagnosed during a mean follow-up of 9.7 years. Overall, 52.6% of patients received radiotherapy. Compared with the general population, breast cancer survivors had a statistically significant higher risk of lung cancer, with subtype-specific standardized incidence ratios being greatest for adenocarcinoma (4,337), followed by squamous cell carcinoma (1,368) and small cell carcinoma (1,026). The increased risk of developing adenocarcinoma after radiotherapy did not vary across strata. In contrast, the increased risk for squamous and transitional cell carcinomas and small cell carcinoma was confined to those who received radiotherapy. The increased risk of lung cancer when treated with radiotherapy was confined to ipsilateral subsequent primary lung cancer for these two subtypes.

Disclosure: The study authors reported no conflicts of interest.

AACR Annual Meeting 2024

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