Non-Small Cell Lung Cancer as a Second Primary Among Patients With Previous Malignancy: Who Is at Risk?

BACKGROUND: Patients with previous malignancies could be at increased risk of non-small cell lung cancer (NSCLC). However, the extent of the risk is unknown for many cancer types; thus, it is unclear who might benefit from screening.
MATERIALS AND METHODS: The Surveillance, Epidemiology, and End Results data set from 1992 to 2012 was used to identify patients with previous malignancies who received a diagnosis of NSCLC ≥ 6 months after their initial cancer diagnosis. Standardized incidence ratios (SIRs) for NSCLC were calculated as a ratio of the observed to expected cases adjusted by person-years at risk. Cancers with a SIR > 1.0 had a risk of NSCLC greater than expected. The analyses were stratified by sex, radiation therapy use, and histologic type.
RESULTS: Among the cancer survivors, 32,058 developed NSCLC. Smoking-related (lung, head and neck, bladder) and hematologic malignancies, regardless of previous radiation therapy, had the greatest SIR for NSCLC (range, 1.97-4.88). Colorectal and renal cancer survivors also had an increased SIR for NSCLC (1.16 and 1.21, respectively). Women with previous pancreatic cancer treated with radiation, breast cancer with or without radiation therapy, and those with thyroid cancer demonstrated a greater SIR for lung adenocarcinoma. Men with previous irradiated prostate cancer also had an elevated SIR (1.08; 99% confidence interval, 1.01-1.15) for lung adenocarcinoma. Patients with melanoma, prostate or uterine cancer had a lower SIR for NSCLC than expected.
CONCLUSION: Smoking-related malignancies had the greatest risk of NSCLC. Radiation therapy conferred an elevated risk of NSCLC for certain cancers. Melanoma, prostate, and uterine cancer survivors had a low risk of NSCLC. These results could help identify high-risk screening candidates in the growing population of cancer survivors.