Association between smoking, tumor genetics, and outcomes in men with metastatic prostate cancer

Smoking has been associated with increased metastatic prostate cancer mortality, but the mechanisms behind this are largely unknown. We hypothesized that smoking increases the risk of genetic alterations associated with aggressive disease and/or the transformation to neuroendocrine prostate cancer (NEPC).

We utilized the Prostate Cancer Precision Medicine Multi-institutional Collaborative Effort (PROMISE) clinical genomic database for this retrospective analysis. We associated patient characteristics and tumor genetic data with smoking exposure at diagnosis (current, former, never and pack years) and with clinical outcomes, including overall survival (OS) from diagnosis or time to developing metastatic disease and NEPC status.

We identified 2353 men with prostate cancer and next generation somatic tumor sequencing evaluable for analysis in PROMISE, including 8% current, 39% former, and 52% never smokers. Current smokers were more likely to be younger and to have metastatic (M1 or N1) disease at diagnosis, and less likely to have prior local therapy (all p < 0.001). Current smoking was associated with worse OS from diagnosis (99.9 mo vs 137.6 mo, HR 1.42, 95% CI 1.14-1.77), which remained significant after adjusting for disease characteristics. We found no difference in the percentage of NEPC at initial diagnosis or at any time between current, former, and never smokers (p = 0.8). We found positive associations between smoking status and genetic alterations in SPOP (current: 15%, former 6.7%, never 3.8%; p = 0.018), FGFR1 (current 10%, former 0.4%, never 1.1% p = 0.001), and ARID1A (current 5.1%, former 2.2%, never 0.4%; p = 0.035) in patients with metastatic androgen pathway modulator sensitive prostate cancer (APMS).

Active smoking is associated with worse overall and prostate cancer specific survival as compared to never/former smoking and was associated with specific tumor genetic alterations but not small cell/NEPC transformation.