Bladder cancer risk: Use of the PLCO and NLST to identify a suitable screening cohort

Bladder cancer (BC) screening is not accepted in part owing to low overall incidence. We used the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial (PLCO) and National Lung Cancer Screening Trial (NLST) to identify optimal high-risk populations most likely to benefit from screening.

Data were extracted from PLCO and NLST to stratify risk of BC by overall population, sex, race, age at inclusion, and smoking status. Incidence rates between groups were compared using chi-square test.

BC was identified in 1,430/154,898 patients in PLCO and 439/53,173 patients in NLST. BCs were grade III/IV in 36.8% and 41.3%. Incidence rates were significantly higher in men than in women (PLCO: 1.4 vs. 0.31/1,000 person-years and NLST: 1.84 vs. 0.6/1,000 person-years, both P<0.0001). In proportional hazards models, male sex, higher age, and duration and intensity of smoking were associated with higher risk of BC (all P<0.0001). In men older than 70 years with smoking exposure of 30 pack-years (PY) and more, incidence rates were as high as 11.92 (PLCO) and 5.23 (NLST) (per 1,000 person-years). In current high-intensity smokers (≥50 PY), the sex disparity in incidence persists in both trials (0.78 vs. 2.99 per 1,000 person-years in PLCO and 1.12 vs. 2.65 per 1,000 person-years in NLST).

Men older than 60 years with a smoking history of>30 PY had incidence rates of more than 2/1,000 person-years, which could serve as an excellent population for screening trials. Sex differences in the incidence of BC cannot be readily explained by the differences in exposure to tobacco, as sex disparity persisted regardless of smoking intensity.