ESTRO 2024 - Abstract Book

S2537

Clinical - Urology

ESTRO 2024

This retrospective cohort study included 1,883 PCa survivors aged 50-79, treated between 2006 and 2013, with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3D-CRT). Clinical data retrieved from patient files (including Charlson Comorbidity items (CCI), and smoking status) were combined with SPC and survival data from the Netherlands Cancer Registry with a 12-month latency period. First, Standardized Incidence Ratios (SIR) were calculated comparing the EBRT cohort with the general Dutch male population. Second, to explore the effect of patient-related and treatment-related characteristics on SPC development we conducted a Cox regression analysis, censoring for end of follow-up, death, or competing SPC endpoints, whichever came first. Lastly, we estimated cumulative incidences of developing any solid SPC, pelvis SPC, and non-pelvis SPC using a competing risk analysis. All analyses were adjusted for age and calendar period of treatment.

Results:

Significantly increased SIRs were observed for the overall SPC endpoint with SIR=1.21, 95% CI (1.08-1.34), pelvic SPC (SIR=1.46, 95% CI 1.18-1.78), and non-pelvic SPC (SIR=1.18, 95% CI 1.04-1.34). Fifty percent had a CCI ≥1 (most frequent item cardiovascular disease in 27%) and 16% were active smokers. Active smoking and a smoking history were significantly associated with increased SPC risks for both pelvis and non-pelvis endpoints ( Table+Figure ). CCI ≥1 (Hazard ratio (HR)=1.5, 95% CI: 1.1-1.9), cardiovascular disease (HR=1.4, 95% CI: 1.2-1.9) and COPD (HR=1.9, 95% CI: 1.3-2.8) were significantly associated with second non-pelvic SPC risk but not with pelvic SPC risks (Table). The proportion of active smoking numbers in the cohort were similar to the general male population (2). Presence of COPD, (previous) cardiovascular disease, and CCI category showed significant correlations with smoking status (all p<0.001). EBRT technique, risk stage, and adjuvant hormonal therapy (ADT) was not significantly associated with SPC risks.

Conclusion:

We observed high patient numbers with comorbidity scores but not a high percentage of smokers compared to the general population. We conclude from the observed correlations with SPC endpoints that the presence of comorbidities in the EBRT population is a relevant factor in observed excess non-pelvic SPC risk, but not for the endpoint of pelvic SPC risk.