e18587 Background: Survivors of chronic lymphocytic leukemia (CLL) face an increased risk of second primary malignancies (SPMs) due to intrinsic immune dysregulation and prolonged survival from novel therapies. Contemporary data quantifying this risk across age, race, and diagnosis era are limited. Methods: Using SEER 17 registries (2000–2022), we identified 83,930 adult patients with CLL as a first primary malignancy. Patients with latency <2 months were excluded. Standardized incidence ratios (SIRs), absolute excess risks (AERs per 10,000 person-years), and 95% confidence intervals (CIs) were calculated, comparing observed SPMs to expected rates in the general population. Analyses were stratified by age, race, and calendar year. Results: Over 546,737 person-years (mean follow-up 6.5 years), 13,570 SPMs occurred (SIR 1.32, 95% CI 1.29–1.34; AER 59.5). Solid tumors (n=10,309) showed a modest but significant excess (SIR 1.17, 95% CI 1.15–1.19; AER 27.6). The highest site-specific risks (SIR; AER) were for: skin excluding basal/squamous (2.16; 13.3), melanoma (1.97; 10.1), lung/bronchus (1.33; 8.8), kidney (1.52; 3.1), salivary gland (2.78; 1.0), and thyroid (1.84; 1.7). Younger patients exhibited the highest relative risk (SIR 11.4 for ages 15–19), while risk increased in recent diagnosis years (peak SIR 1.69 in 2021). Non-White patients, particularly Asian/Pacific Islanders, experienced higher SPM risk (SIR 1.87). Conclusions: CLL survivors face a persistently elevated risk of SPMs, particularly at immune-related sites, with increased risk in younger and non-White populations and in more recent diagnosis years. These findings support enhanced, tailored cancer screening and ongoing monitoring in this growing survivor population.
Soni et al. (Thu,) studied this question.