Second Primary Malignancies in Patients with Hematologic and Solid Tumors: Risk Factors

Aim: This study aimed to evaluate time to second primary malignancy (SPM) development and associated clinical factors in adults with a PM.Methods: This retrospective study included patients with hematologic malignancies (HM) and a prior history of solid organ malignancy (SOM) who had complete clinical data available.We recorded demographic characteristics; diagnoses of the PM and SPM; the interval between PM and SPM; treatments received; and survival outcomes.Time to SPM was calculated for the overall cohort and for predefined subgroups, and comparisons were performed according to demographic variables and treatment exposures.Results: A total of 101 patients were included.Median age was 61 years (26-88).Median time to SPM was 42.9 months overall, longer in the primary hematologic malignancy than primary SOM (54.9 vs. 26.8months, p=0.018).Patients <60 years had longer time to SPM than those 60 (66 vs. 21.4months, p<0.001), a difference consistent across subgroups (<60: 96 vs. 37 months, p=0.001; 60: 41 vs. 8.9 months, p=0.036).Patients receiving chemotherapy (CT) and/or radiotherapy (RT) had longer SPM times than untreated patients (CT: 54.5 vs. 18.9 months, p=0.007).Among SPMs, the most frequent HM was chronic lymphocytic leukemia (chronic lymphocytic leukemia, 24.4%), while lung cancer (17.9%) was the most frequent solid tumor.In multivariate regression, the only independent predictor of shorter SPM time was age 60 years (odds ratio=0.34,95% confidence interval: 0.12-0.88,p=0.023).Conclusion: Advanced age is the main determinant of SPM development in adult cancer survivors, highlighting the need for closer surveillance in elderly patients.