Background: We examined the effect of disease-free interval (DFI) duration on cancer-specific mortality (CSM)-free survival, otherwise known as the effect of conditional survival, in radical urethrectomy nonmetastatic primary urethral carcinoma (PUC) patients.
Methods: Using the Surveillance, Epidemiology, and End Results (SEER) database 2000-2020, patient (age, sex, race/ethnicity, and marital status) and tumor (stage and histology) characteristics, as well as systemic therapy exposure status of nonmetastatic PUC patients were tabulated. Conditional survival estimates at 5-year were assessed based on DFI duration and according to stage at presentation (T1 -2N0 vs. T3-4N0-2).
Results: Of all 512 radical urethrectomy PUC patients, 278 (54%) harbored T1-2N0 stage versus 234 (46%) harbored T3-4N0-2 stage. In 512 PUC patients, 5-year CSM-free survival at initial diagnosis was 61.8%. Provided a DFI duration of 36 months, 5-year CSM-free survival was 85.6%. In 278 T1-2N0 PUC patients, 5-year CSM-free survival at initial diagnosis was 68.4%. Provided a DFI duration of 36 months, 5-year CSM-free survival was 86.9%. In 234 T3-4N0-2 PUC patients, 5-year CSM-free survival at initial diagnosis was 53.8%. Provided a DFI duration of 36 months, 5-year CSM-free survival was 83.6%.
Conclusions: Although intuitively, clinicians and patients are well aware of the concept that increasing DFI duration improves survival probability, only a few clinicians can accurately estimate the magnitude of survival improvement, as was done within the current study. Such information is crucial to survivors, especially in those diagnosed with rare malignancies, where the survival estimation according to DFI duration is even more challenging.
Keywords: SEER program; conditional survival; stage‐specific analysis; survival differences; urethral carcinoma.
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