Development and validation of a prognostic nomogram for overall survival in patients with primary cutaneous T-cell...

The prognosis of cutaneous T-cell lymphoma (CTCL) remains heterogeneous, and clinically applicable prognostic tools are needed. Using population-based Surveillance, Epidemiology, and End Results (SEER) data (2000-2019), we analyzed incidence trends and developed a prognostic nomogram for overall survival. Incidence rates were assessed by joinpoint regression. Patients diagnosed from 2004 to 2010 formed the training cohort (n = 4316), and those from 2011 to 2015 constituted the temporal validation cohort (n = 2875). Multivariable Cox analysis identified independent prognostic factors, which were incorporated into a nomogram predicting 1-, 3- and 5-year overall survival. Among 7191 patients, CTCL incidence increased from 2000 to 2016 [annual percent change (APC) 1.05%] and then declined through 2019 (APC -8.44%). The nomogram integrates 11 variables: age, sex, race, marital status, histological subtype, median household income, TNM stage, prior malignances, surgery, radiation, and chemotherapy. It demonstrated strong discrimination, with time-dependent area under the curve values >0.815 for all timepoints in both cohorts, and good calibration. Based on nomogram-derived scores, patients were stratified into 3 distinct risk groups with significantly different survival (P < .0001). This SEER-based nomogram provides a practical, multivariable tool for risk stratification in CTCL, using routinely available clinical and demographic data. External validation is warranted to confirm its generalisability.