Retrospective Analysis of Second Primary Malignancies in Patients with Mycosis Fungoides and Sézary Syndrome in Croatia

Abstract

Introduction: Patients with mycosis fungoides (MF) have a higher risk of developing second primary malignancy. The type of second malignancy varies across the studies, and no established guidelines currently exist for screening MF patients. Objective: To identify MF and Sézary syndrome (SS) patients at a potentially higher risk of developing a secondary primary malignancy, assess the prevalence of other secondary malignancies, and evaluate whether MF with other primary malignancies leads to a worse prognosis based on MF variants. Methods: This observational single-center retrospective study followed 84 patients for a minimum of five years. Results: We identified 16 patients (19%) with second malignancy, of whom eight (50%) had hematological neoplasms. Among other malignancies, breast cancer was the most common (N=5), followed by other malignancies, including lung cancer, prostate cancer, kidney cancer, and so on. The median age at disease onset was 53.0 years, while median age at second malignancy diagnosis was 60.5 years. No sex predominance was observed. Although not statistically significant, seven of sixteen patients (43.75%) who developed second malignancy had MF variant (such as folliculotropic MF) or Sezary syndrome. Disease progression was more common in patients with MF variant. Conclusion: A higher risk for developing a second primary neoplasm was observed. However, additional cancer screening beyond routine age-and sex-appropriate examinations is not yet included in the current guidelines. Based on our findings, we recommend that MF patients undergo regular preventive screenings for the early detection of other primary malignancies.