Epidemiological trends in cutaneous lymphomas in Greece

Primary cutaneous lymphomas (PCLs) are a heterogenous group of non-Hodgkin lymphomas arising in the skin from T- or B-lymphocytes, for which there is limited epidemiological data available. To describe the disease characteristics and estimate annual incidence rates (IRs) and temporal trends of PCLs and their subtypes in Attica, Greece. A retrospective analysis of all PCL patients, diagnosed in Attica's main haemopathology referral centre from 2009 to 2021, was conducted. In total, 1,189 patients were included; 725 males and 464 females (males__females=1.56). The median age at diagnosis was 62 years. The annual IR was 2.2 new cases per 100,000 individuals. Most patients (n=979, 82.3%) were diagnosed with cutaneous T-cell lymphoma (CTCL) with a crude IR of 1.8 new cases per 100,000 person-years. Mycosis fungoides (MF) was the most common subtype (n=817, 68.7%), followed by lymphomatoid papulosis (LyP) (n=59, 5.0%). The crude IR for MF was 1.5 new cases per 100,000 person-years. Cutaneous B-cell lymphomas (CBCLs) accounted for 17.6% (n=210) of all PCLs (IR: 0.4 new cases per 100,000 person-years). PCL, CTCL and MF incidence rates increased from 2009 to 2019, followed by a decrease in 2020-2021. The incidence rate of CBCL increased steadily during the study period. The annual IRs of PCL in Greece were higher than those reported in other studies from Europe, America and Asia. The increase in IRs from 2009 to 2019 may reflect physicians' improved diagnostic efficiency. The COVID-19 pandemic may be the reason for the decline in PCL, CTCL and MF diagnoses from 2020 to 2021.