Incidence of cutaneous squamous cell carcinoma in a New Zealand population of chronic lymphocytic leukaemia patients

Background and Aim Chronic lymphocytic leukemia (CLL) is associated with an increased incidence and aggressiveness of skin cancers, in particular cutaneous squamous cell carcinoma (cSCC), but little is known of cSCC incidence in Australasian CLL patients. In this retrospective study we analysed the incidence of cSCC in patients seen at a tertiary hospital in New Zealand (NZ). Methods We retrospectively assessed the clinical history and histology data of CLL patients (n = 371) who were seen at the Haematology Department, Christchurch Hospital, NZ during the period 1996-2015. Baseline characteristics, incidence of second cancers, treatment details and overall survival were analysed. Results During follow-up (median = 11.8 years) 221 second cancers were recorded in 88 patients. Of these cancers 185 were cSCC removed from 61 patients. In 56% of these patients >1 cSCC was removed and the majority of cSCC occurred following treatment for CLL. The cumulative incidence of a 1st cSCC was 11% at 5 years whereas the cumulative incidence of a subsequent cSCC was 88% at 5 years. The incidence of cSCC in male patients was three fold higher than that reported for the general NZ population. Conclusions New Zealand CLL patients have a high incidence of cSCC relative to the levels observed in the general population which are themselves among the highest in the world. Careful monitoring of CLL patients is warranted particularly those who have progressive disease or have had a 1st cSCC removed.