Patients with chronic lymphocytic leukemia (CLL) are four to five times more likely to develop aggressive skin cancers one year after their CLL diagnosis.
A retrospective Canadian study of 587 patients with CLL found 28% developed a skin cancer – about a third prior to their CLL diagnosis and two thirds after diagnosis.
The first skin cancers began to increase even 5-6 years before the CLL diagnosis but continued to increase after diagnosis.
Notably, there was a disproportionate increase in the rate of melanomas (4-fold) and SCCs (5- fold) compared to a 3-fold increase in BCCs.
“These results demonstrate that the increased number of SCs in CLL is a result of the hematological malignancy, and not due to a common predisposing factor for the two malignancies. In addition, it demonstrates that the immunosuppression that predisposes these patients to SC is present prior to the diagnosis of CLL, but is significantly greater by one year after diagnosis,” the researchers said.
They found male gender, age ≥70 years and receiving chemotherapy were predictive factors for the development of skin cancer.
The study also found 27% of CLL patients developed a solid tumour including breast, prostate, lung, colon and bladder cancers.
These cancers were the major cause of death during the almost seven years of follow-up, ahead of progressive CLL and infections.
The development of a skin cancer did not increase the risk of developing a subsequent solid tumour and only 10% of patients developed both.
“These data would suggest that different factors, apart from immunosuppression, contribute to the development of these different types of cancer in CLL.”
A Commentary by Australians Professor Stephen Mulligan, Associate Professor Stephen Shumack and Associate Professor Alexander Guminski said immune failure in CLL leading to infection and second malignancy arguably now limits overall survival more than the CLL itself.
CLL patients at Royal North Shore Hospital have a higher rate of mortality from non-haematological malignancy than from their CLL, they said.
“As the survival from better CLL disease control improves further, second malignancy will likely become an even more dominant factor for long-term survival for a higher proportion of patients, and it will require more focus from the CLL community.”
They noted the different UV exposure in Canada compared to Australia.
“In Australian CLL patients, this translates into an NMSC mortality rate 17 times that of the general population,” they said.
In response, combined CLL and dermatology clinics “provide an ideal environment and opportunity to educate patients regarding the need for strict sun avoidance as well as their regular surveillance, and rapid, multidisciplinary intervention when SC occurs.”