PORTLAND, ORE. – A diagnosis of systemic lupus erythematosus (SLE) significantly increases the risk of a subsequent diagnosis of malignant melanoma, according to the results of a large, first-in-kind, single-center longitudinal analysis of electronic medical records.
This finding expands the list of known associations between SLE and cancer, and highlights the need for careful surveillance of this population, Solomiya Grushchak, of the department of dermatology at Northwestern University, Chicago, and her associates, reported in a poster presented at the annual meeting of the Society for Investigative Dermatology.
SLE is increasingly being treated with immune checkpoint inhibitors, which can aggressively disrupt immune reactivity and trigger uncontrolled cellular responses in patients with SLE, Ms. Grushchak noted. “The findings in this large population warrant further exploration of the association between malignant melanoma and SLE to promote optimal patient management, especially in light of recent advances [in the use of] checkpoint inhibitors,” she added.
Past work has linked SLE with several other malignancies, including nonmelanoma skin cancers, non-Hodgkin and Hodgkin lymphomas, and cancers of the larynx, lungs, liver, vulva, vagina, and thyroid gland. Even when patients are not receiving checkpoint inhibitors, SLE causes chronic inflammation and is known to increase cellular dysplasia, which can ultimately trigger uncontrolled proliferation of tumor cells. In 2015, a meta-analysis showed that SLE was associated with a decreased risk of melanoma, but no studies had conclusively evaluated this relationship (PLoS One. 2015;10[4]:e0122964).
Therefore, Ms. Grushchak and her associates analyzed medical records from 2,351 patients from the urban Midwest with SLE diagnosed by a dermatologist or rheumatologist between 2000 and 2016. The data source was the Northwestern Enterprise Data Warehouse, which integrates clinical and research information from more than 50 health data systems used by the Northwestern University Feinberg School of Medicine and its health care partners. To avoid detection bias, the researchers constructed a comparison group from the same database of 1,676 patients diagnosed with systemic sclerosis.
Ten patients (0.4%) with a diagnostic code for SLE were later diagnosed with malignant melanoma, compared with one patient with systemic sclerosis (0.06%), the investigators reported. A Fisher’s exact test confirmed a statistically significant difference between these rates (P = .03). Among the 10 SLE patients with melanoma, 7 were white, 2 were black, and 1 was of Asian ancestry. Nine were females, and one was male. The patient with systemic sclerosis and melanoma was a white male.
The study had several limitations. The investigators did not report how much time elapsed between the diagnoses of SLE and melanoma, or the rates or cumulative exposure to checkpoint inhibitors.
The National Institutes of Health provides support to the Northwestern Enterprise Data Warehouse. The investigators had no relevant financial conflicts.