Background Tumor necrosis factor-alpha (TNF-α) inhibitors have been proposed to increase the risk of malignancy. Skin tumors have been reported among the most common malignancies seen in the use of these drugs and melanoma has a much higher importance compared to other skin tumors.
Objectives To investigate the dermoscopic changes in melanocytic nevi in ankylosing spondylitis (AS) patients, under TNF-α inhibitors or conventional therapy (CT-sulfasalazine, non-steroidal anti-inflammatory drugs).
Methods The study included 94 consecutive ankylosing spondylitis patients with at least one melanocytic nevus. 56 patients (F/M=5/51) in the cohort were patients initiated TNF-α inhibitor treatment and 38 (F/M=1/37) were patients receiving CT. Treatment-related changes that occur in nevi were prospectively followed dermoscopically. All changes detected in the follow-up period were recorded, and evaluated in two groups as substantial and non-substantial changes in terms of melanoma development risk. Substantial changes included expansion of nevi, shape change, regression, discoloration and melanoma-specific structural changes; and non-substantial changes included opening/darkening of the global color of nevi, change in the number of brown globules, reduction/loss of blackheads, diffuse-brown pigmentation at the pigment network and the presence of inflammation.
Results Mean age of the TNF-α inhibitor group was 39.7±7.7 years and disease duration was 11.3±6.0 years. The mean age of CT patients was 37.5±7.2 years and disease duration was 8.4±4.5 years. Among age groups, there was no difference in terms of gender and disease duration (p>0.05). In TNF-α inhibitor group 220 (3.9±4.6) nevi, and in CT group 129 (3.4±1.8) nevi were followed (p=0.823). The median follow-up periods of the TNF-α inhibitor and CT groups were 20.4±4.8 and 16.5±4.2 months, respectively (p=0.052). 5 nevi in TNF-α inhibitor group (5 shape changes) and 4 nevi in CT group (3 shape changes, 1 expansion) had substantial changes in terms of the risk of melanoma (p=0.468). 15 nevi in TNF-α inhibitor group (7 opening in color, 3 darkening in color, 1 change in the number of brown globules, 3 reduction/loss of blackheads, 1 inflammation) and 6 nevi in the CT group (2 opening in color, darkening in 2 colors, 1 change in the number of brown globules, 1 reduction/loss of blackheads) had non-substantial changes in terms of melanoma risk (p=0.590). 3 of 5 nevi having major changes in terms of the risk of melanoma were excised.Pathological examination did not reveal malignancy.
Conclusions In the literature, an association between rheumatoid arthritis and risk of developing melanoma has been reported, but there is no similar data pointing to an increased risk in patients with AS. This study has shown that the TNF-α inhibitors did not cause the development of melanocytic nevi in about 2 years of follow-up in patients with AS. While a limitation of the study is the small number of patients, close monitoring of patients under the risk of melanoma development is an important long-term benefit of the study.
Disclosure of Interest None declared