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Does Methotrexate Use Lead to Melanoma?

Sep 15, 2022 8:00 am

A systematic review suggests that low-dose methotrexate (MTX) use is associated with an increased melanoma risk, but the absolute risk increase could be considered negligible.

Findings  In this systematic review and meta-analysis pooling 16 642 cases of melanoma, individuals exposed to low-dose methotrexate had a 15% increased risk of melanoma compared with the risk in unexposed individuals. However, the melanoma risk associated with methotrexate exposure may not translate to a significant association at a population level, as the number needed to harm was estimated to be large, even for populations with high melanoma incidence rates.

Meaning  Findings suggest that although low-dose methotrexate may be associated with higher risk of malignant melanoma, the true effect could be considered negligible.

This metnalysis included 12 studies (RCTs, cohort studies, case-control studies), and 16 642 melanoma cases in the primary analysis. MTX Indications were primarily for treatment of rheumatoid arthritis, psoriasis, psoriatic arthritis, and inflammatory bowel disease.

When compared to a non-MTX exposed population, those with MTX exposure had a small increased risk of melanoma (pooled relative risk, 1.15; 95% CI, 1.08-1.22). But if the largest study was excluded (sensitivity analysis), this was no longer significant (pooled relative risk, 1.11; 95% CI, 1.00-1.24).

Nonethess the number needed to harm would be 18 630 for Australia, and 41 425 for North America.

While there may be a small, statistically significant risk of melanoma with MTX in these inflammatory disorders, absolute risk increase appears to be negligible.


The author has no conflicts of interest to disclose related to this subject

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