Vitiligo associated with lower incidence of skin cancers

Source: 2 minute medicine, September 2014

Patients with vitiligo had lower risk of having melanoma and non-melanoma skin cancers (NMSCs) than those without vitiligo.

2. Patients with vitiligo who had undergone UV phototherapy had an increased incidence of melanoma and NMSCs compared to patients with vitiligo who had not received phototherapy.

Evidence Rating Level: 2 (Good)

Study Rundown: Vitiligo is a common depigmenting skin disease caused by the idiopathic destruction of melanocytes. Although lack of pigmentation is often associated with increased photo-damage and skin cancers, little is known about cancer risk in patients with vitiligo. As such, these authors sought to determine the incidences of melanoma and NMSCs in patients with vitiligo. Results indicated that patients with vitiligo are 4 times less likely to have melanoma and 5 times less likely to have NMSCs than the controls. Additionally, patients with vitiligo who underwent phototherapy were at higher risk of melanoma and NMSCs than patients with vitiligo who did not receive phototherapy. Strengths of this study include its large population size. However, since the control population was largely younger patients who were vascular surgery candidates, comparisons may be biased.

Relevant Reading: Incidence of nonmelanoma skin cancer in a cohort of patients with vitiligo

In-Depth [retrospective cohort]: This study compared 10,040 patients with vitiligo to 25,956 vascular surgery patients without vitiligo for variations in incidences of melanoma and NMSCs between 1997 and 2013. Because the authors could not distinguish risk of developing melanoma and NMSCs, they observed the risk of having vitiligo and melanoma/NMSCs within these two groups. Multiple logistic regression analysis was performed to compare patients with vitiligo to those without. Results indicated that 11/10,040 patients presented with melanoma in patients with vitiligo (1.1%, 95% CI, 0.5%-2.0%) and 118/25,956 patients presented with melanoma in the control group (4.5%, 95% CI, 3.8%-5.4%). Additionally, 38 vitiligo patients had NMSCs (3.9%, 95% CI, 2.7%-5.2%) while 509 control patients had NMSCs (19.6%, 95% CI, 18.0%-21.4%). Patients with vitiligo had a relative risk of 0.24 (95% CI, 0.13-0.45) for melanoma and a relative risk of 0.19 (95% CI, 0.14-0.27) for NMSCs when compared to the controls. The authors also noted that, interestingly, patients with vitiligo who received phototherapy had a higher risk of skin cancer (14.1% vs. 3.2%).