Lithium exerts protective effect against melanoma and associated mortality
Exposure to lithium yields a reduction in the risk of melanoma and associated mortality, according to a retrospective cohort study.
Researchers looked at a cohort of 2,213,848 adult white Kaiser Permanente Northern California members. Lithium exposure was identified in 11,317 adults with the use pharmacy databases and serum lithium levels obtained from electronic laboratory databases, while a total of 14,056 incident cutaneous melanomas were identified from an established cancer registry.
The incidence of melanoma was found to be 67.4 per 100,000 person-years in lithium-exposed individuals vs 92.5 per 100,000 person-years in unexposed individuals (p=0.027).
Lithium exposure reduced the risk of melanoma by 32 percent (crude hazard ratio [HR], 0.68; 95 percent CI, 0.51 to 0.90), but this risk-lowering benefit was attenuated and nonsignificant after adjusting for potential confounding factors (adjusted HR, 0.77; 0.58 to 1.02).
At melanoma diagnosis, no lithium-exposed individuals presented with tumours thicker than 4 mm or advanced-stage disease. Furthermore, melanoma-associated mortality was better among lithium-exposed vs unexposed patients (mortality rate, 4.68 vs 7.21 per 1,000 person-years).
A malignant tumour of the skin developing from melanin-producing pigment cells known as melanocytes, melanoma is an aggressive skin cancer that has fatal consequences if diagnosed late. Previous reports indicate that external factors, genetic predisposition or both can cause damage to DNA in melanoma cells. [Cutis 2014;94:241-248]
The most important environmental risk factor for melanoma is UV radiation, both natural and artificial. Other factors associated with the skin cancer are skin type, ethnicity, number of melanocytic nevi, number and severity of sunburns, frequency and duration of UV exposure, geographic location, and level of awareness about malignant melanoma and its risk factors. [J Am Acad Dermatol 2011;64:655-662]