Nicotinamide for Skin-Cancer Chemoprevention in Transplant Recipients

BACKGROUND

Immunosuppressed organ-transplant recipients have an increased incidence of, and mortality from, skin cancer. Nicotinamide (vitamin B3) enhances the repair of ultraviolet (UV) radiation-induced DNA damage, reduces the cutaneous immunosuppressive effects of UV radiation, and reduces the incidence of keratinocyte cancers (including squamous-cell and basal-cell carcinomas) and actinic keratoses among high-risk immunocompetent patients. Whether oral nicotinamide is useful for skin-cancer chemoprevention in organ-transplant recipients is unclear.

METHODS

In this phase 3 trial, we randomly assigned, in a 1:1 ratio, organ-transplant recipients who had had at least two keratinocyte cancers in the past 5 years to receive 500 mg of nicotinamide or placebo twice daily for 12 months. Participants were examined for skin lesions by dermatologists at 3-month intervals for 12 months. The primary end point was the number of new keratinocyte cancers during the 12-month intervention period. Secondary end points included the numbers of squamous-cell and basal-cell carcinomas during the 12-month intervention period, the number of actinic keratoses until 6 months after randomization, safety, and quality of life.

RESULTS

A total of 158 participants were enrolled, with 79 assigned to the nicotinamide group and 79 to the placebo group. The trial was stopped early owing to poor recruitment. At 12 months, there were 207 new keratinocyte cancers in the nicotinamide group and 210 in the placebo group (rate ratio, 1.0; 95% confidence interval, 0.8 to 1.3; P = 0.96). No significant between-group differences in squamous-cell and basal-cell carcinoma counts, actinic keratosis counts, or quality-of-life scores were observed. Adverse events and changes in blood or urine laboratory variables were similar in the two groups.

CONCLUSIONS

In this 12-month, placebo-controlled trial, oral nicotinamide therapy did not lead to lower numbers of keratinocyte cancers or actinic keratoses in immunosuppressed solid-organ transplant recipients. (Funded by the National Health and Medical Research Council; ONTRANS Australian New Zealand Clinical Trials Registry number, ACTRN12617000599370.).

Whiplash rove beetle dermatitis in central Queensland

Vesicular dermatitis due to contact with Coleoptera (beetles) is common worldwide, although the condition has been infrequently described in Australia. We document the largest outbreak recognized so far in Australia with a conservative estimate of 250 cases. This occurred in central coastal Queensland over several weeks in late 1998. A survey of the medical practitioners in this district is presented, along with clinical and histopathological illustrations. Our research found that knowledge of the condition was limited even in this region where cases occur each year. This condition is an important differential diagnosis in acute blistering disorders.

Nuchal fibroma associated with scleredema, diabetes mellitus and organic solvent exposure

A case of scleredema diabeticorum of Buschke associated with nuchal fibroma and organic solvent exposure is reported. The patient presented with a neck mass causing discomfort and restriction of movement. Histological examination showed this to be a nuchal fibroma. Additionally, there was widespread induration of the skin of his trunk which was asymptomatic. A biopsy showed features of scleredema. This is the first reported association of these two conditions, both of which show increased and thickened collagen bundles without significant fibroblast proliferation. They differ by the occurrence of mucin in scleredema, although this is not always demonstrable, particularly in late lesions. The possibility that nuchal fibroma is an end stage, localized form of scleredema is canvassed. The patient's medical history included insulin-dependent diabetes mellitus with complications of retinal vessel thrombosis and peripheral neuropathy. The patient also had significant past exposure to a wide variety of chemicals, including organic solvents.