Effect of maintenance chemotherapy in childhood on numbers of melanocytic naevi.

OBJECTIVE (a) To determine whether children given chemotherapy for haematological malignancy have significantly more melanocytic naevi than age matched children in the local population; (b) to establish whether any observed variation in naevus counts from normal is seen at the start of maintenance chemotherapy. DESIGN Follow up of 29 consecutive children starting maintenance chemotherapy, with parental interview and count of all melanocytic naevi > or = 2 mm on the child's skin. Assessment repeated three years later after completion of maintenance chemotherapy. Other dermatological problems identified at either visit were also recorded. SETTING Royal Hospital for Sick Children, Glasgow. RESULTS At the start of maintenance chemotherapy all children had total body counts of melanocytic naevi within the normal range established for age matched children in the local population. Three years later total body naevus counts were significantly increased, the median increase being 66 naevi per child (95% confidence interval 57 to 94). The only other problem noted in these children was relatively poor regrowth of scalp hair. CONCLUSION Children on maintenance chemotherapy for haematological malignancies develop an excessive number of melanocytic naevi. Excessive numbers of melanocytic naevi are the most important risk factor for melanoma in the general population. These children should have periodic skin examinations at their follow up visits, and both child and parent should be educated about clinical features of early melanoma.