More than a quarter (26%) of patients with melanoma have previously been reassured their lesion was harmless, according to a WA study.

The worrying statistic was revealed in a study of 114 patients presenting for follow-up at a melanoma service

Patients were invited to respond to a questionnaire aimed at identifying possible reasons why the median Breslow thickness of melanoma was increasing over time. The cohort had thicker lesions than the WA state mean (2.7 mm v 1.4mm).

The study found non-pigmented lesions were likely to present thicker than the more common pigmented lesions (3.9mm v 2.3mm respectively), a finding consistent with other evidence.

However patients did not perceive any difference in lesion growth between pigmented and non-pigmented lesions. Most melanomas (57%) were not perceived to grow quickly.

The patient survey found almost half (48%) of patients noticed their lesion themselves. In 24% of cases, a health professional had first noticed the lesion.

A family history of melanoma was present in 27% of patients.

Very few (5%) patients delayed seeking medical advice due to fear of treatment.

About a third (34%) of lesions were biopsied before excision but there was no difference in rates between pigmented and non-pigmented lesions.

The researchers wrote in the Australasian Journal of Dermatology that the rate of false reassurance was of concern.

“It is difficult to contextualise these results. For example, the lesion may have been benign at the time of reassurance,” they said.

“Medical practitioners may find it useful to note that a family history was present in over a quarter of patients. Identifying patients at higher risk may allow earlier detection and an improvement in outcomes.”

They said further research was necessary to identify characteristics of the patient, lesion or access to health care that were associated with thicker lesions.