Number needed to treatis an important outcome measure of skin cancer diagnosis quality. Researchers assessed the impact of referral patterns for melanoma and dermatologic consultation quality and found that biopsy rateswere consistently around 20% regardless of age and sex, which the authors said represents “an area for quality and cost improvement.” The results of the study were published as part of the American Academy of Dermatology Virtual Meeting Experience 2020.
Researchers conducted a retrospective review of referrals to a tertiary center practice. Number needed to refer and number needed to biopsy were calculated for melanoma as: biopsy-proven melanoma + benign and dysplastic nevi + seborrheic keratoses / biopsy-proven melanoma. For non-melanoma skin cancer, this was calculated as: biopsy-proven basal cell carcinoma (BCC)/squamous cell carcinoma (SCC) + actinic keratoses + seborrheic keratoses / biopsy-proven BCC/SCC.
There were 707 referrals during a seven-month period (July 2015 to February 2016); 46% (n=327) were male, and women younger than 40 years were disproportionately overrepresented compared with males of same age. Mean patient age among men was 57.5 years, while mean age among women was 53.5 years.
Among all age groups, lesions were more commonly benign. The frequency of pre-malignant and malignant lesions such as actinic keratoses, non-melanoma skin cancer, and melanoma were highest for males and increased with age. Nevi was the most common (28%) benign diagnosis among younger patients (defined as younger than the median patient age of 57 years), while seborrheic keratoses were more common (34%) among older patients.
The number needed to refer to diagnose melanoma was 31.5, and the number needed to biopsy to diagnose melanoma was 7.5, representing a 4.2-fold difference. To diagnose non-melanoma skin cancer, these values were 4.0 and 1.5, respectively, representing a 2.7-fold difference. Despite variable rates of skin cancer between demographics, the mean biopsy rate was 23.4%(range, 18-30%).
“Our results show a large reduction in number needed to treat from the referral to biopsy stage, suggesting that referral level changes could be targeted for cost-savings in skin cancer management,” the researchers concluded.
Klebanov N, Shaughnessy M, Gunasekera N, et al. Number needed to treat analysis of skin cancers among referrals for suspicious lesions. Presented during the AAD Virtual Meeting Experience 2020, June 12-14, 2020.