Disparities in the management of cutaneous malignant melanoma. A population-based high-resolution study.

Population-based cancer registry data from three Spanish areas were used to assess the patterns of care and adherence to guidelines for cutaneous malignant melanoma. We included 934 cases diagnosed in 2009-2013. Completeness of the pathology reports, imaging for detecting distant metastasis and the use of sentinel lymph node biopsy (SLNB) were analysed. The proportion of pathology reports that mentioned the essential pathological features required for T staging was 93%, ranging across geographic areas from 81% to 98% (p < 0.001). The percentage of low-risk patients who underwent no imaging studies, as proposed by guidelines, or only chest imaging ranged among areas from 0.6% to 84% (p < 0.001). Of the patients with clinically node-negative melanoma >1 mm thick and no distant metastases, 68% underwent SLNB, varying by area from 61% to 78% (p = 0.017). This study revealed wide geographic variation in different aspects of melanoma care. The use of a standardised structured pathology report could strengthen the completeness of reporting. Improvement strategies should also include efforts to reduce overuse of imaging in low-risk patients and to increase the adherence to guidelines recommendations on the use of SLNB.