Tumor thickness, location of primary melanoma affects recurrence rates
Researchers suggest that approximately 13% of patients with a high-risk primary melanoma may develop recurrence within 2 years, and informed clinical follow-up should include understanding the patterns and risk factors of disease recurrence.
“Our findings that ulceration and many mitoses are important histopathologic features associated with higher rates of recurrence are consistent with other evidence,” Lean A. von Schuckmann, MBBS, MPH, of the population health department at QIMR Berghofer Medical Research Institute in Australia, and colleagues wrote.
The retrospective study included 700 participants in Queensland, Australia, recruited between October 2010 and October 2014. Mean patient age was 62.2 years and 58.6% were men.
Melanoma recurrences were self-reported using follow-up questionnaires every 6 months and confirmed by histologic or imagining findings. Researchers defined disease-free survival by melanoma tumor category per the 7th vs. 8th editions of the AJCC Cancer Staging Manual.
Independent predictors of recurrence were head or neck site of primary tumor, ulceration, thickness and mitotic rate greater than 3/mm2 (HR = 2.36; 95% CI, 1.19-4.71).
Head or neck tumors were more likely to recur than those on the trunk and lower limbs (HR = 1.67; 95% CI, 1.01-2.76). However, tumors on the upper limbs were less likely to recur (HR, 0.42; 95% CI, 0.18-0.97).
The median time to first recurrence was 40 weeks, and researchers determined that patients’ age, sex or previous melanoma were not associated with recurrence.
Within 2 years of diagnosis, 94 patients (13.4%) developed a recurrence. Of those, 66 tumors (70.2%) were locoregional and 28 tumors (29.8%) developed at distant sites. From the 64 patients whose locoregional disease was excised, 37 patients (57.8%) remained disease free for 2 years.
Seven patients (10.9%) developed new locoregional recurrence and in 20 patients (31.3%), distant disease developed. Second recurrences were found in a variety of sites, including bone (12.2%) abdominal organs (244%) and thyroid (2.7%) and parotid glands (2.7%).
In this population with high-risk primary melanoma, 2-year disease-free survival was 95% for T1b tumors and 67% for T4b tumors, treated by wide local excision with or without sentinel node biopsy, according to the researchers.
Additionally, the presence of ulceration significantly decreased survival across all tumor thicknesses.
Clinicians can inform follow-up recommendations by better understanding the patterns and risks of melanoma recurrence, according to researchers. – by Abigail Sutton
Disclosures: von Schuckmann reports funding from NHMRC Postgraduate Scholarship 1133317. Please see the study for all other authors’ relevant financial disclosures.