Researchers identified a subset of patients who had early-stage melanoma with almost no melanoma-related deaths, potentially representing cases contributing to overdiagnosis, according to a new study published by Eguchi et al in Cancer. The findings may help clinicians determine which patients have a low risk of mortality from melanoma after growth removal.
Although melanoma is the most serious type of skin cancer, most patients have a high chance of survival. There is evidence that many cases of melanoma are being overdiagnosed in patients who will never experience symptoms.
For the study, researchers analyzed data on patients who were diagnosed in 2010 and 2011 with stage I melanoma that was 1.0 mm or less in thickness and had not spread to the lymph nodes. They developed models to identify patients with a low risk of mortality from melanoma 7 years following diagnosis as well as those at higher risk of mortality.
Among the 11,594 cases examined, the overall 7-year rate of mortality from melanoma was 2.5%. However, the models identified a subset of 25% of patients from the large cohort with risk below 1%. These patients tended to be younger, and their cancers exhibited minimal dermal invasion. A subset of patients smaller than 1% of study participants, who skewed older and had slightly more advanced tumors—although considered low risk by current criteria—had a greater than 20% risk of mortality and could be considered for more complex, potentially life-saving therapy.
The findings also showed that the subset of patients who had a low risk of mortality could be identified using standard risk factors. Researchers hope that the study's findings could be used as a starting point for future research using additional study designs and variables to further improve this classification.
"Given the very low risk of death from melanoma associated with some of the cases identified in this study, and if these findings can be verified and perhaps extended in other studies, the use of a different term such as 'melanocytic neoplasm of low malignant potential' may be more appropriate than that of melanoma, as has been done with some other neoplasms or tumors formerly labeled as cancers," said David E. Elder, MBChB, FRCPA, Professor of Pathology and Laboratory Medicine at the Hospital of the University of Pennsylvania. "Such a term may potentially alleviate people's concerns related to prognosis and outcomes and begin to address the problem of overdiagnosis."
Disclosure: For full disclosures of the study authors, visit acsjournals.onlinelibrary.wiley.com.
