Updated Staging Manual Better Predicts Outcomes of Melanoma
NEW YORK (Reuters Health) – The eighth edition of the American Joint Committee on Cancer staging manual (AJCC8) outperforms the previous AJCC7 in predicting relapse-free survival (RFS) and overall survival (OS) in patients with melanoma, researchers report.
“We tried to address a controversial argument of whether the revised AJCC 8th Edition improves prognostication for melanoma patients or adds unnecessary complexity amidst active clinical trials for this disease,” said Dr. Iman Osman of NYU Langone School of Medicine, in New York City.
“I believe the debate was important to address, and the results reveal the importance of continuing to rigorously assess available data in order to reduce confusion in the field, as well as reach a consensus regarding the critical components of melanoma staging,” told Reuters Health by email.
Dr. Osman and colleagues assessed primary tumor and nodal classification of 1,315 patients with stage-I-III melanoma using AJCC7 and AJCC8 to assign disease stages at diagnosis and then compared their RFS and OS, as well as the discriminatory prognostic ability of the two staging manuals.
Stage-IIC patients exhibited significantly worse five-year RFS than did stage IIIA patients using both editions.
For stage-I patients, 27.8% of patients were assigned different sub-stages when using AJCC7 and AJCC8, principally because of the removal of mitotic index as a factor in determining T1 classification in AJCC8. The prognostic accuracy of AJCC7 and AJCC8 for RFS and OS did not differ significantly for stage-I patients.
Only two of 179 patients with stage-II disease were restaged according to AJCC8 (from IIB to IIA), but prognostic accuracy did not differ significantly between AJCC7 and AJCC8, the researchers report in the Journal of the National Cancer Institute.
There was 44.9% discordance in sub-stages for patients with stage-III disease. Overall, the prognostic accuracy of AJCC8 for RFS was significantly improved over that of AJCC7, and there was a nonsignificant trend towards improved prognostic accuracy for OS in AJCC8.
“Our data reproduce the added value of AJCC 8th Edition over the 7th Edition in predicting survival probabilities of melanoma patients in a representative, independent cohort at diagnosis, especially those with stage-III disease,” Dr. Osman said. “Therefore, we endorse its implementation for the most up-to-date and accurate baseline prognosis and hope that physicians and researchers will consider this data in practice in order to continue improving upon this most recent edition.”
“Some patients with thick ulcerated melanoma (stage IIC) can do worse than patients with thin melanoma and lymph node metastases (stage IIIA),” he added. “This is a counter dogma to the fundamentals of the TNM staging system, where lymphatic spread is considered worse. This is an active area of research in melanoma, and it speaks to the need to consider systemic modifications in the impending AJCC 9th Edition that need to address persistent deficiencies.”
Dr. David E. Elder of the Hospital of the University of Pennsylvania, in Philadelphia, who co-authored a linked editorial, told Reuters Health by email, “Clinical trials done under the two systems can be reliably compared.”
“Algorithmic methods that may enhance the utility of staging for patient management are under development,” he said. “Novel staging attributes should not be put into general use until appropriate validation has been done, and this may require funding dedicated for this purpose.”
SOURCE: https://bit.ly/383oW1o and https://bit.ly/376PSft Journal of the National Cancer Institute, online January 24, 2020.