Although Melanoma is the most serious skin cancer, most patients have a high probability of survival. New searches have now identified a subset of patients with early-stage disease who have a very low risk of death from the disease.
In a cohort of 11,594 patients, the overall 7 -year melanoma death rate was 2.5%, but the risk in a 25% subgroup of patients was less than 1%.
In contrast, the study authors also identified a small subset of high-risk patients, for whom the risk of death is greater than 20%.
Although more data is needed and the results need to be confirmed in other studies, it may be more appropriate to use a different term, such as «low-malignant potential melanocytic neoplasm,» which could also help begin to solve the problem of overdiagnosis, the authors note.
«Although the topic of very low-risk melanomas has been presented at national and international congresses, formal discussions to define the classification of ‘low malignant potential melanocytic neoplasms’ are currently lacking,» says first author Megan M.Eguchi, MPH, Department of Medicine, University of California, Los Angeles. «The criteria will have to be established through study drawings in addition to those available using SEER data.»
He points out that currently the authors do not propose any modification of the treatment of these lesions, but only a change in terminology. «A diagnosis of melanocytic neoplasm of low malignant potential (MNLMP) rather than ‘melanoma’ could potentially alleviate patients’ fears about prognosis and begin to address the problem of overdiagnosis,» says Eguchi.
Although melanoma is considered the most common life-threatening skin cancer, the prognosis is often very good for individuals with stage T1 cancer, the lowest risk category. The authors note that prognostic modelling was used to predict the survival of melanoma patients and identify prognostic variables; the most important attributes are Breslow thickness and primary tumor ulceration, which form the basis of the current staging system of the American Joint Committee on Cancer (AJCC).
There is evidence that the increased incidence of melanoma is due in part to overdiagnosis, i.e. the diagnosis of lesions that will not cause symptoms or death.The authors write that their aim was to identify lesions currently diagnosed as melanoma, but which may not possess the ability to metastasize, cases that could potentially fall under the phenomenon of overdiagnosis.
The researchers analyzed information available in the U.S. database Surveillance, Epidemiology, and End Results (SEER) and identified 11,594 patients diagnosed in 2010 and 2011 with a stage I melanoma ≤1.0 mm thick that had not spread to the lymph nodes. Prognostic models of the risk of death from melanoma of patients with low-risk melanoma were developed, and subsequently the ability of the models to identify subsets of very low-risk patients, with melanoma-specific survival higher than the overall survival for stage T1, was evaluated.
The median age of patients was 58 years, median Breslow thickness was 0.45 mm (interquartile range, 0.30–0.65 mm), and 71% of patients were assigned stage IA.Ulceration was present in 4% of cases, 27% were mitogenic and 45% were Clark II level; Within this cohort, 292 patients (2.5%) died from melanoma within 7 years. In the training set, 177 patients out of 7,652 (2.3%) died from melanoma within 7 years; The numbers were similar in the test set (testing set; 115 patients out of 3,942; 2.9%).
Overall, investigators identified 3 large subgroups of patients who fell within the AJCC seventh edition stage I classification («thin») for melanoma, who had a risk of death of approximately less than 1%. A clear improvement over the overall sample rate was observed. In the simplest model (Model 1A), patients younger than 70 years of age at diagnosis with Clark II level invasion were considered very low-risk patients.
In Model 1B, the same initial classification was used, but was further refined and limited to patients aged 43 years or younger or 44–69 years with a Breslow thickness <0.40 mm.After 10 years of diagnosis, this subgroup also had a less than 1% risk of death from melanoma. The logistic regression model (Model 2) was similar, identifying approximately 25% of patients with an expected risk of death of less than 0.5% including age, sex, mitogenicity, Clark's level, and ulceration of patients. Model 2 was also able to further identify a small subset of patients with no deaths.
The logistic regression model was also able to identify a very small subset of patients (0.7% and 0.8%) who had a risk of death greater than 20%, significantly higher than most patients with stage T1b cancers.
The article is an adaptation of the original, written by Roxanne Nelson, appeared on Medscape.com, part of Medscape Professional Network.
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Source — https://www.univadis.it/viewarticle/un-sottogruppo-di-pazienti-con-melanoma-presenta-un-rischio-molto-basso-di-mortalita