The current melanoma staging system does not always reflect actual survival outcomes. In some cases, patients with thick but localized tumors have poorer long-term survival than those with melanoma that has spread to nearby lymph nodes, according to a large Swedish registry study from the University of Gothenburg.
Melanoma is the most serious form of skin cancer and affects around 5,000 people each year in Sweden. The disease is divided into stages intended to reflect how far the cancer has progressed and to guide treatment and follow-up. Typically, spread to the lymph nodes is considered a sign of more advanced disease.
However, the new study shows that patients with stage IIC melanoma, in which the tumor is thick but still confined to the skin, have poorer long-term survival than patients with stage IIIA melanoma, who have lymph node involvement.
"We see lower survival in the stage IIC group than in stage IIIA, even though the latter group has lymph node spread. This pattern remains even after adjusting for age, sex, and tumor thickness," says Michelle Marjanovic, a researcher affiliated with the Sahlgrenska Academy at the University of Gothenburg and a resident physician at Sahlgrenska University Hospital.
Follow-up in a new light
The study analyzed data from 5,815 adult patients with stage II and III melanoma in Sweden between 2001 and 2018. The researchers used information from several national health registries to follow patients over time.
Ten years after diagnosis, 61 percent of patients with stage IIC melanoma were alive, compared with 78 percent of patients with stage IIIA. The researchers also found that patients with stage IIC more often had other conditions, such as high blood pressure, type 2 diabetes, and cardiovascular disease, and on average had lower socioeconomic status.
The findings raise questions about current follow-up routines for melanoma patients. Today, patients with stage III melanoma are monitored more closely than those with stage II, even though long-term survival is, in some cases, worse in the stage IIC group.
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"Our results suggest that follow-up and risk assessment in melanoma may need to be revisited to better reflect the actual prognosis," says Michelle Marjanovic.
The study has been published in the scientific journal British Journal of Dermatology.
Article: Contrasting Survival Outcomes and Patient Characteristics in 5,815 Patients with Stage II and III Melanoma: A Nationwide Population-Based Registry Study from Sweden;
https://doi.org/10.1093/bjd/ljaf478
