CHICAGO – , according to a new analysis of the National Cancer Institute SEER database between 1975 and 2019.
“This is very encouraging data and represents the real-world effectiveness of these therapies. The cost of these therapies can be prohibitive for universal treatment access, so the ways to address the accessibility of these treatments and the health care costs need to be supported,” said lead author Navkirat Kaur Kahlon MD, a hematology/oncology fellow at the University of Toledo (Ohio). The study was presented at the annual meeting of the American Society of Clinical Oncology.
According to the American Cancer Society, the 5-year mortality for regional melanoma metastasis is 68%, and 30% for distant metastasis. However, these numbers may underestimate current survival. “People now being diagnosed with melanoma may have a better outlook than these numbers show. Treatments have improved over time, and these numbers are based on people who were diagnosed and treated at least 5 years earlier,” the American Cancer Society wrote.
Other studies have found similar trends. According to Cancer Research UK, 5-year melanoma skin cancer survival approximately doubled, from 46% to 90%, between 1971 and 2010. And, 1-year survival increased from 74% to 96%, but these improvements predated immune checkpoint inhibitors. An analysis of the Canadian Cancer Registry and Canadian Vital Statistics found an increasing incidence of melanoma, but a drop in mortality since 2013. A study of melanoma outcomes in Hungary also found increased incidence, while mortality declined by 16.55% between 2011 and 2019 (P =.013).
“These new drugs, which include immunotherapies and targeted therapies, are effective treatments in the clinical trial data, so the magnitude of drop seen in population mortality was not surprising but very exciting,” Dr. Kahlon said.
The findings are encouraging, but prevention remains the most important strategy. “The utility of sun-protective strategies and policies should be encouraged,” she added.
Cytotoxic chemotherapy has poor efficacy against metastatic melanoma, but novel therapies such as checkpoint inhibitors increased expected survival from months to years. “Given the magnitude of benefit compared to traditional chemotherapy in clinical trials, we decided to see if the real-world population is deriving the same benefit,” Dr. Kahlon said.
The researchers found that the annual percentage change (APC) melanoma mortality rate (MMR) was +1.65% between 1975 and 1988 (P < .01). The APC was 0.01% between 1988 and 2013, which was not statistically significant (P = .85). Between 2013 and 2017, APC was –6.24% (P < .01), and it was –1.56% between 2017 and 2019 (P = .53).
The increase in melanoma mortality between 1975 and 1988 may be due to changes in the way that SEER data was collected. “It is possible that this increase was at least in part due to better capturing of the data. There may also be a contribution of increased mortality due to increased incidence of diagnoses related to increased UV exposure. From the 1920s, increased sun exposure and bronzed skin became fashionable. In the 1940s-1960s, tanning oils and lotions became more popular, and there may have been an increase in UV exposure during that time, which later led to an increase in diagnosis and, without effective therapies, mortality. Further, the use of indoor tanning beds from the 1970s onward may have contributed to increased UV exposure, incidence, and mortality,” she said.
On the other hand, the researchers noted a slowing of mortality reduction between 2017 and 2019. This was not a surprise, Dr. Kahlon said, since by that time most novel therapies were being introduced in the adjuvant setting. “The mortality benefit, if any, from adjuvant treatments is seen over a longer period and may not yet be captured in SEER data. Even the clinical trial data for most of these treatments have not shown an overall survival advantage and require more time for the data to mature. It will be interesting to see how these trends change in the near future,” Dr. Kahlon said.
The study was limited by its retrospective nature. Dr. Kahlon has no relevant financial disclosures.