The 5-year survival rate over the time period was just 33.8%, the study found.
Skin cancer incidence in the United States rose steadily between 1973 and 2015, according to a new report, particularly among men, White individuals, and people over the age of 65. Over the 4-decade study period, skin cancer rates increased by 2.8% each year.
The study, published in International Journal of General Medicine, is based on an analysis of the Surveillance, Epidemiology, and End Results (SEER) database.
The authors noted that studies from around the world have suggested that rates of skin cancer are increasing and that this problem is confounded by the high rate of recurrence among patients with cancer. Despite a significant amount of existing research, the investigators said little investigation has been conducted into long-term skin cancer occurrence and survival trends in America. They therefore sought to use the SEER database to find out whether trends in the United States are similar to those in other countries and regions.
The investigators identified cases in the database in which skin cancer was pathologically confirmed and demographic data were available. Patients were excluded if their skin cancer was nonmalignant or if their records had incomplete data.
Overall, 3551 cases of skin cancer were identified, and 1080 of the patients died from their cancer. After adjusting for age, the authors found an overall incidence of 27.9 cases per 100,000 people in 2015 vs 7.4 per 100,000 cases in 1973. Both men and women saw significant annual percentage changes, although the increase was more pronounced in men than in women (3.1% vs 2.4%). Similarly, White individuals saw an increase from 8.1 cases per 100,000 in 1973 to 34.7 per 100,000 in 2015, an annual percentage change of 3.1% vs just 0.3% in the Black population and 1.4% for other ethnicities.
Although the incidence of skin cancer changed over time, the investigators found that survival rates did not appear to correlate with the year a patient received their diagnosis. Overall, the 3-year survival rate was 51.4% in the patients studied, and the 5-year survival rate was 33.8%. Risk factors for mortality included being White, male, and older than 66 years, the analysis showed.
The authors said their analysis of trends in the United States aligns with reports from other regions, and they offered a few possible explanations for the increase in incidence.
“It might be the result of increasing awareness of physical examination, access to health care and screening methods, and cumulative intense and complex sunlight exposure,” they wrote.
The difference in incidence between males and females may be due to higher rates of sun exposure because of differing social norms or perhaps due to women paying greater attention to skincare and protection, the authors suggested. That White persons have a higher risk of skin cancer is not a new observation, the investigators said, as European ancestry and fair skin have long been established risk factors for skin cancer.
The investigators concluded that skin cancer prevention efforts should be tailored to the highest-risk groups.
“In view of the increasing incidence of malignant skin cancer and significant difference between sex and ethnicity, the main focus should be on men and White people,” they wrote. “Daily skincare protection and early clinical screening will be recommended to prevent malignant skin cancer.”
Zhu S, Sun C, Zhang L, Du X, Tan X, Peng S. Incidence trends and survival prediction of malignant skin cancer: a SEER-based study. Int J Gen Med. 2022;15:2945-2956. doi:10.2147/IJGM.S340620