Painful, blistering, or severe sunburns increased the risk of developing cutaneous squamous cell carcinoma in a meta-analysis of 17 studies involving more than 321,000 participants. The findings showed surprisingly modest increased odds, with any history of severe sunburn associated with a 38% higher risk of developing the skin cancer.
Medium and high frequencies of severe sunburns throughout a lifetime increased the odds of developing cutaneous squamous cell carcinoma (cSCC) by 51% and 69%, respectively. Childhood sunburns showed the highest threat, with high frequencies of severe sunburns in childhood linked to more than 3-fold higher odds of developing the cancer, wrote lead study researcher Isaac Weber, MD, University of Texas MD Anderson Cancer Center, and colleagues.
A dose-response relationship emerged between sunburn history frequency per decade. The study found no significant association between undefined sunburns and cSCC risk. Only painful, blistering, or severe sunburns showed statistically significant relationships with cancer development.
An accompanying editorial noted the modest effect sizes may be surprising and highlighted measurement challenges in sunburn research. Self-reported sunburn frequency demonstrates only weak to moderate reliability, with validation studies reporting reliability values as low as 49%, wrote editorial authors Dr. Adewole Adamson, University of Texas at Austin and Dr. Howa Yeung, Emory University School of Medicine.
The researchers noted limitations including inconsistent adjustment for skin phenotype across studies. Many studies provided only unadjusted data, which constrained the ability to perform universal statistical adjustment. The measurement of sunburn also presented challenges due to different recording practices across studies.
These findings align with existing research on basal cell carcinoma, where severe sunburns show similar associations with increased cancer risk. The results highlight the role of acute ultraviolet (UV) exposure in cSCC development, beyond the established connection to chronicUV exposure.
Despite the modest effect sizes, sunburns remain an important modifiable risk factor forcSCC and other skin cancers, especially in children with fair skin types. Public health interventions on counseling children, adolescents, and young adults on minimizing UV radiation remain crucial for prevention, as sun protection behaviors can have long-term implications for skin cancer.
The research was supported by the Cancer Prevention and Research Institute of Texas and the National Cancer Institute. The authors reported no conflicts of interest.
Source: JAMA Dermatology
