Yes, radiation can cause skin cancer. Both ultraviolet radiation from sunlight and ionizing radiation from medical treatments or other sources can damage DNA in skin cells in ways that lead to cancer, sometimes decades after the initial exposure. The type of radiation, the dose, and the age at which you’re exposed all influence how much your risk increases.
How UV Radiation Damages Skin Cells
Ultraviolet radiation from the sun is the most common radiation-related cause of skin cancer worldwide. When UV rays penetrate your skin, they directly damage the DNA inside cells by fusing together neighboring molecules in the DNA strand. These fused pairs, called pyrimidine dimers, are the primary lesion responsible for UV-induced skin cancer. Your cells have repair systems that can fix this damage, but the repairs aren’t always perfect.
The problems compound over time. When a damaged section of DNA isn’t repaired correctly, the cell copies the error during its next division. UV radiation also causes indirect damage through oxidative stress, where reactive molecules attack DNA bases and introduce additional mutations. A single bad sunburn doesn’t typically cause cancer on its own. Instead, mutations accumulate over years or decades of repeated exposure until a cell acquires enough errors to grow uncontrollably. This is why skin cancers often appear in your 50s, 60s, or later, on areas of skin that have had the most cumulative sun exposure.
Skin Cancer Risk From Radiation Therapy
Medical radiation therapy uses much higher-energy ionizing radiation than sunlight, and it carries a measurable risk of secondary skin cancers in the treated area. A large study of Hodgkin lymphoma survivors found they were diagnosed with basal cell carcinoma at 5.2 times the rate of the general population. For those treated before age 35, the risk jumped to 8 times higher. The risk didn’t fade with time. It actually climbed, reaching nearly 16 times the general population rate after 35 years of follow-up.
Most of the secondary skin cancers (57%) developed within the radiation field, the area of skin that the treatment beam passed through. Patients who received radiation therapy had roughly 2.75 times the risk of developing a skin cancer compared to those treated with chemotherapy alone. Basal cell carcinoma was the most common type, but squamous cell carcinoma and, less commonly, more aggressive cancers like angiosarcoma can also develop in previously irradiated skin.
Radiation-induced angiosarcoma is rare, occurring in about 0.1% of patients after breast-conserving therapy, but it’s particularly dangerous because it often looks like a harmless skin change from the original treatment. This resemblance to benign post-radiation skin changes frequently delays diagnosis. The typical latency period is at least three to five years after radiation, though it can take much longer to appear.
Children Face the Highest Risk
Age at the time of radiation exposure matters enormously. Childhood cancer survivors who received radiation therapy are among the most affected groups. One study found that survivors who developed basal cell carcinoma were 30 times more likely to get it compared to the general population. Their risk of squamous cell carcinoma was about 7 times higher, and melanoma risk was roughly doubled.
Prior radiation therapy to the skin was the strongest driver, increasing basal cell carcinoma risk more than 14-fold. The greater the surface area of skin exposed to the radiation beam, the higher the risk climbed. Children’s cells divide more rapidly than adults’, which means DNA damage has more opportunities to be copied and passed along to new cells before repair mechanisms can catch it. This is why pediatric cancer survivors need long-term skin monitoring well into adulthood.
Is There a Safe Dose?
The German Commission on Radiological Protection has reviewed the evidence and found that skin cancer risk does not appear to increase at radiation doses below 0.5 Gray (Gy). For context, a single CT scan delivers far less than this to the skin, and a typical course of radiation therapy delivers 40 to 70 Gy to the targeted tumor area, with surrounding skin receiving variable but often significant doses. The risk is clearly dose-dependent: more radiation to the skin means more DNA damage and a higher chance of a future cancer developing in that area.
CT Scans and Diagnostic Imaging
The radiation doses from CT scans are far lower than therapeutic radiation, but they aren’t zero. A 2024 analysis estimated that the 93 million CT scans performed in the United States in 2023 could eventually lead to about 103,000 future cancers across the population. If current imaging trends continue, CT scans might account for roughly 5% of all new cancer diagnoses in the U.S. per year, a population-level risk comparable to alcohol consumption or excess body weight.
The most commonly projected cancers from CT scans were lung and colon cancers rather than skin cancer, largely because abdominal and pelvic scans (which deliver higher doses to internal organs) made up the largest share of projected cases. Children are more vulnerable per scan than adults, with the highest projected risk in children under one year old. For any individual patient, the added cancer risk from a single medically necessary CT scan is small, but it’s a factor worth considering when scans are repeated frequently or ordered without clear clinical need.
Airline Crew and Cosmic Radiation
Pilots and flight attendants are exposed to elevated levels of cosmic radiation at cruising altitude, and studies consistently show they have higher rates of melanoma and other skin cancers than the general population. The CDC acknowledges this increased risk but notes that the exact cause isn’t fully established. Cosmic radiation is one plausible contributor, but flight crews also experience disrupted sleep cycles and may have different sun exposure patterns during layovers in sunny destinations. Separating the contribution of cosmic radiation from these other factors has proven difficult.
How Modern Radiation Therapy Reduces Risk
Radiation technology has improved significantly over the past two decades. Older techniques used broad beams that exposed large areas of healthy skin and tissue to radiation. Modern approaches like intensity-modulated radiation therapy (IMRT) and image-guided radiation therapy (IGRT) shape the beam more precisely to the tumor, reducing the dose that surrounding skin receives.
In a study of breast cancer patients, those treated with IGRT had significantly less severe skin reactions than those treated with IMRT. Only 14% of IGRT patients developed moderate skin inflammation compared to 25% of IMRT patients, and none of the IGRT patients experienced severe reactions. Less acute skin damage generally correlates with lower long-term risk, though secondary cancers take decades to develop, so long-term comparative data on newer techniques is still accumulating. The treatment technique was the single strongest predictor of skin toxicity severity, more influential than patient age, breast size, or other factors.
These improvements don’t eliminate secondary cancer risk entirely, but they meaningfully reduce the amount of radiation healthy skin absorbs. If you’re undergoing radiation therapy, the treatment area of your skin should be monitored periodically for new or changing lesions for years afterward, particularly if you were treated at a young age or received radiation to a large body surface area.