Can you sunbathe if you're undergoing cancer treatment?

The rules for safe sun exposure (avoiding the middle of the day and always wearing a high-level sunscreen) apply to everyone. But cancer patients, especially those taking chemotherapy or complementary medications that increase sun sensitivity, need to be extra careful. In fact, according to experts, in some cases, sun exposure should be avoided altogether. Here's what you need to know.

Chemotherapies that make you more sensitive to UV rays

"When we talk about cancer patients and sun exposure, there are two considerations to make," Mario Mandalà , professor of Medical Oncology at the University of Perugia and director of the Medical Oncology Unit at the Santa Maria Misericordia Hospital in the same city, explains to Oncoline. "On the one hand, some drugs are photosensitizing, such as 5-fluorouracil, anthracyclines, and methotrexate, three traditional chemotherapy drugs." This means that the skin of a patient treated with one of these drugs, and in general with any photosensitizing drug, is more sensitive to solar radiation, especially ultraviolet radiation, and will therefore burn more easily.

No sun in case of skin toxicity and radiotherapy

"On the other hand," the expert continues, "we also have patients treated with drugs that cause skin toxicity, such as anti-EGFR drugs." These drugs block the epidermal growth factor receptor (EGFR), which plays a key role in cell division and survival. In some tumors, the gene encoding EGFR can be mutated, leading to overexpression of this receptor, which stimulates tumor cells to grow and proliferate uncontrollably.

"The side effects of anti-EGFR drugs can manifest as the appearance of skin pustules or other skin lesions," Mandalà explains, "and to limit them, antibiotics such as tetracyclines are often used, which, however, are also photosensitizing. Even in this case, it is necessary to completely avoid sun exposure."

Patients receiving radiation therapy should also avoid sun exposure, the oncologist emphasizes, since exposure to ultraviolet rays can increase the toxicity of the therapy on the skin.

Can people undergoing immunotherapy sunbathe?

What do we know about cancer patients being treated with immunotherapy drugs? Is it safe to expose themselves to the sun in these cases? "Generally speaking, with immunotherapy drugs, it is possible to expose oneself to the sun by following the general recommendations on photoprotection," Mandalà continues. That is, avoiding sun exposure during the central hours of the day (11 am - 5 pm) and always applying a high SPF of 50 or higher. However, the professor explains, similarly to what can happen with other anticancer drugs, some patients being treated with immunotherapy drugs can also develop skin toxicities that can be exacerbated by sun exposure. "Therefore, in the absence of skin toxicity, there are no absolute contraindications to exposure as long as general precautions are followed. However, if skin toxicities develop, or if radiotherapy is being administered concomitantly, exposure should be avoided."

How long can the photosensitizing effect last?

But how long can the photosensitizing effect of cancer treatments last? "It usually ends with medical treatment," Mandalà replies, "but it can last up to a few weeks after the end of therapy." Since different therapies can increase photosensitivity or cause skin toxicity, the expert concludes, it's always advisable to consult with your doctor, who knows your patient's clinical situation and can provide appropriate advice regarding sun exposure.