Sun and Cancer

In honor of Skin Cancer Awareness month, we are reviewing the effect of sunlight on human health and treatment of mesothelioma and lung cancers.

Effect of Sunlight on Human Health

Sunburn damages skin and can increase the rate of some skin cancers, whereas sunlight in moderation promotes a healthy glow in people. Sunlight exposure helps regulate our circadian rhythms (day-night cycle), hormone levels, and vitamin D levels. Humans need 5 minutes of exposure to sunlight in their eyes to maintain the day-night cycles coordinated by the pineal gland. The pineal gland produces higher quantities of melatonin in the evening which helps regulate the circadian rhythms, the immune system, and hormone levels.

Secondly, sunlight on our skin initiates the production of active vitamin D. UV-B waves of sunlight help convert active vitamin D from skin into the blood, where the body can absorb the health benefits. Note that exposure to solely UV-A light, which passes through glass (UV-B light does not pass through glass), can degrade vitamin D1 and folate (essential vitamin B9) in the body.³ Low vitamin D levels are associated with the flu season and the development of some types of cancer including lung cancer. Low vitamin D has not been shown to be associated with mesothelioma initiation or progression yet.

Sunlight and Chemotherapy

Some chemotherapeutic agents increase the sensitivity of the skin to sun damage which is called photosensitivity. Some but not all chemotherapeutic agents increase sensitivity to sunlight; in other words, people treated with these compounds get sunburn much faster than they normally would without the treatment. Because chemotherapy damages rapidly dividing cells such as those in the skin, chemotherapeutic treatments may reduce the skin’s ability to heal.

Treatment of Mesothelioma: Many doctors use a combination of Pemetrexed (Alimta) and Cisplatin; pemetrexed and carboplatin; or cisplatin with gemcitabine to treat mesothelioma. Alternatively, some physicians may treat mesothelioma with one or more of the following: cyclophosphamide, doxorubicin, epirubicin, methotrexate, mitomycin, and/or vinorelbine.

Chemotherapy Treatment of Lung Cancer: Depending on the health of the patients, most oncologists administer combinations of two chemotherapeutic agents during a cycle. Common combinations use cisplatin or carboplatin with one of the following drugs: docataxel, etoposide, gemcitabine, innotecan, paclitaxel, pemetrexed, or vinorelbine.⁵ Other combinations can be used also.

Photosensitivity symptoms are usually itching first, followed by redness, swelling, breaking of the skin, and symptoms may progress to oozing.

Chemotherapeutic agents that can cause photosensitivity (less time to sunburn) include methotrexate, mitomycin, and vinblastine.

Other drugs that cause photosensitivity: Some drugs that reduce side effects or treat accompanying diseases can make patients very sensitive to sunburn.⁶ They include several antibiotics (ciproflaxin, doxycycline, levoflaxin, sulfamethoxane, trimethoprim, cotrimazole, tetracycline); antihistamine (diphenylhydramine (Benadryl)); cardiac medications (amiodarone, dittiazem, nifedipine, quinidine); diabetic drugs (sulfonylureas); and several pain medications (naproxen, piroxicam).

Tips to Help Reduce Symptoms of Photosensitivity

1. Ask your oncologist and pharmacist if any of the treatment drugs make you more sensitive to sun. If so, wear long sleeve shirts, long pants and a hat.
2. Go outside earlier in the morning (before 10am) and later in the day (after 3pm) to reduce the intensity of sunlight exposure.
3. Many groups suggest using sunscreen (SPF15 or higher) to lessen the effects of sunlight on your skin. Lip balm that contains a sunscreen (SPF15 or higher) can help protect your lips.

Source: http://www.mesothelioma.com/blog