Ovarian cancer is the second most common cancer in women and fifth ranked cause of cancer deaths in the USA and Europe. The five-year survival is about 45%, mostly due to difficulty making an early diagnosis.
The incidence is latitude and sunlight dependent, with high negative correlations with lots of sun exposure and positive correlations with high latitude and thick ozone, which blocks vitamin D inducing UVB radiation. In other words, sunlight very likely helps prevent ovarian cancer.
What about treatment, not just prevention? What about women already diagnosed with ovarian cancer? Do low vitamin D levels mean you die earlier? What about low sun exposure? Remember, in most cases, any vitamin D such patients have in their blood came from sun exposure, so any relationship between vitamin D levels and survival are actually relationships between sun exposure and survival.
Dr. Malgorzata Walentowicz-Sadlecka at the Ludwik Rydygier Medical College in Poland looked at these very questions and studied 72 women with ovarian cancer, measuring their vitamin D levels before surgery, comparing their vitamin D levels to matched healthy controls and then looked at outcomes.
First, the ovarian cancer patients were 3.7 times more likely to be vitamin D deficient, with 43% having levels less than 10 ng/ml and 82% having levels less than 20 ng/ml. As obese patients were excluded, the vitamin D levels of average ovarian cancer patients would be even lower, as obesity is associated with low vitamin D levels.
Next, they looked at survival of those women with levels less than 10 ng/ml, comparing them to women with levels greater than 10 ng/ml. Not enough women had levels greater than 30 ng/ml to do a comparison over 30 ng/ml.
Women with the lowest levels lived an average of 28 weeks, while women with levels greater than 10 ng/ml lived a mean of 45 weeks. At five years, almost 50% of the women with higher levels were alive, while only 25% of the women with the lowest levels lived 5 years. We don’t know how long women with levels of 50 ng/ml would have lived.
While the authors recommended vitamin D supplementation for ovarian cancer patients, and I agree, again remember these women were probably not taking supplements and their vitamin D was probably from sunshine. If you have an internal cancer and want vitamin D to be a part of the equation, I think it’s best to get some sun exposure and not just supplements.