Marin County cancer, vitamin D link cheered as progress

This summer, when news hit the airwaves about a new study probing the link between Vitamin D and breast cancer in women in Marin County, confusion ensued.

According to some reports, the study published in the Journal of the American College of Surgeons broke new ground and suggested a clear connection between the vitamin and the disease. But other reports were more equivocal.

The study involved a sample of 338 Marin women, and linked a higher risk for breast cancer with a certain type of VitaminD receptor, not necessarily Vitamin D blood levels.

It indicated that any potential relationship between these two factors is not strong, only apparent.

Finally, the study validated previous efforts — most of which were coordinated under the county-sponsored Marin Women's Study — that already had determined that some types of Vitamin D receptors are associated with higher rates of breast, prostate and colon cancer.

"People were so interested in making this clinically meaningful, they neglected to take a step back and take a closer look," said Dr. Leah Kelley, medical director of the breast cancer program at Marin General Hospital in Greenbrae. "When it comes to cancer, which affects everyone, it's amazing how easy it is to say something that's almost true but not quite right."

Here in Sonoma County, doctors and patients alike said that regardless of how the study was portrayed, news of the development was perceived as a small victory, another step on the long road to finding a cure.

Dr. Amy Shaw, director of the primary-care oncology and survivorship program at Redwood Regional Medical Group in Santa Rosa, said that at the very least, findings of the Marin research should prompt greater numbers of local women to increase consumption of VitaminD, just to be safe.

"We already know that Vitamin D is an essential nutrient for bone health, so there is already a proven reason to promote vitamin D supplementation," Shaw said. "Since moderate doses of Vitamin D appear to be safe, I see no reason not to recommend it."

Tina Luster, communications manager for Sonoma County Tourism and a breast cancer survivor herself, agreed, adding that simply raising awareness about potential causes is worth celebrating.

"When I had the disease 18 years ago, breast cancer was never talked about and was seen as a death sentence for a lot of women," said the 50-year-old Luster, who beat ovarian cancer five years after conquering breast cancer. "The fact that it's now so out in the open, that a study like this might prompt people to change their habits, demonstrates how far we've come."

Elsewhere around the Bay Area, researchers have taken the opportunity to use the Marin study as an educational tool about other modifiable risk factors.

Dr. Elad Ziv, associate professor in residence at the UCSF School of Medicine, said women should be aware that imbibing two or more drinks of alcohol per day has been associated with increased risk of breast cancer. He also warned against hormone-replacement therapy

(HRT)

, a controversial treatment that some doctors won't even allow.

"(HRT) has been associated with increased risk of breast cancer," he wrote in an email earlier this month. "The Marin Women's Study has documented that since the use of these medications has dropped, the risk of breast cancer has also decreased."

Kelley, the cancer doctor from Marin General, agreed, and noted that scientists here in the Bay Area and elsewhere are still investigating potential contributing factors related to genetics, environment, diet and exercise.

With the Journal of the American College of Surgeons study added to the mix, she added, researchers likely will continue to parse through data from the Marin Women's Study to establish newer and more concrete links.

"Obviously, the hope is that someday we can figure out what causes these links and move from there into prevention or a possible cure," Kelley said. Until then, data collection will continue.

The Marin Women's Study is part of an ongoing breast cancer project from the Marin County Department of Health and Human Services. Between its launch in 2006 and 2010, the effort has established a database focusing on health and risk factor data, genetic variables, hormone levels and mammographic breast-density measurements of 14,000 Marin County women.

For more information, visit www.marinwomensstudy.org.