Cancer scares me. It really scares me. That is one of the fundamental reasons that I eat mostly organic and live chemical-free as much as possible. Now I have learned that one of the most unpleasant potential outcomes of obesity is cancer. And my concern grows. I wonder if I have increased my risk owing to all those years that I was morbidly obese? I question if being overweight puts me at increased risk still? As it turns out, the research data unfortunately show that I have cause for concern.
Obesity increases the risk for cancer of the esophagus, pancreas, colon, kidney, thyroid, and breast. The statistics are cause for great concern:
A 2007 estimate of obesity-related cancer in the United States projected 34,000 new cases in men and 50,500 new cases in women.
An additional 500,000 cases are projected in the United States by 2030.
If every adult were to reduce their body mass index by just on percent, the increase in cancer cases would halt and actually prevent 100,00 of those cases.
Obesity and the Risk of Breast Cancer
Postmenopausal women who gain more than sixty pounds in adulthood
are three times more likely to get the most severe types of breast cancer compared to peers who gain twenty pounds or less. The greater the weight gain the greater the risk for cancer. Women who are obese at the time of their diagnoses are five times more likely to die even if they are diagnosed while in the early stages.
The Role of Estrogens
Studies have discovered that women with a body mass index of thirty or more had estrogen concentrations that were between sixty percent and two hundred nineteen percent higher than those in thin women. The risk for breast cancer increased about eighteen percent for every five point increase in body mass index. When adjustments were made for specific types of estrogen, the breast cancer risk associated with each increase in body mass index fell from eighteen percent down to two percent.
This increase of estrogen in obese postmenopausal women is believed to promote an increased risk for breast cancer. Ovaries stop producing hormones after menopause and fat tissues then become the most important source of estrogen. Obese women have more fat tissue. This in turn leads to higher estrogen levels which can lead to a more rapid of breast tumors that are responsive to estrogen.
Obesity and the Recurrence of Breast Cancer
A study recently published in the journal Cancer states that obese women have a higher rate of recurrence of breast cancer than do women of normal weight. Furthermore, the study notes that women who are merely overweight also have a higher rate of recurrence than do normal weight women.
The study involved a review of data for 6,885 patients who had stage one, two, or three cancer. Outcomes for obese or overweight women were compared against outcomes for normal weight women.
An eight follow up recorded a one in four rate of recurrence and 891 deaths. 695 of the reported deaths were the result of breast cancer. The strongest link between excess weight and recurrence of cancer or death from cancer was found to be among women with estrogen receptor positive breast cancer.