Low fat diet may prevent breast cancer

A low-fat diet probably does help reduce the risk of breast cancer, according to a lead researcher for the Women's Health Initiative (WHI) dietary modification trial.
In the study of approximately 49,000 women, breast cancer rates were 9% lower in those who were taught to eat a lower fat-diet than in the comparison group. The original hypothesis was based in part on findings of breast cancer rates that are up to five-fold higher in nations with high-fat diets, such as the United States, compared with those with low fat diets.
A report on the study in the February 8, 2006 JAMA said the low-fat diet did not result in a statistically significant reduction in breast cancer risk.
The researchers indicated that the benefit may not have reached a level of greater significance because dietary fat intake was not low enough in the dietary change group or that the follow-up period was not long enough.
WHI researcher Ross Prentice, PhD, said "We see a greater evidence of reduction in breast cancer risk among the group that started higher [in dietary fat] and made a bigger change. So these are data that you would not expect to see if the intervention was doing nothing relevant to breast cancer risk."
The risk of coronary heart disease was also assessed, and the low-fat diet did not significantly reduce the risk. However, the study did not target specific kinds of fat. "Saturated fat did not command the greatest attention in terms of the overall intervention," said Linda Van Horn, PhD, RD, who noted the first goal was to assess the impact of overall fat reduction on breast cancer. In addition, she noted there was no focus on trans fats because little was known about them at the time the research was conducted.

Types Of Breast Cancer

Your doctor suspects that you have breast cancer. To confirm the diagnosis, a pathologist analyzes a tissue sample (biopsy) taken from the lump or suspicious area in your breast. This will tell if you have cancer or some other, benign condition. If the biopsy does show cancer, the results provide your doctor with information about the type of breast cancer and help determine treatment options.
The biopsy results appear on a pathology report, which provides detailed information including the type of breast cancer, if it's invasive or noninvasive, the tumor grade — how closely the cancer cells resemble normal tissue — if the cancer is sensitive to hormonal therapies and if it has too much of a protein called HER-2.
Sophisticated lab tests can also analyze breast cancer tissue for molecular and genetic features of breast cancer cells. Understanding all these aspects of a cancer helps your doctor tailor your treatment plan.
Common types of breast cancer
The most common types of breast cancer begin either in your breast's milk ducts (ductal carcinoma) or in the milk-producing glands (lobular carcinoma). The point of origin is determined by the appearance of the cancer cells under a microscope.
In situ breast cancerIn situ (noninvasive) breast cancer refers to cancer in which the cells have remained within their place of origin — they haven't spread to breast tissue around the duct or lobule. The most common type of noninvasive breast cancer is ductal carcinoma in situ (DCIS), which is confined to the lining of the milk ducts. The abnormal cells haven't spread through the duct walls into surrounding breast tissue. With appropriate treatment, DCIS has an excellent prognosis.
Invasive breast cancerInvasive (infiltrating) breast cancers spread outside the membrane that lines a duct or lobule, invading the surrounding tissues. The cancer cells can then travel to other parts of your body, such as the lymph nodes.
§ Invasive ductal carcinoma (IDC). IDC accounts for about 70 percent of all breast cancers. The cancer cells form in the lining of your milk duct, then break through the ductal wall and invade nearby breast tissue. The cancer cells may remain localized — staying near the site of origin — or spread (metastasize) throughout your body, carried by your bloodstream or lymphatic system.
§ Invasive lobular carcinoma (ILC). Although less common than IDC, this type of breast cancer invades in a similar way, starting in the milk-producing lobules and then breaking into the surrounding breast tissue. ILC can also spread to more distant parts of your body. With this type of cancer, you typically won't feel a distinct, firm lump but rather a fullness or area of thickening.