Ms. Navratilova has Ductal Carcinoma in Situ (DCIS). Sounds scary, and all cancer is, but DCIS is really a diagnosis of cancer before it starts to invade tissues outside the milk ducts of the breast. It is a cancer that really can only be discovered by imaging, usually by mammography since at this early stage it is rarely large enough to feel on examination. Ms. Navratilova probably got lucky, given that she tells us that she had not had a mammogram for four or five years prior to the one that discovered her cancer. Breast cancer tends to be a slowly developing disease, which is one of the reasons that mammography is so effective. The cancer often develops in the milk ducts, and when it is limited only to the duct itself, and has not invaded through the duct wall and into the surrounding breast tissues it is called “in situ.” In situ is defined as, “situated in the original, natural, or existing place or position” at dictionary.com . THe good news for Martina is that it is almost universally cured with treatment. Treatment is usually local surgical excision (lumpectomy) and radiation therapy, or by mastectomy without radiation therapy. Although lumpectomy and radiation therapy has a slightly higher local recurrence rate than mastectomy survival rates are similar.
The American Cancer Society has a nice discussion of DCIS. It reads as follows:
Ductal carcinoma in situ
Ductal carcinoma in situ (DCIS; also known as intraductal carcinoma) is the most common type of non-invasive breast cancer. DCIS means that the cancer cells are inside the ducts but have not spread through the walls of the ducts into the surrounding breast tissue.
About 1 in 5 new breast cancer cases will be DCIS. Nearly all women diagnosed at this early stage of breast cancer can be cured. A mammogram is often the best way to find DCIS early.
When DCIS is diagnosed, the pathologist (a doctor specializing in diagnosing disease from tissue samples) will look for areas of dead or dying cancer cells, called tumor necrosis, within the tissue sample. If necrosis is present, the tumor is likely to be more aggressive. The term comedocarcinoma is often used to describe DCIS with necrosis.
It is not clear from what I can find whether Ms. Navratilova has comedocarcinoma or a less aggressive type of DCIS, but regardless she has a great prognosis. Score one success for mammography.
Of note Ms Navratilova fits some but not all of the typical risk factors for breast cancer. At 55 years old she is clearly in the age range at risk. Breast cancer incidence increases with age. She certainly is not obese and has had no lack of physical exercise, but women who have not had children are a slightly higher risk for breast cancer as are women who have not breast fed an infant, so Ms. Navratilova fits those aspects of a high risk profile. Family history and estrogen use, either as oral contraceptives or postmenopausal hormone replacement therapy, are also risk factors.