By Richard L. Ellis, M.D.
& Laszlo Tabar, M.D.

This is partly understandable since breast cancer is a many-faceted, heterogeneous disease with varying histologic, mammographic, and clinic presentation resulting in an extremely variable outcome. But during the past 20 years, research clearly demonstrates that these different forms of disease can be most successfully controlled when the tumor is still localized to the breast at the time of diagnosis and treatment. We now know that the outcome of breast cancer will largely depend on the tumor size, axillary node status, and malignancy grade at the time of diagnosis and treatment. These features are the main prognostic factors physicians use to predict outcome for their patients.

Tumor size is commonly measured in millimeters for both the mammographic and histologic examination, and it can be considered as one of the most important prognostic factors. Generally speaking, the larger the tumor size, the higher the probability the cancer will spread to the axillary lymph nodes and also be associated with a less favorable outcome. Women with mammographically detected, nonpalpable breast cancer have the best prognosis.

Tumor grade is a pathologic description designating the degree the tumor has changed or transformed when compared to normal breast tissue, and it is frequently reported as well, moderately, or poorly differentiated. In simplistic terms, tumor grade could be best understood as the cancer’s personality measured as good, average, or bad.

Cells from the breast tumor can travel from their original site to other organs in the body, and this is called metastasis. To determine if the tumor is still localized to the breast or if the cancer cells have started to spread, surgeons remove the lymph nodes from the axilla (under the arm) so the pathologist can examine them under the microscope and provide an answer to this important question. The more localized the disease is to the breast, the better the outcome. But it is important to know that when this examination shows signs of spread to a few axillary lymph nodes, it is only a warning sign, an indicator that the outcome may be worse if treatment will not arrest the process.

A large clinical trial was conducted over 18 years in Sweden where thousands of breast cancer cases were detected with the help of mammography.

This so-called Two-County Trial has provided valuable information demonstrating that women with small breast cancers still localized to the breast have an excellent 20-year survival rate. Both younger women and older women have very good survival at 18 years provided that their tumor was detected at a maximum 10 mm size.

So, how do we detect breast cancer in its early phase? By offering the best available detection method to asymptomatic women–those who do not feel an abnormal lump in their breast. It is the regular screening examination with highquality mammography that has been thoroughly tested in scientific trials and proven that early detection can indeed arrest the cancerous process and save women’s lives.

It is important, however, to understand that there are more than twenty different breast cancer subtypes and if we only have one method to image them all, some of them will be more difficult to see on the mammogram than other types. Approximately 90% of breast cancers can be detected with high-quality screening mammography interpreted by a qualified radiologist. The remaining 10% of breast cancers require monthly self-breast examination and annual clinical breast examination for detection, or can be demonstrated by ultrasound examination.

The current recommendations for early detection are the screening guidelines provided by the American Cancer Society and supported by the American Medical Association and the American College of Radiology.

In the last few years, there has been debate over the value of annual screening mammography for women between ages 40-49. Since the incidence of breast cancer is somewhat lower in premenopausal as compared to postmenopausal women and the screening trials had relatively few women involved in this age category, the individual trials had difficulty to prove the benefit of regular mammography screening. But when the results of all trials from different parts of the world were combined, experts could clearly demonstrate the benefit of early detection also in the premenopausal women.

Since breast cancers have the propensity of developing or transforming into a more aggressive phase during their growth, especially in younger women, we believe that a high proportion of young women with breast cancer would benefit from early detection through yearly mammography screening.

Lastly, there is a misconception by many women that if they do not have a family history of breast cancer, they are not at risk for breast cancer. On the contrary, most women diagnosed with breast cancer do not have a family history of breast cancer. Women with a family history are at a somewhat greater risk of developing cancer, but the leading risk factor for breast cancer is being a woman.

What is the difference between a screening and a diagnostic mammogram? Screening is an examination for women without breast symptoms. The goal of this examination is to provide reassur ance for women who do not have the disease; also, it aims at finding breast cancer years before women themselves are able to find it. Women who have an abnormal finding on their screening mammogram will be called back for a detailed examination using a combination of diagnostic tools. The purpose of this examination is to arrive at the correct diagnosis. This is called diagnostic mammogram. Also, diagnostic mammogram is carried out on women with symptoms such as a lump, nipple retraction, skin changes, or nipple discharge, etc.

Using real numbers, if 1,000 asymptomatic women received a screening mammogram, approximately 10% would be asked to return for a diagnostic mammogram. Out of the 100 women requiring a diagnostic mammogram, approximately 20 would require needle-biopsy, of which 6 to 8 would prove to have breast cancer.

A request for an additional study after a screening mammogram does not imply a woman has breast cancer but rather indicates that additional examination is required for a more thorough and detailed evaluation. In other words, a screening mammogram is like looking at a forest from a half a mile away and the radiologist is able to see everything, but not in great detail. If there is something of concern, it is then best to walk closer to the object in order to get a detailed look corresponding to the diagnostic mammogram. Frequently, the diagnostic mammogram is supplemented by ultrasound to provide additional information.

Once the detected lesion is considered suspicious for breast cancer, confirmation by microscopic examination is needed. This requires cell or tissue sample. There are several methods available to obtain cells or tissue from the breast lesion. Given the advancement in medical technology and training, most nonpalpable breast lesions can be safely sampled with a needle using ultrasound or stereotactic X-ray guidance. For lesions amenable to needle biopsy, there are no stitches required resulting in little to no scarring.

In a minority of cases, open surgical biopsy is necessary to arrive at the accurate diagnosis by removing the entire lesion.

As we enter into the new millennium, women need to be aware that early detection and diagnosis of breast cancer offers the best outcome, with annual screening mammography providing the best opportunity for early detection. When detected, diagnosed, and treated early, most women will be able to live a normal, healthy life.