Breast cancer: Advances in prevention, diagnosis, and treatment

The past five years have brought discovery and advancement in all aspects of breast cancer. More importantly, these advances have resulted in not only better diagnosis and treatment but more individualized care as well. There’s no longer a one-treatment-fits-all approach to breast cancer. Instead, a team of doctors from various specialties is able to work together to tailor a treatment plan for each person based on many factors, such as cancer type, its stage and one’s personal biology (please refer to last week’s column).

The good news is that breast cancer survival rates are among the highest of all cancers. Overall, nearly 89 percent of women diagnosed with breast cancer live for at least five years after treatment. If caught at the very earliest stage — known as carcinoma in situ — that percentage goes up to 98 percent.

Lifestyle Factors

New research has revealed that certain lifestyle factors can reduce your risk of developing breast cancer, including:

• Exercise. Studies have shown that women who exercise about 30 minutes three or four times a week can decrease their breast cancer risk by about 26 percent.

• Alcohol. Studies have also shown that women who drink one or two alcoholic drinks a day increase their risk by 10 percent. That number goes up to 30 percent if you drink three or more alcoholic beverages a day.

• Weight. A study published in the Journal of the American Medical Association in 2006 concluded that women who lost 22 pounds after menopause reduced their risk of developing breast cancer by 45 percent.

Newer Technology

When an abnormality, such as a lump, is detected in the breast, your doctor will order tests or procedures to further evaluate the problem. These may include a diagnostic mammogram, ultrasound, magnetic resonance imaging (MRI), a needle biopsy or aspiration, or a formal surgical biopsy. These can help to determine if an abnormality is breast cancer, and if so, to characterize the tumor.

Technology has brought about new ways to see into the body, but to date, the mammogram is still the standard of care for screening and is the only screening test shown to decrease the chance of dying of breast cancer. Annual screening mammograms have been shown to decrease mortality by 20 to 30 percent in women over the age of 50. The American Cancer Society recommends that woman have regular mammograms beginning at age 40.

Other imaging technologies are used to complement mammography or to further evaluate an abnormality in the breast. Each offers benefits, but also shortcomings. These include:

• Magnetic resonance imaging (MRI). MRIs are particularly useful to evaluate abnormalities in women with dense breasts. Recently, several cancer organizations have made recommendations that women, who are at very high risk of developing breast cancer, get an annual MRI in addition to a mammogram. However, MRIs aren’t recommended for routine screening. That is because they’re expensive, require an IV injection of a contrast agent, and can lead to additional biopsies and give a high rate of false positives and increased anxiety.

• Ultrasound. Often, this is ordered to determine if a lump or suspicious area found during a breast exam or on a mammogram, is a cyst or a solid mass.

• Digital mammography. The use of this method is on the rise. Digital mammography is slightly better in younger women with dense breast tissue. It can decrease radiation dose and decrease the frequency of repeat images. It has the advantage of decreased waiting time since there’s no time needed to develop the film.

Other tests include computer-aided mammography, nuclear tracers, 3-D mammography, optical imaging, optoacoustic tomography, and microwave imaging.

Chemotherapy

This refers to drugs that kill cancer cells. It’s given alone or as several drugs together. In some cases, it has been found to be of benefit to give chemotherapy prior to surgery (neoadjuvant chemotherapy) to shrink a tumor. It is used for this purpose in women with large tumors. The technique has also been shown to significantly decrease the chance of the cancer returning, and allows women to live longer. Chemotherapy can have significant side effects, so doctors try to individualize treatments.

Genetic markers from the blood can identify which women are likely to have a good response to certain medications. Testing the genetic makeup of the tumor itself can help determine which women are at the highest risk of recurrence and which of those women are more likely to benefit from chemotherapy, while allowing women at very low risk of recurrence to avoid the side effects of unnecessary treatment.

The cancer cells can also be tested for the presence of the human epidermal growth factor receptor 2 (HER-2). HER-2 is a protein found in excessive amounts on the surface of about one out of three breast cancers. Those cancers have always tended to be more aggressive, more likely to spread, and less likely to respond to traditional chemotherapy. However, new treatments — such as the drug trastuzumab (Herceptin) — that directly target the HER-2 protein are now available, greatly improving the outlook for these women. Tratuzumab reduces post-surgical cancer recurrence by up to 50 percent for women with HER-2-positive cancers.

If your cancer is considered “hormone receptor positive,” hormone therapies with the use of estrogen blockers such as tamoxifen, anastrazole (Arimidex), letrazole (Femara) and exenestane (Aromasin), can reduce the rates of recurrence.

Radiation

Studies have shown success in two particular types of therapies — partial breast irradiation and short-course radiation. Both therapies reduce the amount of time you spend at the radiation center. In a traditional radiation course, you’ll spend about five days a week for five to six weeks receiving radiation to the breast.

Partial breast radiation is a new method of radiation that may be considered for those who have had a lumpectomy — a surgical option for small tumors relative to the size of the whole breast. In partial breast irradiation, radiation is focused on just where the tumor was before being removed through surgery.

Those with early-stage cancer and no lymph node involvement — but who don’t qualify for partial breast radiation, due to factors such as tumor size or location — may be candidates for short-course radiation. A Canadian study released in 2008 concluded that reducing radiation treatments for certain early-stage breast cancer to 16 sessions given over the course of about three weeks appears to be just as effective as the standard treatment series of 25 treatments over five weeks.

Surgical Treatment Options

If a mastectomy is recommended by either a breast surgeon or an oncologist — or is preferred by the patient — there are several types of breast removal. These include:

• Total, or simple, mastectomy. This involves removal of breast tissue, skin, the nipple and the dark skin (areola) around the nipple but not the lymph nodes.

• Modified radical mastectomy. This removes the same tissues as does a total mastectomy, but also includes the lymph nodes under the armpits (axillary lymph node dissection).

• Radical mastectomy. This is the most extensive form of mastectomy. In addition to the removal of breast and lymph nodes, some chest wall muscle, and additional fat and skin also are removed.

• Others. This includes the skin-sparing mastectomy and the subcutaneous (nipple-sparing) mastectomy.

On The Horizon

Experts expect to see greater individualization of treatment based on a greater understanding of the genetic factors that govern breast cancer biology. More specific abnormal pathways of cancer cells and how to target these with therapy will be identified.

Studies already in progress include genetic research on breast cancer genes and new imaging techniques. Scientists also anticipate that additional drug and hormone discoveries will be made which will be valuable in terms of cancer prevention. –Tyrone M. Reyes, M.D. (The Philippine Star)