Topics: Breast Cancer
October 7, 2020
Early detection is key for effectively fighting breast cancer! The most important screening test in early breast cancer detection is a mammogram. In addition to an improved outcome, some patients diagnosed with early-stage disease are candidates to have less aggressive surgery, can skip chemotherapy or radiation, or will receive a shorter course of treatment for breast cancer.
Breast cancer does not represent “one disease” but, rather, many different and similar diseases all characterized by normal breast cells becoming cancerous breast cells. Although we do not know why most patients develop breast cancer, abnormal genes appear to play a key role in some patients and genetic testing has assumed a greater role in evaluating many newly diagnosed patients.
Breast Cancer Treatment
We can now identify several different subtypes of breast cancer which we recognize as key in formulating an effective breast cancer treatment plan. The vast majority of breast cancers are estrogen-dependent, meaning estrogen promotes the growth of malignant cells. The use of anti-estrogen drugs (hormonal therapy) represents one of the earliest and most successful forms of so-called “targeted therapy” and remains an important part of treatment for patients with estrogen-positive breast cancer. The goal of hormonal therapy is to reduce estrogen production and/or block estrogen, eliminating the “fuel supply” that causes cancer cells to divide and multiply. These drugs, many of them given orally, often with very few side effects, can be used to reduce the risk of recurrence after surgery.
This is called adjuvant therapy, meaning treatment that is given in addition to surgery with the goal of eliminating microscopic cells as well as in patients whose disease has recurred where, in select situations, hormonal therapy can be even more effective than chemotherapy! Several new drugs (the CDK4/6 inhibitors) have been developed in the past few years which, when given with estrogen-blocking drugs, have nearly doubled the duration of remission in patients with advanced disease.
Beyond estrogen-positive breast cancer, we have now identified two other important types of breast cancer - cancers that are driven by the HER-2 gene, and triple negative breast cancer (TNBC) where tumor cells lack hormone receptors (both estrogen and progesterone receptors) and the HER-2 gene (i.e. all three markers are negative).
For patients with HER-2 positive breast cancer, drugs that target HER-2 are often given in combination with chemotherapy after surgery to reduce the risk of recurrence as well as in patients whose cancers have spread. The development of HER-2 targeting drugs represents a major advancement in the treatment of HER-2 positive breast cancer and has significantly improved outcomes for women with this particular type of breast cancer. Currently available treatments greatly reduce the risk of recurrence after initial surgery as well as significantly extend life in patients whose cancers have spread. Many patients now survive with an excellent quality of life for many years after their cancer has metastasized with the use of anti-HER-2 drugs.
TNBC is recognized as a potentially aggressive form of breast cancer. That said, many women with TNBC do very well. For patients who present with large breast masses or lymph node involvement (locally advanced disease), chemotherapy is frequently given prior to surgery (called neoadjuvant therapy) to reduce tumor size and provide early treatment of any microscopic cells that might have spread beyond the breast. Shrinking a tumor prior to surgery may allow a patient the option of breast-conserving surgery (a big lump becomes a small lump allowing a lumpectomy operation which might not have been possible prior to treatment) and is also a test of sorts to determine the responsiveness of an individual’s cancer cells to chemotherapy. It is now known that patients who have a complete disappearance of their cancer at the time of surgery with pre-surgical chemotherapy have a much better long-term prognosis than patients whose cancers shrink but do not disappear completely. In the latter case, additional chemotherapy can be given with the goal of improving the likelihood of cure.
Early detection of breast cancer is associated with earlier stage disease, improved outcome, and less aggressive treatment.
Increasingly, the treatment of breast cancer has become highly individualized as we have come to learn that while sharing commonalities, each cancer is unique. The precise identification of breast cancer subtype and a better understanding of the drivers of cancer cell growth (cancer genomics) will, undoubtedly, lead to new cancer therapies with even better outcomes in the years ahead.
For patients with significant lymph node involvement, further therapy in the form of additional surgery, radiation and/or chemotherapy may be indicated.
Standard surgical options for breast cancer include mastectomy versus breast-conserving surgery. Mastectomy was the traditional surgical approach used for most of the 20th century. This involved removing the entire breast and a number of regional lymph nodes. In the 1980s, there was a slow transition from mastectomy to breast-conserving surgery. Most patients diagnosed with early-stage breast cancer now have the option to save their breast by choosing partial mastectomy or lumpectomy. This involves excising only the cancerous tissue with a rim of normal tissue and sampling lymph nodes. Lymph node surgery has become less aggressive for patients with minimal or no lymph node involvement. Sentinel lymph node dissection, which involves dissecting only a few nodes most likely to contain cancer, is now standard of care. Surgery and radiation go together for optimal local and regional control of the cancer.
Radiation is used after breast-conserving surgery to improve local control. Traditionally this is a 6-week course of daily radiation treatment, Monday through Friday, to the entire breast and sometimes adjacent lymph nodes. External radiation is delivered by a linear accelerator (or linac) which directs radiation toward the cancer. Whole breast radiation is well-tolerated with no nausea or vomiting. Common side effects include fatigue, redness or tanning of the breast and breast firmness. Cosmetic outcome is good to excellent in 90% of patients.
New breast cancer treatment approaches have increased the choices available to patients with early breast cancer, in some cases eliminating the need for 6 weeks of external beam radiation and improving quality of life.
For node-negative patients, a short course of whole breast treatment, delivered over a 3-4 week period, is equally effective and well-tolerated. To be a candidate for the shorter (or hypofractionated) course of whole breast treatment, patients have to meet certain pathologic and dosimetric criteria, and the heart should be blocked (for left-sided breast cancers).
Reduced or Partial Breast Radiation
There is a trend toward reducing not only the length of treatments but also the amount of breast tissue that is exposed to radiation therapy. A recent publication in Lancet showed that reduced breast radiation or partial breast radiation was not inferior to standard whole breast treatment and may be associated with improved cosmetic outcome.
Another form of partial breast radiation for node-negative patients over age 40 is internal radiation or brachytherapy. Brachytherapy is an innovative form of internal radiation that uses a radioactive source that is placed inside the body. High dose rate (HDR) brachytherapy is a technically advanced form of brachytherapy. A high-intensity radiation source is delivered with millimeter precision under computer guidance directly into the lumpectomy cavity (the space left when a tumor is removed). The radiation is targeted to the area where the cancer is most likely to recur. Advantages of HDR brachytherapy are a short 1-5 day course of outpatient treatment, fewer side effects, excellent coverage of possible microscopic tumor extension and improved accuracy and precision of radiation delivery. Typical side effects are minor and include redness, bruising and breast pain. Sometimes there is breast swelling and dry desquamation (shedding or peeling of skin) or a local wound infection may occur. Overall cosmetic results are good to excellent in most patients.
Some patients with early-stage disease may be candidates to skip radiation. Patients with non-invasive (stage 0), low-risk cancers may not require radiation. This recommendation is made on a case by case basis and influenced by patient age and pathologic factors such as tumor size, the width of surgical margin, tumor grade and biology. Patients age 70 and older, with early stage (<2 cm and node negative) invasive cancers that are estrogen-receptor positive, may be able to skip radiation if they agree to receive adjuvant hormonal therapy. This decision is made after careful review of pathology and discussion of risks and benefits of treatment with the patient.
Arizona Oncology has a team of breast cancer oncologists and radiation oncologists who are breast cancer specialists and offer a full range of services at multiple locations throughout the state, including: Deer Valley, East Valley, Flagstaff, Glendale, Goodyear, Mesa, Tempe, Phoenix, Prescott Valley, Scottsdale, Green Valley and Tucson. Remember, early detection of breast cancer is associated with earlier stage disease, improved outcome and, in some cases, less aggressive cancer treatments.
Last published in September 2019. Updated October 2020.