Advances in Breast Cancer
Tennessee Oncology’s Nancy Peacock, M.D.
October is breast cancer awareness month and brings the opportunity to share new and interesting developments in the arena of breast cancer treatment.
As you would expect, prevention remains preferable to treatment. Clearly the risk of developing breast cancer is not in one’s control, but, there are strategies that help women reduce their risk. For women with an increased risk of breast cancer (those with premalignant lesions like DCIS or LCIS), taking the drugs Tamoxifen or aromatase inhibitors can decrease the risk of developing an invasive breast cancer. This strategy is also effective for women with a family risk of breast cancer or even an inherited genetic risk such as a mutation in BRCA 1 or 2. The current recommendations for bilateral prophylactic mastectomy and oophorectomy and hysterectomy are still preferred for women with BRCA 1 and 2 mutations. These women have extraordinarily high risks of developing breast and ovarian and fallopian tube cancers, and preventive surgeries have lowered that risk.
It is worth emphasizing that following a healthy diet by including five to seven servings of fresh fruit and vegetables daily, maintaining a healthy weight, adding 120 minutes of aerobic exercise weekly, and eliminating cigarette smoking decreases the risk of developing breast, colon, and lung cancers.
Early diagnosis remains important. Mammographic screening every other year is the current and updated recommendation for women ages 50 to 75 stated by the Institute of Medicine and the U.S. Preventative Services Task Force. The American Cancer Society, however, continues to recommend annual mammography. For women under 50 or above 75, there can be valid reasons to perform mammography, but there is not enough data to show that these are helpful screening tools in women outside the recommended age range. There are no recommendations that include breast MRI or ultrasound in a screening program, even in women with increased breast density.
Recently we have been able to take advantage of molecular profiling to help understand the risk of relapse and benefit of chemotherapy for specific breast cancers. Molecular profiling tests, including the Oncotype Dx, the Mammaprint, and the Pam50, give clinicians and their patients more accurate predictions of who will really benefit from chemotherapy and who will not.
The results of newly published studies have shown that continuing adjuvant hormonal therapy beyond five years reduces the risk of later relapse in premenopausal women treated with Tamoxifen, and in postmenopausal women treated with Tamoxifen followed by an aromatase inhibitor or an aromatase inhibitor alone. None of these advances would have been possible without the collaboration of scientists, clinical investigators, and most importantly the patients who participated in these trials.
The class of biologic anticancer drugs that target the Her 2 protein like Trastuzumab and Pertuzumab work with chemotherapy in the pre-operative, the post-operative, and the metastatic settings to improve the survival rates in tumors with more aggressive natures. Oncologists continue to struggle with difficult breast cancers, particularly triple negative cancers which do not express the Er, PgR and Her2 proteins. These tumors have proven resistant to many known chemotherapeutics. This is a group of patients for whom clinical trials remain extraordinarily important.
The many benefits seen in the systemic treatment of breast cancer have occurred at a time when we have also seen an improvement in surgical techniques and radiation therapy options. In fact, for select patients, it is possible to receive novel radiation treatments at the time of surgery or even over a one-week course as opposed to the usual six-week course of external beam radiation therapy. Surgeons are able to effectively remove smaller cancers with limited damage to the breast or to the axillary lymph node areas by removing only the lymph nodes most likely to be involved at the time the cancer is diagnosed.
This is a time of great optimism in the treatment of breast cancers. We still have much work to do though, to provide a chance for a cure in all patients affected by this disease.