Advances in diagnosis and treatment of breast cancer in recent years have often been driven by improved radiologic tools. More precise diagnostic imaging methods such as digital mammography, MRI and 3-D ultrasound have allowed us to detect cancer cells at earlier and more curable stages.
At the same time, the development of more targeted radiotherapies in cancer treatment has provided the capability to focus directly on tumors while protecting healthy parts of the body from harmful side effects.
Such innovative, highly targeted therapies bring new hope to patients, especially those diagnosed in early stages.
For many years the gold standard for breast cancer treatment was a mastectomy. But multiple studies have now confirmed that breast-preserving surgery (lumpectomy) followed by radiation therapy is equally effective when compared to mastectomy. The radiation targets and eliminates residual cancer cells that may be left after surgery. Because abnormal cells aren’t able to repair the radiation damage incurred from treatment, only the healthy tissues survive the radiation treatment.
Traditional radiation therapy regimen after a lumpectomy includes six to seven weeks of daily external beams delivered to the entire breast. While this has proven to be highly effective in preventing cancer recurrences, it may expose normal tissue to potentially harmful radiation.
It’s important to note that all radiation technologies have improved vastly since the early days of this treatment, and the major side effects that many patients associate with and fear from radiotherapy are mostly a thing of the past. As a result of significant advances in delivery and treatment planning software, most patients experience minimal lasting side effects.
Nonetheless, and despite its proven benefit, the recommended course of traditional external beam radiotherapy presents difficulties for many patients. The significant time commitment, cost, distance and access to a radiation center have meant that as many as 30 percent of women do not undergo the required radiation following lumpectomy surgery – or they opt for a mastectomy because it is easier. Eliminating the radiation portion of treatment following lumpectomy can significantly increase the risk that breast cancer will recur.
Fortunately, some innovative new methods of delivering radiation have been developed and refined over the past few years. These use a more targeted form of radiation that allows a shorter, more convenient, yet equally effective course of treatment.
Accelerated Partial Breast Irradiation (APBI) offers all these advantages. Unlike external beam radiation, where X-rays are directed into the breast tissue from a machine outside of the body, APBI uses 3-D high-dose-rate brachytherapy that involves placing a temporary small radioactive “seed” directly into or immediately adjacent to cancer risk areas inside the breast.
As a result, the radiation is delivered directly to the region where cancer is most likely to recur, and doesn’t have to pass through healthy tissue to get there. Additionally, given the more limited volume inside the breast, a higher, more focused dose of radiation can be delivered safely while protecting the healthy tissues nearby, including the skin, normal breast tissue, chest wall, heart and lungs.
Not only does APBI work as well for early-stage patients as traditional radiotherapy (confirmed by multiple studies), but best of all, it can be delivered in just five days compared to six or seven weeks of whole-breast radiotherapy. This has eliminated a major hurdle preventing many patients from complying with their treatment regimen.
Simple and quick
APBI involves a simple outpatient procedure. Using ultrasound guidance, the surgeon inserts a temporary catheter that is capped with an applicator through a small incision in the breast. Once the applicator is positioned in the surgical cavity, a 3-D mapping study helps determine the exact timing needed to deliver the required dose.
The resulting treatment plan is designed to target the radiation to areas where cancer is most likely to recur near the original tumor location, while avoiding unnecessary exposure to healthy tissues.
During the entire five-day treatment, the catheter remains in the breast and is connected to the radiation source for just a few minutes during each visit. The radiation seed location is computer-assisted and removed completely after each treatment. The applicator is removed after the final treatment.
APBI has been remarkably successful. Not only are its outcomes equivalent to traditional radiotherapy, but it has been shown to improve patients’ satisfaction and quality of life, and to reduce side effects.
Because it overcomes some of the most significant barriers posed by traditional radiotherapy, APBI has convinced more patients to choose breast-preserving surgery instead of a mastectomy.
Over the past decade, 70,000 U.S. patients have been treated with APBI, and most insurance providers cover it fully. But it’s still only available in less than half of all cancer treatment facilities, and it requires a dedicated surgeon and radiation oncologist team, as well as specialized training and equipment.
Despite continued advances in the technology, not everyone is a candidate for APBI. Today, two of every three women with early-stage breast cancer may be eligible, but there still are some clinical situations where the patient’s outcome may be better with conventional therapy.
APBI is certainly one more reason to celebrate our progress in the battle against breast cancer.
Dr. Rakesh Patel is a radiation oncologist at El Camino Hospital and chairman of the American Brachytherapy Society.