Breast Cancer - How Advantageous Or Detrimental Is Brachytherapy?
An investigation published December 16th in the Journal of the National Cancer Institute reveals that over the last several years in the U.S., accelerated partial breast irradiation using brachytherapy (APBIb) for treating breast cancer has increased rapidly as an alternative treatment to conventional whole-breast irradiation (WBI).
APBI delivers a high dose of radiation to areas of the breast where cancer is most likely to recur. There are various techniques to accomplish the administration of APBI, such as intraoperative radiotherapy, external beam radiation, intracavitary brachytherapy using a ballon catheter, or brachytherapy using multiple interstitial catheters. Advantages of these methods include:
- Less radiation to healthy areas in the breast and normal tissue
- Shorter treatment time
Disadvantages include:
The chance of cancerous cells in different parts of the breast not receiving radiation, which may lead to increased local recurrence
Due to the possible limitations of APBI, a task force of breast cancer experts were brought together in 2009 by the American Society for Radiation Oncology (ASTRO) to develop criteria for use of APBI off-protocol. Three groups of APBI appropriateness were proposed by the experts: cautionary, unsuitable, suitable, and based on clinical factors and patient characteristics.
As the popularity of APBIb in particular has increased over the years, Jona Hattangadi of the Department of Radiation Oncology at the Brigham and Women’s Hospital and Harvard Medical School in Boston, and colleagues, decided to conduct a retrospective study.
The Genetic Link to Cancer
The two most common forms of cancer detected among women are skin and breast cancer. Breast cancer is the second leading cause of death associated with cancer following lung cancer, according to the National Cancer Institute.
Each year more than 40,000 patients will die from breast cancer, with this number rising among women over 50 years of age. One reason is most women’s health declines and immune systems simply do not fight back the way they used to as women age.
Family History and Breast Cancer Statistics
The National Cancer Institute summarizes multiple studies, all of which suggest women with a family history of breast cancer are more at risk than others. For example, according to the NCI, if a woman has a mother or sister with breast cancer, their risk for developing breast cancer may rise by as much as ten percent.
You are at greater risk for developing breast cancer if multiple people in your family have cancer. Cohort studies support this phenomenon. One reason researchers struggle to find a cure for breast cancer is they are working hard to identify and treat the genetic link that puts some women at greater risk for cancer than others.
The people most at risk for developing breast cancer include:
- Those individuals that have family members who developed breast or similar cancers at an early age.
- Having a family member that had more than one type of primary cancer, including breast cancer in both breasts or ovarian cancer combined with breast or other reproductive cancers (like prostate cancer).
- A family history of males in the family with diagnosed breast cancer.
It is important to note a male’s family history is just as important as a woman’s family history when discerning your risk for breast cancer. A male can carry the gene for breast cancer and predispose his female offspring for example, to an increased risk for developing breast cancer.
The team analyzed data from the Surveillance, Epidemiology, and End Results (SEER) database of women who had undergone WBI or APBIb between 2000 and 2007. Following ASTRO guidelines, the team classified the 138,815 women as “unsuitable”, “suitable”, or “cautionary” for APBIb.
Of the 138,815 women, 3,576 had undergone APBIb. The team discovered that of these 3,576 patients, 29.6% would have been considered cautionary, 32% suitable and 36.2% unsuitable.
The overall use of APBIb rose from 0.4% in 2000 to 6.6% in 2007. Across the U.S., the team observed a wide range of utilization patterns with specific geographic regions having higher APBIb use despite other clinical and patient factors.
What is HDR brachytherapy?
HDR (high dose rate) brachytherapy (bray-key-THAIR-uh-pee) is a type of radiation used as part of BCT. HDR brachytherapy delivers a high dose of radiation in and around the tumor. It spares (does not affect) much of the surrounding healthy tissue.
Brachytherapy may be used alone or with surgery, external beam radiation, and chemotherapy. It may cure, control, or relieve symptoms of many types of cancer.
Radiation is given for a set length of time by a small, radioactive source. The radiation dose and length of time depend on the tumor size and location.
In addition, the team found considerable ethnic and racial differences. Black women were less likely to get this treatment than white women among “unsuitable” or “cautionary” patients, and patients living in cities were more likely to get the treatment that patients living in rural areas even though it would possibly provide the rural women greater convenience.
The researchers conclude:
“The wide disparity in use of APBIb suggests that unwarranted variation, practice variation not explained by illness, patient preference, or evidence-based medicine, may be present. Future studies of APBIb use will help elucidate whether patterns change as [the ASTRO guidelines] diffuse into practice and whether the regional and temporal changes in APBIb cost, reimbursement, and insurance coverage affect utilization.”
In an associated report Simona F. Shaitelman, M.D., at the Department of Radiation Oncology at the University of Texas M.D. Anderson Cancer Center, explains that it is reassuring that the researchers discovered the rapid increase in patients classified as “suitable” choosing this treatment, even if most of the women undergoing ABPIb in their investigation were not classified as suitable.
In addition Shaitelman comments on the researchers’ suggestion that financial interests that may be powering usage and states that reimbursement was decreased for the treatment after the end of the period of the investigation.
Shaitelman explains:
Furthermore Shaitelman concludes that further investigations of the effectiveness of APBI are required. “Although population based studies allow us to reflect on changes in patterns of practice, we are still left eagerly awaiting the results of large randomized trials that compare patients outcomes with WBI vs APBI.”
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Written by Grace Rattue