Breast Brachytherapy Use Outpaces Evidence
Use of brachytherapy to treat breast cancer continues to increase despite unresolved questions about long-term outcomes, according to data presented here.
From 2001 through 2006, breast brachytherapy accounted for 5% of all radiation therapy administered to a cohort of more than 6,000 postmenopausal breast cancer patients. However, in the years after 2004 - when Medicare began reimbursing for the modality - use of the modality more than doubled, to 10% in the first half of 2006.
The findings strongly suggest that nonclinical factors will determine breast brachytherapy’s role in coming years.
“Despite ongoing debate over long-term outcomes, breast brachytherapy has been rapidly incorporated into treatment of breast cancer,” Thomas A. Buchholz, MD, of the University of Texas M. D. Anderson Cancer Center in Houston, said here at the American Society for Radiation Oncology meeting.
“The availability of clinical evidence is less likely to be a major force in determining the diffusion of this new technology. Instead, nonclinical factors - such as public policy and socioeconomic factors - are likely to play an important role.”
The efficacy of whole-breast irradiation after conservative surgery has been demonstrated in Phase III clinical trials involving 60,000 to 100,000 patient-years of follow-up, said Buchholz. In contrast, Phase III data of partial breast irradiation with brachytherapy has yet to mature and comprises about 1,500 patient-years of follow-up.
Brachytherapy is a type of radiotherapy that can be used to treat many types of cancer.
It is sometimes known as ‘internal radiotherapy’, or when used in the treatment of prostate cancer, ‘seed therapy’.
Radiotherapy is an important method of treating cancer. It works by destroying cancer cells by targeting them with radiation and stopping them dividing and growing.
About 4 out of 10 people with cancer have some type of radiotherapy as part of their treatment.
The lack of supporting data for breast brachytherapy has created controversy regarding use of the radiation modality, he added.
Access to a nationwide database of Medicare beneficiaries with private supplemental insurance provided an opportunity to examine the use of breast brachytherapy and the factors associated with its use.
Buchholz and his colleagues identified 6,882 women ages 65 and older with newly diagnosed breast cancer from 2001 through 2006. The database provided access to information about inpatient, outpatient, and prescription claims.
There are two basic types of radiotherapy:
External beam radiotherapy (EBRT)
Brachytherapy
Brachytherapy works by precisely targeting the cancerous tumor from inside the body. The source of radiation is placed directly inside or next to the tumor. This tailored approach reduces the risk of any unnecessary damage to healthy tissue and organs that are close to the tumor, therefore reducing potential side effects.
In contrast, EBRT delivers radiation from outside the body. The radiation has to travel through healthy tissue to reach the tumor. As the technique is less targeted and precise than brachytherapy, more healthy tissues and organs can be exposed to harmful levels of radiation.
Brachytherapy is commonly used as an effective treatment for cervical, prostate, breast and skin cancer and can also be used to treat tumors in many other sites of the body. Brachytherapy can be used to treat cancer on its own or in combination with other treatment methods, such as surgery, external beam radiotherapy or chemotherapy. The exact treatment(s) will depend on a number of factors, such as the location, shape and size of the tumor, and individual patient preferences.
All of the patients had breast-conserving surgery followed by radiation therapy - external-beam radiation, brachytherapy, or a combination of the two modalities.
Patients had a mean age of 75, 8% had axillary involvement, and 4% had metastatic disease. Buchholz said that 78% of the cohort had axillary dissection, 10% had chemotherapy, and 65% received endocrine therapy.
Overall, external-beam radiation therapy accounted for 95% of all radiotherapy administered to the patients. Fewer than 1% received both external-beam radiation and brachytherapy, and the remaining patients had brachytherapy as the sole form of radiotherapy.
Trend analysis showed that use of brachytherapy remained stable at about 1% of cases from 2001 to the first half of 2002, when the FDA approved the therapy. Use of brachytherapy increased to about 3% of cases in the second half of 2002 and remained at that level until the first half of 2004, when Medicare started covering brachytherapy.
Brachytherapy continued to account for about 4% of all radiation therapy used to treat breast cancer through 2004, then increased to more than 6% of cases in the first half of 2005, 8% in the second half of 2005, and 10% during the first six months of 2006.