Encouraging Results in Intraoperative Radiation Therapy Use

The use of single-dose intraoperative radiation therapy (IORT) in conjunction with breast conservation surgery, as an alternative to traditional postsurgical external beam whole-breast irradiation, is increasing.

Partial breast radiation’s goal is to limit exposure in selected early-stage patients whose tumors are less aggressive and confined to a single breast segment. TARGIT-A, an international randomized trial comparing a single IORT dose given at the time of lumpectomy to standard radiation therapy given over several weeks after lumpectomy, found that five-year local breast cancer recurrence rates and breast cancer mortality rates were similar for the two modalities. Mortality from other causes was significantly lower with IORT, due to fewer deaths from cardiovascular causes and other cancers.

Need for North American Data

While TARGIT-A’s cohort of 3,451 patients represented 11 countries, less than 10 percent were from North America. Little is currently known about IORT’s frequency of use in North America, the types of patients who receive it and, most important, the therapy’s outcome. While the Targeted Intraoperative Radiotherapy United States (TARGIT-US) Registry Trial is currently being conducted to address questions of long-term efficacy and toxicity, the results of this prospective study will not be available for years.

Cleveland Clinic researchers organized the retrospective TARGIT-R trial to provide an interim snapshot of IORT usage and outcomes, using data from patients treated at selected North American institutions prior to July 2013. Stephanie Valente, DO, a breast surgeon with Cleveland Clinic’s Comprehensive Breast Cancer Program, presented results of the initial TARGIT-R analysis at the 2015 Society for Surgical Oncology meeting. This is the first large-scale evaluation of IORT for breast cancer treatment in North America.

Nineteen institutions, representing academic and community practices, submitted data involving 1,086 women treated with lumpectomy and IORT between 2007 and 2013. The analysis included 1,050 of those patients who had at least six months of follow-up. Their median age was 67. Most of the women had estrogen receptor-positive (91 percent), invasive ductal carcinoma (69 percent), with tumor less than 2 cm in size (86 percent), and were lymph node negative (89 percent).

Most patients (80 percent) received primary IORT (performed at initial lumpectomy); 7 percent received IORT as a secondary procedure and 13 percent as a planned boost. Almost 19 percent of patients who had primary IORT went on to receive external beam radiation. Complications included seroma requiring aspiration (8 percent), hematoma (1 percent) and infection requiring intravenous antibiotics (2.6 percent).

Median follow-up time was 12 months. The crude local in-breast recurrence rate was 1.6 percent, and regional nodal recurrence was 0.2 percent.

Confirming Value in Appropriate Patients

“Our early results from the TARGIT-R registry basically mirror TARGIT-A’s results and confirm that recurrence rates are low in properly selected patients,” says study co-author Stephen Grobmyer, MD, Director of Surgical Breast Oncology and Co-Director of Cleveland Clinic’s Comprehensive Breast Cancer Program.

With the preliminary findings, “we now have a portrait of who’s being treated with IORT in North America,” says Dr. Grobmyer, who is a member of the TARGIT-US steering committee. “Physicians are being very conservative. They’re treating hormone-positive patients with smaller tumors and patients whose average age is 67 ‒ not the younger patients who tend to have more aggressive disease.

“Selecting less aggressive treatments for less aggressive disease is appropriate, and better for patients,” Dr. Grobmyer says. “Patients like IORT because treatment duration is shorter, side effects are less and they’re able to quickly return to normal functioning. We present it as an option for properly selected patients.”

Young Women’s Breast Cancer Clinic

SERVICES

Genetic counseling to review screening options, and genetic testing to detect alterations in BRCA1, BRCA2 or other genes associated with increased breast cancer risk, which may enable management targeted to specific mutations

A thrice-weekly clinic with coordinated medical, surgical, radiology and related consultation appointments, to accelerate treatment time and reduce return visits

Dedicated pathology and imaging specialists who deal exclusively with breast diagnostic issues

Access to the latest strategies for fertility preservation and assisted reproduction, including ovarian cycling suppression during chemotherapy; oocyte, embryo and ovarian tissue harvesting and cryopreservation; and in vitro fertilization

Advanced surgical options for breast conservation, reconstruction and lymphedema reduction, including nipple-sparing mastectomy; single-stage mastectomy and breast implant insertion; and vascularized lymph node flap transfer

Single-dose intraoperative radiation therapy for appropriate patients

Access to a wide array of clinical trials, including areas of research with particular impact on young breast cancer patients

Support groups and other psychological and lifestyle counseling and therapy intended for young breast cancer patients