The American Society for Radiation Oncology (ASTRO) has released an updated clinical practice statement for accelerated partial-breast irradiation (APBI) for early-stage breast cancer in its journal, Practical Radiation Oncology.
The updated guideline expands the pool of suitable candidates for APBI treatment and offers direction for using intraoperative radiation therapy (IORT) for partial-breast irradiation. The guideline is based on studies published since May 2008 and reviewed by an eight-member task force of radiation oncologists, medical oncologists, and experts in IORT (Pract Radiat Oncol, November-December 2016, Vol. 6:6, pp. 1-7).
The guideline recommends considering the following factors for the use of APBI:
- Patients age 50 or older should be considered suitable for APBI, patients ages 40 to 49 who meet other pathologic suitability criteria should be considered cautionary, and patients younger than 40 or those who do not meet the pathologic criteria should be considered unsuitable.
- Patients with low-risk ductal carcinoma in situ (DCIS) should be considered suitable for APBI if they meet all aspects of the definition of low-risk DCIS from the Radiation Therapy Oncology Group's (RTOG) 9804 clinical trial.
- Patients are suitable for APBI if their surgical margins are negative by 2 mm, cautionary if their margins are close or less than 2 mm, and not suitable if their margins are positive.
The guideline also includes recommendations for the use of IORT:
- Physicians should counsel patients that the risk of ipsilateral breast tumor recurrence (IBTR) may be higher with IORT compared with whole-breast irradiation.
- Electron-beam IORT should be restricted to patients with invasive cancer who are also considered suitable for partial-breast irradiation.
- Low-energy x-ray IORT should be used only in the context of a clinical trial, and it should be restricted to women with invasive cancer who are considered otherwise suitable for partial-breast irradiation.
- Given the risk of tumor recurrence over time, all patients treated with IORT should undergo routine long-term follow-up for at least 10 years to screen for tumor recurrence.
"As trials mature and evidence accumulates, we can understand more comprehensively who benefits from accelerated radiation treatment following lumpectomy, and we are finding that the pool of suitable candidates for this emerging treatment is larger than first anticipated," said Dr. Jay Harris, chair of the task force that developed the guideline, in a statement released by ASTRO.
