The American Brachytherapy Society (ABS) published an update to the Accelerated Partial Breast Irradiation (APBI) consensus statement as an update to the 2013 consensus statement.  The paper was authored by ten members of ABS with extensive experience in breast cancer and brachytherapy and was published in the journal Brachytherapy (click here for full article).  These updated guidelines offer a concise summary of the data supporting APBI.

APBI with brachytherapy continues to be an attractive treatment option for many women with early stage breast cancer.  Dr. Frank Vicini offers perspective on the new consensus statement.

The ABS consensus statement addressed both appropriate candidates and APBI techniques, what were the major changes to the patient selection criteria?

The new guidelines support APBI for a broader group of patients by including younger women as well as those with DCIS.  The consensus statement focuses on patients aged 45 years or older; all invasive histologies as well as ductal carcinoma in situ; tumors 3 cm or less; node negative; estrogen receptor positive/negative; no lymphovascular space invasion; and negative margins.

It is important to note that all the major surgical and radiation oncology societies offer consistent support of APBI in the younger age group.

New ABS Guidelines for 2017

 

How do you think these new selection criteria might potentially impact current clinical practice?

Evidence-based guidelines have the potential to change clinical practice and further validate the safety and efficacy of APBI.  I believe lowering the age should continue to expand the number of eligible patients who can benefit from APBI.  This increase could go as high as 20 to 30% in some cases.

In regards to APBI techniques, how were the recommendations ranked?

The recommendations were based on a systematic review of 7 randomized and 5 prospective trials.  Each technique was reviewed and assigned a ranking of evidence that ranges from strong to weak and includes a recommendation on utilization of either off and on protocol or strictly on protocol.

Which APBI techniques are recommended by the society for general use and why?      

Interstitial brachytherapy has an impressive body of long-term follow up and randomized data however it is the most technically complex to perform.  Applicator based brachytherapy demonstrates ease of use, excellent prospective data and low rates of toxicity and received a positive recommendation and should be considered for appropriate for most patients

In contrast IORT, despite its ease of single treatment, showed a higher rate of local recurrence in two phase III trials and up to 20% of women (in one of the trials) requiring subsequent whole breast irradiation.  The data does not support broad clinical use of low-energy IORT, therefore, this specific form of IORT was recommended not to be used unless under a clinical study protocol.

On or Off  Protocol On Protocol/Under Clinical Study
  • Interstitial brachytherapy
  • Applicator based brachytherapy
  • External beam 3DCRT
  • Proton therapy
  • Low-energy IORT
  • Electronic Brachytherapy

 What is the most important take away from this consensus statement?

I think that this update and comprehensive evaluation continues to demonstrate the relevance of APBI.  Physicians can feel confident using the ABS guidelines to treat women with early stage breast cancer that meet the established criteria.

Are there any studies in progress for APBI we should be watching ?

The Triumph T protocol evaluating three fractions of 7.5 Gy after breast conserving surgery has completed accrual of patients in July 2017.  This study is trying to determine if APBI can be given in less fractions with the same low toxicity profile as conventional APBI and potentially improved quality of life.