Positive outlook for a move to accelerated partial breast irradiation

For patients with low-risk early breast cancer, research presented at the San Antonio Breast Cancer Symposium in December 2019 showed that treating only part of the affected breast with accelerated irradiation compares favourably with whole breast irradiation after breast conservation surgery (lumpectomy).

Dr. Icro Meattini of the University of Florence presented the as-yet-unpublished findings of a ten-year study of accelerated partial breast irradiation (APBI) at the San Antonio Breast Cancer Symposium, which was attended by BCAC representatives Fay Sowerby and Emma Crowley.

Partial breast irradiation (PBI) treats the site of the lumpectomy and the surrounding tissue rather than the whole breast. APBI ‘accelerates’ the process, delivering the radiation over a shorter time frame. BCAC Secretary Fay Sowerby says “Reducing the number of times a patient has to have radiation would be a great improvement for a number of women, who would have less travel and less stress. It would bring benefits for quality of life, family life and work.”

Dr Meattini’s findings are the results of a 10-year follow-up to a study known as the Florence, Randomised Phase 3 Trial, Accelerated Partial Breast Intensity-Modulated Radiation Therapy. The study took place against a backdrop of increasing use of APBI in radiation oncology in some countries.

Dr Meattini concluded “In well-selected cases, there is no difference in patients’ outcomes whether they are treated with APBI or whole breast irradiation (WBI). A once-daily regimen of external APBI might also produce an improved quality of life, with less toxicity, and can potentially reduce the overall treatment time.”

BCAC consulted Canterbury radiation oncologist, Dr Melissa James, to see what these results might mean for New Zealand women.

Dr James said that APBI has been under investigation for a number of years. In 2016 a systematic review and meta-analysis of all available data from randomised trials showed that overall survival for patients with APBI was similar to those treated with WBI and there were fewer early side effects such as skin reactions. However, some outcomes were worse. Those who received APBI had more 'elsewhere primaries' (new primary breast cancers in the same breast) and also more late side effects, such as changes in size and texture of the breast.  The review could not draw conclusions about the safety of the procedure and hence it was not developed widely within Australia and New Zealand. 

Dr James noted that evidence from more recent clinical trials on APBI continues to become available. She said “For patients with early-stage breast cancer, our findings support whole breast irradiation following lumpectomy; however, with an absolute difference of less than 1% in the 10-year cumulative incidence of intra breast recurrence, APBI might be an acceptable alternative for some women.  It may be slightly inferior in terms of breast relapse rates compared to whole breast radiation treatment, but the difference is likely to be small. The acute toxicity with APBI may be better but the late toxicity, likely worse.“

Fay also spoke to Auckland radiation oncologist Dr Sue Brooks about APBI. She said that PBI or APBI is a treatment option for carefully selected patients with a low risk of having clinically occult (hidden) disease remote from the lumpectomy cavity. Dr Brooks follows the American ASTRO Guidelines and considers each woman’s breast cancer grade and HER2 status according to a consensus statement published by the UK Royal College of Radiologists. To be considered for the partial irradiation treatment, patients must meet the following criteria: age 50 years or older, Grade 1 or 2 ductal carcinoma, unifocal tumour < 3cm, clear margins after surgery > 2 mm, no lympho-vascular involvement, ER positive, HER2 negative sub-types, and node-negative.

In conclusion, it seems that in New Zealand, the choice between partial or whole breast irradiation will continue to depend on clinician and patient preference and the availability of appropriate technology.  Perhaps as more research is published, we will see a move towards greater use of this option for suitable patients.

For more detailed information about the Italian research trial, please see:

Press release, SABCS 2019: Partial Breast Irradiation May be as Effective as Whole Breast Irradiation in Preventing Recurrence in Patients with Early Breast Cancer 10-year follow-up data supports earlier findings on recurrence and survival

ASCO Post, December 2019: SABCS 2019: 10-Year Follow-up of Adjuvant Accelerated Partial-Breast Irradiation vs Adjuvant Whole-Breast Irradiation

OncLive, 12 December 2019: SABCS 2019: Accelerated Partial Breast Irradiation Could Replace Whole Breast Irradiation in Low-Risk Early Breast Cancer

 

- 19 April 2020

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