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APBI with brachytherapy for early stage breast cancer

Brachytherapy

More positive results on early stage breast cancer technique emerge from GEC-ESTRO study

The GEC-ESTRO phase III clinical trial comparing accelerated partial breast irradiation (APBI) and whole breast irradiation (WBI) has shown that APBI with multicatheter interstitial brachytherapy is associated with significantly fewer grade 2-3 late skin side effects and equivalent cosmesis compared to WBI plus boost treatment. These latest results from the GEC-ESTRO study data were presented in an article published in The Lancet Oncology by Csaba Polgár, et al, February 2017.[1]

The GEC ESTRO study authors conclude that these results support the routine use of interstitial multicatheter brachytherapy-based APBI in the treatment of patients with low-risk breast cancer who opt for breast conservation. APBI is a targeted form of radiation that is delivered after surgical excision of the tumor (lumpectomy) to only the area of the breast where the cancer was removed. This is accomplished by introducing a radiation source through a series of narrow tubes placed inside the breast at the lumpectomy site.

This recent positive finding follows results reported in October 2016 that for post-lumpectomy patients, highly-focused short-course multi-catheter APBI is at least as effective as long-course fractionated WBI.[2]

This prospective randomized multicenter phase III study demonstrated that APBI with multicatheter interstitial brachytherapy (a 4-5 day treatment) is clinically equivalent to the traditional treatment of whole breast irradiation (WBI) plus boost (a 5-6 week treatment) in selected patients with early stage breast cancer who had undergone breast conserving therapy.

This seminal study drove the change in the new 2016 ASTRO guidelines for breast APBI to include younger patients (> 50 years) and patients with DCIS in the “suitable for APBI” category, meaning that more women with early breast cancer are eligible for a short treatment course with APBI brachytherapy.[3]

This validation of APBI brachytherapy in both studies and guidelines is good news for selected patients with early breast cancer who can be offered this shorter course of radiation treatment. Since its introduction in the late 1990s, more than 10,000 women in the United States have received APBI brachytherapy

Elekta offers the full breast brachytherapy package. The combination of the OncoSmart Catheter System and the Breast CT/MR Template sets, completed with Oncentra Brachy Implant Modelling and Flexitron afterloading provides an excellent APBI brachytherapy solution. In addition, breast brachytherapy workshops are run by key experts through the BrachyAcademy (https://www.brachyacademy.com).

References:

  1. Polgar C et al. Lancet Oncol 2017. Published Online http://www.thelancet.com/journals/lanonc/article/PIIS1470-2045(17)30011-6/fulltext
  2. Strnad V, Ott O, Hillebrandt G et al. Lancet 2016;387:229-38
  3. Available at: http://www.practicalradonc.org/article/S1879-8500(16)30184-9/pdf. Accessed February 2017

What is APBI?

APBI is a therapeutic approach that treats only the affected part of the breast. The lumpectomy bed and 1-2 cm of breast tissue beyond the surgical edge are treated with therapeutic doses of ionizing radiation, rather than the whole breast. Because the dose cloud is limited, a higher dose can be delivered in a shorter time – twice a day over four or five days, versus external beam whole breast irradiation, which involves five treatments per week for four to six-and-a-half weeks. Interstitial brachytherapy involves the implantation of multiple thin catheters into the breast, surrounding the tumor site. A high-activity radioactive source is introduced by cables into the catheters. The source then travels sequentially through each cable until the prescribed dose is delivered. Radiobiologists have calculated that 32 Gy in eight fractions over four days, or 34 Gy in 10 fractions over five days, has similar tumor control probability and late normal tissue effects as the whole breast dose of 50 Gy in 25 fractions.

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