Accelerated Partial-Breast Irradiation (APBI) – Ready for Prime Time?

Abstract

EditorialBreast cancer has the highest incidence among all cancer types in females with one in every eight to ten women being affected during her lifetime. The 5 year survival rate averaged over all tumor stages is reaching 90% according to the American Cancer Society [3]. Breast cancer therapy has become more and more risk adapted over the last 3 decades and especially the extent of surgery was reduced without compromising outcome. Breast conserving surgery (BCS) and sentinel node biopsy have replaced radical mastectomy and radical axillary resection in appropriately selected patients based on risk factors.There is no doubt, that adjuvant whole breast radiotherapy (WBRT) after BCS decreases the risk of in breast tumor recurrence (IBTR) from about 30-40% after 10 years to about 5-10% and thus improves overall survival by about 5% after 15 years [20,25,29,30]. Moreover, it has been demonstrated in a large randomized trial that a group of patients benefited from an additional focal dose escalation -the tumor bed boost (review in [29]). Although the results were expected founded on theoretical considerations, this change in practice had to be based on a large prospective randomized trial from the EORTC to exactly document risks and benefits.Like every other adjuvant therapy, WBRT after BCS is an overtreatment for some patients and reducing the intensity of WBRT is currently one of the most fervidly and controversially discussed issues with regard to breast cancer therapy [21][22][23][24]. Although the idea of a risk adapted reduction of breast cancer radiotherapy either in radiation dose and/or in treatment volume is intriguing, it is strongly recommended not to base such a fundamental change in clinical practice on theoretical assumptions alone rather than on solid data from properly designed and conducted trials.There are important lessons learned from the history of breast cancer treatment. 15 years ago, it was hypothesized, that there is a certain percentage of patients with so called low risk features (old age, small tumor, receptor positivity, etc.) who would not benefit from WBRT after BCS at all. Several trials were performed lasting several years, and in parallel, thousands of patients were treated according to the "expected results" outside of these trials. Up to 30% of the patients in the respective age group did not receive the proper treatment [10]. However, in none of these prospective trials any subgroup could be identified which did not benefit from WBRT in terms of a reduced rate of IBTR in all age and risk groups. Moreover, it seems important, that the relative risk reduction was almost constant in all patient groups. This experience should remind us that even though hypotheses are a prerequisite for progress in medicine, any such advancement can only Key Words: Breast cancer · Radiotherapy · Breast-conserving therapy · Partial-breast irradiation Schlüsselwörter: Mammakarzinom · Radiotherapie · Brusterhaltende Therapie · Teilbrustbestrahlung

Intraoperative Radiotherapy as Accelerated Partial Breast Irradiation for Early Breast Cancer

“…This is in accordance with formerly [29] and recently [37] published statements of the DEGRO and current German guidelines [1,12,30].…”

Accelerated partial breast irradiation: advances and controversies

“…It is also worthwhile mentioning that even though the above societies deemed the use of APBI acceptable in certain patient populations, a joint statement from three German oncology societies recommended refraining from APBI use outside of a prospective study [ 35 ]. They felt that there were not enough data available at the time to draw any conclusions about its safety and that it will also decrease the number of women who could be enrolled in ongoing prospective studies [ 35 ].…”

Radiobiological Comparison of Hypofractionated Accelerated Partial-Breast Irradiation (APBI) and Single-Dose Intraoperative Radiotherapy (IORT) with 50-kV X-Rays

“…Interest in accelerated partial breast radiotherapy (APBI) is rising rapidly worldwide [18,20,22,24,27,33,34,38]. Although the rationale varies between different studies [16], it is generally assumed that recurrences after breast-conserving surgery occur near the site of a tumor and that part of the patients may not need adjuvant radiotherapy to the whole breast [6,15].…”