A glance on quality assurance in EORTC study 22922 evaluating techniques for internal mammary and medial supraclavicular lymph node chain irradiation in breast cancer

Abstract

Purpose: To evaluate the irradiation techniques used for the irradiation of the internal mammary and medial supraclavicular lymph node chain (IM-MS) in the EORTC 22922 study, which evaluates its impact on survival in stage I–III breast cancer patients with axillary node invasion and/or central or medial location of the primary tumour. Materials and methods: The analysis was performed based on the dummy run data of the Quality Assurance Programme of the study. A standard irradiation technique was proposed within the study protocol, and the use of other treatment set-up techniques was allowed. Results: By March 2000, 39 centres from 12 different countries had participated in the study; 32 of these had already fulfilled the dummy run procedure. No centres had to be excluded from the study. Seventy-eight percent of the centres are using the standard irradiation technique, 64% of these with minor variations. Twenty-two percent of the centres developed an alternative irradiation technique. The remarks to the centres using the standard set-up were most often related to the junction problem and the possible under- or overdosage in the target volumes. The remarks to the centres with alternative techniques most often concerned the possible enhanced dose to the lungs and the heart. Conclusion: In a multi-centre trial an easy irradiation technique applicable in a large number of centres should be provided. A quality assurance programme allows early detection of possible problems with treatment planning and delivery. The analysis of the dummy run data showed that if the recommendations of the Quality Assurance Committee are applied, both standard and alternative IM-MS irradiation techniques produce acceptable dose distributions.