Abstract PL1: Critical Decision Making in Radiation Therapy for Breast Cancer in 2015

In 2005, the EBCTCG meta-analysis demonstrated for the first time that RT after either breast-conserving surgery (BCS) or mastectomy not only reduced local-regional recurrence (LRR), but also improved long-term survival. At the time, they (erroneously) postulated that for every 4 LRR's avoid at 5 years, there was an additional survivor at 15 years. The EBCTCG subsequently adopted 'any first recurrence' as the primary endpoint for the effect of RT based on 1 – RT's established systemic effect in reducing both local and distant recurrence, 2 – that time to LRR is not strictly valid, and 3 – that the ratio between reduction in LRR and improvement in survival no longer held up. The new 'ratio' is that for every 1.5 first recurrences avoided at 10 years, there is an additional survivor at 20 years.Over the last several decades, there has been a substantial reduction in local recurrence (LR) after BCS and RT. In series of patients treated in the 1970's, 5-year rate of LR was about 10% and in more recent series, it is about 2%. This decrease is attributable to 1 – improved mammographic evaluation, 2 – improved pathologic evaluation, and probably most importantly, 3 – the benefit seen with the addition of adjuvant systemic therapy. Also, over this time frame, risk factors for LR evolved with approximated subtype using ER, PR, HER2 status and either grade or Ki-67 now the main risk factor. 5-year LR is 6% for triple negative cancers and only about 1% for Luminal A cancers....
Source: Cancer Research - Category: Cancer & Oncology Authors: Tags: Invited Speaker Abstracts Source Type: research