PATIENT POPULATION ANALYSIS IN EORTC TRIAL-22881 10882 ON THE ROLE OFA BOOSTER DOSE IN BREAST-CONSERVING THERAPY/

The changing composition of the patient population in breast cancer, w hich has been reported over the last decade, has important consequence s for prognosis. In the present trial, an analysis of the population i n an EORTC trial (22881/10882) on breast-conserving therapy was conduc ted. A shift towards earlier stages has been seen stage per stage, the refore better survival and local control rates are likely to be expect ed in comparison to previously published series. The majority of tumou rs in this trial were small, with a median clinical size of 2 cm and a median pathological size of 1.5 cm. A substantial number of lesions w ere detected in a pre-clinical stage (17.8%). Nodal involvement was pr esent in only 19% of all patients and usually in only a low number of nodes (only 4% of all patients had four or more nodes invaded). The me dian number of nodes examined was 12, the difference between instituti ons was large. There was a significant correlation between the number of nodes examined, the percentage of patients with positive nodes (P = 0.03) and the percentage of patients with massive axillary invasion ( P = 0.003). The correlation between clinical evidence and pathological invasion of the axillary nodes showed that 15% of the clinical examin ations were false-negative and 51% were false-positive. Pathological n odal invasion could be clinically predicted in only 31% of patients, a nd consequently clinical examination of the axilla was a poor predicto r of prognosis in this study. Pathological invasion of axillary lymph nodes was better correlated to pathological tumour size than clinical or radiological size.