Effect of the method of biopsy on the prognosis of and reliability of receptor assays in patients with operable breast cancer.

A comparison has been made of the survival of contemporary patients treated by mastectomy in whom the original diagnosis was made by either Tru-cut biopsy or by excision biopsy. After a minimum of 5 years of follow-up there was no difference in survival between those biopsied by either method. When subdivided by tumour size again no differences emerged. Among those patients in whom the original Tru-cut biopsy was false negative there was no difference in survival compared with those treated by excision biopsy. This suggests that Tru-cut biopsy is a safe method for obtaining a histological diagnosis in operable breast cancer. Furthermore, when the receptor status of the tumours from the two groups was determined, there was no difference in the percentage of oestrogen receptor positive tumours, nor in the mean receptor value. However, there were more progesterone receptor positive tumours among the Tru-cut group, suggesting that a better tumour sample could have been submitted for analysis. This may be yet another advantage for the use of Tru-cut biopsy for the diagnosis of breast cancer.