The importance of histologic grade in long-term prognosis of breast cancer: a study of 1,010 patients, uniformly treated at the Institut Gustave-Roussy.

In a study of 1,010 patients with solitary, unilateral, nonmetastatic breast cancer, the histologic grade, assessed by a multifactorial analysis (Cox model) to study its significance with other prognostic factors, was found to be an important, independent factor. For 612 operable patients, two laboratory characteristics, the number of histologically positive nodes and the histologic grade, were the most valuable predictors. These two factors alone form a predictive index that may be an excellent and simple guide for the clinical decision of subsequent therapy. For 398 patients with inoperable breast cancer (ie, tumor greater than or equal to 7 cm, N2-3, inflammatory, skin fixation, and clinically rapidly growing forms), the histologic grade (performed on drill or cutting needle biopsy) was again a most important (and with inflammatory forms the most important) predictor of prognosis in these patients. Our data support that performing our modified histoprognostic grading of Scarff and Bloom is simple, reproducible, incurs no additional cost, may be carried out in the simplest histology laboratory, and finally, defines an important risk factor in all patients. It should be routine for all breast cancer specimens. Furthermore, studies of adjuvant therapy should stratify patients for this variable.