Role of cytologic grading in prognostication of invasive breast carcinoma

BACKGROUND: Evaluation of cytologic features is indispensable in the preoperative diagnosis and grading of infiltrating ductal breast carcinoma (CA) in fine-needle aspiration cytology (FNAC) material and this method can also provide additional information regarding intrinsic features of the tumor as well as its prognosis. AIM: This study has been done to evaluate comparatively the cytologic and histomorphologic grading of infiltrating ductal carcinoma of breast with specific reference to lymph node metastasis and its role in prognostication. MATERIALS AND METHODS: Forty three patients who underwent FNAC and mastectomy for infiltrating ductal carcinoma were cytologically and histologically graded (employing Robinson's cytologic grading system and Elston's modification of Bloom-Richardson system, respectively). Statistical analysis was done employing ‘z’ test and χ(2) test to compare the two grading system and to examine the degree of correlation between the cytologic and histologic grades. Multiple regression analysis was done to assess the significance of every cytologic and histologic parameter. All 43 cases, graded cyto-histologically were also evaluated for presence or absence of metastasis to the regional lymph nodes employing χ(2) test. RESULTS: With histologic grade taken as the standard, cytology was found to be fairly comparable, for grading breast carcinoma (overall sensitivity 89.1%, specificity 100%). Further comparison of the two grading systems by Z-test showed that difference between the cytologic and histologic grading was insignificant in all the three grade (P > 0.05). Of the six parameters studied, cell dissociation, nucleoli and chromatin pattern were the most influential features (P < 0.001). The statistically significant difference (p < 0.001) was found in incidences of axillary lymph node metastatic rate in three cytologic grades (15.4% in grade I vs. 83.3% in grade III) as well. CONCLUSIONS: Apart from being simple and noninvasive, cytologic grading is comparable to histologic grading and might provide relevant information on the aggressiveness of invasive ductal carcinoma of breast and could be a useful parameter to take into consideration when selecting mode of therapy and to predict tumor behavior.