Is There Prognostic Significance Of Tumor Cellularity In Primary Non-Treated Breast Carcinoma?

Background: Many factors such as tumor size, grade, lymph node and receptor status, either independently or in combination, as with the Nottingham Prognosic Index (NPI), are known to predict outcomes in non-treated breast cancer. With the growing use of neoadjuvant therapies, additional prognostic indicators have been identified for evaluating treated carcinomas. Many post-treatment methods of analysis rely on tumor cellularity (TC) either alone, as in the Miller-Payne system, or in combination with other tumor features, as in the Residual Cancer Burden (RCB) to predict distant relapse-free survival (RFS). It is not clear however, whether TC can predict outcomes in non-treated breast carcinoma. The goal of this study was to evaluate the prognostic value of TC in this particular setting. Design: TC (%), excluding foci of necrosis and in-situ carcinoma, was determined from histologic review of a representative tumor section in the primary excision of 366 invasive breast carcinomas and categorized into quartiles. Prior detailed histology review included tumor size (TS), histological type and grade, receptor and lymph node status, RFS and overall survival (OS). Nottingham Prognostic Index (NPI) was calculated for each case (0.2 x tumor size (cm) + lymph node stage (1, node negative; 2, 1-3 positive nodes; 3, ≥ 4 positive nodes) + histologic grade). Results: Mean patient age was 58 yr (range, 21-91) and median follow-up was 87 mo (range, 0.7-165). Invasive ductal carcinoma of no special type constituted 80% of cases, invasive lobular carcinoma 10%, and other special types of carcinoma, 10%. Nottingham grades I, II and III, represented 25%, 41% and 32% of the cases, respectively (unknown in 4). Mean NPI was 3.93 (range, 2.06–6.8). Estrogen receptor was positive in 66% and negative in 25% of cases (unknown in 9%). TC ranged from 2-99% (mean 47.6%). As expected, NPI was predictive of OS (p=0.000; hazard ratio 1.726; 95% confidence interval 1.45-2.05) and RFS (p=0.000; hazard ratio 2.011; 95% confidence interval 1.62-2.50). TC, unadjusted for other covariates was not predictive of OS or RFS (Table 1). The same analysis of ER positive and negative subgroups continued to show no relation of TC to OS or RFS (Table 2). When adjusted for NPI, TC still showed no significant relation to OS or RFS (data not shown). Conclusion: Despite its utility in the neoadjuvant setting, TC does not offer the same prognostic value in the setting of untreated tumors and is not predictive of OS or RFS in primary non-treated carcinomas. Citation Format: Emily S Reisenbichler, William Dupont, Plummer Dale, Omar Hameed. Is there prognostic significance of tumor cellularity in primary non-treated breast carcinoma? [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P6-08-13.