Prognostic value of nodal ratios in node-positive breast cancer: a compiled update.

The number of positive axillary nodes is a strong prognostic factor in breast cancer, but is affected by variability in nodal staging technique yielding varying numbers of excised nodes. The nodal ratio of positive to excised nodes is an alternative that could address this variability. Our 2006 review found that the nodal ratio consistently outperformed the number of positive nodes, providing strong arguments for the use of nodal ratios in breast cancer staging and management. New evidence has continued to accrue confirming the prognostic significance of nodal ratios in various worldwide population settings. This review provides an updated summary of available data, and discusses the potential application of the nodal ratio to breast cancer staging and prognostication, its role in the context of modern surgical techniques such as sentinel node biopsy, and its potential correlations with new biologic markers such as circulating tumor cells and breast cancer stem cells.

The effect of adjuvant radiotherapy on mortality differs according to primary tumor location in women with node-positive breast cancer.

PURPOSE: To evaluate the prognostic significance of primary tumor location and to examine whether the effect of adjuvant radiotherapy on survival varies according to tumor location in women with axillary node-positive (ALN+) breast cancer (BC). PATIENTS AND METHODS: Data were abstracted from the SEER database for 24,410 women aged 25-95 years, diagnosed between 1988-1997 with nonmetastatic T1-T2, ALN+ BC. Subgroup analyses were performed using interactions within proportional hazards models. Event was defined as death from any cause. Prognostic variables were selected using Akaike Information Criteria. Joint significances of subgroups were evaluated with Wald test. RESULTS: Median follow-up was 10 years. In joint models, statistically significant interactions were found between tumor location, nodal involvement, type of surgery, and radiotherapy. Factorial presentation of interactions showed consistent 13% proportional reduction of mortality in all subgroups, except in women with medial tumors with > or = 4 ALN+ treated with mastectomy. In this subgroup, use of radiotherapy was associated with a 16% proportional increase in mortality. CONCLUSION: Medial tumor location is a significant adverse prognostic factor that should be considered in treatment decision- making for women with ALN+ BC. Improved survival was observed with radiotherapy use in all subgroups, except in women with medial tumors with > or = 4 ALN+ treated with postmastectomy radiotherapy. These findings raise concern that the favorable effect of radiotherapy may be offset by excess toxicities in the latter subgroup.

Ratios of involved nodes in early breast cancer.

INTRODUCTION: The number of lymph nodes found to be involved in an axillary dissection is among the most powerful prognostic factors in breast cancer, but it is confounded by the number of lymph nodes that have been examined. We investigate an idea that has surfaced recently in the literature (since 1999), namely that the proportion of node-positive lymph nodes (or a function thereof) is a much better predictor of survival than the number of excised and node-positive lymph nodes, alone or together. METHODS: The data were abstracted from 83,686 cases registered in the Surveillance, Epidemiology, and End Results (SEER) program of women diagnosed with nonmetastatic T1-T2 primary breast carcinoma between 1988 and 1997, in whom axillary node dissection was performed. The end-point was death from breast cancer. Cox models based on different expressions of nodal involvement were compared using the Nagelkerke R2 index (R2N). Ratios were modeled as percentage and as log odds of involved nodes. Log odds were estimated in a way that avoids singularities (zero values) by using the empirical logistic transform. RESULTS: In node-negative cases both the number of nodes excised and the log odds were significant, with hazard ratios of 0.991 (95% confidence interval 0.986-0.997) and 1.150 (1.058-1.249), respectively, but without improving R2N. In node-positive cases the hazard ratios were 1.003-1.088 for the number of involved nodes, 0.966-1.005 for the number of excised nodes, 1.015-1.017 for the percentage, and 1.344-1.381 for the log odds. R2N improved from 0.067 (no nodal covariate) to 0.102 (models based on counts only) and to 0.108 (models based on ratios). DISCUSSION: Ratios are simple optimal predictors, in that they provide at least the same prognostic value as the more traditional staging based on counting of involved nodes, without replacing them with a needlessly complicated alternative. They can be viewed as a per patient standardization in which the number of involved nodes is standardized to the number of nodes excised. In an extension to the study, ratios were validated in a comparison with categorized staging measures using blinded data from the San Jose-Monterey cancer registry. A ratio based prognostic index was also derived. It improved the Nottingham Prognostic Index without compromising on simplicity.