Primary tumour-vessel tumour-nodal tumour classification for patients with invasive ductal carcinoma of the breast

Abstract

There are many studies that show biological differences between invasive ductal carcinoma (IDC) with and without nodal metastasis, but no prognostic classification taking into consideration any biological differences between them is currently available. We previously investigated the histological characteristics that play an important role in tumour progression of IDCs according to their nodal status, and a new prognostic histological classification, the primary tumour-vessel tumour-nodal tumour (PVN) classification, was devised based on the histological characteristics of IDCs with and without nodal metastasis. Multivariate analyses using the Cox proportional hazard regression models were used to compare the ability of the PVN classification to predict tumour recurrence and death in 393 IDC patients based on the following histological classifications: (1) the pTNM classification, (2) the Nottingham Prognostic Index, (3) the modified Nottingham Prognostic Index, and (4) the histologic grade. In IDCs without nodal metastasis, only the PVN classification significantly increased the hazard rates (HRs) of tumour recurrence and death (P<0.05), independent of the hormone receptor status. Similarly, in IDCs with nodal metastases, only the PVN classification significantly increased the HRs of tumour recurrence and death (P<0.05), independent of the hormone receptor status. We conclude that the PVN prognostic histological classification is the best classification available for IDC of the breast.

Figure 1

The disease-free and the overall survival curves according to the PVN classification system in IDCs without nodal metastasis that were positive for ER and/or PR (A and B), IDCs without nodal metastasis that were negative for both ER and PR (C and D), IDCs with nodal metastasis that were positive for ER and/or PR (E and F), and IDCs with nodal metastasis that were negative for both ER and PR (G and H). The disease-free and overall survival curves of each risk group in each IDC subgroups decrease according to the risk order of the classification, with the very high-risk groups in each IDC subgroup showing the shortest disease-free and overall survival curves independent of nodal status and hormone receptor status.