Determining the Need for Metastatic Staging in Patients with Bilateral Breast Cancers

Sep 21, 2026

Bilateral breast cancers (BBC) diagnosed with an interval are rare, and the value of metastatic staging at contralateral diagnosis is unclear. This study retrospectively identified which BBC subgroups benefit from metastatic staging by stratifying eligible patients into three clinical categories and applying exclusion criteria focused on bilateral DCIS, synchronous presentation, stage IV at first diagnosis, and prior recurrence. Among 4516 new cases, 79 met criteria; systemic metastasis occurred in 15.6% of Group B, with nodal positivity timing associated with risk.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages11

Reading Time28 min

AccessFree to download

Abstract

1. Introduction

2. Materials and Methods

Results

Conclusions

Article Determining the Need for Metastatic Staging in Patients with Bilateral Breast Cancers Veronica Siton Alcantara 1, Sut Mo Zachary Chan 1, Fuh Yong Wong 2, John Carson Allen 3 and Geok Hoon Lim 1,3, * Citation: Alcantara, V.S.; Chan, S.M.Z.; Wong, F.Y.; Allen, J.C.; Lim, G.H. Determining the Need for Metastatic Staging in Patients with Bilateral Breast Cancers. Curr. Oncol. 2024, 31, 1936–1946. [https://doi.org/](https://doi.org/)[ ](https://doi.org/)[10.3390/curroncol31040145](10.3390/curroncol31040145) Received: 29 February 2024 Revised: 23 March 2024 Accepted: 28 March 2024 Published: 2 April 2024 Copyright: © 2024 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ([https://](https://)[ ](https://)[creativecommons.org/licenses/by/](creativecommons.org/licenses/by/)[ ](creativecommons.org/licenses/by/)[4.0/](4.0/)) . 1 Breast Department, KK Women’s and Children’s Hospital, Singapore 229899, Singapore 2 Division of Radiation Oncology, National Cancer Centre, Singapore 168583, Singapore 3 Duke-NUS Medical School, Singapore 169857, Singapore; [john.allen@duke-nus.edu.sg](john.allen@duke-nus.edu.sg) * Correspondence: [ghlimsg@yahoo.com.sg](ghlimsg@yahoo.com.sg) Abstract: Introduction: Bilateral breast cancers (BBC) diagnosed at an interval apart are uncommon. While metastatic staging guidelines are established in patients with unilateral breast cancer, its role in BBC diagnosed at an interval apart is unclear. We aim to identify the subgroup who would benefit from metastatic staging at contralateral cancer diagnosis. Methods: Eligible patients were divided into three categories: (A) ipsilateral invasive cancer and contralateral ductal carcinoma in situ (DCIS),(B) bilateral invasive cancers and (C) ipsilateral DCIS and contralateral invasive cancer and reviewed retrospectively. We excluded patients with bilateral DCIS, synchronous BBC diagnosed within 6 months from first cancer, patients who were stage IV at first cancer diagnosis and patients with recurrence prior to contralateral cancer. Results: Of 4516 newly diagnosed breast cancer patients, 79 patients were included. Systemic metastasis occurred in 15.6% of patients in Group B. Having nodal positivity of either cancer which were diagnosed ≤30 months apart and nodal positivity of only the contralateral cancer when diagnosed >30 months apart was significantly associated with systemic metastasis (p = 0.0322) . Conclusions: Both the nodal status and a 30 months cut-off time interval between the two cancers can be used to identify patients who will benefit from metastatic staging. This finding requires validation in larger studies. Keywords: metastatic staging; breast cancer; bilateral cancers; metachronous cancers; systemic metastasis 1. Introduction Bilateral breast cancer (BBC) is uncommon and has a reported incidence of 1.4–11.8%[1] . In women diagnosed with a primary breast cancer, there is a two to six-fold risk of developing cancer in the contralateral breast [1] . BBC can be further categorized, based on the time interval between the primary and contralateral breast cancer diagnosis, into synchronous BBC or cancers which occurred at an interval apart, with metachronous bilateral breast cancers (MBBC) usually referred to as the group with bilateral invasive cancers. The time interval used for defining synchronous bilateral cancers however varies from one month [2] to a year [3], depending on the definition used in various studies. Nonetheless, synchronous bilateral breast cancer was reported to occur in 1.6 per 105 person-years at risk while MBBC had a higher incidence rate of 440 per 105 person-years at risk [4] . Patients with MBBC were also reported to have a different prognosis from patients with unilateral breast cancer. MBBC patients with contralateral cancer diagnosed within five years of pri

FAQs

Why is metastatic staging at contralateral diagnosis uncertain for bilateral breast cancer patients?

Bilateral breast cancers diagnosed with an interval apart are uncommon, and established metastatic staging guidance for unilateral disease does not clearly address this subgroup.

How were eligible patients categorized in the study?

Patients were divided into three categories: (A) ipsilateral invasive cancer with contralateral DCIS, (B) bilateral invasive cancers, and (C) ipsilateral DCIS with contralateral invasive cancer.

What factors were significantly associated with systemic metastasis?

Nodal positivity of either cancer when the two cancers were diagnosed within 30 months, and nodal positivity limited to the contralateral cancer when the interval exceeded 30 months were significantly linked to systemic metastasis (p = 0.0322).

Sep 21, 2026

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