Primary invasive breast cancer

Last reviewed: 2 Sep 2023

Last updated: 20 Sep 2023

Breast cancer is a malignancy that is often strongly influenced by age, family history, genetic factors, hormonal exposure, and lifestyle factors.

The majority of patients are asymptomatic and present with abnormal calcifications and/or architectural distortion, or asymmetric density, on a routine screening mammogram.

Clinical breast exam may demonstrate a firm breast mass, which may be associated with axillary lymphadenopathy, skin changes, and nipple discharge.

Treatment requires a multidisciplinary approach, involving medical oncologists, breast surgeons, and radiation oncologists.

Complications of therapy are specific to each modality of treatment, and careful monitoring and preventive therapy for adverse events (e.g., antiemetic pre-medications in the prevention of chemotherapy-induced nausea) are essential.

Definition

Primary invasive breast cancer is a malignancy originating in the ducts or lobules. The term "invasive" indicates that the malignancy has penetrated past the basement membrane of the duct or lobule of the breast and has spread to the surrounding tissues, but has not spread to other organs.

The American Joint Committee on Cancer TNM (tumor, node, metastasis) staging system classifies invasive breast cancer into the following stages based on the extent of disease: IA, IB, IIA, IIB, IIIA, IIIB, and IIIC.[1]

Stages IA, IB, and IIA are generally considered early-stage breast cancer. Stages IIIA, IIIB, and IIIC are generally considered locally advanced breast cancer.

Staging can also be defined by the pathologic node status (pN0 - pN3), which is dependent on the number of axillary nodes with metastases.

History and exam

Key diagnostic factors

breast mass
nipple discharge
axillary lymphadenopathy

More key diagnostic factors

Other diagnostic factors

skin thickening or discoloration
retraction or scaling of the nipple

Other diagnostic factors

Risk factors

increasing age
female sex
ethnic origin
positive family history
genetic mutations
endogenous estrogen exposure
exogenous estrogen/progestin exposure
alcohol consumption
radiation exposure
atypical breast disease
increased breast density
mild, moderate, or marked background parenchymal enhancement (BPE) on breast MRI
reduced physical activity
poor diet
high socioeconomic status
smoking
obesity
high dibutyl-phthalate exposure

More risk factors

Diagnostic investigations

1st investigations to order

mammogram

More 1st investigations to order

Investigations to consider

breast ultrasound
breast MRI
biopsy
hormone receptor testing
HER2 testing
gene expression assays
computed tomography
genetic testing
CBC
LFTs
alkaline phosphatase

More investigations to consider

Treatment algorithm

ACUTE

early-stage breast cancer (stages I to IIB [T2 N1 M0])

locally advanced breast cancer (stages IIB [T3 N0 M0] to III)

ONGOING

disease recurrence

Contributors

Authors

Krystal Cascetta, MD

Assistant Professor

Division of Hematology and Medical Oncology

Icahn School of Medicine at Mount Sinai

New York

Disclosures

KC declares that she has no competing interests.

Amy Tiersten, MD

Professor

Division of Hematology and Medical Oncology

Dubin Breast Center of the Tisch Cancer Institute

New York

Disclosures

AT is on the advisory board for Immunomedics, AstraZeneca, Novartis, Eisai, and Healthline. She receives research funding from Pfizer, Novartis, Genentech, Lilly, and AstraZeneca and does expert testimony work.

Acknowledgements

Dr Krystal Cascetta and Professor Amy Tiersten would like to gratefully acknowledge Dr Hope S. Rugo, Dr Amal Melhem-Bertrandt, Dr Gabriel N. Hortobagyi, and Dr Phuong Khanh H. Morrow, the previous contributors to this topic.

Disclosures

AMB, GNH, and PKHM declare that they have no competing interests. HSR receives research funding through the University of California from Novartis, Pfizer, Genentech, Macrogenics, Plexxikon, Merck, Nektar, and GSK; has been reimbursed for travel by Novartis, Genentech, and Nektar; and has received speaker honorarium from Genomic Health.

Peer reviewers

Kandace P. McGuire, MD

Professor of Surgery

Virginia Commonwealth University

Richmond

Disclosures

KPM declares that she has no competing interests.

Katherine H.R. Tkaczuk, MD, FACP

Professor of Medicine

University of Maryland School of Medicine

Baltimore

Disclosures

KHRT declares that she has no competing interests.

Susan Tannenbaum, MD

Associate Professor, Medicine

Chief, Division of Hematology/Oncology

Medical Director, Neag Comprehensive Cancer Center

University of Connecticut

Farmington

Disclosures

ST declares that she has no competing interests.

Emily Hsu, MD

Fellow

Division of Hematology/Oncology

University of Connecticut

Farmington

Disclosures

EH declares that she has no competing interests.

Anees Chagpar, MD

Assistant Professor

University of Louisville

Louisville

Disclosures

AC declares that she has no competing interests.

Gurhan Celik, MD

General Surgeon

General Surgery Department

Istanbul Training and Research Hospital

Istanbul

Turkey

Disclosures

GC is an author of a number of references cited in this topic.

Edward R. Sauter, MD, PhD

Medical Officer

Breast and Gynecologic Cancer Working Group

Division of Cancer Prevention

National Cancer Institute

Bethesda

Disclosures

ERS declares that he has no competing interests.

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Primary invasive breast cancer

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations to consider

Treatment algorithm

early-stage breast cancer (stages I to IIB [T2 N1 M0])

locally advanced breast cancer (stages IIB [T3 N0 M0] to III)

disease recurrence

Contributors

Authors

Krystal Cascetta, MD

Disclosures

Amy Tiersten, MD

Disclosures

Acknowledgements

Disclosures

Peer reviewers

Kandace P. McGuire, MD

Disclosures

Katherine H.R. Tkaczuk, MD, FACP

Disclosures

Susan Tannenbaum, MD

Disclosures

Emily Hsu, MD

Disclosures

Anees Chagpar, MD

Disclosures

Gurhan Celik, MD

Disclosures

Edward R. Sauter, MD, PhD

Disclosures

Differentials

Guidelines

Patient leaflets

Log in or subscribe to access all of BMJ Best Practice

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