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Otto Metzger, MD

Instructor in Medicine
Dana-Farber Cancer Institute
Boston, Massachusetts
Conquer Cancer Foundation of ASCO

Current Research

  • Seeking to improve outcomes for patients with invasive lobular breast cancer.
  • A clinical trial is planned to identify strategies to reduce resistance to anti-estrogen therapies.
  • These studies will provide valuable information on an understudied form of breast cancer.
Invasive lobular breast cancer (ILC) is the second most common breast cancer after invasive ductal carcinoma (IDC). Both diseases are usually positive for the estrogen receptor, but resistance to anti-estrogen therapies is more frequent in patients with ILC compared to those with IDC. Dr. Metzger is conducting a clinical trial in patients with either IDC or ILC to study patterns of response to anti-estrogen therapy and identify mechanisms of drug resistance.

Full Research Summary

Invasive Lobular Carcinoma (ILC) accounts for 10% of all breast cancers and is the second most common histological subtype after Invasive Ductal Carcinoma (IDC). When compared to IDC, ILC has unique clinico-pathologic features. Despite distinct differences from IDC, most clinical studies have not considered ILC as a unique subset of breast cancer. 

Previous studies by Dr. Metzger’s group have shown partial resistance to tamoxifen among patients diagnosed with ILC.  Based on this observation, Dr. Metzger is conducting a preoperative clinical study that will include patients diagnosed with either ILC or IDC.

Newly diagnosed breast cancer patients will receive a two-phase course of treatment prior to surgery. The first phase will compare two types of antiestrogen therapy (tamoxifen vs. letrozole). The second phase will test the addition of a new targeted therapy called CDK4/6 inhibitor (palbociclib). Dr. Metzger’s team will evaluate the response to therapy at the time of surgery and use tumor tissue to identify mechanisms of resistance to endocrine therapy either alone or in combination with palbociclib.

This study will provide important information to reduce resistance to endocrine therapies and improve outcomes for patients with invasive lobular breast cancer


Otto Metzger received his MD from Federal University of Minas Gerais in his native Brazil. He then completed an internal medicine residency in a top-ranked general hospital, Hospital Felicio Rocho, and a medical oncology fellowship at the Brazilian National Cancer Institute (INCA). Motivated to be more involved in research, he joined a research fellowship program at the Institute Jules Bordet in Belgium. While in Brussels he conducted a series of translational research investigations focused on understanding the molecular underpinnings of lobular tumors. He identified a subpopulation of lobular tumors classified as high-risk using the Genomic Grade Index gene signature.

Upon completing his research fellowship in Brussels, Otto Metzger moved to Dana-Farber Cancer Institute as a Breast Cancer Goldfarb Fellow. In Boston, in conjunction with his clinical duties, he continued his research projects involving lobular breast cancer. In collaboration with the Breast International Group and using data from the HERA trial, he demonstrated that patients diagnosed with lobular tumors classified as HER2-positive derive the same magnitude of benefit from adjuvant trastuzumab when compared to HER2-positive ductal carcinoma. Subsequently, in collaboration with the International Breast Cancer Study Group, he performed an analysis using data from the phase III study BIG 1-98. His results points to a tamoxifen-resistant phenotype among patients diagnosed with lobular carcinoma.

In addition to his work as a physician at Dana-Farber, Otto Metzger holds an executive officer position at the Alliance for Clinical Trials in Oncology where he oversees the scientific and operational aspects of national and international clinical trials dedicated to breast cancer. Otto Metzger is also actively involved in teaching and advancing education efforts both within DFCI and abroad

Large Researcher Headshot - Metzger Otto

BCRF Investigator Since


Area(s) of Focus