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World J Clin Oncol. Dec 10, 2017; 8(6): 437-446
Published online Dec 10, 2017. doi: 10.5306/wjco.v8.i6.437
Metronomic chemotherapy for non-metastatic triple negative breast cancer: Selection is the key
Connie Rabanal, Rossana Ruiz, Silvia Neciosup, Henry Gomez
Connie Rabanal, Rossana Ruiz, Silvia Neciosup, Henry Gomez, Department of Medical Oncology, Instituto Nacional de Enfermedades Neoplasicas, Lima 15038, Peru
Author contributions: Rabanal C and Ruiz R contributed to the conception, design of the review and performed the research; all authors contributed to this manuscript with conception and design of the study, literature review and analysis, editing, critical revision and approval of the final version.
Conflict-of-interest statement: No conflict of interest exists.
Open-Access: This article is an open-access article which was selected by an in-house editor and fully peer-reviewed by external reviewers. It is distributed in accordance with the Creative Commons Attribution Non Commercial (CC BY-NC 4.0) license, which permits others to distribute, remix, adapt, build upon this work non-commercially, and license their derivative works on different terms, provided the original work is properly cited and the use is non-commercial. See: http://creativecommons.org/licenses/by-nc/4.0/
Correspondence to: Connie Rabanal, MD, Department of Medical Oncology, Instituto Nacional de Enfermedades Neoplasicas, Av. Angamos Este 2520 Surquillo, Lima 15038, Peru. crabanal@auna.pe
Telephone: +51-1-921139544
Received: January 15, 2017
Peer-review started: January 16, 2017
First decision: May 2, 2017
Revised: August 11, 2017
Accepted: September 6, 2017
Article in press: September 6, 2017
Published online: December 10, 2017
Processing time: 323 Days and 19.2 Hours
Abstract

Triple negative breast cancer (TNBC) accounts for 15%-20% of all breast cancer, and is still defined as what it is not. Currently, TNBC is the only type of breast cancer for which there are no approved targeted therapies and maximum tolerated dose chemotherapy with taxanes and anthracycline-containing regimens is still the standard of care in both the neoadjuvant and adjuvant settings. In the last years, metronomic chemotherapy (MC) is being explored as an alternative to improve outcomes in TNBC. In the neoadjuvant setting, purely metronomic and hybrid approaches have been developed with the objective of increasing complete pathologic response (pCR) and prolonging disease free survival. These regimens proved to be very effective achieving pCR rates between 47%-60%, but at the cost of great toxicity. In the adjuvant setting, MC is used to intensify adjuvant chemotherapy and, more promisingly, as maintenance therapy for high-risk patients, especially those with no pCR after neoadjuvant chemotherapy. Considering the dismal prognosis of TNBC, any strategy that potentially improves outcomes, specially being the oral agents broadly available and inexpensive, should be considered and certainly warrants further exploration. Finally, the benefit of MC needs to be validated in properly designed clinical trials were the selection of the population is the key.

Keywords: Metronomic chemotherapy; Triple negative breast cancer; Neoadjuvant; Adjuvant; Maintenance

Core tip: Triple negative breast cancer (TNBC) is the only type of breast cancer for which there are no approved targeted therapies. Metronomic chemotherapy (MC) is being explored as an alternative to improve outcomes in TNBC. In neoadjuvant setting, purely metronomic and hybrid approaches achieve complete pathologic response (pCR) rates between 47%-60%, but at the cost of great toxicity. In the adjuvant setting, MC is used to intensify adjuvant chemotherapy and, promisingly, as maintenance therapy for high-risk patients, especially those with no pCR. Considering the dismal prognosis of TNBC, any strategy that improves outcomes, specially being broadly available and inexpensive, should be considered.