Combination of Modern Radiotherapy and New Targeted Treatments for Breast Cancer Management

Abstract

Background: The objective of the present study was to review the essential knowledge about the combinations of the most commonly used or under development targeted treatments and radiation therapy (RT). Methods: Preclinical and clinical studies investigating this combination were extensively reviewed. Results: Several studies showed that the combination of RT and tamoxifen increased the risk of radiation-induced pulmonary toxicity; therefore, both modalities should not be given concomitantly. The combination of HER2 inhibitors (trastuzumab, pertuzumab) and RT seems to be safe. However, trastuzumab emtansine (T-DM1) should not be administered concurrently with brain RT since this combination could increase the risk of brain radionecrosis. The combination of RT and other new target treatments such as selective estrogen receptor degradants, lapatinib, cell cycle inhibitors, immune checkpoint inhibitors, or molecules acting on DNA damage repair seems feasible but was essentially evaluated on retrospective or prospective studies with a small number of patients. Furthermore, there is considerable heterogeneity among these studies regarding the dose and fractionation of radiation, the dosage of drugs, and the sequence of treatments used. Conclusions: The combination of RT with most targeted therapies for BC appears to be well-tolerated, but these results need to be confirmed in prospective randomized studies.

Effect of postmastectomy radiotherapy on pT1-2N1 breast cancer patients with different molecular subtypes: A real-world study based on the inverse probability of treatment weighting method

“…Pietras et al [ 26 ] reported that MCF-7 cells transfected with HER2 were more resistant to radiation than parental MCF-7 cells, and antiHER2-targeted therapy could reverse the radiation resistance of HER2-overexpressing cell lines by regulating the repair of radiation induced DNA damage. [ 27 ] Indeed, antiHER2 therapy can be administered under RT and has been shown to be safe, although special attention should be given with regard to cardiotoxicity. [ 28 – 30 ]…”

Post-Neoadjuvant Treatment Strategies for Patients with Early Breast Cancer

“…Finally, when NAC is indicated, optimizing and coordinating the timing of the different treatment modalities (i.e., systemic therapy, surgery, RT) is important [ 53 ]. Capecitabine, olaparib and abemaciclib are generally started after RT completion in order to avoid potential toxicity (concomitant use is under debate and investigation), whereas trastuzumab, pertuzumab and T-DM1 can safely be given concomitantly with RT [ 54 ].…”

“…Currently, there is no consensus guidelines for the re-testing of biomarkers after NAC, and practices vary widely [ 54 ]. The College of American Pathologists recommends that if biomarkers were negative prior to therapy, re-testing should be performed on residual invasive carcinoma after NAC.…”

Stereotactic Radiation and Dual Human Epidermal Growth Factor Receptor 2 Blockade with Trastuzumab and Pertuzumab in the Treatment of Breast Cancer Brain Metastases: A Single Institution Series

“…Even if there are some data on the association of RT and PT in other settings such as palliative bone treatment and postoperative BC treatment [ 17 , 18 , 19 ] with a favourable tolerance profile, no literature data is available on the association between PT and brain fSRT.…”