Timing of post mastectomy radiotherapy in immediate or delayed- immediate breast reconstruction: an algorithm to the sentinel first principle

Abstract

About one out of eight women will be dealing with breast cancer throughout their life. The prevalence of this disease has jet-fueled breast cancer research, causing an immense leap in treatment modalities over the last decades. A better understanding of the disease, its subtypes, its genome and its treatment strategies has allowed us to evolve from aggressive to targeted, from debulking to breast conserving and from avoiding death to ensuring quality of life after survival. Despite major advances in medical therapy, surgery remains an indispensable step in breast cancer treatment. The novelties in breast conserving surgery and reconstructive surgery have made the treatment more versatile, which allows the oncoplastic team to provide a tailor-made surgical plan for each patient. The treatment regimen must aim for synergism between the different treatment modalities, without compromising either the oncological or reconstructive objective. While adjuvant therapy may downstage the tumor and make breast conservative surgery possible, adjuvant treatments like radiotherapy might also compromise the reconstructive outcome. Most patients who undergo breast conserving surgery are treated with radiotherapy, whereas the indication for postmastectomy radiotherapy (PMRT) is mainly based on tumor stage and the extent of lymph node involvement. Radiotherapy of the breast is indicated after breast conserving surgery for all invasive tumors, most ductal carcinoma in situ and Paget’s disease. It will also be applied when mastectomy margins were not clear from disease or when the tumors appeared to be more than 4 cm in diameter. Locoregional radiotherapy is indicated when nodal disease is confirmed (≥N1) and will be more extensive according to the degree of nodal disease. In patients needing PMRT, the definite reconstruction can be delayed by placing an expander in the mastectomy pocket. Although the consequences of radiotherapy on the autologous reconstructed breast is the subject of discussion, the literature suggests a higher occurrence of fat necrosis, late flap failure and decreased esthetic outcome from radiotherapy after free flap breast reconstruction (1). Since autologous breast reconstruction requires proper organization regarding surgery time and available surgeons, it is not advisable to rely on a preoperative diagnosis to decide whether or not to proceed with an autologous reconstruction. A problem arises in clinical node-negative breast cancer patients, where the definite tumor and nodal staging is not complete until full tumor and sentinel node resection. It is logistically not feasible to foresee both immediate and delayed reconstructive surgery depending on an intraoperative decision. Therefore, the sentinel first principle was introduced in our center. This paper outlines the algorithm applied in our center, in which the sentinel procedure is done in a separate surgery before the mastectomy for definite staging. This method, called the “sentinel first procedure”, allows the oncoplastic team to decide whether immediate or delayedimmediate reconstruction is indicated. This paper describes an algorithm for this principle, which was introduced in our center in 2017, and reviews thirteen cases. The objective Editorial