From modified radical mastectomy to infra-radical mastectomy: a phase I study for surgical de-escalation focusing on pathological analyses.

Abstract

Despite that breast conservative therapy became the standard of care in breast cancer, modified radical mastectomy, a large mutilating surgery, is still required for an important number of patients. In order to improve the quality of life and the psychological aspects of a surgery involving the femininity of woman, we developed a new less invasive procedure called infra-radical mastectomy. It aims to save the neckline of patients by the maintenance of the peripheral skin-fatty flap that constitutes the base for implantation of the breast. This phase I study analyzed the feasibility of this procedure using outcome of anatomo-pathological analyses as primary endpoint. Between March 2015 and July 2017, all women with operable breast cancer without signs of lymph node invasion were invited to participate in the study in the 2 participating institutions. After a water-assisted dissection of the peri-glandular space, an enucleation of the breast was performed by a cold knife which represents the infra-radical mastectomy. A peri-glandular re-excision (PGR) of the skin and the fat tissue surrounding the gland was then achieved to obtain an MRM. This PGR underwent a careful pathological examination (10 samples per patient). Moreover, the tissue volume and the skin surface of the PGR were quantified. A total of 53 patients (median age: 60 years) were prospectively recruited. The pathological analysis of peri-glandular biopsies revealed none residual invasive carcinoma, 1% of biopsies contained focal ductal carcinoma in situ (DCIS) and 0.4% atypical hyperplasia corresponding to 4 and 2 patients respectively. These 4 patients with residual DCIS were preoperatively diagnosed with extensive DCIS. On average after an infra-radical mastectomy, 37% of the volume and 53% of the skin surface of a complete modified radical mastectomy were sparred. The evaluation of biopsies from peri-glandular tissue suggests that infra-radical mastectomy should be further evaluated except for patients diagnosed with extensive DCIS which must be excluded of this infra-radical approach. Additional work is needed to evaluate cosmetic outcome and impact on quality of life, the need of radiotherapy and the oncological long-term outcome.