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

ABSTRACT

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.