Should patients with hormone receptor-positive, HER2-negative breast cancer and one or two positive sentinel nodes undergo axillary dissection to determine candidacy for adjuvant abemaciclib?

BACKGROUND

The monarchE trial demonstrated improved outcomes with the use of adjuvant abemaciclib in patients with high-risk hormone receptor-positive, HER2-negative (HR+/HER2-) breast cancer defined as ≥4 positive lymph nodes (+LNs) or one to three +LNs with one or more additional high-risk features (HRFs). The proportion of patients with one or two positive sentinel lymph nodes (+SLNs) without HRFs who had ≥4 +LNs at the time of completion axillary lymph node dissection (cALND), and who therefore qualified for receipt of abemaciclib, was investigated.

METHODS

Females with pathologically node-positive nonmetastatic HR+/HER2- breast cancer stratified by the number of +SLNs and +LNs and the presence of one or more HRFs were identified from the National Cancer Database (2018-2019). The proportion of patients meeting the criteria for abemaciclib both before and after ALND was assessed.

RESULTS

Of the 22,048 patients identified, 1578 patients underwent upfront surgery, had one or two +SLNs without HRFs, and went on to cALND. Only 213 (13%) of these patients had ≥4 +LNs; thus, cALND performed solely to determine abemaciclib candidacy would have constituted surgical overtreatment in 1365 patients (87%). When stratified by the number of +SLNs, only 10% of those with one +SLN and 24% of those with two +SLNs had ≥4 +LNs after cALND, which meets the criteria for abemaciclib.

CONCLUSIONS

Patients with one +SLN without HRFs are unlikely to have ≥4 +LNs and should not be subjected to the morbidity of ALND in order to inform candidacy for abemaciclib. An individualized multidisciplinary discussion should be undertaken about the risk:benefit ratio of ALND and abemaciclib for those with two +SLNs.

The Impact of Premastectomy Versus Postmastectomy Radiation Therapy on Outcomes in Prepectoral Implant-Based Breast Reconstruction

PURPOSE

Prepectoral implant-based breast reconstruction is being increasingly performed over subpectoral reconstruction because of the reduced invasiveness of the procedure, postoperative pain, and risk of animation deformity. Radiation therapy is a well-known risk factor for complications in implant-based breast reconstruction. The effect of premastectomy versus postmastectomy radiation therapy on outcomes after prepectoral breast reconstruction has not been well-defined. The purpose of this study was to compare the impact of premastectomy versus postmastectomy radiation therapy on outcomes after prepectoral breast reconstruction.

METHODS

A retrospective chart review was performed on all patients who underwent prepectoral implant-based breast reconstruction with inferior dermal flap and acellular dermal matrix performed by a single surgeon from 2010 to 2019. Demographic, clinical and operative data were reviewed and recorded. Outcomes were assessed by comparing rates of capsular contracture, infection, seroma, hematoma, dehiscence, mastectomy skin flap necrosis, rippling, implant loss, local recurrence and metastatic disease, between patients receiving premastectomy and postmastectomy radiation therapy and nonradiated patients.

RESULTS

Three hundred and sixty-nine patients (592 breasts) underwent prepectoral implant-based breast reconstruction. Twenty-six patients (28 breasts) received premastectomy radiation, 45 patients (71 breasts) received postmastectomy radiation, and 305 patients (493 breasts) did not receive radiation therapy. Patients with premastectomy radiation had higher rates of seroma (14.3% vs 0.2%), minor infection (10.7% vs 1.2%), implant loss (21.4% vs 3.4%) and local recurrence (7.1% vs 1.0%), compared with nonradiated patients (P < 0.05). Patients with postmastectomy radiation had higher rates of major infection (8.4% vs 2.4%), capsular contracture (19.7% vs 3.2%), implant loss (9.9% vs 3.4%), and local recurrence (5.6% vs 1.0%) when compared with nonradiated patients (P < 0.03). Outcomes after prepectoral breast reconstruction were comparable between premastectomy and postmastectomy radiation patients, respectively, with regard to major infection (7.1% vs 8.4%), dehiscence (3.6% vs 1.4%), major mastectomy skin flap necrosis (7.1% vs 2.8%), capsular contracture (10.7% vs 19.7%), implant loss (21.4% vs 9.9%), and local recurrence (7.1% vs 5.6%) (P ≥ 0.184). However, premastectomy radiation patients had a higher rate of seroma compared with postmastectomy radiation patients (14.3% vs 0%; P = 0.005).

CONCLUSIONS

In prepectoral implant breast reconstruction, premastectomy and postmastectomy radiation therapy were associated with higher rates of infection and implant loss compared with nonradiated patients. Postmastectomy radiation was associated with a higher rate of capsular contracture compared with nonradiated patients, and a comparable rate of capsular contracture compared with premastectomy radiation therapy patients. Premastectomy radiation was associated with a higher rate of seroma compared with postmastectomy radiation and nonradiated patients.