NOVEMBER, A Phase 2 Trial of a 9-Day Course of Whole Breast Radiation Therapy With a Simultaneous Lumpectomy Boost for Early-Stage Breast Cancer.

Abstract

Purpose/objectives: A phase 2 prospective noninferiority trial evaluating a novel 9 fraction course of whole breast radiation and simultaneous lumpectomy boost.

Materials and methods: Tis and T1-3N0 patients enrolled to receive 3420 cGy radiation to the breast with 3960 cGy to the lumpectomy cavity. The primary endpoint was averaged photographic cosmetic scores at 24 months with a hypothesis of >70% good to excellent cosmetic breast scoring 24 months after completing radiation, assuming a baseline excellent/good cosmetic scoring of 80% with an 80% power, α = 0.1.

Results: From 2018 to 2020, with institutional review board approval, 103 patients were enrolled. Patients had mostly invasive ductal carcinoma (75%), tumor size ≤ 2cm (88%), negative margins (92%), no lympho-vascular invasion (80%), and estrogen receptor positive (85%). Patients had a mean age of 59.5 years (33-82). With a mean follow-up of 51 months, there were no local recurrences and 1 patient with both regional (axilla) and distant (brain) recurrence. Twenty-four-month post-radiation therapy (RT) cosmetic photos were 68% excellent/good, and 32% fair/poor. The null hypothesis was not rejected with one-sided 95% exact binomial confidence interval of 59.1% (59.1%-100%). There were no reported late ≥grade 3 radiation toxicity events and only 4 patients with late grade 2 events. Patient-reported outcomes utilizing the Breast-Q survey revealed breast satisfaction in 85% of women.

Conclusions: We demonstrate an effective novel 9 fraction whole breast + lumpectomy boost radiation schedule. This trial uses one of the shortest published radiation schedules for a lumpectomy boost. Although we did not meet our prespecified cosmetic endpoint, no significant cosmetic change from baseline was seen in 80% of patients. We demonstrate excellent local control, and patient-reported satisfaction with low RT-related toxicity. We hope to move this concept forward in a randomized trial against the 5-day United Kingdom (UK) Fast Forward regimen, inclusive of a simultaneous lumpectomy cavity boost.