Omission of breast surgery for predicted pCR patients with MRI and vacuum-assisted biopsy in breast cancer after neoadjuvant chemotherapy: A multicenter, single-arm, non-inferiority trial (OPTIMIST trial).

• DOI: 10.1200/jco.2023.41.16_suppl.tps627
• Publication Date: 2023-06-04T14:02:11Z
• Authors: Ji-Jung Jung; Soo-Yeon Kim; Jiwon Koh; Jong-Ho Cheun; Min Kyoon Kim; Jai Min Ryu; Tae-Kyung Yoo; Seho Park; Hee-Chul Shin; Sung Gwe Ahn; Woosung Lim; Sang Eun Nam; Min Ho Park; Jeeyeon Lee; Taewoo Kang; Ku Sang Kim; Hyun Jo Youn; Yoo Seok Kim; Wonshik Han; Han-Byoel Lee
• Keywords: Neoadjuvant Therapy

TPS627 Background: Advances in chemotherapeutic and targeted agents have increased pathologic complete response (pCR) rates after neoadjuvant systemic therapy (NST). The role of surgery is essential to remove cancer when residual tumor present, but it may be limited confirmation those with a pCR. As an alternative, pCR can accurately evaluated vacuum-assisted biopsy (VAB) patients suggested on imaging. We aim show non-inferiority omitting breast image-guided VAB. Methods: OPTIMIST trial prospective, multicenter, single-arm, clinical study. Sixteen tertiary care hospitals South Korea are participating. Women diagnosed invasive ductal carcinoma, clip marker placed the tumor, who had completed NST exceptional screened for eligibility. Inclusion criteria: women aged 19-75; cT1-2N0-2M0; triple-negative, HER2+, or low estrogen receptor (<10%); post-NST MRI size ≤1cm lesion-to-background signal enhancement ratio ≤1.6. Exclusion malignant calcification >2cm; multifocal, bilateral, inflammatory cancer; other malignancy within five years; BRCA1/2 mutation carrier. Under ultrasound stereotactic guidance, VAB performed targeting obtain minimum 6 cores using 7-10 G needles. When confirmed, omitted. cN0 ≤0.5cm no suspicious lymph nodes, axillary node could also Patients atypical cells proceed routine surgery. All required receive whole irradiation bed boost. According previous studies, 5-year disease-free survival (DFS) was assumed 88%. one-sided test margin 4% statistical power 80% at significance level 0.05 resulted sample 384 forego An expected 20% 10% dropout total 533 subjects. Primary endpoint: DFS. Secondary ipsilateral recurrence-free survival, overall DFS, rate, quality life scores, symptoms (VAS), medical cost. interim analysis planned 50% enrollment median follow-up period 1 year. data safety monitoring board will determine continuation study considering 1-year first patient enrolled September 22, 2022, 12 been as February 14, 2023. plan target accrual by December 2025. Clinical information: NCT05505357 .