NCT06938724

Omission of Local Therapies in Women Patients With HER2-positive or Triple-negative Breast Cancer

Omission of Local Therapies in Women Patients With HER2-positive or Triple-negative Breast Cancer: A Two Arm, Phase 2, Non-inferiority Trial for Surveillance in Maximum Responders to Neoadjuvant Systemic Therapy

• Status: Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 152 (estimated)
• Sponsor: Fondazione IRCCS Istituto Nazionale dei Tumori, Milano · Academic / Other
• Sex: Female
• Age: 18 Years
• Healthy volunteers: Not accepted

Summary

HER2-positive and Triple-negative are subtypes of breast cancer more sensitive to systemic therapies, where the complete pathological response rate may be higher than 50%. This gave rise to doubts about the usefulness of traditional local treatments for such responders. Omission of surgery after vacuum assisted breast biopsy (VABB) as well omission of radiotherapy after conservative surgery would now seem to be reasonable alternatives to standard care for highly selected patients, in whom systemic treatments have provided the maximum response.

Detailed description

This is a prospective phase 2 non-randomized non-inferiority trial with two independent investigational arms. In each arm a 2-stage non-inferiority group-sequential design will be implemented; the overall sample per arm is of 76 patients, 43 of which will be recruited at the first stage. For each arm a futility evaluation is foreseen at the first stage, the results of which will be presented to an independent Data Safety and Monitoring Committee (iDSMC) (see "Statistical analyses" paragraph). Arm A will evaluate the omission of surgery in unifocal T1-2 clinically N0, M0 patients who will demonstrate maximum response after neoadjuvant systemic treatment (i.e. whole breast irradiation only). Arm B will evaluate the omission of radiotherapy in patients with complete pathological response proved by standard conservative surgical treatment (i.e. conservative surgery only). Patients candidate to arm A, who refuse the omission of surgery and then operated, are eligible for arm B if complete pathological response is confirmed after standard surgical treatment. Moreover, patients who refuse VABB and N1 patients with complete pathological response confirmed by partial mastectomy and surgical staging of axilla (SLNB and or TAD) are also eligible for arm B. Arm B patients must have confirmed complete pathological response by local-regional surgery. Therefore, omission of radiotherapy will be ultimately offered to a cohort of patients with T1-2, N0-1, M0 breast cancer conservatively operated, in whom complete pathological response to a neoadjuvant therapies is confirmed on the entire surgical specimen of the tumor bed and of the sampled nodes. In each study arm non inferiority of 5-year EFS will be tested against historical data. No between arms statistical comparison is foreseen.

Conditions

• Breast Neoplasm Malignant Female

Interventions

Type	Name	Description
OTHER	Omission of local therapies	Omission of surgery (arm A) or radiotherapy (arm B) in those patients who have had the maximum response by neoadjuvant treatments. Maximum responders are those patients with no evidence of residual disease after neoadjuvant treatment at imaging -including mammography, US evaluation and contrast imaging procedures (MRI and/or CEM)-, confirmed by VABB on marked site of ascertained lesion. This study is open to all patients with T1-2, N0-1, M0 HER2-positive or triple negative breast cancer, treated with neoadjuvant systemic treatment, irrespective of treatments delivered.

Timeline

• Start date: 2025-07-25
• Primary completion: 2035-07-25
• Completion: 2035-07-25
• First posted: 2025-04-22
• Last updated: 2025-09-15

Locations

1 site across 1 country: Italy