Omitting radiation therapy for certain breast cancer patients after surgery

Radiation OmisSion in PAtients With CLinically Node Negative Breast Cancer Undergoing Lumpectomy and With a PathologIc Complete REsponse After Neoadjuvant Chemotherapy

This study is testing if women with certain types of breast cancer who have no signs of cancer after treatment can skip radiation therapy after surgery and still do well.

Quick facts

• Study type: Observational
• Enrollment: 352 (estimated)
• Ages: 50 Years and up
• Sex: Female
• Sponsor: Ontario Clinical Oncology Group (OCOG) (Academic / other)
• Drugs / interventions: chemotherapy, radiation
• Locations: 12 sites (Prince George, British Columbia and 11 other locations)
• Trial ID: NCT05866458 on ClinicalTrials.gov

What this trial studies

This observational study aims to evaluate the omission of adjuvant whole breast radiation therapy (WBRT) in women with clinically node negative breast cancer who achieve a pathological complete response (pCR) after neoadjuvant chemotherapy and breast conserving surgery. It is a prospective, multi-center, single arm cohort study that will enroll female patients with newly diagnosed T1-3 node negative breast cancer, following specific eligibility criteria. Participants will be monitored for ipsilateral breast tumor recurrence and other outcomes over a median follow-up period of 5 years, without receiving the standard adjuvant WBRT treatment.

Who should consider this trial

Good fit: Ideal candidates are female patients aged 50 and older with newly diagnosed T1-3 node negative breast cancer who have achieved a pathological complete response after neoadjuvant chemotherapy.

Not a fit: Patients with inflammatory breast cancer, multicentric disease, or those under 50 years of age may not benefit from this study.

Why it matters

Potential benefit: If successful, this approach could reduce unnecessary radiation exposure and associated side effects for patients with specific breast cancer characteristics.

How similar studies have performed: Other studies have explored de-escalation of radiation therapy in breast cancer, indicating potential for success in similar approaches.

Eligibility criteria

Inclusion Criteria:

1. Female patient with a new histological diagnosis of clinical T1-3 N0 breast cancer (any tumour sub-type).
2. Negative lymph node involvement at initial presentation, documented by imaging (US or MRI), fine needle aspiration (FNA) or core needle biopsy.
3. Treated with a minimum of 8 weeks NAC, with patients with Her2+ disease receiving targeted anti-Her2+ therapy.
4. Marker clip placed in the tumour bed prior to or during neoadjuvant chemotherapy when the tumour can still be identified.
5. Treated by BCS with complete excision of the tumour bed and axillary staging surgery (either sentinel lymph node biopsy or axillary lymph node dissection).
6. Final pathology demonstrating a pCR \[defined as absence of residual invasive and in-situ breast cancer within the breast or lymph nodes (ypT0N0)\].

Exclusion Criteria:

1. Age less than 50 years.
2. Inflammatory breast cancer or breast cancer invading the skin or chest wall (T4 disease).
3. Multicentric disease (i.e., breast cancer involving more than one quadrant in the same breast).
4. Prior history of ipsilateral or contralateral in-situ or invasive breast cancer. Patients with a history of lobular carcinoma in-situ (LCIS) are ineligible.
5. Synchronous contralateral in-situ or invasive breast cancer.
6. BRCA (breast cancer gene) 1 or 2 genetic mutation carrier, or other genetic mutation present associated with increased risk of breast cancer.
7. Other previous non-breast malignancies except adequately treated non-melanoma skin cancers, in situ cancers or other cancers curatively treated with no evidence of disease for ≥ 5 years.
8. Inability to complete entire course of neoadjuvant therapy (minimum of 8 weeks of treatment).
9. Patients with HR+ (hormone receptor) disease who are not planned to have endocrine therapy initiated.
10. Patients with Her2+ disease who have not received or are not planned to receive Her2 targeted therapy.
11. ECOG (Eastern Cooperative Oncology Group) performance status \> 3.
12. Inability to provide informed consent.

Where this trial is running

Prince George, British Columbia and 11 other locations

• BC Cancer - Centre for the North — Prince George, British Columbia, Canada (Recruiting)
• Royal Victoria Regional Health Centre — Barrie, Ontario, Canada (Recruiting)
• Juravinski Cancer Centre — Hamilton, Ontario, Canada (Recruiting)
• Cancer Centre of Southeastern Ontario at Kingston — Kingston, Ontario, Canada (Recruiting)
• Thunder Bay Regional Health Sciences Centre — Thunder Bay, Ontario, Canada (Recruiting)
• Sunnybrook Health Sciences -Odette Cancer Centre — Toronto, Ontario, Canada (Recruiting)
• CHUM - Centre Hospitalier de L'Université de Montréal — Montreal, Quebec, Canada (Recruiting)
• Jewish General Hospital — Montreal, Quebec, Canada (Recruiting)
• CHU de Quebec - Universite Laval — Québec, Quebec, Canada (Recruiting)
• Centre hospitalier de Lanaudière — Saint-Charles-Borromée, Quebec, Canada (Recruiting)
• Centre Hospitalier Trois Rivieres Ste-Marie — Trois-Rivières, Quebec, Canada (Recruiting)
• McGill University Health Centre (MUHC) — Montreal, Q, Canada (Recruiting)

Study contacts

• Principal investigator: Elena Parvez, MD — Juravinski Cancer Centre
• Study coordinator: Adrianne Van Dam

Conditions Breast Cancer; Clinically node negative breast cancer; Ipsilateral breast tumour recurrence; Neoadjuvant chemotherapy