radiation therapy in women with low risk early-stage breast cancer who have undergone breast conservation surgery

Conditions: Breast Cancer

Summary: rationale: radiation therapy uses high-energy x-rays to kill tumor cells. giving radiation therapy after surgery may kill any tumor cells that remain after surgery. it is not yet known whether intensity-modulated radiation therapy is more effective than standard radiation therapy in treating patients with early-stage breast cancer. purpose: this randomized phase iii trial is comparing radiation therapy regimens in treating women with early-stage breast cancer who have undergone breast-conservation surgery.

objectives: * to test partial breast radiotherapy using intensity-modulated techniques following complete local tumor excision in women with low-risk, early stage breast cancer. outline: this is a multicenter study. patients are stratified according to center (not participating in sub-studies vs participating in sub-studies). patients are randomized to 1 of 3 treatment arms. * arm i (control): patients undergo standard whole breast radiotherapy once daily on days 1-5 (15 fractions) for 3 weeks. * arm ii: patients undergo reduced whole breast radiotherapy (15 fractions) and standard partial breast radiotherapy (15 fractions) once daily on days 1-5 for 3 weeks. * arm iii: patients undergo standard partial breast radiotherapy once daily on days 1-5 (15 fractions) for 3 weeks. all patients complete a family history questionnaire at baseline. patients also undergo blood sample collection at baseline and paraffin-embedded tissue collection at follow-up for molecular studies analyzing inter-patient variation by microarrays. patients in centers participating in sub-studies undergo quality of life and health economic assessment at baseline, 6 months, and 1, 2, and 5 years. these patients also undergo photographic assessment at baseline, 2 years, and 5 years. after completion of study treatment, patients are followed for 10 years.

Eligibility criteria:
disease characteristics: * diagnosis of low-risk early stage breast cancer, meeting the following criteria: * invasive adenocarcinoma * no invasive carcinoma of classical lobular type * lympho-vascular invasion present or absent * tumor size pathologically determined to be ≤ 3.0 cm in diameter (pt1-2) (\< 3.1 cm maximum microscopic diameter of invasive component) * unifocal disease * grade i, ii, or iii disease * axillary lymph nodes negative or 1-3 nodes positive (pn0 or pn+(1-3)) * must have undergone breast conservation surgery with or without adjuvant systemic therapy * minimum microscopic margin of non-cancerous tissue ≥ 2 mm (excluding deep margin if this is at deep fascia) * at low risk of local recurrence after radiotherapy (\< 1% annual risk local recurrence) * no prior mastectomy * no blood-borne metastases patient characteristics: * no prior malignancy except nonmelanoma skin cancer prior concurrent therapy: * see disease characteristics * no prior endocrine therapy or chemotherapy * neoadjuvant endocrine therapy allowed provided the tumour is \< 3.0 cm and all other inclusion criteria are met * no primary endocrine therapy as a replacement for surgery * no concurrent chemoradiotherapy

Keywords: recurrent breast cancer stage ia breast cancer stage ii breast cancer invasive ductal breast carcinoma invasive ductal breast carcinoma with predominant intraductal component