RATIONALE: Radiation therapy may kill any tumor cells remaining after surgery.

PURPOSE: This randomized phase III trial is studying radiation therapy to see how well it works compared to no further therapy in treating women with stage I, stage II, or stage III breast cancer that has been surgically removed.

OBJECTIVES:

• Compare the effect of irradiation of the homolateral internal mammary and medial supraclavicular lymph node chains vs no further therapy on survival, disease-free survival, metastasis-free survival, and cause of death in women with resected stage I/II/III breast cancer.

OUTLINE: This is a randomized, multicenter study. Patients are stratified by participating institution, tumor location, type of prior breast surgery, pathologic T and N stage, menopausal status, and time sequence of radiotherapy and adjuvant chemotherapy. Patients are randomized to 1 of 2 arms.

• Arm I: Patients receive no nodal irradiation.
• Arm II: Patients receive irradiation of the internal mammary and medial supraclavicular lymph node chains delivered at 1 fraction per day, 5 sessions per week, for a total of 25 fractions over 5 weeks. Radiotherapy must begin no later than 8 weeks after surgery. If adjuvant chemotherapy is given, radiotherapy begins within 6 weeks after the last course of chemotherapy and within 8 months after surgery.

Patients are followed at least yearly after randomization for up to 20 years.

PROJECTED ACCRUAL: A total of 4,000 patients will be accrued for this study within 4 years.

• Procedure: adjuvant therapy
• Radiation: low-LET electron therapy
• Radiation: low-LET photon therapy

• Musat E, Poortmans P, den Bogaert WV, Struikmans H, Fourquet A, Bartelink H, Kirkove C, Budach V, Pierart M, Collette L. Quality assurance in breast cancer: EORTC experiences in the phase III trial on irradiation of the internal mammary nodes. Eur J Cancer. 2007 Mar;43(4):718-24. Epub 2007 Jan 19.
• Poortmans P, Kouloulias V, van Tienhoven G, Collette L, Struikmans H, Venselaar JL, Van den Bogaert W, Davis JB, Lambin P; EORTC Radiation Oncology and Breast Cancer Groups. Quality assurance in the EORTC randomized trial 22922/10925 investigating the role of irradiation of the internal mammary and medial supraclavicular lymph node chain works. Strahlenther Onkol. 2006 Oct;182(10):576-82.
• Poortmans P, Kouloulias VE, Venselaar JL, Struikmans H, Davis JB, Huyskens D, van Tienhoven G, Hurkmans C, Mijnheer B, Van den Bogaert W. Quality assurance of EORTC trial 22922/10925 investigating the role of internal mammary--medial supraclavicular irradiation in stage I-III breast cancer: the individual case review. Eur J Cancer. 2003 Sep;39(14):2035-42.
• Poortmans PM, Venselaar JL, Struikmans H, Hurkmans CW, Davis JB, Huyskens D, van Tienhoven G, Vlaun V, Lagendijk JJ, Mijnheer BJ, De Winter KA, Van der Hulst MH, Van den Bogaert WF. The potential impact of treatment variations on the results of radiotherapy of the internal mammary lymph node chain: a quality-assurance report on the dummy run of EORTC Phase III randomized trial 22922/10925 in Stage I--III breast cancer(1). Int J Radiat Oncol Biol Phys. 2001 Apr 1;49(5):1399-408.

DISEASE CHARACTERISTICS:

• Histologically confirmed unilateral adenocarcinoma of the breast

• Stage I/II/III (Tx, T0-3, N0-2) disease in one of the following categories or multifocal tumors if one of the foci is in agreement with the following:

  • Centrally or medially located with any lymph node status

    • Central location defined as underlying the areola
    • Medial location defined as at least partial involvement of upper or lower medial quadrant of breast
  • Externally located with axillary node involvement

• Prior mastectomy or breast-conserving surgery and axillary dissection required

  • Sentinel node procedure as axillary intervention without further axillary surgery is allowed
  • No prior internal mammary chain dissection

  • No upper inner lesion treated with breast-conserving surgery that precludes sparing of internal mammary lymph node chain from radiotherapy volume

    • Decision at radiation oncologist's discretion

• Hormone receptor status:

  • Not specified

PATIENT CHARACTERISTICS:

Age:

• 75 and under

Sex:

• Female

Menopausal status:

• Not specified

Performance status:

• Not specified

Hematopoietic:

• Not specified

Hepatic:

• Not specified

Renal:

• Not specified

Cardiovascular:

• No prior cardiac disease

Other:

• No prior malignancy except adequately treated nonmelanomatous skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy:

• Not specified

Chemotherapy:

• Not specified

Endocrine therapy:

• Not specified

Radiotherapy:

• Not specified

Surgery:

• See Disease Characteristics

Other:

• Concurrent enrollment in other randomized trials allowed