Breast radiotherapy after breast-conserving surgery. The Steering Committee on Clinical Practice Guidelines for the Care and Treatment of Breast Cancer. Canadian Association of Radiation Oncologists

Abstract

Objective: To help physicians and their patients arrive at optimal strategies for breast radiotherapy after breast-conserving surgery (BCS) for early breast cancer.

Outcomes: Local control, survival, quality of life, adverse effects of irradiation and cosmetic results.

Evidence: A literature search using MEDLINE from 1966 and CANCERLIT from 1983, to Jan. 1, 1997. The evidence is graded in 5 levels (page S2).

Benefits: A decrease in local recurrence of breast cancer.

Harms: Adverse effects of breast irradiation.

Recommendations: Women who undergo BCS should be advised to have postoperative breast irradiation. Omission of radiotherapy after BCS almost always increases the risk of local recurrence. Contraindications to breast irradiation include pregnancy, previous breast irradiation (including mantle radiation for Hodgkin's disease) and inability to lie flat or to abduct the arm. Scleroderma and systemic lupus erythematosus constitute relative contraindications. The commonest fractionation schedule used in Canada is 50 Gy in 25 fractions to the whole breast without a boost when excision margins are clear of disease. Alternative schedules that may be used range from 40 Gy in 16 fractions to the whole breast, with or without a boost, to 45 Gy in 25 fractions with a boost of 16 Gy in 8 fractions to the primary site. The role of boost irradiation to the primary site is unclear. Irradiation of the whole breast rather than partial irradiation is recommended. When choices are being made between different treatment options, patients must be made aware of the acute and late complications that can result from radiotherapy. Physicians should adhere to standard treatment regimens to minimize the adverse effects of irradiation. It is recommended that local breast irradiation should be started as soon as possible after surgery and not later than 12 weeks after, except for patients in whom radiotherapy is preceded by chemotherapy. However, the optimal interval between BCS and the start of irradiation has not been defined. The optimal sequencing of chemotherapy and irradiation is not clearly defined for patients who are also candidates for chemotherapy. Most centers favour the administration of chemotherapy before radiotherapy. Selected chemotherapy regimens are sometimes used concurrently with radiotherapy. There is no evidence that this results in better outcome, and there is an increased chance of toxic effects, especially for anthracycline-containing regimens.

Validation: Earlier drafts of these guidelines were reviewed, discussed and approved by the Breast Disease Site Group of the Ontario Cancer Treatment and Research Foundation. They were next revised by a writing committee and by expert primary reviewers and secondary reviewers selected from all regions of Canada. The final version was approved by the Steering Committee and reflects a consensus of all these contributors. It has been endorsed by the Canadian Association of Radiologists.