BREAST RADIOTHERAPY AFTER BREAST-CONSERVING SURGERY

Objective: To help physicians and their patients arrive at optimal str ategies 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, t o Jan. 1, 1997. The evidence is graded in 5 levels (page S2). Benefits : A decrease in local recurrence of breast cancer. Harms: Adverse effe cts of breast irradiation. Recommendations: Women who undergo BCS shou ld be advised to have postoperative breast irradiation. Omission of ra diotherapy after BCS almost always increases the risk of local recurre nce. Contraindications to breast irradiation include pregnancy, previo us breast irradiation (including mantle radiation for Hodgkin's diseas e) and inability to lie flat or to abduct the arm. Scleroderma and sys temic lupus erythematosus constitute relative contraindications. The c ommonest fractionation schedule used in Canada is 50 Gy in 25 fraction s 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 i n 25 fractions with a boost of 16 Gy in 8 fractions to the primary sit e. The role of boost irradiation to the primary site is unclear. Irrad iation of the whole breast rather than partial irradiation is recommen ded. When choices are being made between different treatment options, patients must be made aware of the acute and late complications that c an result from radiotherapy. Physicians should adhere to standard trea tment regimens to minimize the adverse effects of irradiation. It is r ecommended that local breast irradiation should be started as soon as possible after surgery and not later than 12 weeks after, except for p atients in whom radiotherapy is preceded by chemotherapy. However, the optimal interval between BCS and the start of irradiation has not bee n defined. The optimal sequencing of chemotherapy and irradiation is n ot clearly defined for patients who are also candidates for chemothera py. Most centres favour the administration of chemotherapy before radi otherapy. Selected chemotherapy regimens are sometimes used concurrent ly with radiotherapy. There is no evidence that this results in better outcome, and there is an increased chance of toxic effects, especiall y for anthracycline-containing regimens. Patients should be offered th e opportunity to participate in clinical trials whenever possible. Val idation: Earlier drafts of these guidelines were reviewed, discussed a nd approved by the Breast Disease Site Group of the Ontario Cancer Tre atment and Research Foundation. They were next revised by a writing co mmittee and by expert primary reviewers and secondary reviewers select ed from all regions of Canada. The final version was approved by the S teering Committee and reflects a consensus of all these contributors. It has been endorsed by the Canadian Association of Radiologists.