Impact of baseline BMI and weight change in CCTG adjuvant breast cancer trials.

BACKGROUND: We hypothesized that increased baseline BMI and BMI change would negatively impact clinical outcomes with adjuvant breast cancer systemic therapy. METHODS: Data from chemotherapy trials MA.5 and MA.21; endocrine therapy MA.12, MA.14 and MA.27; and trastuzumab HERA/MA.24 were analyzed. The primary objective was to examine the effect of BMI change on breast cancer-free interval (BCFI) landmarked at 5 years; secondary objectives included BMI changes at 1 and 3 years; BMI changes on disease-specific survival (DSS) and overall survival (OS); and effects of baseline BMI. Stratified analyses included trial therapy and composite trial stratification factors. RESULTS: In pre-/peri-/early post-menopausal chemotherapy trials (N = 2793), baseline BMI did not impact any endpoint and increased BMI from baseline did not significantly affect BCFI (P = 0.85) after 5 years although it was associated with worse BCFI (P = 0.03) and DSS (P = 0.07) after 1 year. BMI increase by 3 and 5 years was associated with better DSS (P = 0.01; 0.01) and OS (P = 0.003; 0.05). In pre-menopausal endocrine therapy trial MA.12 (N = 672), patients with higher baseline BMI had worse BCFI (P = 0.02) after 1 year, worse DSS (P = 0.05; 0.004) after 1 and 5 years and worse OS (P = 0.01) after 5 years. Increased BMI did not impact BCFI (P = 0.90) after 5 years, although it was associated with worse BCFI (P = 0.01) after 1 year. In post-menopausal endocrine therapy trials MA.14 and MA.27 (N = 8236), baseline BMI did not significantly impact outcome for any endpoint. BMI change did not impact BCFI or DSS after 1 or 3 years, although a mean increased BMI of 0.3 was associated with better OS (P = 0.02) after 1 year. With the administration of trastuzumab (N = 1395) baseline BMI and BMI change did not significantly impact outcomes. CONCLUSIONS: Higher baseline BMI and BMI increases negatively affected outcomes only in pre-/peri-/early post-menopausal trial patients. Otherwise, BMI increases similar to those expected in healthy women either did not impact outcome or were associated with better outcomes. CLINICAL TRIALS NUMBERS: CAN-NCIC-MA5; National Cancer Institute (NCI)-V90-0027; MA.12-NCT00002542; MA.14-NCT00002864; MA.21-NCT00014222; HERA, NCT00045032;CAN-NCIC-MA24; MA-27-NCT00066573.

Tumor factors predictive of response to hypofractionated radiotherapy in a randomized trial following breast conserving therapy.

PURPOSE: To determine whether tumor grade, molecular subtype and hypoxia predict response to hypofractionated versus standard radiotherapy (RT) following breast-conserving surgery (BCS) for node-negative breast cancer in a randomized controlled trial (RCT). PATIENTS AND METHODS: Formalin-fixed paraffin-embedded (FFPE) tumor blocks were available on 989 of 1234 patients enrolled in the Hypofractionation Whole Breast Irradiation (HWBI) Trial. A central pathology review and assessment of tumor grade using the Nottingham grading system was carried out. Tumors were classified by molecular subtype as luminal A, luminal B, HER2 enriched, basal-like or unclassified using a six-biomarker panel; ER, PR, HER-2, Ki67, CK5/6 and EGFR. Tumors were also classified as hypoxic based on the expression of HIF1α, CAIX or GLUT-1. The primary end point was local recurrence (LR). RESULTS: Median follow-up was 12 years. In the multivariable Cox model, molecular subtype was the only factor predictive of LR, the 10-year cumulative incidence was 4.5% for luminal A and basal-like, 7.9% for luminal B and 16.9% for HER-2 enriched tumors (P < 0.01). Tumor grade, molecular subtype or hypoxia did not predict response to hypofractionation. CONCLUSIONS: In women enrolled in the HWBI trial following BCS tumor molecular subtype predicted LR. However tumor grade, molecular subtype and hypoxia did not predict response to hypofractionation suggesting that patients with node-negative breast tumors of all grades and molecular subtypes may be safely treated with hypofractionated RT regimens.

Do alternative methods of measuring tumor size, including consideration of multicentric/multifocal disease, enhance prognostic information beyond TNM staging in women with early stage breast cancer: an analysis of the NCIC CTG MA.5 and MA.12 clinical trials.

The AJCC staging criteria consider tumor size to be the largest dimension of largest tumor. Some case series suggest using summation of all tumor dimensions in patients with multicentric/multifocal (MC/MF) disease. We used data from NCIC CTG MA.5 and MA.12 clinical trials to examine alternative methods of assessing tumor size on breast-cancer-free-interval (BCFI). The 710 MA.5 pre-/peri-menopausal node positive and 672 MA.12 pre-menopausal node-negative/-positive patients have 10-year median follow-up. All patients received adjuvant chemotherapy. Tumors were centrally reviewed for grade, hormone receptor, and HER2 status. Continuous pathologic tumor size was: (1) largest dimension of largest tumor (cm); (2) tumor area (cm(2)); (3) volume of tumor (cm(3)); (4) with MC/MF disease, summation of (1)-(3) for up to 3 foci. We examined univariate and multivariate effects of tumor size on BCFI utilizing (un)stratified Cox regression and the Wald test statistic. In univariate analysis, larger tumor dimension was significantly associated with worse BFCI in node positive patients: p < 0.0001 for MA.5; p = 0.01 for MA.12. In MA.5 multivariate analysis, larger summation of largest tumor dimensions was associated with worse BCFI (p = 0.0003), while larger single dimension was associated with worse BCFI (p = 0.02) for MA.12. Presence of MC/MF and other tumor size measurements were not associated (p > 0.05) with BFCI. While physicians could consider the largest diameter of the largest focus of disease or the sum of the largest diameters of all foci in their T-stage determination, it appears that the current method of T-staging offers equivalent determinations of prognosis.

Lymphedema in women with breast cancer: characteristics of patients screened for a randomized trial.

INTRODUCTION: Accrual rates for a randomized trial of decongestive therapy in breast cancer patients with lymphedema were lower than anticipated. In two centres, patients presenting to lymphedema clinic were screened for eligibility to understand the accrual process and help define the patient population. MATERIALS AND METHODS: All breast cancer patients presenting to two lymphedema clinics in regional cancer centres were screened for study entry. Circumferential arm measurements were taken and volumes calculated. Patients were then screened for trial eligibility. All report forms were sent to the trial coordinating centre. RESULTS: A total of 408 patients were screened. Median arm volume excess was 239 ml (9.5%). One third of patients had little or no excess volume. Only 28.3% of patients had sufficient excess volume for trial eligibility. Of these, a significant number of patients were excluded because of active malignancy or previous decongestive therapy. CONCLUSIONS: The finding of moderate to severe lymphedema observed in clinics screening for trial eligibility was less than expected. The natural history of lymphedema in breast cancer patients is potentially changing. Some patients may be presenting with sensory changes suggestive of lymphedema but due to other causes, such as nerve disruption following axillary dissection.

Clinical outcomes of ethnic minority women in MA.17: a trial of letrozole after 5 years of tamoxifen in postmenopausal women with early stage breast cancer.

BACKGROUND: Aromatase inhibitors are widely employed in the adjuvant treatment of early stage breast cancer. The impact of aromatase inhibitors has not been established in ethnic minority women. PATIENTS AND METHODS: The purpose of this study was to evaluate the impact of letrozole on minority women in MA.17, a placebo-controlled trial of letrozole following 5 years of tamoxifen in postmenopausal women with early stage breast cancer. Retrospective comparison of disease-free survival (DFS), side effects, and mean changes in quality of life (QOL) scores from baseline between Caucasian and minority women was performed. RESULTS: Minority (n = 352) and Caucasian (n = 4708) women were analyzed. There was no difference between these groups in DFS (91.6% versus 92.4% respectively for 4 year DFS). Letrozole, compared with placebo, significantly improved DFS for Caucasians (HR = 0.55; P < 0.0001) but not for minorities (HR = 1.39; P = 0.53). Among women who received letrozole, minorities had a significantly lower incidence of hot flashes (49% versus 58%; P = 0.02), fatigue (29% versus 39%; P = 0.005), and arthritis (2% versus 7%; P = 0.006) compared with Caucasians. Mean change in QOL scores for minority women who received letrozole demonstrated improved mental health at the 6-month assessment (P = 0.02) and less bodily pain at the 12-month assessment (P = 0.046). CONCLUSION: Letrozole improved DFS in Caucasians but a definite benefit in minority women has not yet been demonstrated. Minority women tolerated letrozole better than Caucasians in terms of toxicity. These results need confirmation in other trials of aromatase inhibitors.

Cross-border referral for early breast cancer: an analysis of radiation fractionation patterns.

Because of increasing waiting times for adjuvant radiation in the province of Ontario, patients from one Canadian centre were referred to two centres in the United States. This situation provided an opportunity to compare radiation practices.We performed a retrospective review of radiation prescribed to patients following breast-conserving surgery for invasive breast cancer. Patients with positive margins, 4 or more positive lymph nodes, recurrent disease, or large tumours (>5 cm) were excluded. For comparison, we reviewed a random sample of similar patients treated at the Canadian centre during the same period. A total of 120 referred and 217 non-referred patients were eligible for comparison. The analysis included 98 pairs of patients (N = 196), fully matched on age, nodal status, T stage, grade, and estrogen receptor (er) status.Mean patient age was 60.7 years. The median total dose and number of fractions differed between centres [6040 cGy in 32 fractions (United States) vs. 4250 cGy in 16 fractions (Canadian), both p < 0.001). Boost was used more often in the United States (97% vs. 9%, p < 0.001). Variation in prescribing patterns was seen. In the United States, seven different schedules for whole-breast irradiation were used; at the Canadian centre, two schedules were prescribed. Predicted radiobiologic effects of these schedules were calculated to be similar.Differences in fractionation patterns were observed between and within U.S. and Canadian centres. Such variability is likely to affect patient convenience and resource utilization. Although patient selection, referring surgeon, and change in policies may account for some of the observed differences, further research is necessary to better understand the causes.

The difference between study recommendations, stated policy, and actual practice in a clinical trial.

BACKGROUND: We determined whether physicians involved in a clinical trial adhere to the study recommendations or the stated policy of their treatment centre with respect to the administration of boost radiation after breast conserving surgery. PATIENTS AND METHODS: Boost radiation treatment policy was determined by survey at 25 oncology centres involved in a randomised trial of breast or breast plus nodal radiation in Canada. Actual practice was compared with stated policy and study recommendations. RESULTS: Among 248 subjects, 201 (81%) were treated according to stated policy [kappa=0.40, 95% confidence intervals (CI) 0.27-0.52; P<0.0001], indicating only a fair to moderate agreement between stated and actual practice, while 232 (94%) were treated according to study recommendations (kappa=0.59, 95% CI 0.40-0.77; P<0.0001), indicating moderate to near substantial agreement between study recommendations and actual practice (P=0.88 for z-test of difference). In a multivariate analysis, subjects who had invasive disease at a resection margin were more likely to get a boost than those with margins clear of invasive tumour by 2 mm [odds ratio (OR) 49, 95% CI 7.6-322; P<0.0001]. CONCLUSIONS: Physicians appear compliant with study recommendations for a non-randomised manoeuvre in a clinical trial, possibly at the expense of compliance with stated local policy. Clinical trial protocols should incorporate standard practice.

Postmastectomy radiotherapy: clinical practice guidelines of the American Society of Clinical Oncology.

OBJECTIVE: To determine indications for the use of postmastectomy radiotherapy (PMRT) for patients with invasive breast cancer with involved axillary lymph nodes or locally advanced disease who receive systemic therapy. These guidelines are intended for use in the care of patients outside of clinical trials. POTENTIAL INTERVENTION: The benefits and risks of PMRT in such patients, as well as subgroups of these patients, were considered. The details of the PMRT technique were also evaluated. OUTCOMES: The outcomes considered included freedom from local-regional recurrence, survival (disease-free and overall), and long-term toxicity. EVIDENCE: An expert multidisciplinary panel reviewed pertinent information from the published literature through July 2000; certain investigators were contacted for more recent and, in some cases, unpublished information. A computerized search was performed of MEDLINE data; directed searches based on the bibliographies of primary articles were also performed. VALUES: Levels of evidence and guideline grades were assigned by the Panel using standard criteria. A "recommendation" was made when level I or II evidence was available and there was consensus as to its meaning. A "suggestion" was made based on level III, IV, or V evidence and there was consensus as to its meaning. Areas of clinical importance were pointed out where guidelines could not be formulated due to insufficient evidence or lack of consensus. RECOMMENDATIONS: The recommendations, suggestions, and expert opinions of the Panel are described in this article. VALIDATION: Seven outside reviewers, the American Society of Clinical Oncology (ASCO) Health Services Research Committee members, and the ASCO Board of Directors reviewed this document.

Cancer care workers in Ontario: prevalence of burnout, job stress and job satisfaction.

BACKGROUND: Cancer Care Ontario's Systemic Therapy Task Force recently reviewed the medical oncology system in the province. There has been growing concern about anecdotal reports of burnout, high levels of stress and staff leaving or decreasing their work hours. However, no research has systematically determined whether there is evidence to support or refute these reports. To this end, a confidential survey was undertaken. METHODS: A questionnaire was mailed to all 1016 personnel of the major providers of medical oncology services in Ontario. The questionnaire consisted of the Maslach Burnout Inventory, the 12-item General Health Questionnaire, a questionnaire to determine job satisfaction and stress, and questions to obtain demographic characteristics and to measure the staff's consideration of alternative work situations. RESULTS: The overall response rate was 70.9% (681 of 961 eligible subjects): by group it was 63.3% (131/207) for physicians, 80.9% (314/388) for allied health professionals and 64.5% (236/366) for support staff. The prevalence of emotional exhaustion were significantly higher among the physicians (53.3%) than among the allied health professionals (37.1%) and the support staff (30.5%) (p < or = 0.003); the same was true for feelings of depersonalization (22.1% v. 4.3% and 5.5% respectively) (p < or = 0.003). Feelings of low personal accomplishment were significantly higher among physicians (48.4%) and allied health professionals (54.0%) than among support staff (31.4%) (p < or = 0.002). About one-third of the respondents in each group reported that they have considered leaving for a job outside the cancer care system. Significantly more physicians (42.6%) than allied health professionals (7.6%) or support staff (4.5%) stated that they have considered leaving for a job outside the province. INTERPRETATION: The findings support the concern that medical oncology personnel are experiencing burnout and high levels of stress and that large numbers are considering leaving or decreasing their work hours. This is an important finding for the cancer care system, where highly trained and experienced health care workers are already in short supply.

The effects of radiation therapy on quality of life of women with breast carcinoma: results of a randomized trial. Ontario Clinical Oncology Group.

BACKGROUND: The purpose of this study was to evaluate the effect of breast irradiation on quality of life, including cosmetic outcome, for patients enrolled in a clinical trial. METHODS: Between 1984 and 1989, a randomized trial was conducted in Ontario, Canada, in which women with lymph node negative breast carcinoma who had undergone lumpectomy and axillary lymph node dissection were randomized to either breast irradiation or no further treatment. A modified version of the Breast Cancer Chemotherapy Questionnaire (BCQ) was administered to women at baseline, 1 month (4 weeks), and 2 months (8 weeks) after randomization. Irritation of the skin of the breast, breast pain, and appearance of the breast to the patient were also assessed every 3 months for the first 2 years of the study. RESULTS: Of 837 patients, 416 were randomly allocated to radiation therapy and 421 to no further treatment. The mean change in quality of life from baseline to 2 months was -0.05 for the radiation group and +0.30 for the control group. The difference between groups was statistically significant (P = 0.0001). Longer term radiation therapy increased the proportion of patients who were troubled by irritation of the skin of the breast and breast pain. Radiation therapy did not increase the proportion of patients at 2 years who were troubled by the appearance of the treated breast; 4.8% in irradiated and nonirradiated patients (P = 0.62). CONCLUSIONS: Breast irradiation therapy had an effect on quality of life during treatment. After treatment, irradiated patients reported increased breast symptoms compared with controls. However, no difference was detected between groups at 2 years in the rates of skin irritation, breast pain, and being upset by the appearance of the breast.

Does locoregional radiation therapy improve survival in breast cancer? A meta-analysis.

PURPOSE: Recent randomized trials in women with node-positive breast cancer who received systemic treatment report that locoregional radiation therapy improves survival. Previous trials failed to detect a difference in survival that results from its use. A systematic review of randomized trials that examine the effectiveness of locoregional radiation therapy in patients treated by definitive surgery and adjuvant systemic therapy was conducted. METHODS: Randomized trials published between 1967 and 1999 were identified through MEDLINE database, CancerLit database, and reference lists of relevant articles. Relevant data was abstracted. The results of randomized trials were pooled using meta-analyses to estimate the effect of treatment on any recurrence, locoregional recurrence, and mortality. RESULTS: Eighteen trials that involved a total of 6,367 patients were identified. Most trials included both pre- and postmenopausal women with node-positive breast cancer treated with modified radical mastectomy. The type of systemic therapy received, sites irradiated, techniques used, and doses of radiation delivered varied between trials. Data on toxicity were infrequently reported. Radiation was shown to reduce the risk of any recurrence (odds ratio, 0.69; 95% confidence interval [CI], 0.58 to 0.83), local recurrence (odds ratio, 0.25; 95% CI, 0.19 to 0.34), and mortality (odds ratio, 0.83; 95% CI, 0.74 to 0.94). CONCLUSION: Locoregional radiation after surgery in patients treated with systemic therapy reduced mortality. Several questions remain on how these results should be translated into current-day clinical practice.

Direct identification and quantitation of prednisone in the presence of overlapping hydrocortisone by liquid chromatography with electrospray and atmospheric-pressure chemical-ionisation mass spectrometry.

The paper describes the application of liquid chromatography interfaced to a triple quadrupole mass spectrometer utilising the multiple reaction monitoring (MRM) mode. The technique was shown to provide detection limits lower than 0.01% for the analysis of prednisone in the presence of hydrocortisone. Prednisone was mixed in concentrations from 0.500 to 0.0005 ppm (corresponding to 1% to 0.001% of the hydrocortisone concentration). These solutions were assayed using MRM observing the product ion transitions of 359.2-->147.1 and 359.2-->171.2 and was shown to be capable of detecting co-eluting impurities at concentrations of less than 0.001% of the major component. The assay of prednisone was shown to be linear over the range 0.500-0.0005 ppm with a correlation coefficient of 0.999 and a precision of 6.9% at the concentration of 0.005 ppm. The analysis was carried out using both atmospheric pressure chemical ionisation (APCI) and electrospray ionisation (ESI) as an interface. However, for these compounds APCI provided significantly more sensitive data compared to ESI.

Offering a choice between two adjuvant chemotherapy regimens: a pilot study to develop a decision aid for women with breast cancer.

BACKGROUND: The primary objective of this study was to develop a decision aid which would encourage and assist patients to become involved in treatment decision making, and help clinicians to objectively educate patients about the benefits and risks of adjuvant chemotherapy for breast cancer. A secondary objective was to investigate the factors influencing this treatment decision-making process for women when choosing between adriamycin and cyclophosphamide (AC) versus cyclophosphamide, methotrexate and 5-fluorouracil (CMF) chemotherapy. METHODS: An educational visual instrument called a Decision Board was developed consisting of written and graphical material. The Decision Board displays general information about chemotherapy and detailed information about each chemotherapy regimen, including the schedule and side effects, and was presented to patients with a scripted standardized oral explanation. The instrument was evaluated in 46 premenopausal women newly diagnosed with node-positive breast cancer. Following presentation of the board, the patients were given a take home version to review and asked to return 1-2 weeks later with a decision. During the second visit each patient was asked to complete a questionnaire regarding demographics, learning and comprehension, treatment preference, and factors influencing their decision. RESULTS: Recall of information was acceptable (> or = 80%). The Decision Board was found helpful by all, but the level of difficulty with decision making was variable. Out of 46 women, 23 women chose AC, 21 chose CMF, and two chose no treatment. The major factors affecting treatment preference were related to the impact on quality of life, the length of therapy, and the side effects, in particular, vomiting and alopecia. CONCLUSIONS: The Decision Board appears to be a valuable educational tool that enables patients to become well-informed and directly involved in their treatment decisions.

Evaluation of a patient file folder to improve the dissemination of written information materials for cancer patients.

BACKGROUND: Many cancer centers make available to patients written information material to supplement verbal information provided by clinicians. Randomized trials have demonstrated that providing such information can increase patient knowledge and satisfaction. However, little data are available regarding effective means of dissemination of such materials. The purpose of this study was to determine whether providing patients with a personal file folder after their first clinic appointment would improve the dissemination of written information materials and increase patient satisfaction. METHODS: A before/after study was performed. Consecutive patients with newly diagnosed cancer attending the Hamilton Regional Cancer Centre were selected randomly and interviewed by telephone within 1-2 weeks of the first clinic appointment regarding the number of information pamphlets received, patient satisfaction, and general preference for written information materials. The preintervention evaluation (T1) occurred over a 4-month period followed by the introduction of the personal file folder into the clinical practice. Six weeks after its introduction, the postintervention (T2) evaluation took place over the ensuing 4 months. RESULTS: A total of 300 patients completed the evaluation (150 each in T1 and T2). Responding patients in the two time periods were comparable with respect to background demographic variables. The mean number of information pamphlets received by patients increased with the introduction of the personal file folder from 2.4+/-2.0 standard deviations (SD) in T1 to 3.6+/-2.5 SD in T2 (P=0.0001). The percentage of patients planned for treatment who received treatment-related information increased from 36% (42 of 116 patients) in T1 to 65% (68 of 105 patients) in T2 (P=0.002). Mean patient satisfaction increased from 3.3+/-1.1 SD to 3.8+/-1.0 SD over the 2 time periods (P=0.0001). The majority of patients (87%) believed it was important to receive written information materials. CONCLUSIONS: The patient file folder increased the dissemination of written information materials and currently is being incorporated into routine practice.

The supportive care needs of newly diagnosed cancer patients attending a regional cancer center.

BACKGROUND: The objective of this study was to examine the physical and emotional health status, self-perceived problems, and needs of newly diagnosed cancer patients to determine and plan supportive care strategies. METHODS: A cross-sectional survey of newly diagnosed cancer patients attending a regional cancer center during a 6-month period was performed. Patients with breast, colorectal, head and neck, lung, and prostate carcinoma as well as nonmelanoma of the skin were selected randomly. Patients were interviewed prior to their first appointment at the clinic. Physical health status was assessed using the Symptom Distress Scale, psychologic health status was assessed with the General Health Questionnaire (GHQ), day-to-day functioning with the Rapid Disability Scale, and social support with the modified Sarason's Social Support Scale. Perceived needs were assessed in a number of ways, including identification of patients' specific social concerns and informational needs, and by asking them to list their current problems or concerns. RESULTS: Of 156 eligible patients, 134 completed the interview. One hundred and twenty-nine patients (96%) reported current symptoms that included fatigue (66%), worried outlook (61%), difficulty sleeping (48%), and pain (42%). Forty-four patients (33%) were identified as psychologically distressed with a GHQ score of > or = 6. One hundred and fourteen patients (85%) had informational needs, 89 (66%) indicated > or = 1 social concerns, and 55 (41%) reported a need for assistance with day-to-day living. CONCLUSIONS: Patients with newly diagnosed cancer commonly report symptoms related to fatigue, pain, and psychologic distress. Other frequently reported issues relate to the need for information and social concerns regarding the patients' ability to take care of their home and maintain family and other relationships. Awareness of these issues is important for planning supportive care interventions for newly diagnosed cancer patients.

Breast irradiation in women with early stage invasive breast cancer following breast conservation surgery. Provincial Breast Disease Site Group.

GUIDELINE QUESTIONS: 1) Should breast irradiation be given to women with early stage invasive breast cancer (stage I and II) following breast conservation surgery (lumpectomy with clear resection margins and axillary dissection)? 2) Is there an optimal schedule for breast irradiation? 3) What is a reasonable interval between definitive surgery and the start of breast irradiation? 4) Are there patients who can be spared breast irradiation after lumpectomy? OBJECTIVE: To make recommendations about the use of breast irradiation in women with early stage invasive breast cancer following breast conservation surgery. OUTCOMES: Local control is the primary endpoint of interest. Survival, quality of life (addressed through the adverse effects of radiotherapy) and cosmesis are also considered. PERSPECTIVE (VALUES): Evidence was selected and reviewed by 6 members of the Breast Disease Site Group (Breast DSG) of the Ontario Cancer Treatment Practice Guidelines Initiative. Earlier drafts of the evidence-based recommendation were reviewed, discussed and approved by the Breast DSG, which comprises medical oncologists, radiation oncologists, surgeons, epidemiologists, pathologists and a medical sociologist. There was no participation by a community representative in the development of this guideline. QUALITY OF EVIDENCE: There are 5 randomized controlled trials (RCTs) and 1 meta-analysis comparing breast irradiation with no breast irradiation following breast conservation surgery; 6 randomized trials comparing breast conservation surgery plus breast irradiation with mastectomy are also included, as well as several retrospective studies. BENEFITS: All of the 5 RCTs showed a significant decrease in local recurrence rates among patients receiving radiotherapy. In the 4 trials with a median follow-up of 5 years or longer, the relative risk reduction with breast irradiation ranged from 69% to 88%. The absolute differences ranged from 16% (p < 0.001) to 25% (p < 0.001). Despite the effect on local recurrence, no difference in survival was detected in any of the 5 trials. Most of the patients with local recurrence in these trials underwent mastectomy. HARMS: Major adverse effects of breast irradiation occur very infrequently. PRACTICE GUIDELINE: Women with early stage invasive breast cancer (stage I and II) who have undergone breast conservation surgery should be offered postoperative breast irradiation. The optimal fractionation schedule for breast irradiation has not been established, and the role of boost irradiation is unclear. Outside of a clinical trial, 2 commonly used fractionation schedules are suggested: 50 Gy in 25 fractions to the whole breast, or 40 Gy in 16 fractions to the whole breast with a local boost to the primary site of 12.5 Gy in 5 fractions. Shorter schedules (e.g., 40 or 44 Gy in 16 fractions) have also been used routinely in some centres. The enrollment of patients in ongoing clinical trials is encouraged. Women who have undergone breast conservation surgery should receive local breast irradiation as soon as possible after wound healing. A safe interval between surgery and the start of radiotherapy is unknown, but it is reasonable to start breast irradiation within 12 weeks after definitive surgery. For women who are candidates for chemotherapy, the optimal sequencing of chemotherapy and breast irradiation is unknown. It is reasonable to start radiotherapy after the completion of chemotherapy, or concurrently if anthracycline-containing regimens are not used. For further information, please refer to Ontario Cancer Treatment Practice Guidelines Initiative's practice guideline "Surgical Management of Early Stage Invasive Breast Cancer (stage I and II)."