A.M. Moody

Randomized Controlled Trial of Intensity-Modulated Radiotherapy for Early Breast Cancer: 5-Year Results Confirm Superior Overall Cosmesis

PURPOSE There are few randomized controlled trial data to confirm that improved homogeneity with simple intensity-modulated radiotherapy (IMRT) decreases late breast tissue toxicity. The Cambridge Breast IMRT trial investigated this hypothesis, and the 5-year results are reported. PATIENTS AND METHODS Standard tangential plans of 1,145 trial patients were analyzed; 815 patients had inhomogeneous plans (≥ 2 cm(3) receiving 107% of prescribed dose: 40 Gy in 15 fractions over 3 weeks) and were randomly assigned to standard radiotherapy (RT) or replanned with simple IMRT; 330 patients with satisfactory dose homogeneity were treated with standard RT and underwent the same follow-up as the randomly assigned patients. Breast tissue toxicities were assessed at 5 years using validated methods: photographic assessment (overall cosmesis and breast shrinkage compared with baseline pre-RT photographs) and clinical assessment (telangiectasia, induration, edema, and pigmentation). Comparisons between different groups were analyzed using polychotomous logistic regression. RESULTS On univariate analysis, compared with standard RT, fewer patients in the simple IMRT group developed suboptimal overall cosmesis (odds ratio [OR], 0.68; 95% CI, 0.48 to 0.96; P = .027) and skin telangiectasia (OR, 0.58; 95% CI, 0.36 to 0.92; P = .021). No evidence of difference was seen for breast shrinkage, breast edema, tumor bed induration, or pigmentation. The benefit of IMRT was maintained on multivariate analysis for both overall cosmesis (P = .038) and skin telangiectasia (P = .031). CONCLUSION Improved dose homogeneity with simple IMRT translates into superior overall cosmesis and reduces the risk of skin telangiectasia. These results are practice changing and should encourage centers still using two-dimensional RT to implement simple breast IMRT.

A randomised controlled trial of forward-planned radiotherapy (IMRT) for early breast cancer: baseline characteristics and dosimetry results.

BACKGROUND AND PURPOSE This large trial was designed to investigate whether correction of dose inhomogeneities using intensity-modulated radiotherapy (IMRT) reduces late toxicity and improves quality of life in patients with early breast cancer. This paper reports baseline characteristics of trial participants and dosimetry results. MATERIALS AND METHODS Standard tangential plans of 1145 trials were analysed. Patients with inhomogeneous plans, defined by ICRU recommendations, were randomised to forward-planned IMRT or standard radiotherapy. RESULTS Twenty-nine percentage of patients had adequate dosimetry with standard 2D radiotherapy. In the randomised patients, the decreases in mean volumes receiving greater than 107% (Vol>107) and less than 95% (Vol<95) of the prescribed dose in the IMRT compared with the control group were 34.0 cm(3) (95% CI 26.4-41.6; P<0.0001) and 48.1 cm(3) (95% CI 34.4-61.9; P<0.0001), respectively. In this study, 90% of patients who had a breast separation greater > or = 21 cm had Vol>107>2 cm(3) on standard radiotherapy plans. CONCLUSION This large trial, in which patients with all breast sizes were eligible, confirmed that breast dosimetry can be significantly improved with a simple method of forward-planned IMRT and has little impact on radiotherapy resources. It is shown that patients with larger breasts are more likely to have dose inhomogeneities and breast separation gives some indication of this likelihood. Photographic assessment of patients at 2 years after radiotherapy, as the next part of this randomised controlled trial, will show whether these results for IMRT translate into improved cosmetic outcome in patients with early breast cancer. This would provide impetus for the widespread adoption of 3D planning and IMRT.

The Cambridge Breast Intensity-modulated Radiotherapy Trial: patient- and treatment-related factors that influence late toxicity.

AIMS The effect of patient- and treatment-related factors in the development of late normal tissue toxicity after radiotherapy is not yet fully established. The aim of this study was to elucidate the relative importance of such factors in the development of late toxicity after breast-conserving surgery and adjuvant breast radiotherapy. MATERIALS AND METHODS Patient- and treatment-related factors were analysed in 1014 patients who had received adjuvant radiotherapy to the breast in the Cambridge Breast Intensity-modulated Radiotherapy (IMRT) Trial. Late toxicity data were collected using photographic and clinical assessments and patient-reported questionnaires at 2 years after radiotherapy. RESULTS On multivariate analysis, a larger breast volume was statistically significantly associated with the development of breast shrinkage assessed by serial photographs (odds ratio per litre increase in breast volume = 1.98, 95% confidence interval 1.41, 2.78; P < 0.0005), telangiectasia (odds ratio = 3.94, 95% confidence interval 2.49, 6.24; P < 0.0005), breast oedema (odds ratio = 3.65, 95% confidence interval 2.54, 5.24; P < 0.0005) and pigmentation (odds ratio = 1.75, 95% confidence interval 1.21, 2.51; P = 0.003). Current smokers had an increased risk of developing pigmentation (odds ratio = 2.09, 95% confidence interval 1.23, 3.54; P = 0.006). Patients with a moderate or poor post-surgical cosmesis had a greatly increased risk of moderate or poor overall cosmesis (odds ratio = 38.19; 95% confidence interval 21.9, 66.7; P < 0.0005). Postoperative infection requiring antibiotics was associated with increased risk of telangiectasia (odds ratio = 3.39, 95% confidence interval 1.94, 5.91; P < 0.0005) and breast oversensitivity (odds ratio = 1.78, 95% confidence interval 1.27, 2.49; P = 0.001). CONCLUSIONS In this study, the greatest risk factors for the development of late toxicity 2 years after breast-conserving surgery and adjuvant radiotherapy were larger breast volume, baseline pre-radiotherapy surgical cosmesis, postoperative infection and possibly smoking. These factors seem to be more important than relatively small differences in dose inhomogeneity and the addition of boost radiotherapy at 2 years after the completion of radiotherapy. The modification of potentially preventable risk factors, such as postoperative infection and smoking, may limit the development of late toxicity after breast radiotherapy.

Association of breast tumour bed seroma with post-operative complications and late normal tissue toxicity: Results from the Cambridge Breast IMRT trial

AIMS There are two main surgical techniques for managing the tumour bed after breast cancer excision. Firstly, closing the defect by suturing the cavity walls together and secondly leaving the tumour bed open thus allowing seroma fluid to collect. There is debate regarding which technique is preferable, as it has been reported that a post-operative seroma increase post-operative infection rates and late normal tissue side effects. METHODS Data from 648 patients who participated in the Cambridge Breast IMRT trial were used. Seromas were identified on axial CT images at the time of radiotherapy planning and graded as not visible/subtle or easily visible. An association was sought between the presence of seroma and the development of post-operative infection, post-operative haematoma and 2 and 5 years normal tissue toxicity (assessed using serial photographs, clinical assessment and self assessment questionnaire). RESULTS The presence of easily visible seroma was associated with increased risk of post-operative infection (OR = 1.80; p = 0.004) and post-operative haematoma (OR = 2.1; p = 0.02). Breast seroma was an independent risk factor for whole breast induration and tumour bed induration at 2 and 5 years. The presence of breast seroma was also associated with inferior overall cosmesis at 5 years. There was no significant association between the presence of seroma and the development of either breast shrinkage or breast pain. CONCLUSION The presence of seroma at the time of radiotherapy planning is associated with increased rates of post-operative infection and haematoma. It is also an independent risk factor for late normal tissue toxicity. This study suggests that full thickness surgical closure may be desirable for patients undergoing breast conservation and radiotherapy.

A Randomised Controlled Trial of Forward-Planned Intensity Modulated Radiotherapy (IMRT) for Early Breast Cancer: Interim Results at 2 Years Follow-Up.

Background: This large single centre trial was designed to investigate whether correction of dose inhomogeneities using IMRT reduces late toxicity and improves quality of life in patients with early breast cancer. We report interim results at 2 years follow-up. Materials and Methods: Standard tangential breast radiotherapy plans of 1145 trial patients were assessed for dose inhomogeneity as defined by ICRU recommendations. Patients with inhomogeneous plans were randomised to either IMRT or standard radiotherapy. Patients with homogenous plans were treated with standard radiotherapy, but were followed up within the trial as per randomised patients. The primary endpoint of the trial was photographic assessment of breast shrinkage. Secondary endpoints included photographic assessment of final cosmesis, clinical assessment of toxicity, and patient-reported symptoms and quality of life. All endpoints were scored using validated assessment methods. Data were collected on potential confounding factors which included: age at randomisation, smoking history, body mass index, co-morbidity such as diabetes mellitus, cardiovascular and peripheral vascular disease, use of hormones and/or chemotherapy, treated breast volume, and presence or absence of breast boost. Results: 330/1145 (29%) of patients had adequate dosimetry with standard 2D radiotherapy and were not randomised. In the 815 randomised patients, dosimetry was significantly improved in the interventional (IMRT) arm compared to the control. Currently, data from 632 randoimsed patients who have reached 2 years of follow up have been analysed. This interim analysis demonstrates that the incidence of telangiectasia in the control arm was significantly greater than in the interventional group (P = 0.024). Pre-radiotherapy surgical cosmesis significantly affected photographic assessment of final cosmesis, and clinical assessment of breast shrinkage and induration (P Discussion: This trial shows that the use of forward-planned IMRT can significantly improve dose homogeneity, and suggests that this translates into improvements in late toxicity at only 2 years from completion of radiotherapy. Surgical cosmesis appears to be a very important determinant of overall final cosmesis after 2 years of follow-up, and may mask any beneficial effects of IMRT at this early stage. It is highly likely that these trial patients will have not expressed their final level of toxicity at 2 years post-radiotherapy, and re-analysis is planned at 5 years from completion of radiotherapy. Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 71.