|Intensity-modulated radiotherapy for breast cancer: a systematic review
|Ye X, Su L, Wang X, Yang K, Tian J, Zhang Q, Wang Q, Li X, Kang Y, Guo L, Liu R, Feng S
The review concluded that intensity modulated radiotherapy (IMRT) significantly reduced occurrence of moist acute dermatitis anywhere in the breast and alleviated the suffering and improved the quality of life of patients. The overall poor quality of the included trials and lack of evidence for most outcomes means that caution is warranted when interpreting the authors’ conclusions.
To assess the long-term effect of breast conservation with breast intensity modulated radiotherapy for early stage breast cancer.
PubMed, EMBASE, The Cochrane Library and Chinese Biomedical Literature database were searched to June 2009 for articles published in any language. Search terms were reported. Reference lists of retrieved articles were searched. Annual Meetings of the American Society of Clinical Oncology conference proceedings were handsearched to 2009.
Randomised controlled trials (RCTs) of IMRT versus convention radiotherapy in patients with early stage breast cancer were eligible for inclusion. Primary outcome measures were incidence rates of acute moist dermatitis, oedema of the mammary gland and hyperpigmentation. The included trials studied IMRT with a various radiotherapy modalities.
Two reviewers performed study selection.
Assessment of study quality
Trial quality was assessed using the Quality Assess Criteria of randomisation, blinding, allocation concealment, intention-to-treat and loss to follow-up.
Two reviewers performed quality assessment. Disagreements were resolved by discussion.
Data on incidence rates of acute moist dermatitis, oedema of the mammary gland and hyperpigmentation were extracted and used to calculate odds ratios (OR) and 95% confidence intervals (CIs).
Two reviewers performed data extraction. Disagreements were resolved by discussion.
Methods of synthesis
Where there was no significant statistical heterogeneity a fixed-effect meta-analysis was used to calculate pooled odds ratios, together with 95% CIs. Statistical heterogeneity was assessed using Ι² and Χ². Where statistical heterogeneity was detected a random-effect meta-analysis was used. Sensitivity analysis was conducted on the basis of study quality and statistical heterogeneity.
Results of the review
Four trials (1,440 patients) were included in the review. The quality of the included trials was generally suboptimal: none of the trials reported loss to follow-up, allocation concealment, selective reporting or intention-to-treat. Randomisation was adequate in only one trial. One trial was single-blinded; other trials did not report blinding. Study sample sizes ranged from 133 to 804 patients.
Compared with conventional radiotherapy, IMRT was associated with a statistically significantly decrease in occurrence of acute moist dermatitis (OR 0.28, 95% CI 0.17 to 0.48, Ι²=75%; four RCTs). One trial also showed a statistically significant reduction in oedema and occurrence of hyperpigmentation. One trial showed no difference in pain and quality of life.
The available evidence showed that IMRT significantly reduced occurrence of moist acute dermatitis anywhere in the breast and alleviated the suffering and improved the quality of life of patients.
Inclusion criteria for the review were clearly defined. Several relevant data sources were searched without language restrictions. Publication bias was not formally assessed; the authors rightly pointed out that funnel plots would not be reliable with only four trials. Efforts were made to locate unpublished studies, which should minimise the risk of publication bias. Attempts were made to reduce reviewer error and bias throughout the review process. Quality assessment indicated that most of the trials were of low quality, which may have been due to reporting. No details of trial characteristics were provided, which made judging the clinical heterogeneity of the trials difficult.
Trials were combined using standard statistical methods and statistical heterogeneity was assessed. The dermatitis outcome had high levels of statistical heterogeneity. None of the other outcomes had more than one trial providing evidence so conclusions on these outcomes may not be reliable. The one trial that reported pain and quality of life showed no difference and this was not reflected in the authors’ conclusions. The overall poor quality of the included trials and lack of evidence for most outcomes means that caution is warranted when interpreting the authors’ conclusions.
Implications of the review for practice and research
Practice: The authors stated that use of IMRT in clinical practice was a practical and feasible technique for delivering a homogenous dose to the whole breast and resulted in an overall reduction in clinical toxicities.
Research: The authors stated that future large-scale, high-quality, double-blind trials were needed.
Ye X, Su L, Wang X, Yang K, Tian J, Zhang Q, Wang Q, Li X, Kang Y, Guo L, Liu R, Feng S. Intensity-modulated radiotherapy for breast cancer: a systematic review. Chinese-German Journal of Clinical Oncology 2010; 9(12): 708-713
Subject indexing assigned by CRD
Breast Neoplasms; Radiotherapy Planning, Computer-Assisted; Radiotherapy, Intensity-Modulated; Humans; Radiotherapy Dosage; Mastectomy, Segmental; Female
Date bibliographic record published
Date abstract record published
This is a critical abstract of a systematic review that meets the criteria for inclusion on DARE. Each critical abstract contains a brief summary of the review methods, results and conclusions followed by a detailed critical assessment on the reliability of the review and the conclusions drawn.