Assessment of non-inferiority with meta-analysis: example of hypofractionated radiation therapy in breast and prostate cancer.

The aim of this study was to propose a methodology for the assessment of non-inferiority with meta-analysis. Assessment of hypofractionated RT in prostate and breast cancers is used as an illustrative example. Non-inferiority assessment of an experimental treatment versus an active comparator should rely on two elements: (1) an estimation of experimental treatment's effect versus the active comparator based on a meta-analysis of randomized controlled trials and (2) the value of an objective non-inferiority margin. This margin can be defined using the reported effect of active comparator and the percentage of the active comparator's effect that is desired to be preserved. Non-inferiority can then be assessed by comparing the upper bound of the 95% confidence interval of experimental treatment's effect to the value of the objective non-inferiority margin. Application to hypofractionated RT in breast cancer showed that hypofractionated whole breast irradiation (HWBI) appeared to be non-inferior to conventionally fractionated RT for local recurrence. This was not the case for accelerated partial breast irradiation (APBI). Concerning overall survival, non-inferiority could not be claimed for either HWBI or APBI. For prostate cancer, the lack of demonstrated significant superiority of conventional RT versus no RT precluded any conclusion regarding non-inferiority of hypofractionated RT.

Correlation between anthropometric parameters and acute skin toxicity in breast cancer radiotherapy patients: a pilot assessment study.

OBJECTIVE: The objective of the present study was to identify acute skin toxicity risk factors linked to the anthropometric characteristics of patients with breast cancer treated with radiation therapy. METHODS: Consecutive patients with breast cancer were enrolled after breast-conserving surgery and before radiotherapy course. Acute skin toxicity was assessed weekly during the 7 weeks of radiotherapy with the International Classification from National Cancer Institute. Grade 2 defined acute skin toxicity. Patient characteristics and anthropometric measurements were collected. RESULTS: 54 patients were enrolled in 2013. Eight patients (14.8%) had grade ≥2 toxicity. The average weight and chest size were 65.5 kg and 93.6 cm, respectively. Bra cup size is significantly associated with a risk of grade 2 dermatitis [odds ratio (OR) 3.46, 95% confidence interval (CI) (1.29-11.92), p = 0.02]. Anthropometric breast fat mass measurements, such as thickness of left [OR 2.72, 95% CI (1.08-8.26), p = 0.04] and right [OR 2.45, 95% CI (0.99-7.27), p = 0.05] axillary fat, are correlated with an increased risk. Distance between the pectoral muscle and nipple is a reproducible measurement of breast size and is associated with acute skin toxicity with significant tendency (OR = 2.21, 95% CI (0.97-5.98), p = 0.07). CONCLUSION: Breast size and its different anthropometric measurements (thickness of left and right axillary fat, nipple-to-pectoral muscle distance) are correlated with the risk of skin toxicity. ADVANCES IN KNOWLEDGE: The present article analyses several characteristics and anthropomorphic measurements of breast in order to assess breast size. A standardized and reproducible protocol to measure breast volume is described.