Dosimetric Effects of the Interfraction Variations during Whole Breast Radiotherapy: A Prospective Study.

INTRODUCTION: The aim of this work was to assess the dosimetric impact of the interfraction variations during breast radiotherapy. MATERIALS AND METHODS: Daily portal imaging measurements were prospectively performed in 10 patients treated with adjuvant whole breast irradiation (50 Gy/25 fractions). Margins between the clinical target volume and the planning target volume (PTV) were 5 mm in the three dimensions. Parameters of interest were the central lung distance (CLD) and the inferior central margin (ICM). Daily movements were applied to the baseline treatment planning (TP1) to design a further TP (TP2). The PTV coverage and organ at risk exposure were measured on both TP1 and TP2, before being compared. RESULTS: A total of 241 portal images were analyzed. The random and systematic errors were 2.6 and 3.7 mm for the CLD, 4.3 and 6.9 mm for the ICM, respectively. No significant consequence on the PTV treatments was observed (mean variations: +0.1%, p = 0.56 and -1.8%, p = 0.08 for the breast and the tumor bed, respectively). The ipsilateral lung and heart exposure was not significantly modified. CONCLUSION: In our series, the daily interfraction variations had no significant effect on the PTV coverage or healthy tissue exposure during breast radiotherapy.

Genomic classifications and radiotherapy for breast cancer.

The current therapeutic strategy in breast cancer rests on standard prognostic factors such as size, histological grade, nodal and hormone receptor status. However, over the last decade, a new form of molecular classification has emerged to complement the classical clinico-pathological staging. Models based on tumour genome have been developped to help predict the risk of relapse, and are currently being evaluated. This improved risk stratification tool would enable the identification of patients who would benefit from systemic as well as local treatments. This paper aims to give an overview of the radiobiological implications in particular of this new classification, by looking at on the one hand, predictors of local relaspe, and on the other hand, the modulation in radiotherapy according to molecular type.

The multidisciplinary management of gastrointestinal cancer. Pancreatic cancer: from pathogenesis to cure.

Pancreatic cancer is the fourth leading cause of cancer-related death in the USA. The disease has a high mortality rate and the 5-year survival rate is estimated to be 4%. Currently, surgical resection is only possible in 20% of patients; even then, the overall 5-year survival rate is only 25%. As such, surgical therapy alone is not sufficient for pancreatic carcinoma, and prospective investigation of additional modalities is crucial. Numerous negative trials have shown that chemotherapy alone is the standard of care after resection of pancreatic carcinoma. However, results remain poor and progress with new drugs is needed in this setting. For locally advanced disease, the situation is more complicated; the ideal chemoradiation schedule has not been clearly defined, and improvements could come in the near future from the use of new radiotherapy tools and targeted therapies. For advanced disease, chemotherapy alone has given very disappointing results. A multidisciplinary approach combining biological assessment of targets with clinical trials to evaluate new targeted drugs should be considered.