Based on previous reports, we propose a practical guide to choose dabigatran 150 mg twice daily or apixaban 5 mg twice daily for patients with atrial fibrillation. We recommend the use of dabigatran 150 mg twice daily for patients with atrial fibrillation who have a high risk of embolism (e.g., ischemic stroke on other oral anticoagulants, presence of left atrial appendage thrombus) and a low risk of bleeding. However, the prevalence of such patients with atrial fibrillation is considered low because patients with atrial fibrillation with a high risk of embolism usually have a high risk of bleeding. In most other patients with atrial fibrillation, the use of apixaban 5 mg twice daily should be considered.

BACKGROUNDAlthough various studies have been conducted on the effects of radiation therapy for prostate cancer, rectal toxicity after radiation therapy for prostate cancer, which is an important late adverse event associated with radiation therapy, has not been sufficiently examined. This study aimed to assess the associations of late rectal disorder (LRD) with dosimetric, anatomic, and clinical factors in patients with prostate cancer who underwent three-dimensional conformal radiation therapy (3D-CRT).

METHODSWe retrospectively analyzed 104 patients undergoing 3D-CRT between January 2009 and October 2011. Thirty patients were administered anticoagulation/antiplatelet (AC/AP) agents. The standard dose was 74 Gy. Uni- and multi-variate analyses were performed to identify factors predictive of LRD after 3D-CRT.

RESULTSThe median follow-up period was 66 (range: 14-87) months. LRD occurred in 10.6% (11/104) of patients. The median time from RT to LRD was 15 months (range: 7-41 months). Sixty-four percent of those with LRD (7/11 patients) had been given AC/AP agents. Fifty-five (6/11) patients had severe internal iliac artery calcification. By univariate analysis, significant predictors of LRD were internal iliac artery calcification, administration of AC/AP agents, and age. Being very elderly was the significant predictor identified by multivariate analysis (P = 0.0276). For patients receiving AC/AP agents and those with severe internal iliac artery calcification, the LRD incidences were 23.3% (7/30 patients) and 23.1% (6/26 patients), respectively, and being 75 years of age or older was a significant predictor in these subsets.

CONCLUSIONSOur results suggest advanced age, administration of AC/AP agents, and severe internal iliac artery calcification to be risk factors for LRD in patients undergoing standard RT. Therefore, it is necessary to administer radiation with particular caution in the very elderly, especially those receiving AC/AP agents and/or with severe internal iliac artery calcification.