Atsunori Yorozu

Postmortem radiation safety and issues pertaining to permanent prostate seed implantation in Japan

PURPOSEnIf a prostate cancer patient treated with (125)I brachytherapy dies within 12 months after the treatment, prostate removal before cremation is recommended to avoid problems related to radioactivity in the ashes, such as inhalation of airborne particulate matter by crematorium staff or nearby residents. To provide guidance for such cases, a manual prepared under the editorial supervision of several professional associations was issued in 2008 in Japan. Herein, we investigated the incidence and causes of death, and the actions taken subsequent to death, among prostate cancer patients who died within 12 months after (125)I brachytherapy over a 10-year period in Japan; and we compared the results before and after the manual was issued.nnnMETHODS AND MATERIALSnData extracted from the Japan Radioisotope Association database for the period from September 2003 to the end of December 2013 were used.nnnRESULTSnOf 27,976 patients who underwent (125)I brachytherapy during the specified period, 79 died within 12 months after implantation, including 3 who died in the 2011 earthquake and tsunami. The prostate and brachytherapy source were retrieved at autopsy from 69 of the 79 patients. Autopsy could not be performed on the other 10 patients, 2 of whom died in the earthquake. Autopsy and retrieval of the brachytherapy source were significantly more common after issuance of the manual than before (22/28 cases before; 47/49 cases after; p=0.021).nnnCONCLUSIONnIn most cases of early death after (125)I brachytherapy in Japan, the brachytherapy source was retrieved.

A Review of Permanent Prostate Brachytherapy as Practiced in Japan

Iodine-125 permanent prostate brachytherapy (PPB) was introduced in Japan in 2003. The Japanese guidelines of radiation safety control for PPB regulate radiation safety parameters including the qualifications of the institutions and doctors to perform this treatment. To evaluate the safety and efficacy of PPB for localized prostate cancer, the nationwide Japanese Prostate Cancer Outcome Study of Permanent Iodine-125 Seed Implantation (J-POPS) was conducted between 2005 and 2010. The J-POPS study is the largest multi-institutional prospective cohort study to achieve state-of-the-art clinical outcomes for localized prostate cancer treated using PPB. This study, along with regular training courses and joint radiation oncology-urology conferences, has promoted and achieves quality PPB. Every year, 3000 patients are treated with this modality in Japan. In this article, the early results of J-POPS and many clinical investigations are reviewed to provide the current status of PPB as practiced in Japan. This review covers planning techniques, postimplant dosimetry, toxicity, clinical outcomes, and special issues of radiation safety control.

Brachytherapy for Esophageal Cancer: Optimum Dose and Indications in the Modern Era

Endoluminal brachytherapy (BT) is an effective means of delivering high doses to esophageal lesions while delivering much lower doses to surrounding tissues. In the 1980s and 1990s, esophageal BT was a common treatment option. However, some influential studies suggested that dose escalation with BT resulted in significant and devastating toxicity. The cause for this relatively high rate of severe complications could be the high total biological radiation dose to the mucosa. In a wide esophageal lumen, larger applicators should be used, whereas applicators with small diameters are limited to obstructing lesions. The important dosimetry and esophageal BT emphasizes lumen diameter, applicator diameter, wall thickness, dose at 5 mm from the applicator surface into the esophageal wall, and dose at the applicator surface. Different treatment geometries can achieve positive oncologic and palliative outcomes without excessive toxicity. To optimize BT, it is beneficial to perform 3D CT-based treatment planning, especially in curative settings. Modern BT could play a role in the management of locally advanced, recurrent, or superficial cancer in patients without surgical options. Herein, we recommend some optimum regimens for superficial and advanced tumors based on published literature and our long-term follow-up data over 20 years.