The current state and future perspectives of radiotherapy for cervical cancer.

Radiotherapy is an effective treatment method for cervical cancer and is typically administered as external beam radiotherapy followed by intracavitary brachytherapy. In Japan, center shielding is used in external beam radiotherapy to shorten treatment time and reduce the doses delivered to the rectum or bladder. However, it has several challenges, such as uncertainties in calculating the cumulative dose. Recently, external beam radiotherapy has been increasingly performed with intensity-modulated radiotherapy, which reduces doses to the rectum or bladder without center shielding. In highly conformal radiotherapy, uncertainties in treatment delivery, such as inter-fractional anatomical structure movements, affect treatment outcomes; therefore, image-guided radiotherapy is essential for appropriate and safe performance. Regarding intracavitary brachytherapy, the use of magnetic resonance imaging-based image-guided adaptive brachytherapy is becoming increasingly widespread because it allows dose escalation to the tumor and accurately evaluates the dose delivered to the surrounding normal organs. According to current evidence, a minimal dose of D90% of the high-risk clinical target volume is significantly relevant to local control. Further improvements in target coverage have been achieved with combined interstitial and intracavity brachytherapy for massive tumors with extensive parametrical involvement. Introducing artificial intelligence will enable faster and more accurate generation of brachytherapy plans. Charged-particle therapies have biological and dosimetric advantages, and current evidence has proven their effectiveness and safety in cervical cancer treatment. Recently, radiotherapy-related technologies have advanced dramatically. This review provides an overview of technological innovations and future perspectives in radiotherapy for cervical cancer.

Stereotactic radiotherapy for ventricular tachycardia: A study protocol.

Background: Currently, the standard curative treatment for ventricular tachycardia (VT) and ventricular fibrillation (VF) is radiofrequency catheter ablation. However, when the VT circuit is deep in the myocardium, the catheter may not be delivered, and a new, minimally invasive treatment using different energies is desired. Methods: This is a protocol paper for a feasibility study designed to provide stereotactic radiotherapy for refractory VT not cured by catheter ablation after at least one catheter ablation. The primary end point is to evaluate the short-term safety of this treatment and the secondary endpoint is to evaluate its efficacy as assessed by the reduction in VT episode. Cyberknife M6 radiosurgery system will be used for treatment, and the prescribed dose to the target will be 25Gy in one fraction. The study will be conducted on three patients. Conclusion: Since catheter ablation is the only treatment option for VT that is covered by insurance in Japan, there is currently no other treatment for VT/VF that cannot be cured by catheter ablation. We hope that this feasibility study will provide hope for patients who are currently under the stress of ICD activation. Trial registration: The study has been registered in the Japan Registry of Clinical Trials (jRCTs042230030).

High-dose-rate intracavitary brachytherapy for recurrent cervical cancer in the vaginal stump after hysterectomy.

This study aimed to evaluate the treatment outcomes of patients who received high-dose-rate intracavitary brachytherapy (HDR-BT) using Iridium-192 with or without external beam radiotherapy as definitive treatment for recurrent cervical cancer after hysterectomy. Thirty-six patients with local recurrence after hysterectomy received radiotherapy including HDR-BT from 2005 to 2013. Overall survival, local control rate, and progression-free survival were estimated retrospectively via the Kaplan-Meier method. Late adverse events were also scored using the Common Terminology Criteria for Adverse Events (version 3.0). Median follow-up time was 38 (range, 7.4-101.3) months. The 3-year estimates of overall survival, local control rate, and progression-free survival were 100.0%, 82.8%, and 76.8%, respectively. Two patients (5.6%) had grade 2 lymphedema, but no other adverse events greater than grade 2 were reported. In conclusion, HDR-BT was an effective treatment modality for patients with cervical cancer recurrence in the vaginal stump.

Study Protocol: Prospective Study of Concurrent Chemoradiotherapy with S-1 and Hypofractionated Radiotherapy for Outpatients with Early Glottic Squamous Cell Carcinomas

Background: The recommended treatment strategies for early glottic carcinoma with intent of larynx preservation are primarily radiotherapy. However, the outcomes of radiotherapy for bulky T1 or T2 glottic carcinoma are unsatisfactory. We designed a protocol consisting of concurrent chemoradiotherapy using S-1 as the radiosensitizer. We have performed this protocol in patients with favorable T2 lesions and demonstrated its efficacy and safety. In contrast, we have treated non-bulky T1 glottic carcinomas with 2.25 Gy per fraction, for a total of 25-28 fractions, starting in 2011 to improve efficacy and shorten the treatment period. Since this treatment strategy was implemented for T1 disease, no local failure has occurred to date, and it appears to be almost as safe as radiotherapy using 2.0 Gy per fraction. With the aim of improving the local control rate and shortening the treatment period primarily for favorable T2 disease, we changed the dose of radiation in our protocol from 2.0 Gy to 2.25 Gy per fraction, for a total of 25 fractions (from 30 fractions). The present study aims to evaluate the efficacy and safety of this new protocol. Methods: This study will be conducted as a clinical, prospective, single-armed, non-randomized trial. Patients are to receive S-1 (55.3 mg /m2 /day, once daily) and radiotherapy (2.25 Gy per fraction, for a total of 25 fractions). S-1 and radiotherapy are started on the same day that radiotherapy is performed, 3-6 hours after oral administration of S-1. The primary study aim is the 3-year local control rate. The secondary study aims are overall survival, voice-preservation survival, disease-free survival, complete response rate, completion rate, and toxicity. Result and conclusion: This is the first single-center, non-randomized, prospective study of concurrent chemoradiotherapy with S-1 and hypofractionated radiotherapy to be conducted. The trial will evaluate the efficacy and safety of our protocol.

Optimized treatment strategy of radiotherapy for early glottic squamous cell carcinomas: An initial analysis.

The purpose of this study was to evaluate the clinical outcomes of radiotherapy for patients with T1/T2 glottic carcinoma. Patients with T1/T2 glottic carcinoma histopathologically diagnosed with squamous cell carcinoma and treated at our hospital between 2007 and 2015 were analyzed retrospectively. Our strategy for T1/T2 glottic carcinoma was as follows: radiotherapy alone with 2.25 Gy per fraction to a total of 25-28 fractions for patients with non-bulky T1 glottic carcinoma; concurrent chemoradiotherapy with oral S-1 and radiotherapy with 2 Gy per fraction to a total of 30 fractions for patients with T1 bulky/T2 favorable glottic carcinoma; or chemoradiotherapy with high-dose cisplatin and radiotherapy with 2 Gy per fraction to a total of 35 fractions for T2 unfavorable glottic carcinoma. Forty-eight patients were eligible. The median follow-up period among surviving patients was 38 months (range, 11-107). The disease was T1a in 23%, T1b in 13%, and T2 in 65% of patients. The 3-year local control rate in all patients, T1a, T1b, and T2 was 96.7%, 100%, 100%, and 96.0%, respectively. Of the 46 patients, one with T2 glottic carcinoma developed recurrent disease at the primary site, and one with T2 glottic carcinoma had lymph node recurrences in the neck. Acute Grade 3 dermatitis occurred in 8 (17%) patients and late Grade 2 hypothyroidism occurred in 2 (4%) patients. This retrospective study shows that our optimized treatment strategy of radiotherapy depending on the stage of early glottic carcinoma is not only effective but also well-tolerated.