Ken Yoshida

Background/Objectives To evaluate the efficacy and safety of unique magnetic resonance imaging (MRI)-guided interstitial brachytherapy (ISBT) for locally advanced cervical cancer that is unsuitable for intracavitary brachytherapy (ICBT) or intracavitary/interstitial brachytherapy (ICISBT). Methods: We analyzed the clinical outcomes, including toxicity, of 68 previously untreated patients with cervical cancer treated between 2014 and 2024. Results: The median high-risk clinical target volume (HR-CTV) was 53.20 cc (range, 16.34–147.03 cc) with ISBT. With a median follow-up time of 37.5 months (7–115 months), the three-year local control, progression-free survival, and overall survival rates were 89.8%, 52.4%, and 70.9%, respectively. Multivariate analyses showed significant associations of histology with local control, overall treatment times, HR-CTV volume with overall survival rate, over all treatment times, and HR-CTV volume and M category with progression-free survival. Toxicity grade 3 occurred in 12 patients (17.6%) and consisted of four genitourinary (5.8%) and seven gastrointestinal (10.2%) toxicities. Conclusions: MRI-guided ISBT is an effective treatment strategy for obtaining a favorable local control rate for selected advanced diseases with an acceptable complication rate. Future research is warranted to elucidate who would be good candidates for MRI-guided ISBT.

Background/Objectives: To evaluate the efficacy and safety of unique magnetic resonance imaging (MRI)-guided interstitial brachytherapy (ISBT) for locally advanced cervical cancer that is unsuitable for intracavitary brachytherapy (ICBT) or intracavitary/interstitial brachytherapy (ICISBT). Methods: We analyzed the clinical outcomes, including toxicity, of 68 previously untreated patients with cervical cancer treated between 2014 and 2024. Results: The median high-risk clinical target volume (HR-CTV) was 53.20 cc (range, 16.34–147.03 cc) at ISBT. With a median follow-up time of 37.5 months (7-115 months), the three-year local control, progression-free survival, and overall survival rates were 89.8%, 52.4%, and 70.9%, respectively. Multivariate analyses showed significant associations of histology with local control, overall treatment times, HR-CTV volume with overall survival rate, over all treatment times, and HR-CTV volume and M category with progression-free survival. Toxicity grade 3 were occurred in 12 patients (17.6%) consist of 4 genitourinary (5.8%), 7 gastrointestinal (10.2%) toxicities. Conclusion: MRI-guided ISBT is an effective treatment strategy for obtaining a favorable local control rate for selected advanced diseases with an acceptable complication rate. Future research is warranted to elucidate who is a good candidate for MRI-guided ISBT.

Kochi Oxydol Radiation Therapy for Unresectable Carcinoma (KORTUC) is a novel radiosensitizer invented by Professor Ogawa at Kochi University (Japan) in 2006. The current study aimed to report the experience of the present authors with the use of KORTUC treatment in combination with interstitial brachytherapy (ISBT), with or without external beam (EB) radiotherapy (RT), in patients with locally recurrent cervical cancer (LRCC), who were likely to have a high risk of poor prognosis. Between April 2012 and January 2020, 14 female patients (15 tumoral lesions) with LRCC underwent KORTUC with ISBT. Their previous treatments included surgery (n=4), radiation therapy (n=8) and surgery plus RT (n=3). The primary lesions were located in the vaginal stump (n=5), pelvic wall (n=3), cervix (n=3), vaginal wall (n=2) and lymph nodes (n=2). At 2 h before RT, KORTUC was injected intratumorally via direct colposcopy. The dose of KORTUC ranged from 4‑12 ml, adjusted for the tumor size. For patients who underwent ISBT, KORTUC was administered before and after insertion of the applicator before irradiation. Intratumoral injection of KORTUC was completed without any technical or safety issues in all 15 patients; it was well tolerated with no adverse events observed. KORTUC also showed preferable efficacy; a clinical complete response was observed in 87% of patients and the initial response rate was 100%. The 2‑year local control rate in patients who underwent ISBT + KORTUC was 79%, whereas it was 63% in the re‑irradiation group which was significantly lower (P=0.02) than that in the non‑irradiation group (100%). Based on this finding, KORTUC with external irradiation is considered to be an optimal treatment strategy for patients with newly diagnosed LRCC this disease. Additionally, KORTUC may be an effective radiation response enhancer in multiple cancer types in which locoregional control after RT alone remains poor.

Objective: Compared with the implementation speed of image-guided adaptive brachytherapy for uterine cervical cancer, that of intracavitary and interstitial brachytherapy is slow, possible because it requires more invasive procedure of inserting needles directly into tumours. To accelerate the implementation speed of intracavitary and interstitial brachytherapy, a first hands-on seminar for image-guided adaptive brachytherapy and intracavitary and interstitial brachytherapy for uterine cervical cancer was held on 26 November 2022, supported by Japanese Society for Radiology and Oncology. This article deals with this hands-on seminar and difference of degree of confidence of participants in starting intracavitary and interstitial brachytherapy before and after the seminar. Methods: The seminar consisted of lectures regarding intracavitary and interstitial brachytherapy in the morning and hands-on practice of needle insertion and contouring, as well as dose calculation practice using the radiation treatment system in the evening. Prior to and following the seminar, participants completed a questionnaire asking about their level of confidence in performing intracavitary and interstitial brachytherapy, expressed between 0 and 10 (the higher the number, the stronger the confidence). Results: A total of 15 physicians, six medical physicists and eight radiation technologists from 11 institutions attended the meeting. The median level of confidence before and after the seminar was 3 (range, 0–6) and 5.5 (range, 3–7), respectively, and a statistically significant improvement was observed (P<0.001). Conclusion: It was suggested that the hands-on seminar on intracavitary and interstitial brachytherapy for locally advanced uterine cervical cancer improved the level of confidence of the attendees and propelled their motivation, through which it is expected that the implementation of intracavitary and interstitial brachytherapy will be accelerated.

Purpose: We investigated the long-term oncological outcome of high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIB) for adjuvant accelerated partial breast irradiation (APBI) after breast conserving surgery in Japanese patients. Material and methods: Between June 2002 and...

This study examined the role of brachytherapy boost (BT-boost) and external beam radiotherapy (EBRT) in intermediate- to high-risk prostate cancer, especially in patients with very high-risk factors (VHR: T3b–4 or Gleason score 9–10) as patients with double very high-risk factors (VHR-2: T3b–4 and Gleason score 9–10) previously showed worst prognosis in localized prostate cancer. We retrospectively reviewed multi-institutional data of 1961 patients that were administered radiotherapy (1091 BT-boost and 872 EBRT: 593 conventional-dose RT (Conv RT: equivalent to doses of 2 Gy per fraction = EQD2 ≤ 72 Gy) and 216 dose-escalating RT (DeRT = EQD2 ≥ 74 Gy). We found that BT-boost improved PSA control and provided an equivalent overall survival rate in the intermediate- and high-risk groups, except for patients within the VHR factor group. In the VHR-1 group (single VHR), BT-boost showed a superior biochemical control rate to the Conv RT group but not to the DeRT group. In the VHR-2 group, BT-boost did not improve outcomes of either Conv RT or DeRT groups. In conclusion, BT-boost showed no benefit to modern DeRT in the patients with VHR; therefore, they are not good candidates for BT-boost to improve outcome and may be amenable to clinical trials using multimodal intensified systemic treatments.

We analyzed the efficacy and toxicity following reirradiation for locoregional recurrence of rare head and neck tumors. We retrospectively analyzed 17 patients who had received reirradiation for rare head and neck tumors. Primary tumor sites included nine ears (auditory organ), four salivary glands, and four orbits. The median follow-up time was 13.2 months for surviving patients. The median survival time was 12.6 months with one- and two-year survival rates of 53.1% and 44.3%, respectively. Nine out of 17 patients experienced local failure. The one- and two-year local control rates were 42.4% and 31.8%, respectively. The median survival times were 12.6, 5.3, and 11.0 months for orbit, auditory organ, and salivary glands, respectively. Three patients experienced grade 3 toxicity, including meningitis, brain necrosis, and facial nerve disorders. No grade ≥4 toxicities were observed. Reirradiation of rare head and neck tumors is feasible, with acceptable toxicity.

This study aimed to examine the role of very high-risk (VHR) factors (T3b–4 and Gleason score 9–10) for prognosis of clinically localized high-risk prostate cancer. We reviewed multi-institutional retrospective data of 1413 patients treated with radiotherapy (558 patients treated with external beam radiotherapy (EBRT) and 855 patients treated with brachytherapy (BT) ± EBRT. We introduced an index by simple summation of the number of VHR factors—VHR-0, VHR-1, and VHR-2. With median follow-up of 69.6 months, the 5-year biochemical disease free survival rate (bDFS), prostate cancer-specific mortality (PCSM), and distant metastasis-free survival (DMSF) rates were 59.4%, 7.65%, and 83.2% for the VHR-2 group, respectively; 86.7%, 1.50%, and 95.4% for the VHR-1 group, respectively; and 93.1%, 0.12%, and 98.2% for the VHR-0 group, respectively. The VHR-2 group had significantly worse bDFS, PCSM, and DMSF than the VHR-0 (hazard ratios: 4.55, 9.607, and 7.904, respectively) and VHR-1 (hazard ratios: 1.723, 2.391, and 1.491, respectively) groups. The VHR-2 group could be identified as a super high-risk group compared with other groups, and could be a good candidate for clinical trials using multimodal intensified treatments. Simple summation of the number of VHR factors is an easy and useful predictive index for bDFS, PCSM, and DMSF.

To examine the efficacy of dose escalating radiotherapy into patients with cT3b or T4 localized prostate cancer, we compared Group A (86 conventional dose external beam radiotherapy: EBRT group, treated with 70–72 Gy) and group B (39 high dose EBRT group (HDEBRT group, 74–80 Gy) and 124 high-dose-rate brachytherapy (HDR) + EBRT (HDR boost)) using multi-institutional retrospective data. The actuarial 5-year biochemical disease-free survival (bDFS) rate, prostate cancer specific survival rate (PSS), and overall survival rate (OS) were 75.8%, 96.8%, and 93.5%. Group B showed superior 5-year bDFS rate (81.2%) as compared to the group A (66.5%) (p < 0.0001) with a hazard ratio of 0.397. Equivocal 5-year PSS (98.3% and 94.8% in group B and group A) and OS (both 93.7%) were found between those groups. Accumulated late grade ≥ 2 toxicities in gastrointestinal and genitourinary tracts were similar among those three groups. Therefore, both HDEBRT and HDR boost could be good options for improving the bDFS rate in cT3–T4 localized prostate cancer without affecting PSS and OS.

Androgen deprivation therapy (ADT) is used to improve overall survival (OS) in prostate cancer treatment; however, we encountered that long-term ADT in elderly patients may be related to high other-cause mortality (OCM). This study aimed to confirm the potential risk associated with long-term ADT in elderly patients using a different large cohort. A comparison analysis was conducted between the ≥2- and p = 0.0006) in their younger counterparts. If dividing into HDR and EBRT groups. This inclination was found in brachytherapy group but not in EBRT group. The overall survival rate was also lower in the elderly patients in the ≥2-year ADT group than in the <2-year ADT group; however, the 10-year prostate cancer-specific survival rate was the same in both groups. Long-term ADT in elderly patients resulted in not only higher OCM rates but also poorer OS rates; therefore, longer-term ADT in elderly patients should be performed with meticulous care.