Koichi Wadasaki’s research while affiliated with Hiroshima Prefectural University and other places

Background Few studies have assessed hydrogel spacer shrinkage during external-beam radiation therapy following brachytherapy for localized high-risk prostate cancer. This case presentation evaluated the changes in hydrogel spacer appearance by magnetic resonance imaging during external-beam radiation therapy after brachytherapy for prostate cancer and analyzed the effect of this shrinkage on the dose distribution in four cases. Case presentation In all cases, we implanted ¹²⁵I sources using a modified peripheral loading pattern for seed placement. The prescribed dose for each implant was 110 Gy. After delivering the sources, a hydrogel spacer was injected. All cases underwent external-beam radiation therapy approximately 1–2 months after brachytherapy. The prescribed dose of external-beam radiation therapy was 45 Gy in 1.8-Gy fractions. Magnetic resonance imaging was performed for evaluation on the day following seed implantation (baseline), at external-beam radiation therapy planning, and during external-beam radiation therapy. The median hydrogel spacer volume was 16.2 (range 10.9–17.7) cc at baseline, 14.4 (range, 9.4–16.1) cc at external-beam radiation therapy planning, and 7.1 (range, 2.0–11.4) cc during external-beam radiation therapy. The hydrogel spacer volume during external-beam radiation therapy was significantly lower than that at external-beam radiation therapy planning. The rectum V60–80 (rectal volume receiving at least 60–80% of the prescribed dose of external-beam radiation therapy) during external-beam radiation therapy was significantly higher than that at external-beam radiation therapy planning. Conclusions The potential reduction in hydrogel spacer size during external-beam radiation therapy following brachytherapy can lead to unexpected irradiation to the rectum. This case presentation would be helpful for similar cases.

We aimed to demonstrate a single institution experience of treatment of pancreatic ductal carcinoma and to identify the role of radiation therapy. We assessed all patients who were diagnosed with pancreatic ductal carcinoma from January 2011 to December 2017. A total of 342 patients were enrolled. Thirteen, 131, 36, and 162 patients had stage I, II, III, and IV disease, respectively (UICC TNM, 7th edition). Among the patients with stages I–III disease, 94 underwent surgery, and the median overall survival (OS) was 33 months. Of patients with stages I–III disease who were not suitable for surgery, 58 patients received chemotherapy, and the median OS was 12 months. Among them, 17 patients received chemoradiotherapy added on chemotherapy and their OS was significantly better than that of patients who received chemotherapy alone. Of patients with stage IV disease, 111 received chemotherapy, and the median OS was 6 months. This study evaluated the demand, role, and outcome of each treatment modality and demonstrated a single institution experience of treatment of pancreatic ductal carcinoma. The demand and role of radiation therapy remained small; however, radiation therapy might have some importance as a local treatment.

This study aimed to analyze the clinical results of radiotherapy for cervical cancer using two-dimensional (2D) intracavitary brachytherapy (ICBT) and computed tomography (CT)-based image-guided brachytherapy (IGBT) at our institution. Patients with stage IB-IVA cervical cancer who received ICBT between April 2008 and April 2014 were included in this study. In total 58 patients were assessed. The first 38 patients received ICBT with the 2D treatment plan (the 2D group), and the remaining 20 patients received CT-based IGBT (the IGBT group). The dose of point A tended to be lower in the IGBT group (mean value, 60.6 Gy vs. 62.5 Gy; p = .07), though the minimum dose to the 90% (D90) of the clinical target volume (CTV) was equivalent in both groups (mean value, 66.0 Gy vs. 66.2 Gy; p = .91). The rectum minimum dose to 2 cc (D2cc) was significantly lower in the IGBT group than in the 2D group (mean value, 61.2 Gy vs. 69.1 Gy; p = .001). With a median follow-up time of 60 months, the 5-year local control rates (LCRs) of the IGBT group and 2D group were 100% and 83%, respectively (p = .12). The 5-year incidence of rectal complications in the IGBT group and the 2D group were 11% and 29%, respectively (p = .26). Our study showed favorable LCR and preferred incidence of rectal complications in patients treated with CT-based IGBT.

A 69-year-old man with stage IIIB lung adenocarcinoma received durvalumab following chemoradiotherapy. The prescribed dose was 50 Gy in 2 Gy fractions, and the maximum spinal cord dose was 40 Gy. After three cycles of durvalumab, he experienced bladder and rectal disturbance, muscle weakness in the lower limbs, and sensory loss in the lower body. Magnetic resonance imaging revealed T2 signal hyperintensity involving the thoracic spinal cord. As the thoracic spinal cord with T2 signal hyperintensity matched with the irradiated site, the patient was diagnosed with radiation myelitis. This case report shows the clinical and radiographic features of a case of locally advanced non-small cell lung cancer that demonstrated radiation myelitis following durvalumab administration. The time of onset was very early and the influence of durvalumab was suspected as the cause of myelitis.

Purpose To identify predictive factors for local control of locally advanced esophageal cancer by chemoradiotherapy, the relationship between clinical features, including macroscopic tumor type, and treatment outcome was analyzed in 83 patients. Materials and methods Macroscopic tumor type was defined by endoscopy as follows: type 1: protruding type; type 2: ulcerative and localized type; type 3: ulcerative and infiltrative type; type 4: diffusely infiltrative type; and type 5: unclassifiable type. We analyzed the overall survival, cause-specific survival, local progression-free rate, and predictive factors for locally advanced esophageal cancer after chemoradiotherapy. Results The median follow-up period at the time of evaluation was 59 months among survivors. The 5-year overall survival, cause-specific survival, and local progression-free rates for type 1 and other types were 37.0% and 23.3% (P = 0.4255), 71.8% and 30.3% (P = 0.0325), and 100% and 63.3% (P = 0.0246), respectively. Macroscopic tumor type (type 1) was the most significant predictive factor of cause-specific survival and local progression-free rates. Conclusions Macroscopic tumor type 1 was the significant favorable predictive factor for local control. The study results suggested that the macroscopic tumor type was useful in predicting tumor responses.

The aim of this study was to analyse the clinical features of prostate-specific antigen (PSA) bounce and the difference between biochemical failure and large-magnitude PSA bounce. The cases of 352 patients with prostate cancer who underwent brachytherapy were analysed. PSA bounce was defined as an increase in PSA of ≥0.2 ng/ml above an initial PSA nadir, with subsequent decline to or below that initial nadir without treatment. PSA bounce +2 was defined as an increase in PSA of ≥2.0 ng/ml above the nadir with subsequent decline to or below that initial nadir without treatment. We analysed the rates, time to onset, and predictive factors for PSA bounce and PSA bounce +2. The median follow-up period at the time of evaluation was 82 months. One hundred and seventeen patients had PSA bounce; of them, 10 had PSA bounce +2. Biochemical failure occurred in 29 patients. The median times to onset of PSA bounce, PSA bounce +2, and biochemical failure were 20, 17.5 and 51 months, respectively. Younger age at implant and larger prostate volume were significant predictive factors for PSA bounce. Age was a significant factor for PSA bounce +2, and PSA bounce +2 patients were significantly younger than biochemical failure patients. The maximum duration from the date of PSA bounce +2 to the date when PSA level decreased was 12 months. Age at implant, time to onset, and 1-year follow-up after an increase in PSA level of ≥2 ng/ml above nadir level are useful for distinguishing between biochemical failure and PSA bounce +2.

Radiation recall is regarded as an acute inflammatory reaction that is triggered by cytotoxic agents within a previously irradiated area, and the most common site is the skin. Gemcitabine-related radiation recall is rare, and most reported cases involving gemcitabine occur in the muscle, unlike those of other chemotherapeutic agents. Here, we report 2 cases of chemotherapy- induced radiation myositis. Combination chemotherapy with gemcitabine and S-1 was performed in both patients after radiation therapy. The irradiation dose to the muscle was quite low compared to the muscle tolerance dose in both cases. To the best of our knowledge, there are no reports on radiation recall with S-1. Therefore, it is unclear whether S-1 is related to myositis in these cases. Although radiation recall with gemcitabine is rare and uncommon, it has the potential to occur in any organ in forms such as myositis or central nervous system necrosis, and careful observation is required for patients who received chemotherapy that includes gemcitabine after radiation therapy.

Purpose: The purpose of this study was to analyze the clinical results of concurrent chemoradiotherapy (CCRT) with volumetric modulated arc therapy (VMAT) for nasopharyngeal carcinoma (NPC) patients. Materials and methods: Patients with stage II-IVB NPC who received CCRT with VMAT between 2010 and 2014 were included in this study. The planned dose was 70 Gy in 35 fractions. Results: Twenty patients aged between 28 and 85 years (median 60 years) were assessed. With a median follow-up time of 47 months, the 3-year overall survival and progression-free survival rates were 85 and 65%, respectively. The 3-year local, regional and distant control rates were 78, 88 and 79%, respectively. At 0, 3, 6 and 12 months from CCRT, 19, 6, 3, and 1 patients had grade 2 dry mouth, respectively. No cases of grade 3 or worse dry mouth were observed. The severity of dry mouth was downgraded from grade 2 to grade 0 or 1 significantly earlier in younger patients (<70 years, p = 0.02) or patients in whom the mean dose to one parotid gland was lower (<26 Gy, p = 0.04). Conclusions: Our clinical results regarding CCRT with VMAT for NPC patients showed favorable survival rates while maintaining organ function.