Five-year clinical outcomes of scanning carbon-ion radiotherapy for prostate cancer.

BACKGROUND: Carbon-ion radiotherapy (CIRT) has been associated with favorable clinical outcomes in patients with prostate cancer. At our facility, all patients are treated using scanning CIRT (sCIRT). We retrospectively analyzed five-year clinical outcomes of prostate cancer treated with sCIRT to investigate treatment efficacy and toxicity. METHODS: In this study, we included 253 consecutive prostate cancer patients treated with sCIRT at the Kanagawa Cancer Center from December 2015 to December 2017. The total dose of sCIRT was set at 51.6 Gy (relative biological effect) in 12 fractions over three weeks. We employed the Phoenix definition for biochemical relapse. The overall survival (OS), biochemical relapse-free (bRF) rate, and cumulative incidence of late toxicity were estimated using the Kaplan-Meier method. Toxicity was assessed using the Common Terminology Criteria for Adverse Events version 4.0. RESULTS: The median age of the patients was 70 years (range: 47-86 years). The median follow-up duration was 61.1 months (range: 4.1-80.3 months). Eight (3.2%), 88 (34.8%), and 157 (62.1%) patients were in the low-risk, intermediate-risk, and high-risk groups, respectively, according to the D'Amico classification system. The five-year OS and bRF were 97.5% and 93.3%, respectively. The five-year bRF rates for the low-risk, intermediate-risk, and high-risk groups were 87.5%, 93.7%, and 93.4%, respectively (p = 0.7215). The five-year cumulative incidence of Grade 2 or more late genitourinary and gastrointestinal toxicity was 7.4% and 1.2%, respectively. CONCLUSION: The results of this study show that sCIRT has a favorable therapeutic effect and low toxicity in the treatment of prostate cancer.

Definitive S-1/mitomycin-C chemoradiotherapy for stage II/III anal canal squamous cell carcinoma: a phase I/II dose-finding and single-arm confirmatory study (JCOG0903).

BACKGROUND: Definitive chemoradiotherapy (CRT) with 5-fluorouracil plus mitomycin-C is a standard treatment for stage II/III squamous cell carcinoma of the anal canal (SCCA). We performed this dose-finding and single-arm confirmatory trial of CRT with S-1 plus mitomycin-C to determine the recommended dose (RD) of S-1 and evaluate its efficacy and safety for locally advanced SCCA. METHODS: Patients with clinical stage II/III SCCA (UICC 6th) received CRT comprising mitomycin-C (10 mg/m2 on days 1 and 29) and S-1 (60 mg/m2/day at level 0 and 80 mg/m2/day at level 1 on days 1-14 and 29-42) with concurrent radiotherapy (59.4 Gy). Dose-finding used a 3 + 3 cohort design. The primary endpoint of the confirmatory trial was 3-year event-free survival. The sample size was 65, with one-sided alpha of 5%, power of 80%, and expected and threshold values of 75% and 60%, respectively. RESULTS: Sixty-nine patients (dose-finding, n = 10; confirmatory, n = 59) were enrolled. The RD of S-1 was determined as 80 mg/m2/day. Three-year event-free survival in 63 eligible patients who received the RD was 65.0% (90% confidence interval 54.1-73.9). Three-year overall, progression-free, and colostomy-free survival rates were 87.3%, 85.7%, and 76.2%, respectively; the complete response rate was 81% on central review. Common grade 3/4 acute toxicities were leukopenia (63.1%), neutropenia (40.0%), diarrhea (20.0%), radiation dermatitis (15.4%), and febrile neutropenia (3.1%). No treatment-related deaths occurred. CONCLUSIONS: Although the primary endpoint was not met, S-1/mitomycin-C chemoradiotherapy had an acceptable toxicity profile and favorable 3-year survival and could be a treatment option for locally advanced SCCA. CLINICAL TRIAL INFORMATION: jRCTs031180002.

Safety of Carbon-ion Radiotherapy for Prostate Cancer After Rectal Cancer Surgery.

BACKGROUND/AIM: The safety of carbon-ion radiotherapy (CIRT) for patients with prostate cancer after rectal cancer surgery remains unknown. This is a retrospective analysis of the safety of CIRT in patients with prostate cancer after rectal cancer surgery. PATIENTS AND METHODS: The subjects were 13 consecutive patients with prostate cancer who underwent CIRT after rectal cancer surgery at the Kanagawa Cancer Center from December 2015 to April 2022. A total dose of 51.6 Gy (relative biological effectiveness) was administered in 12 fractions over 3 weeks. The criteria stated in the Common Terminology Criteria for Adverse Events, version 5.0, were used to assess toxicity. Fisher's exact test was performed to assess the associations between patient clinical factors and rectal toxicity. RESULTS: The median patient age was 71 years (range=66-83 years). The median observation period was 27.4 months (range=10.6-82.4 months). The median duration from rectal surgery to CIRT was 6.9 years (1.0-16.8 years). Five (38.5%) and six (46.2%) patients had a planning target volume (PTV)-adjacent rectal anastomosis and diabetes mellitus, respectively, and two (15.4%) patients had both. Grades 1 and 2 late gastrointestinal toxicities were observed in one case each. Development of gastrointestinal toxicity was significantly associated with both a PTV adjacent rectal anastomosis and diabetes mellitus (p=0.013). CONCLUSION: Late gastrointestinal toxicity was tolerable in patients with prostate cancer treated with CIRT after rectal cancer surgery. Patients with both a PTV adjacent rectal anastomosis and diabetes mellitus were more likely to experience late gastrointestinal toxicity.

Clinical Outcomes of Intensity-modulated Carbon-ion Radiotherapy for Bone and Soft Tissue Tumors.

BACKGROUND/AIM: Carbon-ion radiotherapy (CIRT) for bone and soft tissue tumors (BSTs) has been reported to have favorable clinical outcomes. Intensity-modulated CIRT (IMCT) techniques have been developed to further reduce dose delivery to adjacent organs compared to conventional CIRT. We retrospectively analyzed the clinical results of IMCT for BSTs and investigated treatment efficacy and toxicity. PATIENTS AND METHODS: This study included 9 consecutive BSTs patients who underwent IMCT at the Kanagawa Cancer Center from January 2016 to April 2021. IMCT was administered at a dose of 60.8-70.4 Gy (relative biological effect) in 16 fractions. The time to event was calculated from the initiation of IMCT. Toxicities were evaluated using the Common Terminology Criteria for Adverse Events version 5.0. RESULTS: The median age was 49 (range=16-71) years. The median observation period was 57.6 (range=7.0-77.8) months. There were 7 and 2 cases for IMCT because of proximity to the spinal cord and intestinal tract, respectively. There was one death during the observation period, which occurred 7.0 months after the initiation of treatment. Clinical recurrence occurred in 3 patients at 1.3, 17.8, and 22.4 months after the initiation of treatment, respectively. Acute toxicity of Grade 2 or higher was seen in 2 patients with Grade 2 pharyngeal mucositis. Late toxicities of Grade 2 or higher included 1 case each of Grade 2 neuralgia and peripheral neuropathy, as well as 1 case of Grade 3 fracture. CONCLUSION: IMCT for BSTs showed good local therapeutic efficacy and tolerable toxicity in patients with bone and soft tissue tumors.

Carbon-ion Radiotherapy for Inoperable Solitary Fibrous Tumor of the Skull Base: A Case Report.

BACKGROUND/AIM: The curative treatment for solitary fibrous tumors (SFTs) consists of surgery. However, surgery for SFTs in the skull base is difficult due to the anatomy and curative surgery may not be possible. Carbon-ion radiotherapy (C-ion RT) might be useful in the treatment of inoperable SFTs in the skull base because of its biological and physical nature. This study presents the clinical outcomes of C-ion RT for an inoperable SFT of the skull base. CASE REPORT: A 68-year-old female patient experienced hoarseness, deafness on the right side, right facial nerve paralysis, and dysphagia. Magnetic resonance imaging revealed a tumor located in the right cerebello-pontine angle with destruction of the petrous bone, and immunohistochemical studies of the biopsy specimen showed a grade 2 SFT. Firstly, the patient underwent tumor embolization and surgery. However, 5 months after surgery, magnetic resonance imaging revealed regrowth of residual tumor. Subsequently, the patient was referred to our hospital for C-ion RT because curative surgery was unsuitable. The patient received 64 Gy (relative biological effectiveness) of C-ion RT in 16 fractions. Two years after C-ion RT, the tumor showed a partial response. The patient was still alive at the last follow-up without evidence of local recurrence, distant metastasis, or late toxicities. CONCLUSION: These findings suggest that C-ion RT is a suitable treatment option for inoperable SFTs of the skull base.

Robust treatment planning in scanned carbon-ion radiotherapy for pancreatic cancer: Clinical verification using in-room computed tomography images.

Purpose: Carbon-ion beam (C-beam) has a sharp dose distribution called the Bragg peak. Carbon-ion radiation therapy, such as stereotactic body radiotherapy in photon radiotherapy, can be completed in a short period by concentrating the radiation dose on the tumor while minimizing the dose to organs at-risk. However, the stopping position of C-beam is sensitive to density variations along the beam path and such variations can lower the tumor dose as well as cause the delivery of an unexpectedly high dose to the organs at risk. We evaluated the clinical efficacy of a robust planning technique considering gastrointestinal gas (G-gas) to deliver accurate radiation doses in carbon-ion radiotherapy for pancreatic cancer. Materials and methods: We focused on the computed tomography (CT) value replacement method. Replacement signifies the overwriting of CT values in the CT images. The most effective replacement method for robust treatment planning was determined by verifying the effects of the three replacement patterns. We selected 10 consecutive patients. Pattern 1 replaces the CT value of the G-gas contours with the value of the region without G-gas (P1). This condition indicates a no-gas state. Pattern 2 replaces each gastrointestinal contour using the mean CT value of each contour (P2). The effect of G-gas was included in the replacement value. Pattern 3 indicates no replacement (P3). We analyzed variations in the target coverage (TC) and homogeneity index (HI) from the initial plan using in-room CT images. We then performed correlation analysis on the variations in G-gas, TC, and HI to evaluate the robustness against G-gas. Results: Analysis of variations in TC and HI revealed a significant difference between P1 and P3 and between P2 and P3. Although no statistically significant difference was observed between P1 and P2, variations, including the median, tended to be fewer in P2. The correlation analyses for G-gas, TC, and HI showed that P2 was less likely to be affected by G-gas. Conclusion: For a treatment plan that is robust to G-gas, P2 mean replacement method should be used. This method does not necessitate any particular software or equipment, and is convenient to implement in clinical practice.

Clinical Outcomes of Scanning Carbon-ion Radiotherapy for Soft Tissue Sarcoma of the Extremities.

BACKGROUND/AIM: Carbon-ion radiotherapy (CIRT) has been reported to obtain favorable results in the treatment of bone and soft tissue malignancies; however, studies on CIRT for soft tissue sarcomas (STS) of the extremities are limited. Here, we have retrospectively evaluated the therapeutic efficacy and adverse events associated with scanning CIRT (sCIRT) for STS of the extremities at our institution. PATIENTS AND METHODS: Thirteen consecutive patients with STS who underwent sCIRT between January 2017 and January 2020 were included in the study. The total dose of sCIRT was set at 67.2-70.4 Gy (RBE), which was provided in 16 fractions. Overall survival (OS), progression-free survival (PFS), and local control (LC) were estimated using the Kaplan-Meier method. Toxicity was evaluated using Common Terminology Criteria for Adverse Events v5.0. RESULTS: The cohort consisted of 10 males and 3 females with a median age of 69 years (range=38-95 years). Median duration of observation was 31.8 months (range=7.4-56.4 months). Tumors were localized to the upper extremity in 2 cases and to the lower extremity in 11 cases. Median maximum tumor diameter was 11.7 cm (range=3.0-36.6 cm), while 3-year OS, PFS, and LC were 61.5%, 44.9%, and 79.1%, respectively. Acute toxicity of grade 3 or higher was not observed. Late toxicity included grade 3 peripheral nerve palsy and decreased range of motion in 1 and 1 patient each. Late toxicity of Grade 4 or higher was not observed. CONCLUSION: sCIRT for STS of the extremities demonstrates favorable therapeutic results with acceptable toxicity.

Evaluation of Safety for Scanning Carbon-Ion Radiotherapy in Hemodialysis Patients With Prostate Cancer.

Background/Aim The efficacy and safety of carbon-ion radiotherapy (CIRT) for prostate cancer have already been demonstrated. The number of hemodialysis (HD) patients is increasing. Although the toxicity of CIRT in HD patients may be more severe, it has been insufficiently investigated. Therefore, we retrospectively analyzed the safety of CIRT for HD patients with prostate cancer in the present study. Materials and methods Five HD patients with prostate cancer who underwent CIRT at the Kanagawa Cancer Center during November 2015-2020 were included in this study. CIRT was delivered by the raster scanning method (sCIRT). Adverse events were assessed using the Common Terminology Criteria for Adverse Events version 5.0. The dose-volume histogram (DVH) parameters of the target volume and normal organs were evaluated between initial planning computed tomography (CT) and in-room CT images. Results In the acute phase, Grade 1 genitourinary toxicity was recorded in one patient. In the late phase, Grade 1 genitourinary toxicity was recorded in two patients. No gastrointestinal toxicities were noted during the follow-up period. In-room CT analysis revealed no significant differences among all DVH parameters of the target volume and normal organs when compared with the treatment plan dose. Conclusions The safety of sCIRT for prostate cancer in HD patients was investigated in the present study. In-room CT analysis suggested the robustness of the treatment plan. According to the present results, sCIRT for prostate cancer can be safely performed in HD patients.

Clinical Outcomes of Radiotherapy in Elderly and Younger Patients With T4 Esophageal Cancer: A Retrospective Single-center Analysis.

BACKGROUND/AIM: The standard of treatment for esophageal cancer with adjacent organ invasion (T4) has not been established. We retrospectively analyzed the clinical outcomes of radiotherapy (RT) in elderly and younger patients with T4 esophageal cancer. PATIENTS AND METHODS: Sixty-nine patients with T4 esophageal cancer who underwent RT at the Kanagawa Cancer Center between January 2014 and November 2020 were included in this study. Patients aged ≥70 years were defined as the elderly group and those aged <70 years were defined as the younger group. The total dose of RT was set at 60 Gy in 30 fractions. Chemotherapy combined with 5-fluorouracil and cisplatin was administered concurrently with RT in general. The overall survival (OS) rate was estimated using the Kaplan-Meier method. Adverse events were assessed using CTCAE v4.0. RESULTS: The median survival time (MST) of the elderly group (n=35) was 21.5 months, and the OS rates at 1, 3, and 5 years were 63.7%, 31.3%, and 15.6%, respectively. The MST of the younger group (n=34) was 12.5 months, and the OS rates at 1, 3, and 5 years were 52.2%, 29.4%, and 29.4%, respectively. No significant difference in OS was observed between the two groups (p=0.767). Toxicities were not significantly different between the two groups except for thrombocytopenia and esophageal fistula (p=0.012 and p=0.022, respectively). CONCLUSION: The clinical outcomes of RT for T4 esophageal cancer in elderly patients were generally similar to those in the younger group.

Three cases of retroperitoneal sarcoma in which bioabsorbable spacers (bioabsorbable polyglycolic acid spacers) were inserted prior to carbon ion radiotherapy.

From August 2019 to August 2020, we inserted polyglycolic acid (PGA) spacers and administered carbon ion radiotherapy (CIRT) to three cases of retroperitoneal sarcoma at our hospital. We aimed to investigate its utility and safety for retroperitoneal sarcoma. We analyzed changes in PGA spacer volume and corresponding computed tomography (CT) values in addition to the dose distribution using in-room CT images that were obtained during treatment. We assessed adverse events and investigated the suitability, safety and effectivity of PGA spacer insertion. During treatment, changes in PGA spacer volumes and CT values were confirmed. Volumes increased in patients with a folded PGA spacer, and it increased 1.6-fold by the end of irradiation compared with planning CT. The CT values decreased by 20-50 Hounsfield units at the end of irradiation compared to the planning CT. Dose distribution evaluation showed that the dose to the gastrointestinal tract adjacent to the tumor was maintained below the tolerable dose, and a sufficient dose was delivered to the target by PGA spacer insertion. One case of subileus caused during abdominal surgery for PGA spacer insertion occurred. No other adverse events, such as digestive disorders, were observed. CIRT with PGA spacer insertion for retroperitoneal sarcomas is safe and effective. For cases in which there is no option but to perform irradiation using a PGA spacer, precautionary measures such as verification of dose distributions using CT images are necessary.

Carbon-Ion Radiotherapy Using Metal Artifact Reduction Computed Tomography in a Patient with Prostate Cancer with Bilateral Hip Prostheses: A Case Report.

Carbon-ion radiotherapy (CIRT) for prostate cancer is both safe and efficacious; beam range calculations use relative stopping power ratio, which is derived from computed tomography (CT) values. However, hip prostheses are made of high atomic number materials and show severe artifacts on CT images. Therefore, it is not possible to accurately calculate dose distribution for CIRT in patients with prostate cancer with hip prostheses. Here, we describe the management of a 77-year-old man with prostate cancer who had previously undergone bilateral hip replacement. CIRT, in combination with androgen deprivation therapy, was recommended as definitive treatment for prostate cancer. Planning CT, magnetic resonance (MRI), and CT images with metal artifact reduction (MAR) were acquired for CIRT planning. MRI and MAR images were superimposed on the planning CT to delineate target volume and organs at risk. The radiation treatment plan consisted of a total dose of 51.6 Gy (relative biological effect) to be delivered in 12 fractions over 3 weeks, and the patient was irradiated in the supine and prone positions with a vertical beam, on alternating days. CIRT was completed as scheduled. No adverse events were observed during treatment or at 3 months after treatment initiation. While we show that CIRT may be a treatment option for patients with prostate cancer with bilateral hip prostheses, further studies are needed to evaluate treatment efficacy and late toxicity and to determine how CIRT can be administered to patients with prostate cancer with bilateral hip prostheses.

Comparison of Clinical Outcomes of Definitive and Postoperative Radiotherapy for Adenoid Cystic Carcinoma of the Head and Neck: Can Definitive Radiotherapy Be a Treatment Option?

BACKGROUND: The standard treatment for adenoid cystic carcinoma of the head and neck is surgical resection followed by postoperative radiotherapy (PORT). Currently, definitive radiotherapy (defRT) is considered an inadequate treatment; however, its data are based on studies using classical radiotherapy techniques. Therefore, the therapeutic effects of current radiotherapy techniques have not been adequately evaluated, and it may have underestimated the efficacy of defRT. METHODS: We retrospectively analyzed 44 adenoid cystic carcinoma patients treated with radiotherapy based on modern treatment techniques from 1993 to 2017. RESULTS: Twenty-four patients underwent PORT and 20 patients underwent defRT. The 5-year overall survival rates for patients treated with PORT and defRT were 85.3% and 79.7%, respectively. The 5-year local control rates were 82.5% and 83.1%, respectively. There were no statistically significant differences in the overall survival and local control of patients treated with PORT and defRT (p = 0.4392 and p = 0.0904, respectively). CONCLUSION: Our results show that defRT is comparable to surgical resection followed by PORT with respect to overall survival and local control. The results suggest that defRT can be an effective treatment option for adenoid cystic carcinoma of the head and neck.

Comparison of Moderate Hypofractionated Volumetric-Modulated Arc Therapy Plans With and Without Flattening Filter for Localized Prostate Cancer.

Background/Aim The aim of this study was to compare volumetric-modulated arc therapy (VMAT) radiation plans between conventional VMAT with flattening filter (cFF-VMAT) and flattening filter-free VMAT (FFF-VMAT) for localized prostate cancer. Materials and methods Ten patients with localized prostate cancer who underwent cFF-VMAT at Yokosuka General Hospital Uwamachi, Yokosuka, Japan, from July 2020 to October 2020 were enrolled. Dose-volume histogram (DVH) parameters of the target volume, normal organs, monitor units (MU), and beam-on time (BOT) were compared between cFF-VMAT and FFF-VMAT plans. Results No significant difference was observed for DVH parameters for the target volume. No significant difference was observed in all parameters for the bladder and rectum between the cFF-VMAT and FFF-VMAT groups. The mean values of MU were 686 ± 52 and 784 ± 80 in cFF-VMAT and FFF-VMAT, respectively (p < 0.001). The mean BOT was 97.0 ± 6.6 s and 72.9 ± 1.4 s for cFF-VMAT and FFF-VMAT, respectively (p < 0.001). Conclusion DVH parameters of the target volume and normal organs were not significantly different between the cFF-VMAT and FFF-VMAT plans. In FFF-VMAT, MU was significantly higher, and the BOT was significantly shorter than those in cFF-VMAT.

Comparison of Dose Distribution Between VMAT-SBRT and Scanning Carbon-ion Radiotherapy for Early-stage NSCLC.

BACKGROUND/AIM: The purpose of this study was to compare the dose distribution between scanning carbon-ion radiotherapy (sCIRT) and volumetric-modulated arc therapy with stereotactic body radiation therapy (VMAT-SBRT) for stage I non-small cell lung cancer (NSCLC). PATIENTS AND METHODS: Fifteen patients with early-stage NSCLC who underwent sCIRT at Kanagawa Cancer Center between 2018-2020 were enrolled. Dose-volume histogram parameters of the planned target volume and normal organs for sCIRT and VMAT-SBRT were evaluated. RESULTS: The homogeneity index of the target volume of sCIRT was significantly lower than that of VMAT-SBRT. The dose of sCIRT was significantly lower than that of VMAT-SBRT at low volumes in the lung, heart, spinal cord, and esophagus. CONCLUSION: The dose distribution of sCIRT for early-stage NSCLC was better than that of VMAT-SBRT.

Interfractional robustness of scanning carbon ion radiotherapy for prostate cancer: An analysis based on dose distribution from daily in-room CT images.

PURPOSE: We analyzed interfractional robustness of scanning carbon ion radiotherapy (CIRT) for prostate cancer based on the dose distribution using daily in-room computed tomography (CT) images. MATERIALS AND METHODS: We analyzed 11 consecutive patients treated with scanning CIRT for localized prostate cancer in our hospital between December 2015 and January 2016. In-room CT images were taken under treatment conditions in every treatment session. The dose distribution on each in-room CT image was recalculated, while retaining the pencil beam arrangement of the initial treatment plan. Then, the dose-volume histogram (DVH) parameters including the percentage of the clinical target volume (CTV) with 95% and 90% of the prescribed dose area (V95% of CTV, V90% of CTV) and V80% of rectum were calculated. The acceptance criteria for the CTV and rectum were set at V95% of CTV ≥95%, V90% of CTV ≥98%, and V80% of rectum < 10 ml. RESULTS: V95% of CTV, V90% of CTV, and V80% of rectum for the reproduced plans were 98.8 ± 3.49%, 99.5 ± 2.15%, and 4.39 ± 3.96 ml, respectively. Acceptance of V95% of CTV, V90% of CTV, and V80% of rectum was obtained in 123 (94%), 125 (95%) and 117 sessions (89%), respectively. Acceptance of the mean dose of V95% of CTV, V90% of CTV, and V80% of rectum for each patient was obtained in 10 (91%), 10 (91%), and 11 patients (100%), respectively. CONCLUSIONS: We demonstrated acceptable interfractional robustness based on the dose distribution in scanning CIRT for prostate cancer.

Dosimetric Comparison of Radiation Therapy Using Hybrid-VMAT Technique for Stage I Esophageal Cancer.

BACKGROUND/AIM: This study focused on the hybrid-volumetric modulated arc therapy (hVMAT) for stage I esophageal cancer and compared the effects on dose distribution induced by changes in the ratio of three-dimensional conformal radiotherapy (3DCRT) to VMAT. PATIENTS AND METHODS: Fifteen patients who underwent 3DCRT for cT1bN0M0 esophageal cancer at Kanagawa Cancer Center from January 2014 to April 2019 were included in the study. The dose-volume histogram (DVH) parameters of the target volume and normal organs were evaluated in the 3DCRT, hVMAT, and VMAT treatment plans. RESULTS: The homogeneity index of the target volume was significantly lower for hVMAT. In hVMAT, as the ratio of VMAT increased, the volume of low-dose region in the heart and lung increased, whereas the volume of the middle- to high-dose region decreased. As the ratio of VMAT increased, the mean dose in the heart decreased, whereas the mean dose in the lung increased. CONCLUSION: Favorable dose concentration was obtained for the target volume in hVMAT for stage I esophageal cancer. Altering the ratio of VMAT significantly changed the DVH parameters in normal organs.

Dosimetric Comparison Between Carbon-ion Radiotherapy and Photon Radiotherapy for Stage I Esophageal Cancer.

BACKGROUND/AIM: The present study aimed to compare the radiation dose distribution of carbon-ion radiotherapy (CIRT) for stage I esophageal cancer with three-dimensional conformal radiotherapy (3DCRT) and volumetric modulated arc therapy (VMAT). PATIENTS AND METHODS: Fifteen patients with cT1bN0M0 esophageal cancer who received 3DCRT at Kanagawa Cancer Center between January 2014 and April 2019 were enrolled. The dose-volume histogram parameters of the target volume and normal organs planned with CIRT, 3DCRT, and VMAT were evaluated. RESULTS: The homogeneity index for the target volume of CIRT was significantly lower than that of 3DCRT and VMAT. In addition, the radiation dose of CIRT to the heart, lungs, spinal cord, and skin was significantly lower than that of 3DCRT and VMAT. CONCLUSION: Favorable dose distributions with CIRT were demonstrated compared with 3DCRT and VMAT for esophageal cancer.

Prostate-specific antigen dynamics after neoadjuvant androgen-deprivation therapy and carbon ion radiotherapy for prostate cancer.

BACKGROUND: This study aimed to explain the dynamics of prostate-specific antigen (PSA) levels in patients with prostate cancer who were treated with carbon ion radiotherapy (CIRT) and neoadjuvant androgen-deprivation therapy (ADT). METHODS: Eighty-five patients with intermediate-risk prostate cancer who received CIRT and neoadjuvant ADT from December 2015 to December 2017 were analyzed in the present study. The total dose of CIRT was set at 51.6 Gy (relative biological effectiveness) delivered in 12 fractions over 3 weeks. The PSA bounce was defined as a ≥0.4 ng/ml increase of PSA levels from the nadir, followed by any decrease. PSA failure was defined using the Phoenix criteria. RESULTS: The median patient age was 68 (range, 48-81) years. The median follow-up duration was 33 (range, 20-48) months. The clinical T stage was T1c, T2a, and T2b in 27, 44, and 14 patients, respectively. The Gleason score was 6 in 3 patients and 7 in 82 patients. The median pretreatment PSA level was 7.37 (range, 3.33-19.0) ng/ml. All patients received neoadjuvant ADT for a median of 6 (range, 2-117) months. PSA bounces were observed in 39 patients (45.9%), occurring a median of 12 (range, 6-30) months after CIRT. PSA failure was observed in eight patients (9.4%), occurring a median of 21 (range, 15-33) months after CIRT. The 3-year PSA failure-free survival rate was 88.5%. No clinical recurrence was observed during the follow-up period. Younger age and lower T stage were significant predictors of PSA bounce. Younger age was a significant predictor of PSA failure. CONCLUSIONS: In this study, we identified the significant predictors of the occurrence of PSA bounce and failure. Further follow-up is needed to reveal the clinical significance of PSA dynamics.

Preliminary result of carbon-ion radiotherapy using the spot scanning method for prostate cancer.

BACKGROUND: Carbon-ion radiotherapy (CIRT) for prostate cancer was initiated at Kanagawa Cancer Center in 2015. The present study analyzed the preliminary clinical outcomes of CIRT for prostate cancer. METHODS: The clinical outcomes of 253 patients with prostate cancer who were treated with CIRT delivered using the spot scanning method between December 2015 and December 2017 were retrospectively analyzed. The irradiation dose was set at 51.6 Gy (relative biological effectiveness) delivered in 12 fractions over 3 weeks. Biochemical relapse was defined using the Phoenix definition. Toxicities were assessed according to CTCAE version 4.0. RESULTS: The median patient age was 70 (47-86) years. The median follow-up duration was 35.3 (4.1-52.9) months. According to the D'Amico classification system, 8, 88, and 157 patients were classified as having low, intermediate, and high risks, respectively. Androgen deprivation therapy was administered in 244 patients. The biochemical relapse-free rate in the low-, intermediate-, and high-risk groups at 3 years was 87.5, 88.0, and 97.5%, respectively (P = 0.036). Grade 2 acute urinary toxicity was observed in 12 (4.7%) patients. Grade 2 acute rectal toxicity was not observed. Grade 2 late urinary toxicity and grade 2 late rectal toxicity were observed in 17 (6.7%) and 3 patients (1.2%), respectively. Previous transurethral resection of the prostate was significantly associated with late grade 2 toxicity in univariate analysis. The predictive factor for late rectal toxicity was not detected. CONCLUSION: The present study demonstrated that CIRT using the spot scanning method for prostate cancer produces favorable outcomes.