The Japanese nationwide cohort data of proton beam therapy for liver oligometastasis in breast cancer patients

A nationwide multicenter cohort study on particle therapy was launched by the Japanese Society for Radiation Oncology in Japan in May 2016. We analyzed the outcome of proton beam therapy (PBT) for liver oligometastasis in breast cancers. Cases in which PBT was performed at all Japanese proton therapy facilities between May 2016 and February 2019 were enrolled. The patients were selected based on the following criteria: the primary cancer was controlled, liver recurrence without extrahepatic tumors and no more than three liver lesions. Fourteen females, with a median age of 57 years (range, 44-73) and 22 lesions, were included. The median lesion size, fraction (fr) size and biological effective dose were 44 (20-130) mm, 6.6 (2-8) gray (Gy) (relative biological effectiveness)/fr and 109.6 (52.7-115.2) Gy, respectively. The median follow-up period was 22.8 (4-54) months. The 1-, 2- and 3-year local control (LC) rates of liver metastasis from breast cancer were 100% for all. The 1-, 2- and 3-year overall survival rates were 85.7, 62.5 and 62.5%, respectively. The 1-, 2- and 3-year progression-free survival (PFS) rates were 50.0%, 33.3%, and 16.7%, respectively. The median PFS time was 16 months. Only one patient did not complete PBT due to current disease progression. One patient had Grade 3 radiation-induced dermatitis. None of the patients experienced radiation-induced liver failure during the acute or late phase. Owing to the low incidence of adverse events and the high LC rate, PBT appears to be a feasible option for liver oligometastasis in breast cancers.

Salvage skull base surgery after proton beam therapy for recurrent sinonasal malignancies: A retrospective study

BACKGROUND

This study aimed to examine treatment outcomes and postoperative complications associated with salvage skull base surgery following radical proton beam therapy (PBT).

METHODS

Nine patients who underwent salvage skull base surgery following curative PBT as the initial treatment at our institution between September 2002 and May 2023 were retrospectively reviewed.

RESULTS

The cohort comprised four males and five females with a mean age of 48.1 years. The average proton dose administered during initial therapy was 68.5 Gy (relative biological effectiveness). Among the salvage surgeries, eight were anterior skull base surgeries, and one was an anterior middle skull base surgery. No local recurrences or perioperative deaths were observed. Postoperative complications occurred in three patients (33.3%), all experiencing surgical site infections, with one also having cerebrospinal fluid leakage.

CONCLUSION

The study demonstrates that salvage skull base surgery after PBT effectively achieves local control and safety in patients with recurrent sinonasal malignancies.

The Incidence of Severe Radiation-Induced Lymphopenia during Chemoradiotherapy for Stage Ⅲ Non-Small Cell Lung Cancer: A Comparative Study of Proton Versus Photon-Based Radiotherapy

PURPOSE/OBJECTIVE(S)

To investigate the incidence of severe radiation-induced lymphopenia (SRL) and the survival in patients with stage Ⅲ non-small cell lung cancer treated with concurrent chemoradiotherapy with passive scattering proton beam (PSPT) or photon-based radiotherapy (XRT) including 3D-CRT and IMRT.

MATERIALS/METHODS

We conducted a retrospective cohort study including 355 patients who received definitive concurrent chemoradiotherapy with PSPT (n = 38) or XRT (n = 317) at our institution between January 2010 and December 2020. SRL during concurrent chemoradiotherapy was defined as absolute lymphocyte counts (ALCs) of <500 cells/mm3. Propensity score matching (PSM) analysis was performed to adjust for the patient characteristics between the PSPT and XRT groups. Propensity scores were calculated using age, sex, PS (0-1 vs. 2), primary tumor location (upper/middle vs. lower lobe), pathology (Adeno vs. Others), PTV volume, ALCs at pretreatment, year of treatment (before vs. after July 2018, when durvalumab approved in Japan), and platinum-based chemotherapy regimen (CDDP based vs. CBDCA based). After PSM, the incidence of SRL and the overall survival (OS) were analyzed.

RESULTS

The GTV and PTV volumes were significantly lower in the PSPT group than in the XRT group (median, 57 vs. 103 mm3; p < 0.05, 322 vs. 399 mm3; p < 0.05, respectively). ALCs at pretreatment were significantly lower in the PSPT group than in the XRT group (median, 1531 vs. 1718 cells/mm3; p < 0.05). SRL was observed in 275 patients (87%) in the XRT group and 27 patients (71%) in the PSPT group (p < 0.05). After PSM, PSPT significantly reduced the incidence of SRL compared to XRT (68.6 % vs. 88.6 %, p < 0.05), and the patients without SRL may have better 3-year OS than those with SRL (71.1 % vs. 55.3 %; p = 0.062).

CONCLUSION

Compared with XRT, PSPT significantly reduced the incidence of SRL, and the patients without SRL had a good prognosis.

Pacemaker Malfunction During Passive Proton Beam Therapy for Localized Prostate Cancer: Case Reports and a Literature Review

We report two cases of pacemaker malfunction occurring during proton beam therapy (PBT) for localized prostate cancer treatment. The first case involved mode changes in the pacemaker, while the second exhibited prolongation of the RR interval. Remarkably, both cases did not manifest significant clinical changes. Our findings indicate that careful consideration should be given to passive PBT in patients with localized prostate cancer who have pacemakers, like the considerations in patients with thoracic and abdominal cancers. Moreover, our report highlights the importance of recognizing potential cardiac implantable electronic devices malfunction in various PBT scenarios.

Particle beam therapy for pelvic recurrence of colorectal cancer: a registry data analysis in Japan and a systematic review

The aim of this study was to investigate the efficacy and safety of particle beam therapy (PBT) with proton or carbon ion beam for pelvic recurrence of colorectal cancer (PRCC) by comparing the clinical outcomes of a dataset of prospectively enrolled patients for PBT with those from the literature, which were collected by a systematic review of external X-ray radiotherapy (XRT) and PBT. Patients with PRCC treated at 14 domestic facilities between May 2016 and June 2019 and entered the database for prospective observational follow-up were analyzed. The registry data analyzed included 159 PRCC patients treated with PBT of whom 126 (79%) were treated with carbon ion radiation therapy (CIRT). The 3-year overall survival and local control rate were 81.8 and 76.4%, respectively. Among these PRCC patients, 5.7% had Grade 3 or higher toxicity. Systematic search of PubMed and Cochrane databases published from January 2000 to September 2020 resulted in 409 abstracts for the primary selection. Twelve studies fulfilled the inclusion criteria. With one additional publication, 13 studies were selected for qualitative analysis, including 9 on XRT and 4 on PBT. There were nine XRT studies, which included six on 3D conformal radiotherapy and three on stereotactic body radiation therapy, and four PBT studies included three on CIRT and one on proton therapy. A pilot meta-analysis using literatures with median survival time extractable over a 20-month observation period suggested that PBT, especially CIRT, may be a promising treatment option for PRCC not amenable to curative resection.

Head pleomorphic sarcoma showing murine double minute 2 amplification without a well-differentiated liposarcoma component in a pediatric patient

BACKGROUND

Murine double minute 2 (MDM2) is an oncogene that inhibits p53, leading to decreased apoptosis. Sarcomas showing MDM2 amplification are rare among pediatric patients.

CASE

A 14-year-old boy presented with pleomorphic sarcoma of the head showing MDM2 amplification without a well-differentiated liposarcoma component. Although chemotherapy was initially performed to reduce the tumor size before surgery, the tumor did not shrink. The patient underwent complete surgical resection. Microscopic examination revealed a positive surgical margin; thus, postoperative proton-beam radiotherapy was performed. 3 years after the therapy, no sign of recurrence was observed.

CONCLUSION

Macroscopic surgical resection combined with adjuvant postoperative radiotherapy was effective against MDM2-amplified pleomorphic sarcoma refractory to neoadjuvant chemotherapy in a pediatric patient.

Feasibility of linac-based fractionated stereotactic radiotherapy and stereotactic radiosurgery for patients with up to ten brain metastases

BACKGROUND

Linac-based fractionated stereotactic radiotherapy (fSRT) and stereotactic radiosurgery (SRS) are increasingly being used to manage patients with multiple metastases. This retrospective cohort study aimed to compare the outcomes after linac-based fSRT and SRS between three patient groups classified based on the number of brain metastases (BMs): 1 BM, 2-4 BM, 5-10 BM.

METHODS

The data of consecutive patients with 1-10 BMs treated with fSRT or SRS between July 2016 and June 2018 at a single institution were collected. Patients with previous whole-brain radiotherapy (WBRT), concurrent use of WBRT, or surgical resection were excluded from the analysis. A total of 176 patients were classified into three groups according to the number of BMs: 78, 67, and 31 patients in 1 BM, 2-4 BM, and 5-10 BM, respectively. The Kaplan-Meier method was used to estimate overall survival (OS) curves, and the cumulative incidence with competing risks was used to estimate local control (LC), distant intracranial failure (DIF), and radiation necrosis (RN).

RESULTS

Median OS was 19.8 months (95% confidence interval [CI] 10.2-27.5), 7.3 months (4.9-11.1), and 5.1 months (4.0-9.0) in 1 BM, 2-4 BM, and 5-10 BM, respectively. Compared to 2-4 BM, 1 BM had significantly better OS (hazard ratio [HR] 0.59, 95% CI 0.40-0.87; p = 0.0075); however, 5-10 BM had comparable OS (HR 1.36, 95% CI 0.85-2.19; p = 0.199). There was no significant difference in LC, DIF, and RN between tumor number groups, but DIF was lower in 1 BM. RN of grade 2 or higher occurred in 21 patients (13.5%); grade 4 and 5 RN were not observed.

CONCLUSIONS

The linac-based fSRT and SRS for patients with 5-10 BMs is comparable to that for patients with 2-4 BMs in OS, LC, DIF, and RN. It seems reasonable to use linac-based fSRT and SRS in patients with 5-10 BMs.

Therapeutic efficacy of intra-arterial docetaxel and nedaplatin infusion concomitant with radiotherapy for T4 maxillary sinus squamous cell carcinoma

The aim of this study was to evaluate the efficacy of intra-arterial chemoradiotherapy with docetaxel and nedaplatin for T4 maxillary sinus squamous cell carcinoma (MSSCC). Data were retrospectively analysed for 22 consecutive patients with T4 MSSCC who underwent intra-arterial chemoradiotherapy. Participants received intensity-modulated radiotherapy (70 Gy in 35 fractions) concomitantly with docetaxel (60 mg/m²) and nedaplatin (80 mg/m²) administered every 4 weeks for a total of three sessions. The median follow-up period was 49 months (range 12-91 months). T4a tumours were found in 16 patients (73%) and T4b tumours in six patients (27%). Cervical metastasis was found in nine patients (41%; five N2b, four N2c). The 5-year loco-regional control, disease-free survival, and overall survival rates for patients with T4a disease were 92.3%, 92.3%, and 90.3%, respectively, compared to 83.3% (P = 0.42), 66.7% (P = 0.07), and 83.3% (P = 0.46), respectively, for those with T4b disease. The 5-year loco-regional control, disease-free survival, and overall survival rates for patients with cervical lymph node metastasis were all 87.5% compared to 92.3% (P = 0.86), 84.6% (P = 0.69), and 92.3% (P = 0.93), respectively, for those without cervical metastasis. Intra-arterial chemoradiotherapy with docetaxel and nedaplatin may provide favourable loco-regional control and increased survival in T4 MSSCC.

Particle therapy using protons or carbon ions for cancer patients with cardiac implantable electronic devices (CIED): a retrospective multi-institutional study

PURPOSE

To evaluate the outcomes of particle therapy in cancer patients with cardiac implantable electronic devices (CIEDs).

MATERIALS AND METHODS

From April 2001 to March 2013, 19,585 patients were treated with proton beam therapy (PBT) or carbon ion therapy (CIT) at 8 institutions. Of these, 69 patients (0.4%, PBT 46, CIT 22, and PBT + CIT 1) with CIEDs (64 pacemakers, 4 implantable cardioverter defibrillators, and 1 with a cardiac resynchronization therapy defibrillator) were retrospectively reviewed. All the patients with CIEDs in this study were treated with the passive scattering type of particle beam therapy.

RESULTS

Six (13%) of the 47 PBT patients, and none of the 23 CIT patients experienced CIED malfunctions (p = 0.105). Electrical resets (7) and over-sensing (3) occurred transiently in 6 patients. The distance between the edge of the irradiation field and the CIED was not associated with the incidence of malfunctions in 20 patients with lung cancer. A larger field size had a higher event rate but the test to evaluate trends as not statistically significant (p = 0.196).

CONCLUSION

Differences in the frequency of occurrence of device malfunctions for patients treated with PBT and patients treated with CIT did not reach statistical significance. The present study can be regarded as a benchmark study about the incidence of malfunctioning of CIED in passive scattering particle beam therapy and can be used as a reference for active scanning particle beam therapy.

Multi-Institutional Retrospective Analysis of the Outcomes of Proton Beam Therapy for Patients With 1 to 3 Pulmonary Oligometastases From Various Primary Cancers

Purpose

Our purpose was to evaluate the efficacy of proton beam therapy (PBT) in patients with 1 to 3 pulmonary oligometastases from various primary cancers in Japan.

Methods and Materials

This multi-institutional retrospective survey included 118 patients with 141 metastatic lung tumors from miscellaneous primary cancers, across 6 Japanese institutions, and involved the analyses of local progression-free rate (LPF), distant progression-free rate, progression-free survival rate, cause-specific survival rate, and overall survival rate (OS). Treatment-induced adverse effects of grade ≥2 were evaluated according to the Common Terminology Criteria for Adverse Events (version 4.0). Cox proportional hazards regression models were used in univariable analysis and multivariable analysis (MVA) for the identification of the prognostic factors of LPF and OS.

Results

The median follow-up duration from the time of PBT was 25.5 months. The major primary disease sites included colorectal cancer (42.4%), lung cancer (11.9%), head and neck cancer (8.5%), and kidney cancer (8.5%). For years 1, 2, and 3, LPFs were 92.2%, 86.3%, and 78.4%; distant progression-free rates were 59.1%, 44.1%, and 34.0%; progression-free survival rates were 49.6%, 31.7%, and 24.2%; cause-specific survival rates were 83.4%, 72.5%, and 64.8%; and OS rates were 79.0%, 67.8%, and 59.6%, respectively. Eight patients developed acute adverse effects (grade ≥2). Ten patients developed radiation pneumonitis (grade 2) as a late adverse effect. None of the patients developed severe late toxicity (grade ≥3). Colorectal cancer as the primary disease was the only prognostic factor associated with LPF that remained independently significant in the MVAs performed using 3 sets of parameters (hazard ratio [HR], 3.31-4.76 in 3 MVA sets). In the MVA, the significant prognostic factors for OS were performance status (HR, 2.78; 95% confidence interval, 1.01-7.67) and total tumor volume (HR, 1.01; 95% confidence interval, 1.00-1.02).

Conclusions

PBT provides promising outcomes for pulmonary oligometastasis with acceptable toxicities.

Radiotherapy for local recurrence of non-small-cell lung cancer after lobectomy and lymph node dissection-can local recurrence be radically cured by radiation?

BACKGROUND

There is no standard therapeutic approach for local recurrence of non-small cell lung cancer (NSCLC) after complete resection. We investigated the outcomes of radiotherapy (RT) for patients with local recurrence.

METHODS

We reviewed 46 patients who underwent curative-intent RT for local recurrence after lobectomy or pneumonectomy accompanied with mediastinal lymph node dissection between 2002 and 2014. We analyzed overall survival (OS), progression-free survival (PFS), local control, tumour response and the re-recurrence pattern.

RESULTS

Among the 46 patients, 16 received concurrent chemotherapy. The median follow-up period was 48 months. The response rate was 91%. The 5-year OS and local control rates were 47.9 and 65.3%, respectively, and the 5-year PFS rate was 22.8%. Female sex and complete response to radiation were favourable prognostic factors. Of the 33 patients with recurrence after radiation, 32 (97%) had distant metastasis.

CONCLUSIONS

Although RT for local recurrence has high efficacy, distant relapse after radiation remains a major issue. Therefore, combination systemic therapy for local recurrence at any site should be further investigated. Since it is difficult to achieve a radical cure for local recurrence using RT, further study, for the administration of post-operative adjuvant therapy, is recommended.

The comparisons of the outcomes between surgical resection and proton beam therapy for single primary hepatocellular carcinoma

482

Background: There are many treatment choices for hepatocellular carcinoma (HCC). Proton beam therapy (PBT) is considered a treatment option for HCC. The purpose of this study was to compare surgical resection (SR) and PBT in order to clarify the prognostic factors for operable HCC based on a single institution’s database. Methods: Patients with single primary nodular HCC ≤ 100 mm without vessel invasion on pretreatment imaging were divided into the SR group and PBT group. In the PBT group, the patients with unresectable HCC due to their liver function and/or performance status (PS) were excluded. Results: There were 314 and 31 patients who underwent SR and PBT, respectively. The median survival time in the SR group was significantly better than in the PBT group (104.1 vs. 64.6 months, p = 0.008). Regarding the relapse-free survival (RFS), there was no significant difference between the SR and PBT groups (33.8 vs. 14.0 months, p = 0.099). Conclusions: In RFS, the PBT group and the SR group were comparable. However, the PBT group was significantly worse than SR group in overall survival. SR may therefore be favorable as an initial treatment for HCC compared to PBT. Clinical trial information: 1856.

Proton Beam Therapy for Histologically or Clinically Diagnosed Stage I Non-Small Cell Lung Cancer (NSCLC): The First Nationwide Retrospective Study in Japan

PURPOSE

To investigate the efficacy and safety of proton beam therapy (PBT) for the treatment of stage I non-small cell lung cancer (NSCLC).

METHODS AND MATERIALS

Six hundred sixty-nine patients with 682 tumors histologically or clinically diagnosed stage I NSCLC according to the seventh edition of Union for International Cancer Control who received passive-scattering PBT from April 2004 and December 2013 in Japan were retrospectively reviewed to analyze survival, local control, and toxicities.

RESULTS

Of 669 patients, 486 (72.6%) were men, with a median age of 76 years (range, 42-94 years). NSCLC was histologically confirmed in 440 patients (65.7%). Clinical T stages included T1a (n = 265; 38.9%), T1b (n = 216; 31.7%), and T2a (n = 201; 29.4%). The total irradiation doses of PBT ranged from 74.4 to 131.3 biological effective dose GyE (median, 109.6 biological effective dose GyE). The median follow-up period was 38.2 months (range, 0.6-154.5 months) for all patients. The 3-year overall survival and progression-free survival rates for all patients were 79.5% and 64.1%, respectively. For patients with stage IA tumors, the 3-year overall survival and progression-free survival rates were 82.8% and 70.6%, respectively, and the corresponding rates for patients with stage IB tumors were 70.8% and 47.3%, respectively. The 3-year local progression-free rates for all, stage IA, and stage IB patients were 89.8%, 93.5%, and 79.4%, respectively. The incidence of grade 2, 3, 4, and 5 pneumonitis was 9.8%, 1.0%, 0%, and 0.7%, respectively. The incidence of grade ≥3 dermatitis was 0.4%. No grade 4 or severe adverse events, other than pneumonitis, were observed.

CONCLUSIONS

PBT appears to yield acceptable survival rates, with a low rate of toxicities.

Particle therapy for prostate cancer: The past, present and future

Although prostate cancer control using radiotherapy is dose‐dependent, dose–volume effects on late toxicities in organs at risk, such as the rectum and bladder, have been observed. Both protons and carbon ions offer advantageous physical properties for radiotherapy, and create favorable dose distributions using fewer portals compared with photon‐based radiotherapy. Thus, particle beam therapy using protons and carbon ions theoretically seems suitable for dose escalation and reduced risk of toxicity. However, it is difficult to evaluate the superiority of particle beam radiotherapy over photon beam radiotherapy for prostate cancer, as no clinical trials have directly compared the outcomes between the two types of therapy due to the limited number of facilities using particle beam therapy. The Japanese Society for Radiation Oncology organized a joint effort among research groups to establish standardized treatment policies and indications for particle beam therapy according to disease, and multicenter prospective studies have been planned for several common cancers. Clinical trials of proton beam therapy for intermediate‐risk prostate cancer and carbon‐ion therapy for high‐risk prostate cancer have already begun. As particle beam therapy for prostate cancer is covered by the Japanese national health insurance system as of April 2018, and the number of facilities practicing particle beam therapy has increased recently, the number of prostate cancer patients treated with particle beam therapy in Japan is expected to increase drastically. Here, we review the results from studies of particle beam therapy for prostate cancer and discuss future developments in this field.

Preliminary results of proton radiotherapy for pediatric rhabdomyosarcoma: a multi-institutional study in Japan

To evaluate preliminary results of proton radiotherapy (PRT) for pediatric patients with rhabdomyosarcoma (RMS). From 1987 to 2014, PRT was conducted as initial radiotherapy in 55 patients (35 males, 20 females, median age 5 years, range 0–19) with RMS at four institutes in Japan. Thirty‐one, 18, and six patients had embryonal, alveolar, and other RMS, respectively. One, 11, 37, and six patients were in IRSG groups I, II, III, and IV, respectively, and the COG risk group was low, intermediate, and high for nine, 39, and seven patients, respectively. The irradiation dose was 36–60 GyE (median: 50.4 GyE). The median follow‐up period was 24.5 months (range: 1.5–320.3). The 1‐ and 2‐year overall survival rates were 91.9% (95% CI: 84.3–99.5%) and 84.8% (95% CI 75.2–94.3%), respectively, and these rates were 100% and 100%, 97.1% and 90.1%, and 57.1% and 42.9% for COG low‐, intermediate‐, and high‐risk groups, respectively. There were 153 adverse events of Grade ≥3, including 141 hematologic toxicities in 48 patients (87%) and 12 radiation‐induced toxicities in nine patients (16%). Proton‐specific toxicity was not observed. PRT has the same treatment effect as photon radiotherapy with tolerable acute radiation‐induced toxicity.

Effect and safety of proton beam therapy for locally recurrent rectal cancer

743

Background: The first choice of treatment for locally recurrent rectal cancer is surgical resection. However, the operation is often difficult with high perioperative risk. For surgically unfit cases, proton beam therapy (PBT) is proposed as the treatment option. However, its efficacy for locally recurrent rectal cancer remains unclear. Therefore, this study aimed to evaluate the efficacy and safety of PBT for locally recurrent rectal cancer. Methods: A total of 23 patients with locally recurrent rectal cancer who received PBT were retrospectively evaluated, from November 2005 to July 2014. Patients with single lesion, who refuse the radical surgical therapy, or who were considered unfit for the operation were included in this study. All patients were treated with 2.8Gy relative biological effectiveness (RBE)/fraction. Twenty-five irradiations were performed, with a total irradiation of 70Gy RBE. Unfit for operation criteria include invasion to the vertebra higher than the third sacrum or lateral lymph node recurrence after a lateral lymph node dissection. To assess the safety of PBT, adverse events were evaluated by using the Common Terminology Criteria for Adverse Effects (CTCAE version4.0). To assess the efficacy, the overall and relapse-free survival rates and local control rate were evaluated. Results: Sixteen patients were unfit for operation, and seven refused surgery. Three patients experienced Grade 3 late adverse events in the CTCAE (two ileum fistula and one urinary tract obstruction). The median follow-up time was 28.9 months. The 5-year overall and relapse-free survival rates were 47.6% and 20.2%, respectively. Fifteen patients (65.2%) showed distant metastasis or regrowth at the locally recurrent site. The 5-year local control rate was 39.0%. Ten patients (43.4%) showed regrowth at the proton beam irradiation site. Conclusions: PBT was relatively effective for locally recurrent rectal cancer with manageable adverse effects. Therefore, PBT may be considered as the therapeutic option for selected locally recurrent rectal cancer patients.

Occlusal Support, Dysphagia, Malnutrition, and Activities of Daily Living in Aged Individuals Needing Long-Term Care: A Path Analysis

OBJECTIVES

This study aimed to examine the interrelationships among occlusal support, dysphagia, malnutrition, and activities of daily living in aged individuals needing long-term care.

DESIGN

Cross-sectional study and path analysis.

SETTING

Long-term health care facilities, acute care hospitals, and the community.

PARTICIPANTS

Three hundred and fifty-four individuals aged ≥ 65 years with dysphagia or potential dysphagia in need of long-term care.

MEASUREMENTS

The modified Eichner Index, Dysphagia Severity Scale, Mini Nutritional Assessment Short Form, and Barthel index.

RESULTS

The participants included 118 males and 236 females with a mean (standard deviation) age of 83 (8) years. A total of 216 participants had functional occlusal support with or without dentures. Of the total participants, 73 were within normal limits regarding the severity of dysphagia, 119 exhibited dysphagia without aspiration, and 162 exhibited dysphagia with aspiration. Only 34 had a normal nutritional status, while 166 participants were malnourished, and 154 were at risk of malnutrition. The median Barthel index score was 30. Path analysis indicated two important findings: occlusal support had a direct effect on dysphagia (standard coefficient = 0.33), and dysphagia was associated directly with malnutrition (standard coefficient = 0.50). Dysphagia and malnutrition were associated directly with impaired activities of daily living (standard coefficient = 0.57, 0.22).

CONCLUSION

In aged individuals needing long-term care, occlusal support is associated directly with dysphagia and indirectly with malnutrition and activities of daily living via dysphagia.

Proton beam therapy in non-small cell lung cancer: state of the art

This review summarizes the past and present status of proton beam therapy (PBT) for lung cancer. PBT has a unique characteristic called the Bragg peak that enables a reduction in the dose of normal tissue around the tumor, but is sensitive to the uncertainties of density changes. The heterogeneity in electron density for thoracic lesions, such as those in the lung and mediastinum, and tumor movement according to respiration necessitates respiratory management for PBT to be applied in lung cancer patients. There are two types of PBT - a passively scattered approach and a scanning approach. Typically, a passively scattered approach is more robust for respiratory movement and a scanning approach could result in a more conformal dose distribution even when the tumor shape is complex. Large tumors of centrally located lung cancer may be more suitably irradiated than with intensity-modulated radiotherapy (IMRT) or stereotactic body radiotherapy (SBRT). For a locally advanced lung cancer, PBT can spare the lung and heart more than photon IMRT. However, no randomized controlled trial has reported differences between PBT and IMRT or SBRT for early-stage and locally advanced lung cancers. Therefore, a well-designed controlled trial is warranted.

Long-term follow-up after proton beam therapy for pediatric tumors: a Japanese national survey

Proton beam therapy (PBT) is a potential new alternative to treatment with photon radiotherapy that may reduce the risk of late toxicity and secondary cancer, especially for pediatric tumors. The goal of this study was to evaluate the long‐term benefits of PBT in cancer survivors. A retrospective observational study of pediatric patients who received PBT was performed at four institutions in Japan. Of 343 patients, 62 were followed up for 5 or more years. These patients included 40 males and 22 females, and had a median age of 10 years (range: 0–19 years) at the time of treatment. The irradiation dose ranged from 10.8 to 81.2 GyE (median: 50.4 GyE). The median follow‐up period was 8.1 years (5.0–31.2 years). The 5‐, 10‐ and 20‐year rates for grade 2 or higher late toxicities were 18%, 35% and 45%, respectively, and those for grade 3 or higher late toxicities were 6%, 17% and 17% respectively. Univariate analysis showed that the irradiated site (head and neck, brain) was significantly associated with late toxicities. No malignant secondary tumors occurred within the irradiated field. The 10‐ and 20‐year cumulative rates for all secondary tumors, malignant secondary tumors, and malignant nonhematologic secondary tumors were 8% and 16%, 5% and 13%, and 3% and 11%, respectively. Our data indicate that PBT has the potential to reduce the risk of late mortality and secondary malignancy. Longer follow‐up is needed to confirm the benefits of PBT for pediatric tumors.

Lifetime attributable risk of radiation-induced secondary cancer from proton beam therapy compared with that of intensity-modulated X-ray therapy in randomly sampled pediatric cancer patients

To investigate the amount that radiation-induced secondary cancer would be reduced by using proton beam therapy (PBT) in place of intensity-modulated X-ray therapy (IMXT) in pediatric patients, we analyzed lifetime attributable risk (LAR) as an in silico surrogate marker of the secondary cancer after these treatments. From 242 pediatric patients with cancers who were treated with PBT, 26 patients were selected by random sampling after stratification into four categories: (i) brain, head and neck, (ii) thoracic, (iii) abdominal, and (iv) whole craniospinal (WCNS) irradiation. IMXT was replanned using the same computed tomography and region of interest. Using the dose-volume histograms (DVHs) of PBT and IMXT, the LARs of Schneider et al. were calculated for the same patient. All the published dose-response models were tested for the organs at risk. Calculation of the LARs of PBT and IMXT based on the DVHs was feasible for all patients. The means ± standard deviations of the cumulative LAR difference between PBT and IMXT for the four categories were (i) 1.02 ± 0.52% (n = 7, P = 0.0021), (ii) 23.3 ± 17.2% (n = 8, P = 0.0065), (iii) 16.6 ± 19.9% (n = 8, P = 0.0497) and (iv) 50.0 ± 21.1% (n = 3, P = 0.0274), respectively (one tailed t-test). The numbers needed to treat (NNT) were (i) 98.0, (ii) 4.3, (iii) 6.0 and (iv) 2.0 for WCNS, respectively. In pediatric patients who had undergone PBT, the LAR of PBT was significantly lower than the LAR of IMXT estimated by in silico modeling. Although a validation study is required, it is suggested that the LAR would be useful as an in silico surrogate marker of secondary cancer induced by different radiotherapy techniques.

Proton beam therapy for bone sarcomas of the skull base and spine: A retrospective nationwide multicenter study in Japan

We conducted a retrospective, nationwide multicenter study to evaluate the clinical outcomes of proton beam therapy for bone sarcomas of the skull base and spine in Japan. Eligibility criteria included: (i) histologically proven bone sarcomas of the skull base or spine; (ii) no metastases; (iii) ≥20 years of age; and (iv) no prior treatment with radiotherapy. Of the 103 patients treated between January 2004 and January 2012, we retrospectively analyzed data from 96 patients who were followed-up for >6 months or had died within 6 months. Seventy-two patients (75.0%) had chordoma, 20 patients (20.8%) had chondrosarcoma, and four patients (7.2%) had osteosarcoma. The most frequent tumor locations included the skull base in 68 patients (70.8%) and the sacral spine in 13 patients (13.5%). Patients received a median total dose of 70.0 Gy (relative biological effectiveness). The median follow-up was 52.6 (range, 6.3-131.9) months. The 5-year overall survival, progression-free survival, and local control rates were 75.3%, 49.6%, and 71.1%, respectively. Performance status was a significant factor for overall survival and progression-free survival, whilst sex was a significant factor for local control. Acute Grade 3 and late toxicities of ≥Grade 3 were observed in nine patients (9.4%) each (late Grade 4 toxicities [n = 3 patients; 3.1%]). No treatment-related deaths occurred. Proton beam therapy is safe and effective for the treatment of bone sarcomas of the skull base and spine in Japan. However, larger prospective studies with a longer follow-up are warranted.

Simplified estimation method for dose distributions around field junctions in proton craniospinal irradiation

In radiotherapy involving craniospinal irradiation (CSI), field junctions of therapeutic beams are necessary, because a CSI target is generally several times larger than the maximum field size of the beams. The purpose of this study was to develop a simplified method for estimating dose uniformity around the field junctions in proton CSI. We estimated the dose profiles around the field junctions of proton beams using a simplified field-junction model, in which partial lateral dose distributions around the field edge were assumed to be approximated using the error function. We measured the lateral dose distributions of the proton beams planned for the CSI treatment using a two-dimensional (2D) ionization chamber array. Although dose hot spots and cold spots tend to be underestimated by a chamber array because of the partial volume effect of the sensitive volume and discrete chamber positions, the model estimation results were fairly consistent with the measurements obtained using a 2D chamber array subjected to CSI-simulated serial irradiation. The simplified junction model enabled us to estimate the dose distributions and dependence of the setup position gap on the dose uniformity around the field junctions on the basis of the field-by-field dose profiles measured using the 2D chamber array.

Ultrasonographic Abdominal Screening of Atomic Bomb-Exposed Subjects

Abdominal ultrasonographic screening for cancer was performed in 6001 Hiroshima and Nagasaki A-bomb exposed and comparison subjects, all members of the Adult Health Study of the Radiation Effects Research Foundation, formerly the Atomic Bomb Casualty Commission. This study yielded 20 cancers, including 7 hepatocellular, 3 gastric, 3 renal and 2 urinary bladder cancers; one cancer each of the ovary, pancreas, colon and ureter; and one cancer metastatic to the liver, whose primary was unknown. Seventeen of these 20 subjects manifested no symptoms or signs of their disease. A variety of additional tumors, unproven and probably benign, including uterine myomata, and other abnormalities were also detected. Abdominal ultrasonographic screening greatly assisted in the detection of cancers, most of which neither the patients nor their physicians were aware. In this screened fixed population sample the cancer detection rate was 0.33%, exceeding any such rates previously reported in the medical literature.

Radiographic Changes in Cardiac Contours following Heart Transplantation

Chest radiographs of 46 patients who had undergone heart transplantation were reviewed with special attention to abnormalities of the cardiac contours. MR imaging in 3 such patients revealed 3 types of double right cardiac contours: the recipient right atrium combined with the donor right atrium; the donor right atrium combined with the recipient left atrium; and a cardiac fat pad combined with the right atrium. A prominent main pulmonary artery was shown by MR imaging to result from leftward displacement of the main pulmonary artery caused by clockwise rotation and transverse position of the transplanted heart. Recognition of these unique radiographic appearances is of value in assessing transplanted hearts and in avoiding misdiagnosis.

Mr Imaging of Pediatric Hematologic Disorders

The present report illustrates the efficiency of MR imaging in evaluating children with hematologic disorders.

Correlation of immunologic status with high-resolution CT and distributions of pulmonary tuberculosis

Purpose: To investigate the correlation of cluster of differentiation (CD)4 lymphocyte counts with high-resolution CT (HRCT) findings and distribution of pulmonary tuberculosis.

Material and Methods: Thirty-seven bacteriologically proven pulmonary tuberculosis, clinically non-AIDS, patients underwent HRCT and CD4 lymphocyte counts in peripheral blood cells were obtained within 3 days after the CT examinations. Patients were categorized into four groups according to CD4 lymphocyte counts (A &gt;800; B 800-500; C 500-200; D &lt;200). HRCT findings analyzed were as follows: typical, atypical, and mixed findings of post-primary tuberculosis, common, uncommon, and mixed distribution, and number of lobes involved.

Results: CD4 lymphocyte counts correlated with the degree of the mixture of atypical CT findings (ρ=0.565, p&lt;0.001) and the degree of the mixture of uncommon distribution (ρ=0.431, p&lt;0.01). Number of involved lobes showed no statistically significant correlation (ρ=0.209, p=0.21).

Conclusion: In patients with low CD4 levels, atypical HRCT findings co-exist with typical findings, and uncommon sites are involved in addition to common sites.

Re-irradiation for locoregionally recurrent tumors of the thorax: a single-institution, retrospective study

BACKGROUND

Re-irradiation (re-RT) of the thorax is challenging due to the impact of prior therapies on normal tissues, and there are few reports of definitive re-RT. The treatment toxicities and efficacy of re-RT are not well known. The aim of the present study was to assess the safety and efficacy of definitive re-RT of the thorax.

METHODS

Patients who were treated with thoracic re-RT between March 2007 and December 2014 were retrospectively analyzed. Primary and re-irradiation plans were required to have an overlap of dose distributions for the 80 % isodose level. All doses were recalculated to an equivalent dose of 2 Gy per fraction (EQD2). When possible, analysis of dose accumulation was carried out using the medical image merge (MIM) (®) software program (version 6.5, MIM Software Inc., Cleveland, OH). Administration dosages for organs at risk were defined.

RESULTS

Fourteen (67 %) and seven (33 %) patients with non-small cell carcinoma (NSCLC) and small cell carcinoma (SCLC), respectively, were identified. The patients' median age was 72 (range 53-85) years. Fifteen patients (71 %) had "proximal" tumors, defined as tumors at the distal 2 cm of the trachea, carina, and main bronchi. The median interval from initial RT to re-RT was 26.8 (range 11.4-92.3) months. Re-RT was delivered by X-ray beam and proton beam therapy in 20 (95 %) patients and 1 (5 %) patient, respectively. The median radiation dose of re-RT was 60 (range 54-87.5) Gy10 and 50 (range 50.0-87.5) Gy10 for patients with NSCLC and SCLC, respectively. Grade 3 acute radiation pneumonitis occurred in only one patient. There were no other serious complications. The median follow-up time was 22.1 (range 2.3-56.4) months. The median local progression-free survival time (LPFS) and overall survival time (OS) were 12.9 (95 % confidence interval (CI): 8.9-27.9) months and 31.4 (95 % CI: 16.9-45.9) months, respectively. Patients receiving ≥ 60 Gy10 at re-RT had longer LPFS (p = 0.04).

CONCLUSIONS

Good safety with longer OS than in previous reports was demonstrated. Re-RT seems to be a promising treatment option. Further study to define the risk-benefit ratios is necessary.