International Journal of Particle Therapy最新文献

Purpose: To compare Patient-Reported Outcomes version of the Common Terminology Criteria for Adverse Events (PRO-CTCAE) in patients with endometrial cancer receiving adjuvant pelvic radiation therapy with proton beam therapy (PT) versus intensity-modulated radiation therapy (IMRT).

Materials and methods: Patients with uterine cancer treated with curative intent who received either adjuvant PT or IMRT between 2014 and 2020 were identified. Patients were enrolled into a prospective registry using a gynecologic-specific subset of PRO-CTCAE designed to assess symptom impact on daily living. Questions included gastrointestinal (GI) symptoms of diarrhea, flatulence, bowel incontinence, and constipation in addition to other pertinent gynecologic, urinary, and other general symptoms. Symptom-based questions were on a 0- to 4-point scale, with grade 3+ symptoms occurring frequently or almost always. Patient-reported toxicity was analyzed at baseline, end of treatment (EOT), and at 3, 6, 9, and 12 months after treatment. Unequal variance t tests were used to determine if treatment type was a significant factor in baseline-adjusted PRO-CTCAE.

Results: Sixty-seven patients met inclusion criteria. Twenty-two received PT and 45 patients received IMRT. Brachytherapy boost was delivered in 73% of patients. Median external beam dose was 45 Gy for both PT and IMRT (range, 45-58.8 Gy). When comparing PRO-CTCAE, PT was associated with less diarrhea at EOT (P = .01) and at 12 months (P = .24) than IMRT. Loss of bowel control at 12 months was more common in patients receiving IMRT (P = .15). Any patient reporting grade 3+ GI toxicity was noted more frequently with IMRT (31% versus 9%, P = .09).

Discussion: Adjuvant PT is a promising treatment for patients with uterine cancer and may reduce patient-reported GI toxicity as compared with IMRT.

Purpose: Radiation therapy is an independent risk factor for adverse sequelae to the oral cavity and dentition in childhood cancer survivors. However, dental toxicities after radiation therapy often are underreported and there are minimal published data on disturbances in tooth development after proton beam therapy (PBT). We present the long-term clinical and radiographic dental findings 8 years after treatment completion for a patient treated with PBT and chemotherapy for rhabdomyosarcoma.

Materials and methods: Clinical follow-up data of patients treated with PBT within the Proton Overseas Programme (POP) is stored in a National Database and curated by a dedicated outcomes unit at the Christie NHS PBT center. This case report was identified from the extraction and analysis of data for pediatric head and neck cancer patients in this database for a service evaluation project.

Results: The permanent dentition in this patient aged 3.5 years at the time of treatment was severely affected with abnormal dental development first observed 3.5 years after treatment completion. PBT delivered mean doses of 30 Gy(RBE = 1.1) to the maxilla and 25.9 Gy(RBE = 1.1) to the mandible.

Conclusion: Significant dental development abnormalities occurred in this pediatric patient, despite doses in areas being lower than the proposed thresholds in the literature. Improved descriptions of dental toxicities and routine contouring of the maxilla and mandible are needed to correlate dosimetric data. The dose to teeth should be kept as low as reasonably possible in younger patients until the dose thresholds for dental toxicities are known.

Purpose: Photon radiation therapy (RT) is important in the treatment of many brain tumors but can negatively affect neurocognition. Proton therapy (PT) can reduce doses to normal brain structures. We compared photon and proton plans to estimate the potential benefit in cognition if the patient were treated with PT.

Materials and methods: We analyzed 23 adult patients with proton and photon plans for the treatment of a primary brain tumor. Cognitive outcomes were predicted using converted equivalent dose (EQD2) with an α/β ratio of 3 to left temporal lobe and normal brain tissue. Risks of cognitive decline on 2 specific tests, the Controlled Oral Word Association Test (COWAT [letter S], a test of verbal fluency) and the Wechler Adult Intelligence Scale (WAIS-IV Coding Test, a test of processing speed) were derived from a previously published model.

Results: Dose reductions to left temporal lobe and normal brain tissue translated into lower estimated probabilities of impairment in specific neurocognitive test scores after PT. With a mean dose reduction from 1490 to 1092 cGy in EQD2 to the left temporal lobe (P < .001), there was reduction in probability of impairment in the COWAT (Letter S) test from 6.8% to 5.4%. Similar results were seen with the normal brain (750 to 451 cGy in EQD2, P < .001), with reduction in probability of impairment in the WAIS-IV Coding test from 5% to 4.1%. Other structures experiencing dose reduction with PT included each cochlea, posterior fossa, each temporal lobe, and each hippocampus.

Conclusion: We confirmed an association between PT and lower doses to brain substructures, which is expected to result in a modest decrease in probability of impairment in neurocognitive test scoring. These findings should be confirmed in prospective cohorts of patients treated with PT.

Primary adenoid cystic carcinoma of the trachea (ACC-T) is an extremely rare cancer of the central bronchial system. It is usually associated with an excellent prognosis. Surgery is the standard treatment for resectable tumors, while radiation therapy is used for unresectable tumors or medically inoperable patients. Radiation therapy can be delivered with photons, protons, or carbon ion therapy. In this report, we review a case of unresectable ACC-T in a middle-aged female patient who was treated with radiation therapy and review the potential benefits of the different types of radiation therapy.

Introduction: Proton radiation therapy (PBT) may reduce cardiac doses in breast cancer treatment. Limited availability of proton facilities could require significant travel distances. This study assessed factors associated with travel distances for breast PBT.

Materials and methods: Patients receiving breast PBT at the University of Pennsylvania from 2010 to 2021 were identified. Demographic, cancer, and treatment characteristics were summarized. Straight-line travel distances from the department to patients' addresses were calculated using BatchGeo. Median and mean travel distances were reported. Given non-normality of distribution of travel distances, Wilcoxon rank sum or Kruskal-Wallis test was used to determine whether travel distances differed by race, clinical trial participation, disease laterality, recurrence, and prior radiation.

Results: Of 1 male and 284 female patients, 67.8% were White and 21.7% Black. Median travel distance was 13.5 miles with interquartile range of 6.1 to 24.8 miles, and mean travel distance was 13.5 miles with standard deviation of 261.4 miles. 81.1% of patients traveled less than 30 and 6.0% more than 100 miles. Black patients' travel distances were significantly shorter than White patients' and non-Black or non-White patients' travel distances (median = 4.5, 16.5, and 11.3 miles, respectively; P < .0001). Patients not on clinical trials traveled more those on clinical trials (median = 14.7 and 10.2 miles, respectively; P = .032). There was no difference found between travel distances of patients with left-sided versus right-sided versus bilateral disease (P = .175), with versus without recurrent disease (P = .057), or with versus without prior radiation (P = .23).

Conclusion: This study described travel distances and demographic and clinicopathologic characteristics of patients receiving breast PBT at the University of Pennsylvania. Black patients traveled less than White and non-Black or non-White patients and comprised a small portion of the cohort, suggesting barriers to travel and PBT. Patients did not travel further to receive PBT for left-sided or recurrent disease.

Purpose: To determine the rib fracture rate in a cohort of patients with breast cancer treated with proton therapy.

Patient and methods: From a prospective database, we identified 225 patients treated with proton therapy between 2012 and 2020 (223 women; 2 men). Clinical and dosimetric data were extracted, the cumulative incidence method assessed rib fracture rate, and Fine-Gray tests assessed prognostic significance of select variables. In-field rib fracture was defined as a fracture that occurred in a rib located within the 10% isodose line. Out-of-field rib fracture was defined as a fracture occurring in a rib location outside of the 10% isodose line.

Results: Of the patients, 74% had left-sided breast cancer; 5%, bilateral; and 21%, right-sided. Dual-energy x-ray absorptiometry scans showed normality in 20%, osteopenia in 34%, and osteoporosis in 6% (test not performed in 40%). Additionally, 57% received an aromatase inhibitor. Target volumes were breast ± internal mammary nodes (IMNs) (16%), breast and comprehensive regional lymphatics (32%), chest wall ± IMNs (1%), and chest wall/comprehensive regional lymphatics (51%). Passive-scattered proton therapy was used for 41% of patients, 58% underwent pencil-beam scanning (PBS), and 1% underwent a combination (passive scattering/PBS), with 85% of patients receiving a boost. Median follow-up was 3.1 years, with 97% having >12-month follow-up. The 3-year cumulative in-field rib fracture incidence was 3.7%. Eight patients developed in-field rib fractures (1 symptomatic, 7 imaging identified) for a 0.4% symptomatic rib fracture rate. Median time from radiation completion to rib fracture identification was 1.8 years (fractures were identified within 2.2 years for 7 of 8 patients). No variables were associated with rib fracture on univariate analysis. Three fractures developed outside the radiation field (0.9% cumulative incidence of out-of-field rib fracture).

Conclusion: In this series of patients with breast cancer treated with proton therapy, the 3-year rib fracture rates remain low (in-field 3.7%; symptomatic 0.4%). As in photon therapy, the asymptomatic rate may be underestimated owing to a lack of routine surveillance imaging. However, patients experiencing symptomatic rib fractures after proton therapy for breast cancer are rare.

Purpose: When treating esophageal cancer with radiation therapy, it is critical to limit the dose to surrounding structures, such as the lung and/or heart, as much as possible. Proton radiation therapy allows a reduced radiation dose to both the heart and lungs, potentially reducing the risk of cardiopulmonary toxicity. Here, we report disease control, survival, and toxicity outcomes among patients with esophageal cancer treated with proton radiation therapy and concurrent chemotherapy (chemoradiation therapy; CRT) with or without surgery.

Materials and methods: We enrolled 17 patients with thoracic esophageal carcinoma on a prospective registry between 2010 and 2021. Patients received proton therapy to a median dose of 50.4-GyRBE (range, 50.4-64.8) in 1.8-Gy fractions.Acute and late toxicities were graded per the Common Terminology Criteria for Adverse Events, version 4.0 (US National Cancer Institute, Bethesda, Maryland). In addition, disease control, patterns of failure, and survival outcomes were collected.

Results: Nine patients received preoperative CRT, and 8 received definitive CRT. Overall, 88% of patients had adenocarcinoma, and 12% had squamous cell carcinoma. With a median follow-up of 2.1 years (range, 0.5-9.4), the 3-year local progression-free, disease-free, and overall survival rates were 85%, 66%, and 55%, respectively. Two patients (1 with adenocarcinoma and 1 with squamous cell carcinoma) recurred at the primary site after refusing surgery after a complete clinical response to CRT. The most common acute nonhematologic and hematologic toxicities, respectively, were grades 1 to 3 esophagitis and grades 1 to 4 leukopenia, both affecting 82% of patients. No acute cardiopulmonary toxicities were observed in the absence of surgical resection. Reagarding surgical complications, 3 postoperative cardiopulmonary complications occurred as follows: 1 grade 1 pleural effusion, 1 grade 3 pleural effusion, and 1 grade 2 anastomotic leak. Two severe late CRT toxicities occurred: 1 grade 5 tracheoesophageal fistula and 1 grade 3 esophageal stenosis requiring a feeding tube.

Conclusion: Proton radiation therapy is a safe, effective treatment for esophageal cancer with increasing evidence supporting its role in reducing cardiopulmonary toxicity.

Fast neutron therapy has been used for decades. In conjunction with recent advances in photonic techniques, fast neutrons are no longer of much oncologic interest, which is not unequivocally positive, given their undoubted therapeutic value. This mini-review recalls the history of medical research on fast neutrons, considers their physical and radiobiological properties alongside their benefits for cancer treatment, and discusses their place in modern radiation oncology.

Purpose: Proton therapy is an emerging therapy for several malignancies owing to its favorable therapeutic ratio. There are very limited data on the use of proton therapy in the management of thyroid carcinoma. Our objective was to review the safety, feasibility, and outcomes of proton therapy for patients with thyroid cancer treated to the head and neck.

Methods: From our institution's proton database from 2012 to 2021, we identified 22 patients with thyroid cancer treated with proton beam therapy. We evaluated outcomes and toxicities.

Results: Median follow-up was 26 months. Of the 22 patients, 50% were female. The mean age was 65 years. Three patients had anaplastic cancer; 13, papillary carcinoma; 2, follicular carcinoma; and 2, poorly differentiated carcinoma. Forty-six percent had T4 disease. Primary targets were the central neck compartment, level VI, and upper mediastinum. Radiation dose was 60 GyRBE adjuvantly, and 70 GyRBE for gross disease (range, 6000-7600 GyRBE). Eight patients underwent upfront adjuvant radiation, and 3 received definitive radiation for unresectable disease upfront. Eleven patients received either salvage or palliative radiation. Fifty-nine percent of patients had extrathyroidal extension, and 64% of patients had gross disease in the neck before treatment. Fifty percent of patients had metastatic disease before treatment. Sixteen patients received concurrent chemotherapy, 63% of these patients received doxorubicin. For all patients, 1-year local regional recurrence (LRR) was 0%, and overall survival (OS) was 90%. Acute grade 3+ toxicities occurred in 27% of patients, the most frequent being dermatitis (27%). Three patients required a percutaneous endoscopic gastrostomy tube after radiation therapy (RT), 2 owing to progression. There were no grade 4+ toxicities.

Conclusions: Proton therapy for thyroid cancer appears feasible and effective with minimal toxicities. Prospective studies comparing proton therapy with intensity-modulated RT, to evaluate the clinical efficacy of using proton therapy to reduce toxicities in patients undergoing radiation for thyroid cancer, are warranted.

Purpose: Reports of proton beam therapy (PBT) utilization for cutaneous melanoma of the head and neck (HN) region is virtually non-existent. This study reports on the efficacy and acute toxicities of PBT for primary HN cutaneous melanoma.

Materials and methods: We queried the prospectively collected, multi-institutional Proton Collaborative Group registry for all consecutive patients with HN cutaneous melanoma receiving PBT from May 2010 to December 2019. Kaplan-Meier methods were used to estimate overall survival (OS), progression free survival (PFS), and local regional recurrence free survival (LRFS). Toxicity was reported per CTCAE version 4.0.

Results: A total of 8 patients were identified with a median age of 69 (range, 37-88). All patients (100%) underwent surgery followed with postoperative PBT. There were 3 patients (37.5%) with T3 or T4 disease and 4 (50%) with N2 or N3 disease. The median radiation dose was 46 GyRBE (range, 27-70) and median dose per fraction was 2.4 GyRBE (range, 2.0-6.0) with the most common dose fractionation being 44 or 48 GyRBE in 20 fractions (n = 4). At a median follow-up of 40.1 months (range, 1.6-62.4) the 1 and 3 year OS rates were 85.7% and 35.7%, respectively. The median PFS was 25.40 months (95% CI, 2.53-58.70) while PFS at 1 year and 3 years was 85.7% and 35.7%, respectively. LRFS was 100% at 1 year and 85.7% at 3 years. Five of the 8 patients developed distant metastases, of which 3 received immunotherapy. Acute G2+ and G3+ toxicities occurred in 5 of 8 patients and 2 of 8 patients, respectively. G3 toxicities included radiation dermatitis (n = 1) and immunotherapy-related rash (n = 1). No G4+ toxicities were reported.

Conclusion: Single modality PBT for HN melanomas in the definitive setting provides effective and durable local control rates with tolerable acute toxicity. Distant failure remains the primary pattern of failure.