Dosimetric impact of VMAT delivery angles for early glottic cancer treatment

This study investigates the dosimetric effects of different gantry rotation angles used in volumetric modulated arc therapy (VMAT) for early glottic carcinoma. VMAT treatment plans using full-arc, half-arc, and partial-arc gantry rotation angles were generated from 22 computed tomography datasets of early-stage (T1-2N0) glottic laryngeal cancer. Dosimetric parameters associated with the planning target volume (PTV) and organs at risk (OARs), specifically the carotid arteries and thyroid, were compared. To assess the robustness of the VMAT plans, dose variations were analyzed by introducing positional shifts of 1, 3, and 5 mm from the isocenter of each plan along the superior-inferior, left-right, and anterior-posterior axes. Furthermore, we examined the size of the PTV, the air cavity volume within the PTV, and the variability of the beam path length through the gantry angles to investigate their correlations with PTV dose variations in the presence of positioning errors. Compared to full-arc and half-arc plans, the dosimetric parameters of partial-arc plans were found to be higher in PTV (D2%, D5%, D50%, and Dmean) and lower in OARs, while their dose variations of OAR parameters were greater for positioning errors. In addition, a correlation was observed between PTV size and PTV dose variations. Air cavity volume and depth variability were also correlated with some PTV parameters, depending on the arc plan. The results presented in this study suggest that the partial-arc gantry angles can allow higher PTV doses while minimizing OAR doses in VMAT treatment planning for early glottic cancer. However, the small delivery angles may lead to greater dose variations in the OARs when positioning errors occur.

Novel approach of prophylactic radiation to reduce toxicities comparing 2-step40 with 56-Gy simultaneous integrated boost intensity-modulated radiation therapy for locally advanced squamous cell carcinoma of the head and neck, an intergroup phase III trial (JCOG1912, NEW BRIDGE)

BACKGROUND

Chemoradiotherapy (CRT) with concurrent cisplatin is the standard of care as a nonsurgical definitive treatment for patients with locally advanced squamous cell carcinoma of the head and neck (LA-SCCHN). However, CRT is associated with increased severe late adverse events, including swallowing dysfunction, xerostomia, ototoxicity, and hypothyroidism. Few strategies aimed at less invasive CRT without compromising treatment outcomes have been successful. The purpose of this study is to confirm the non-inferiority of reduced dose prophylactic radiation with 40 Gy compared to standard dose prophylactic radiation with 56 Gy in terms of the time to treatment failure (TTF) among patients with clinical stage III-IVB LA-SCCHN.

METHODS

This study is a multicenter, two-arm, open-label, randomized phase III trial. Patients with LA-SCCHN excluding p16 positive oropharynx cancer are randomized to the standard arm or experimental arm. A total dose of 70 Gy for tumors with concurrent cisplatin at 100 mg/m2 are administered in both arms. For prophylactic field, patients in the standard arm receive a total dose of 56 Gy in 35 fractions for 7 weeks using simultaneous integrated boost (SIB56) and those in the experimental arm receive 40 Gy in 20 fractions using two-step methods for 4 weeks (2-step40). A total of 400 patients will be enrolled from 52 Japanese institutions within 5 years. The primary endpoint is TTF, and the secondary endpoints are overall survival, complete response rate, progression-free survival, locoregional relapse-free survival, acute and late adverse events, quality of life score, and swallowing function score.

DISCUSSION

If the experimental arm is non-inferior to the standard arm in terms of TTF and superior on the safety endpoints, the 2-step40 procedure is the more useful treatment than SIB56 for definitive CRT.

TRIAL REGISTRATION

This trial has been registered in the Japan Registry of Clinical Trials as jRCTs031210100 ( https://jrct.niph.go.jp/latest-detail/jRCTs031210100 ). Date of Registration: May 2021.

Re-irradiation for local primary-recurrence esophageal squamous cell carcinoma treated with IMRT/VMAT

PURPOSE

Local primary-recurrence of esophageal squamous cell carcinoma (ESCC) after definitive treatment has the potential for increasing overall survival with re-irradiation (Re-RT), especially with advanced technique. This study aimed to evaluate the efficacy and toxicities of Re-RT using intensity-modulated radiotherapy (IMRT)/volumetric modulated arc therapy (VMAT) for local primary-recurrence of ESCC.

MATERIALS AND METHODS

A total of 130 ESCC patients with local primary-recurrence from Xijing hospital between 2008 and 2021 were enrolled and 30 patients underwent IMRT/VMAT based salvage Re-RT. Cox regression analysis was used to analyze the prognostic factors for overall survival (OS) and after recurrence survival (ARS). The toxicities of 30 patients receiving Re-RT were also assessed.

RESULTS

The median OS and ARS of the 130 recurrent patients were 21 months (1-164 months) and 6 months (1-142 months). The 1-, 2-, and 3-year OS rates were 81.5%, 39.2%, and 23.8%, respectively. Besides, the 1-, 2-, and 3-year ARS rates were 30.0%, 10%, and 6.2%. Multivariate analysis showed that Re-RT ± chemotherapy (p = 0.043) and chemotherapy alone (p < 0.001) and esophageal stents (p = 0.004) were independent prognostic factors for OS. The median OS of 30 patients treated with Re-RT were significantly better than that of 29 patients treated with chemotherapy (34.5 months vs. 22 months, p = 0.030). Among 30 ESCC patients treated with Re-RT, the median OS and ARS were 34.5 months (range 12-163 months) and 6 months (range 1-132 months), respectively. The recurrence-free interval (RFI) (> 12 months) and initial radiation dose (> 60 Gy) were significantly associated with improved OS. Radiation esophagitis (Grade 1-2) occurred in 16 patients and myelosuppression (Grade1-2) occurred in 10 patients. Grade 3 toxicities (radiation esophagitis and myelosuppression) were only 13.3%. There were no grade 4 toxicities.

CONCLUSION

Our results demonstrated that IMRT/VMAT-based Re-RT was an effective therapeutic option for ESCC patients with local primary-recurrence compared with chemotherapy alone or without any treatment. Re-RT had improved OS but unfavorable ARS.

A plan comparison study between rapid arc and conventional intensity-modulated radiation treatment plans in nasopharyngeal carcinoma patients

Introduction

Head and neck cancers are one of the common malignancies in Indian population. It's entity, nasopharyngeal carcinoma is among the aggressive malignancies with its location and spread near very critical structures. Thus requires a highly conformal radiotherapy delivery techniques.

Purpose

The aim of the study is to dosimetrically evaluate and to compare Intensity modulated radiation therapy (IMRT) plans and RAPID ARC plans for irradiation of nasopharyngeal carcinoma.

Material and Method

A retrospective study is done on 10 nasopharyngeal carcinoma patients, who were treated with Radiotherapy at ATRCTRI Bikaner. Radiotherapy was delivered by IMRT technique (Total of 70 Gy in 33 fractions). Same patients are now planned on Rapid arc technique. Dosimetric comparison is done in terms of PTV coverage, OAR dose, conformity index, homogeneity index.

Result

PTV coverage is similar with both the plans. Homogeneity index is higher for IMRT plans 0.119+/- 0.020 compared to 0.104 +/- 0.018 for Rapid arc plans (statistically significant).The Rapid arc plans achieved slightly better conformity 1.018+/-0.09, whereas 1.105+/-0.12 for IMRT plans. Rapid arc achieved better results for OAR, statistically significant for Brainstem (54.4 +/-10.4 Gy for IMRT and 49.7+/-4.2 Gy for Rapid Arc, Lens (Left lens and Right lens received 10.55+/-5.8 Gy and 9.44+/-9.08 by IMRT and 6.12+/-6.1 Gy and 5.45+/-6.05 Gy for Rapid Arc), optic nerves (Right and Left optic nerve received 34.36 and 35.01 Gy for IMRT plans and 30.06 and 30.05 Gy for Rapid Arc plans. However the gains are statistically insignificant for spinal cord and vestibulocochlear nerve. No major difference found for Right and left parotid between both the arms.

Conclusions

Rapid Arc is better technique compared to IMRT for Nasopharyngeal carcinoma treatment, that provides better dose conformity, more homogeneous coverage and OAR sparing. However study is retrospective and has lesser patients, thus requires prospective study with more number of patients along with comparison of clinical outcome.

Partial breast irradiation: An updated consensus statement from the American brachytherapy society

PURPOSE

In recent years, results with mature follow-up have been reported for several Phase III trials randomizing women to receive whole breast irradiation (WBI) versus varying modalities of partial breast irradiation (PBI). It is important to recognize that these methods vary in terms of volume of breast tissue treated, dose per fraction, and duration of therapy. As such, clinical and technical guidelines may vary among the various PBI techniques.

METHODS

Members of the American Brachytherapy Society with expertise in PBI performed an extensive literature review focusing on the highest quality data available for the numerous PBI options offered in the modern era. Data were evaluated for strength of evidence and published outcomes were assessed.

RESULTS

The majority of women enrolled on randomized trials of WBI versus PBI have been age >45 years with tumor size <3 cm, negative margins, and negative lymph nodes. The panel also concluded that PBI can be offered to selected women with estrogen receptor negative and/or Her2 amplified breast cancer, as well as ductal carcinoma in situ, and should generally be avoided in women with extensive lymphovascular space invasion.

CONCLUSIONS

This updated guideline summarizes published clinical trials of PBI methods. The panel also highlights the role of PBI for women facing special circumstances, such as history of cosmetic breast augmentation or prior breast irradiation, and discusses promising novel modalities that are currently under study, such as ultrashort and preoperative PBI. Updated consensus guidelines are also provided to inform patient selection for PBI and to characterize the strength of evidence to support varying PBI modalities.

Clinical application of radiotherapy in patients with oligometastatic ovarian cancer: a sharp tool to prolong the interval of systemic treatment

BACKGROUND

With the advances of radiation technology, treatment of oligometastatic disease, with limited metastatic burden, have more chances to achieve long-term local control. Here we aim to evaluate the efficacy and safety of radiotherapy (RT) in oligometastatic ovarian cancer patients.

METHODS

A retrospective analysis collecting 142 patients (189 lesions) with oligometastatic ovarian cancer were included in the study. All pateints received radiotherapy and the curative effect and response rate were evaluated by diagnostic imaging after 1-3 months of radiotherapy with RECIST. Endpoints were the rate of complete response (CR), chemotherapy-free interval (CFI), local control (LC) rate and overall survival (OS) rate. Toxicity was evaluated by the Radiation Therapy Oncology Group (RTOG). Logistic and Cox regression were used for the uni- and multivariate analysis of factors influencing survival outcomes.

RESULTS

From 2013.1.1 to 2020.12.30, a total of 142 ovarian cancer patients (189 oligometastasis lesions) were included in the analysis. Prescribed doses to an average GTV of 3.10 cm were 1.8-8 Gy/fraction, median BED (28-115, a/b = 10 Gy), 5-28 fractions. For 179 evaluable lesions, the cases of CR, partial response (PR), stable disease (SD) and progressive disease (PD) after radiotherapy were 22,39,38 and 80 respectively. The disease control rate (DCR): CR + PR + SD was 55.31%, and the objective response rate (ORR): CR + PR was 34.08%. No patient developed grade 3 or higher side effect. The median CFI was 14 months (1-99 months), and the LC rate was 69.7%, 54.3% and 40.9% in 1 year, 2 years and 5 years respectively. GTV < 3 cm before treatment, platinum sensitivity, time from the last treatment ≥ 6 months, single lesion and BED(a/b = 10 Gy) ≥ 60 are the factors of good LC (p < 0.05). The total OS of 1 year, 2 years and 5 years were 67.1%, 52.6% and 30.3%, respectively. Single lesion (HR 0.598, 95%CI 0.405-0.884), DCR (HR 0.640, 95% CI 0.448-0.918) and ORR(HR 0.466, 95% CI 0.308-0.707) were the significant factors influencing 5-year OS.

CONCLUSION

For patients with oligometastatic ovarian cancer, radiotherapy has high LC, long chemotherapy-free interval, and survival benefits. Subgroup analysis shows that patients with single lesion and good local treatment results have higher overall survival rate, suggesting that active treatment is also beneficial for oligometastatic ovarian cancer patients.

Applicability of a pathological complete response magnetic resonance-based radiomics model for locally advanced rectal cancer in intercontinental cohort

BACKGROUND

Predicting pathological complete response (pCR) in patients affected by locally advanced rectal cancer (LARC) who undergo neoadjuvant chemoradiotherapy (nCRT) is a challenging field of investigation, but many of the published models are burdened by a lack of reliable external validation. Aim of this study was to evaluate the applicability of a magnetic resonance imaging (MRI) radiomic-based pCR model developed and validated in Europe, to a different cohort of patients from an intercontinental cancer center.

METHODS

The original model was based on two clinical and two radiomics features extracted from T2-weighted 1.5 T MRI of 161 LARC patients acquired before nCRT, considered as training set. Such model is here validated using the T2-w 1.5 and 3 T staging MRI of 59 LARC patients with different clinical characteristics consecutively treated in mainland Chinese cancer center from March 2017 to January 2018. Model performance were evaluated in terms of area under the receiver operator characteristics curve (AUC) and relative parameters, such as accuracy, specificity, negative and positive predictive value (NPV and PPV).

RESULTS

An AUC of 0.83 (CI 95%, 0.71-0.96) was achieved for the intercontinental cohort versus a value of 0.75 (CI 95%, 0.61-0.88) at the external validation step reported in the original experience. Considering the best cut-off threshold identified in the first experience (0.26), the following predictive performance were obtained: 0.65 as accuracy, 0.64 as specificity, 0.70 as sensitivity, 0.91 as NPV and 0.28 as PPV.

CONCLUSIONS

Despite the introduction of significant different factors, the proposed model appeared to be replicable on a real-world data extra-European patients' cohort, achieving a TRIPOD 4 level.

Current status and application of proton therapy for esophageal cancer

Esophageal cancer remains one of the leading causes of death from cancer across the world despite advances in multimodality therapy. Although early-stage disease can often be treated surgically, the current state of the art for locally advanced disease is concurrent chemoradiation, followed by surgery whenever possible. The uniform midline tumor location puts a strong importance on the need for precise delivery of radiation that would minimize dose to the heart and lungs, and the biophysical properties of proton beam makes this modality potential ideal for esophageal cancer treatment. This review covers the current state of knowledge of proton therapy for esophageal cancer, focusing on published retrospective single- and multi-institutional clinical studies, and emerging data from prospective clinical trials, that support the benefit of protons vs photon-based radiation in reducing postoperative complications, cardiac toxicity, and severe radiation induced immune suppression, which may improve survival outcomes for patients. In addition, we discuss the incorporation of immunotherapy to the curative management of esophageal cancers in the not-too-distant future. However, there is still a lack of high-level evidence to support proton therapy in the treatment of esophageal cancer, and proton therapy has its limitations in clinical application. It is expected to see the results of future large-scale randomized clinical trials and the continuous improvement of proton radiotherapy technology.

Trends and variations in utilization and costs of radiotherapy for prostate cancer: A SEER medicare analysis from 2007 through 2016

OBJECTIVE

To assess recent changes and disparities in utilization and costs of radiotherapy in Medicare beneficiaries with prostate cancer.

METHODS

Surveillance, Epidemiology and End Results (SEER) -Medicare linked data from 2006-2016 were used to identify continuously enrolled Medicare beneficiaries with a first-time diagnosis of prostate cancer who, within 12 months of diagnosis, underwent at least one radiotherapy related service. Trends in the utilization of different radiotherapy techniques over time, yearly changes in per-patient costs of radiotherapy, and effect of socio-demographic and clinical characteristics on total cost were measured. Per patient annual costs, annual incidence of prostate cancer, and utilization of radiotherapy were used to estimate total costs of radiotherapy to the Medicare program.

RESULTS

For Medicare beneficiaries with a first-time diagnosis of prostate cancer, the utilization of intensity modulated radiation therapy (IMRT), proton therapy, and stereotactic body radiation therapy (SBRT) increased 23.62%, 0.74% and 1.61% respectively (p <0.0001) while brachytherapy decreased 17.04% (p <0.0001). Cost per beneficiary decreased $340.24 (95% CI: $136.05 - $544.43) annually (p = 0.0065). Age, registry region, and Gleason score were all associated with expenditures. The total cost to the Medicare program was estimated at US $1.16 billion in the year 2016.

DISCUSSION

In Medicare beneficiaries with prostate cancer treated with radiotherapy, IMRT is the primary mode of treatment. Utilization of brachytherapy decreased significantly despite the efficacy and cost-effectiveness. Although per patient costs have decreased, the share of patient responsibility remained unaltered across years. The current costs to Medicare of radiotherapy for newly diagnosed prostate cancer patients is substantial.

Does the sequence of high-dose rate brachytherapy boost and IMRT for prostate cancer impact early toxicity outcomes? Results from a single institution analysis

•

The optimal sequence of HDR-BT boost and EBRT for prostate cancer is unclear.

•

We compared early toxicity based on the timing of HDR-BT boost.

•

The timing of HDR-BT was not based on any specific patient or clinical factors.

•

We found no difference in early GI/GU toxicity between the two groups.

•

Longer follow-up is needed to evaluate late toxicity and long-term disease control.

Background

We present the first report comparing early toxicity outcomes with high-dose rate brachytherapy (HDR-BT) boost upfront versus intensity modulated RT (IMRT) upfront combined with androgen deprivation therapy (ADT) as definitive management for intermediate risk or higher prostate cancer.

Methods and Materials

We reviewed all non-metastatic prostate cancer patients who received HDR-BT boost from 2014 to 2019. HDR-BT boost was offered to patients with intermediate-risk disease or higher. ADT use and IMRT target volume was based on NCCN risk group. IMRT dose was typically 45 Gy in 25 fractions to the prostate and seminal vesicles ± pelvic lymph nodes. HDR-BT dose was 15 Gy in 1 fraction, delivered approximately 3 weeks before or after IMRT. The sequence was based on physician preference. Biochemical recurrence was defined per ASTRO definition. Gastrointestinal (GI) and Genitourinary (GU) toxicity was graded per CTCAE v5.0. Pearson Chi-squared test and Wilcoxon tests were used to compare toxicity rates. P-value < 0.05 was significant.

Results

Fifty-eight received HDR-BT upfront (majority 2014–2016) and 57 IMRT upfront (majority 2017–2018). Median follow-up was 26.0 months. The two cohorts were well-balanced for baseline patient/disease characteristics and treatment factors. There were differences in treatment sequence based on the year in which patients received treatment. Overall, rates of grade 3 or higher GI or GU toxicity were <1%. There was no significant difference in acute or late GI or GU toxicity between the two groups.

Conclusion

We found no significant difference in GI/GU toxicity in intermediate-risk or higher prostate cancer patients receiving HDR-BT boost upfront versus IMRT upfront combined with ADT. These findings suggest that either approach may be reasonable. Longer follow-up is needed to evaluate late toxicity and long-term disease control.

Intensity modulated radiation therapy may improve survival for tracheal-bronchial adenoid cystic carcinoma: A retrospective study of 133 cases

PURPOSES

This study aimed to evaluate the role of radiotherapy (RT) and intensity modulated radiation therapy (IMRT) in adjuvant and definitive settings of tracheal-bronchial adenoid cystic carcinoma (TACC) treatment.

MATERIALS/METHODS

TACC patients (n = 133) treated with surgery and/or RT curatively in our institution between January 1^st, 1984 and December 31^st, 2017 were analyzed retrospectively.

RESULTS

Among the 116 patients undergoing surgery, 50 (43.1 %) achieved complete resections and 66 (56.9 %) had positive surgical margins. For patients with positive margins, overall adjuvant RT was correlated with no significantly improved OS (10-year: 58.0 % vs. 47.9 %; P =  0.340) and a slight LRFS benefit (5-year: 81.9 % vs.75.6 %; P =  0.056), but adjuvant IMRT showed significant superiority in both OS (10-year: 82.9 % vs. 47.9 %; P =  0.031) and LRFS (5-year: 100.0 % vs. 75.6 %; P =  0.001) in comparison with no postoperative RT. Multivariate analysis also identified adjuvant IMRT as a significant favorable factor with OS (HR = 0.186, 95 %CI: 0.039-0.883; P =  0.034). For 17 patients receiving definitive RT, IMRT achieved promising 5-year OS of 88.9 % and LRFS of 64.3 %, yet no significant difference from non-IMRT group was reached (P = 0.447 and 0.706). Different therapies presented no significantly different impact on DMFS, whilst DMFS explained more of the OS variances (P < 0.001, R² = 0.480) than LRFS (P < 0.001, R² = 0.323).

CONCLUSION

IMRT could confer greatly improved OS and LRFS in postoperative setting for TACC patients with positive surgical margins. IMRT was also a good therapeutic option for definitive TACC with promising survival and local control.

Lifetime radiation-induced sarcoma risk in patients subjected to IMRT or VMAT for uterine cervix carcinoma

This study was conducted to estimate the lifetime radiation-induced bone and soft tissue sarcoma risks from intensity modulated radiation therapy (IMRT) and volumetric modulated arc therapy (VMAT) for uterine cervix carcinoma. 13 cervical cancer patients were included. The bone and soft tissue structures were defined on patients' treatment planning computed tomography (CT) scans. Both CT-based IMRT and VMAT plans with 6 MV photons delivering 45 Gy to the target site were designed for each patient. The organ equivalent dose (OED) and the lifetime attributable risk (LAR) for developing bone or soft tissue sarcoma were estimated using treatment planning data and a non-linear mechanistic model. The estimation method did not consider the survival rates following radiotherapy and the use of brachytherapy treatments. The patient-specific OEDs of the bone structure from IMRT and VMAT were 2.33-2.83 and 2.34-2.82 Gy, respectively. The corresponding values for the soft tissue structure were 1.27-1.70 and 1.32-1.73 Gy. An insignificant difference was found between the patient-specific OEDs and the directly proportional sarcoma risks (bone: P = 0.07; soft tissue: P = 0.38). The LAR for the development of a bone sarcoma varied from 0.05 to 0.16% by the patient's age during irradiation and the applied treatment delivery technique. The corresponding LAR range for radiation-induced soft-tissue sarcoma was 0.08-0.27%. The above LARs resulted in a relative risk of more than 1.20 indicating that IMRT or VMAT may lead to a considerable risk increase of developing bone or soft tissue sarcoma exceeding 20% in respect to the current incidence of these malignancies in unexposed population.

Quality assurance for dynamic tumor tracking

The purpose of this work was to develop a treatment plan verification routine for a linear accelerator dedicated to SBRT treatments with gimbal based dynamic tumor tracking using three commercially available phantoms. The accelerator system has two special features: It operates with a rotation of the ring shaped gantry instead of a couch rotation and target motion can be compensated for via a gimbal system (dynamic tumor tracking, DTT). DTT plans were each measured with the three different phantoms. Afterwards the measured dose distribution was compared with the calculated dose distribution via global Gamma Index analysis (3mm / 3%, threshold: 10%). The global gamma pass rates were on average (93.5±7.2) % for ArcCHECK, (98.0±2.6) % for OCTAVIUS® 4D and (98.4±4.2) % for MatriXX Evolution. All three systems could be used for quality assurance with ring rotations and DTT, however, each with limitations.

Evaluating cardiac substructure radiation exposure in breast rotational intensity modulated radiation therapy: Effects of cancer laterality, fractionation and deep inspiration breath-hold

PURPOSE

Rotational intensity-modulated radiation therapy currently has a growing role in breast cancer radiation therapy, since this radiation technique reduces cardiac radiation exposure while homogeneously covering target volumes. This study aims to evaluate radiation exposure of cardiac substructures across a broad spectrum of breast cancer cases differing by cancer laterality, fractionation regimen and addition of deep-inspiration breath hold.

MATERIALS AND METHODS

Cardiac substructures were delineated following guidelines endorsed by the European Society for Radiotherapy and Oncology (ESTRO) for forty-four breast cancer patients having undergone conserving surgery and adjuvant rotational intensity-modulated radiation therapy. Target volumes consisted of the whole breast with a boost, axillary and internal mammary nodes. Patients were treated using free-breathing technique for left-sided or right-sided, normofractionated or hypofractionated helical tomotherapy or volumetric modulated arc therapy, or using deep-inspiration breath hold for left-sided normofractionated volumetric modulated arc therapy. Mean and maximum doses to cardiac substructures were retrieved. Correlations were performed between mean- and maximum radiation doses to cardiac substructures.

RESULTS

Left-sided and right-sided irradiations were associated with different cardiac substructure exposure patterns despite comparable mean heart dose: 7.21Gy for left-sided normofractionated regimen, 6.28Gy for right-sided normofractionated regimen. Deep-inspiration breath hold reduced mean doses to almost all cardiac substructures for left-sided irradiation, but did not decrease maximum doses to coronary arteries. Correlations between mean- and maximum doses to cardiac substructures were usually moderate, but stronger for right-sided irradiation.

CONCLUSION

Despite comparable mean heart dose, cardiac substructure radiation exposure patterns with rotational intensity-modulated radiation therapy strongly depend on the breast side, which could trigger clinically different long-term cardiotoxicity events. Deep-inspiration breath hold improves cardiac substructure dosimetry. Mean- and maximum heart dose could probably not be used as surrogate markers for precise cardiac substructure evaluation. In a near future, clinical practice and cardiotoxicity studies could possibly gain by considering cardiac substructure in a more systematic manner, possibly relying on cardiac autosegmentation algorithms.

Stereotactic body radiotherapy as a boost after external beam radiotherapy for high-risk prostate cancer patients

Background

The effect of high-dose-rate (HDR) brachytherapy after external radiation in high-risk prostate cancer patients has been proven. Stereotactic body radiotherapy as a less invasive method has similar dosimetric results with HDR brachytherapy. This study aims to evaluate the prostate-specific antigen (PSA) response, acute side effects, and quality of life of patients who underwent stereotactic body radiotherapy (SBRT) as a boost after pelvic radiotherapy (RT).

Methods

A total of 34 patients diagnosed with high-risk prostate cancer treated with SBRT boost (21 Gy in three fractions) combined with whole pelvic RT (50 Gy in 25 fractions) were evaluated. Biochemical control has been evaluated with PSA before, and after treatment, acute adverse events were evaluated with radiation therapy oncology group (RTOG) grading scale and quality of life with the Expanded Prostate Cancer Index Composite (EPIC) scoring system.

Results

The mean follow-up of 34 patients was 41.2 months (range 7-52). The mean initial PSA level was 22.4 ng/mL. None of the patients had experienced a biochemical or clinical relapse of the disease. Grade 2 and higher acute gastrointestinal (GI) was observed in 14%, and genitourinary (GU) toxicity was observed in 29%. None of the patients had grade 3-4 late toxicity.

Conclusions

SBRT boost treatment after pelvic irradiation has been used with a good biochemical control and acceptable toxicity in high-risk prostate cancer patients. More extensive randomized trial results are needed on the subject.

The influence of respiratory motion on dose distribution in accelerated partial breast irradiation using volumetric modulated arc therapy

PURPOSE

Accelerated partial breast irradiation (APBI) is alternative treatment option for patients with early stage breast cancer. The interplay effect on volumetric modulated arc therapy APBI (VMAT-APBI) has not been clarified. This study aimed to evaluate the feasibility of VMAT-APBI for patients with small breasts and investigate the amplitude of respiratory motion during VMAT-APBI delivery that significantly affects dose distribution.

METHODS

The VMAT-APBI plans were generated with 28.5 Gy in five fractions. We performed patient-specific quality assurance using Delta⁴ phantom under static conditions. We also measured point dose and dose distribution using the ionization chamber and radiochromic film under static and moving conditions of 2, 3 and 5 mm. We compared the measured and calculated point doses and dose distributions by dose difference and gamma passing rates.

RESULTS

A total of 20 plans were generated; the dose distributions were consistent with those of previous reports. For all measurements under static conditions, the measured and calculated point doses and dose distributions showed good agreement. The dose differences for chamber measurement were within 3%, regardless of moving conditions. The mean gamma passing rates with 3%/2 mm criteria in the film measurement under static conditions and with 2 mm, 3 mm, and 5 mm of amplitude were 95.0 ± 2.0%, 93.3 ± 3.3%, 92.1 ± 6.2% and 84.8 ± 7.8%, respectively. The difference between 5 mm amplitude and other conditions was statistically significant.

CONCLUSIONS

Respiratory management should be considered for the risk of unintended dose distribution if the respiratory amplitude is >5 mm.

Neoadjuvant chemoradiotherapy for locally advanced gastric cancer with bulky lymph node metastasis: Five case reports

BACKGROUND

Neoadjuvant chemoradiotherapy (NACRT) has not been accepted as a general therapy for gastric cancer because of its localized effect and toxicity for radiosensitive organs. However, if radiation therapy could compensate for the limited or inadequate treatment choices available for elderly patients and/or those at high risk, the available therapeutic options for advanced gastric cancer might increase. From this perspective, we present our experiences of five patients with advanced gastric cancer in whom we used NACRT therapy with interesting results.

CASE SUMMARY

We admitted five patients with clinical Stage III gastric cancer and bulky lymph node metastasis or adjacent organ invasion at the time of diagnosis. A total of 50 Gy of preoperative intensity modulated radiation therapy was delivered to the patients in doses of 2.0 Gy/d, together with a regimen of concomitant chemotherapy comprising two courses of oral tegafur/gimeracil/oteracil (S-1; 65 mg/m2 per day) for three consecutive weeks followed by two weeks of rest, starting at the same time as radiotherapy. All patients underwent no residual tumor resection and a pathological complete response of the primary tumors was achieved in two patients. The incidence of hematological toxicity was low, although the digestive toxicities of anorexia and diarrhea developed in three of the five patients, necessitating termination of radiation therapy at 30 Gy and S-1 at three weeks. However, even 30 Gy of irradiation and half the dose of S-1 resulted in sufficient downstaging, indicating that even a reduced amount of NACRT could confer considerable effects.

CONCLUSION

Slightly reduced NACRT might be useful and safe for patients with locally advanced gastric cancer.

Radiation therapy strategies for skull-base malignancies

INTRODUCTION

The management of skull base malignancies continues to evolve with improvements in surgical technique, advances in radiation delivery and novel systemic agents.

METHODS

In this review, we aim to discuss in detail the management of common skull base pathologies which typically require multimodality therapy, focusing on the radiotherapeutic aspects of care.

RESULTS

Technological advances in the administration of radiation therapy have led to a wide variety of different treatment strategies for the treatment of skull base malignances, with outcomes summarized herein.

CONCLUSION

Radiation treatment plays a key and critical role in the management of patients with skull base tumors. Recent advancements continue to improve the risk/benefit ratio for radiotherapy in this setting.

Dose cluster model parameterization of the parotid gland in irradiation of head and neck cancer

To explore the parotid normal tissue complication probability (NTCP) modeling with percolation-based dose clusters for head-and-neck patients receiving concomitant chemotherapy and radiation therapy. Cluster models incorporating the spatial dose distribution in the parotid gland were developed to evaluate the radiation induced complication. Cluster metrics including the mean cluster size (NMCS) and the largest cluster size both normalized by the gland volume (NSLC) were evaluated and scrutinized against the benchmark NTCP. Two fitting strategies to the Lyman-Kutcher-Burman (LKB) model using the maximum likelihood method were devised: the volume parameter n fixed at 1.0 (mean dose model) and unrestricted (full LKB model). The fitted parameters TD50 and m were assessed with the LKB NTCP models with the available xerostomia data. NSLC was a better metric than NMCS with reference to the LKB model and strong correlation (r ~ 0.95) was observed between NTCP and NSLC. The mean dose model returned the parameter TD50 (39.9 Gy) and m (0.4) from the NSLC of threshold dose at around 40 Gy. Drastically different TD50 and m values were obtained from the fittings via the full LKB model, where the threshold dose would be near 27 Gy. Bootstrapping analyses further confirmed the fitting outcomes. Strong correlation with the traditional NTCP models revealed that the cluster model could achieve what NTCP models attain and may offer additional information. Parameterization of the model indicated that the model could have different predictions from current clinical recommendations. Further investigation using toxicity data is under way to validate the cluster model.

IMRT national audit in Portugal

PURPOSE

The IAEA newly developed "end-to-end" audit methodology for on-site verification of IMRT dose delivery has been carried out in Portugal in 2018. The main goal was to evaluate the physical aspects of the head and neck (H&N) cancer IMRT treatments. This paper presents the national results.

METHODS

All institutions performing IMRT treatments in Portugal, 20 out of 24, have voluntarily participated in this audit. Following the adopted methodology, a Shoulder, Head and Neck End-to-End phantom (SHANE) - that mimics an H&N region, underwent all steps of an IMRT treatment, according to the local practices. The measurements using an ionization chamber placed inside the SHANE phantom at four reference locations (three in PTVs and one in the spinal cord) and an EBT3 film positioned in a coronal plane were compared with calculated doses. FilmQA Pro software was used for film analysis.

RESULTS

For ionization chamber measurements, the percent difference was within the specified tolerances of ±5% for PTVs and ±7% for the spinal cord in all participating institutions. Considering film analysis, gamma passing rates were on average 96.9%±2.9% for a criterion of 3%/3 mm, 20% threshold, all above the acceptance limit of 90%.

CONCLUSIONS

The national results of the H&N IMRT audit showed a compliance between the planned and the delivered doses within the specified tolerances, confirming no major reasons for concern. At the same time the audit identified factors that contributed to increased uncertainties in the IMRT dose delivery in some institutions resulting in recommendations for quality improvement.

[Recurrence pattern and influencing factors of intensity-modulated radiotherapy for cervical cancer]

With the rapid development of precise radiotherapy technology, the use of intensity-modulated radiation therapy (IMRT) in gynecological malignant tumor has been gradually increased. IMRT could result in a good local control rate as well as superior clinical outcome in patients with cervical cancer after radical radiotherapy. The recurrence pattern of radiotherapy includes in-field recurrence, out-of-field and combined failure. The recurrence pattern of radical IMRT for cervical cancer is mainly out-of-field recurrence. Out-of-field recurrence may be related to inadequate imaging evaluation before treatment. In-field recurrence may be related to insufficient radiation dose in target area and differences of tumor sensitivity.

Results of a multicenter intensity modulated radiation therapy treatment planning comparison study for a sample prostate cancer case

PURPOSE

To determine the influence of different medical physicists, photon energies, treatment planning systems and treatment machines on the resulting external beam radiotherapy dose distribution for a sample prostate cancer case.

METHODS

A pre-contoured computed tomography (CT) dataset containing planning target volume 1 (PTV1) prostate and seminal vesicles (single dose [SD] 1.8 Gy, total dose [TD] 59.4 Gy), PTV2 prostate (simultaneously integrated boost [SIB], SD 2.0 Gy, TD 66 Gy), PTV3 prostate and seminal vesicles approach (SD 1.8 Gy, TD 73.8 Gy/80.4 Gy SIB) as well as organs at risk (OAR: rectum, bladder, femoral heads, bowel, anus) was offered to the members of the task group IMRT (intensity-modulated radiation therapy) of the German Society for Medical Physics. The purpose was to calculate one combined treatment plan (TP) for PTV1 and PTV2, as well as a separate one for PTV3. Dose volume histograms (DVH), different dose values, conformity index (CI), homogeneity index (HI), gradient index (GI) and a new "better than average score" were used to analyse the dose distributions.

RESULTS

Altogether 44 institutions took part in this study and submitted acceptable dose distributions for the PTVs. However, there were statistically significant differences, especially for the doses administered to the OAR, such as rectum, bladder and femoral heads. Differences between the treatment plans were not easily detectable by visual inspection of the isodose distribution. Dose maxima may occur outside the PTV. Even though scoring indices are already published, the new "better than average score" was needed to identify a plan that minimises dose to all OAR simultaneously.

CONCLUSION

Different medical physicists or dosimetrists, photon energies, treatment planning systems, and treatment machines have an impact on the resulting dose distribution. However, the differences only become apparent when comparing DVH, analysing dose values, comparing CI, HI, GI, as well as reviewing the dose distribution in every single plane. A new score was introduced to identify treatment plans that simultaneously deliver a low dose to all OAR. Such inter- and intra-institutional comparison studies are needed to explore different treatment planning strategies; however, there is still no automatic solution for an "optimal" treatment plan.

Modeling scattered radiation from multi-leaf collimators (MLCs) to improve calculation accuracy of in-air output ratio

This study aims to model an extra-focal source for the scattered radiation from multi-leaf collimators (MLCs), namely an MLC scatter source, and to correct in-air output ratio (S_c) calculated using the conventional dual source model (DSM) to achieve better accuracy of point dose calculation. To develop the MLC scatter source, a 6 MV photon beam from a Varian Clinac® iX linear accelerator with millennium 120 MLCs was used. It was assumed that the position for the MLC scatter source was located at the center of the MLC, consisting of line-based and area-based sources to consider the characteristics of the scattered radiation from the MLCs empirically. Based on the measured S_c values for MLC-defined fields, optimal parameters for the line-based and area-based sources were calculated using optimization process. For evaluation of proposed method, measurements were taken for various MLC-defined square and irregular fields. The S_c values calculated using the proposed MLC scatter source and conventional DSM were compared with the measured data. For MLC-defined square fields, the measured S_c values showed better agreement with those calculated using the MLC scatter source (the mean difference was − 0.03%) compared with those calculated using the DSM (the mean difference was 0.18%). For MLC-defined irregular fields, the maximum dose differences between measurements and calculations using the MLC scatter source and DSM were 0.54% and 1.45%, respectively. The developed MLC scatter source could improve the accuracy of S_c calculation for both square and irregular fields defined by MLCs.

Advantages of using reduced-volume intensity modulated radiation therapy for the treatment of nasopharyngeal carcinoma: a retrospective paired study

BACKGROUND

The definition of clinical target volume (CTV) in intensity modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) has not been addressed. We performed this study to assess the feasibility and efficacy of using IMRT with reduced-volume CTV for the treatment of nasopharyngeal carcinoma.

METHODS

We retrospectively reviewed 293 non-metastatic NPC patients treated with IMRT from 2002 to 2013. A total of 180 matched cases finally included with 90 received conventional-volume IMRT (CV-IMRT) and 90 received reduced-volume IMRT (RV-IMRT). Kaplan-Meier method and log-rank tests were used to compare NPC-specific survival. Multivariate analyses using the Cox proportional hazards model were conducted to detect independent predictors.

RESULTS

With a median follow-up of 70 months, the 3-year overall survival, progression-free survival, distant metastasis-free survival, local recurrence-free survival, regional recurrence-free survival, locoregional recurrence-free survival rates were 88.9, 84.4, 92.2, 91.1, 98.9, 91.1% for the CV-IMRT arm and 92.2, 85.6, 90.0, 93.3, 98.9, 93.3% for the RV-IMRT arm, respectively. None significant survival difference was observed. Additionally, RV-IMRT was associated with reduced risk of late xerostomia (P = 0.039) and hearing loss (P = 0.008), compared versus CV-IMRT.

CONCLUSIONS

The use of RV-IMRT for the treatment of NPC led to comparable survival condition and truly reduced toxicity reactions compared versus CV-IMRT.

Treatment outcomes of prostate cancer patients with Gleason score 8-10 treated with definitive radiotherapy : TROD 09-001 multi-institutional study

PURPOSE

To validate the clinical outcomes and prognostic factors in prostate cancer (PCa) patients with Gleason score (GS) 8-10 disease treated with external beam radiotherapy (EBRT) + androgen deprivation therapy (ADT) in the modern era.

METHODS

Institutional databases of biopsy proven 641 patients with GS 8-10 PCa treated between 2000 and 2015 were collected from 11 institutions. In this multi-institutional Turkish Radiation Oncology Group study, a standard database sheet was sent to each institution for patient enrollment. The inclusion criteria were, T1-T3N0M0 disease according to AJCC (American Joint Committee on Cancer) 2010 Staging System, no prior diagnosis of malignancy, at least 70 Gy total irradiation dose to prostate ± seminal vesicles delivered with either three-dimensional conformal RT or intensity-modulated RT and patients receiving ADT.

RESULTS

The median follow-up time was 5.9 years (range 0.4-18.2 years); 5‑year overall survival (OS), biochemical relapse-free survival (BRFS) and distant metastases-free survival (DMFS) rates were 88%, 78%, and 79%, respectively. Higher RT doses (≥78 Gy) and longer ADT duration (≥2 years) were significant predictors for improved DMFS, whereas advanced stage was a negative prognosticator for DMFS in patients with GS 9-10.

CONCLUSIONS

Our results validated the fact that oncologic outcomes after radical EBRT significantly differ in men with GS 8 versus those with GS 9-10 prostate cancer. We found that EBRT dose was important predictive factor regardless of ADT period. Patients receiving 'non-optimal treatment' (RT doses <78 Gy and ADT period <2 years) had the worst treatment outcomes.

[Skull base meningioma: Clinical and radiological efficacy based on a quantitative volumetric analysis]

PURPOSE

To date, no correlation has been found between clinical and radiological efficacy after irradiation of skull base meningiomas. However, the evaluation of the radiological response was most often made by questionable methods that may have underestimated the radiological effectiveness of radiotherapy. The objective of this work is to verify this hypothesis by quantitative volumetric analysis.

MATERIAL AND METHODS

Data from 35 patients treated with either helical tomotherapy (45.7%) or fractionated stereotactic radiotherapy (54.3%) were retrospectively analysed. These were mainly women (94%) aged 59 (43-81) with lesions mainly of the cavernous sinus (60%). There was a median of 2 (1-4) symptoms and the main symptoms were visual impairment (39%), cranial nerve deficits (23.4%) and headaches (17.2%).

RESULTS

Median tumour volume decreased significantly (P<0.05) from 9.6mL (0.3-36.6) to 6.8mL (0.1-26.5) after median follow-up of 44 months (24-77). Sixty-three percent of patients had an improvement of at least one symptom. In univariate analysis, clinical efficacy (P<0.05), radiotherapy technique (P<0.05), tumor topography (P<0.05) and initial tumor volume (P<0.05) were predictive factors for radiological response. In multivariate analysis, only the inverse correlation between radiological response and initial tumor volume remained significant (ρ: -0.47 95% CI -3.2 to 5.7; P<0.05).

CONCLUSION

The quantitative volumetric monitoring demonstrates a major radiological efficiency of radiotherapy. However, no clear correlation between clinical and radiological efficacy was found.

Voxel-based automatic multi-criteria optimization for intensity modulated radiation therapy

Background

Automatic multi-criteria optimization is necessary for intensity modulated radiation therapy (IMRT) because of low planning efficiency and large plan quality uncertainty in current clinical practice. Most studies focused on imitating dosimetrists’ planning procedures to automate this process and ignored the fact that organ-based objective functions typically used in commercial treatment planning systems (such as dose-volume function) usually lead to sub-optimal plans. To guarantee the optimum results and to automate this process, we incorporate an improved automation strategy and a voxel-based optimization algorithm to generate a novel automatic multi-criteria optimization framework. We then evaluate it in clinical cases.

Methods

This novel automatic multi-criteria optimization framework incorporates a ranked priority-list based automatic constraints adjustment strategy and an in-house developed voxel-based optimization algorithm. Constraints are sequentially adjusted following a pre-defined priority list. Afterward, a voxel-based fluence map optimization (FMO) with an orientation to the newly updated constraints is launched to find a Pareto optimal solution. Loops of constraints adjustment are repeated until each of them could not be relaxed or tightened. The feasibility of the framework is evaluated with 10 automatic generated gynecology (GYN) cancer IMRT cases by comparing the dosimetric performance with the original.

Results

Plan quality improvement is observed for our automatic multi-criteria optimization method. Comparable DVHs are found for the planning target volume (PTV), but with better organs-at-risk (OAR) dose sparing. Among 13 evaluated dosimetric endpoints, 5 of them show significant improvements in automatically generated plans compared with the original plans. Investigation of improvement tendency during optimization exhibits gradual change as the optimization stage proceeds. An initial voxel-based optimization stage and in-low-priority dosimetric criteria tighten can significantly contribute to the optimization procedure.

Conclusions

We have successfully developed an automatic multi-criteria optimization framework that can dramatically reduce the current trial-and-error patterned planning workload while affording an efficient method to assure high plan quality consistency. This optimization framework is expected to greatly facilitate precise radiation therapy because of its advantages of planning efficiency and plan quality improvement.

Multivariable model for predicting acute oral mucositis during combined IMRT and chemotherapy for locally advanced nasopharyngeal cancer patients

INTRODUCTION/OBJECTIVE

Oral and oropharyngeal mucositis (OM) represents amultifactorialand complexinterplayof patient-, tumor-, and treatment-related factors. We aimed to build a predictive model for acute OM for locally advanced nasopharyngeal carcinoma (NPC) patients by combining clinical and dosimetric factors.

MATERIALS/METHODS

A series of consecutive NPC patients treated curatively with IMRT/VMAT + chemotherapy at 70 Gy (2-2.12 Gy/fr) was considered. For each patient, clinical- tumor- and treatment-related data were retrospectively collected. oral cavity (OC) and parotid glands (PG, considered as a single organ) were selected as organs-at-risk (OARs). Acute OM was assessed according to CTCAE v4.0 at baseline and weekly during RT. Two endpoints were considered: grade ≥3 and mean grade ≥1.5. DVHs were reduced to Equivalent Uniform Dose (EUD). Dosimetric and clinical/treatment features selected via LASSO were inserted into a multivariable logistic model. Goodness of fit was evaluated through Hosmer-Lemeshow test and calibration plot.

RESULTS

Data were collected for 132 patients. G ≥ 3 and mean G ≥ 1.5 OM were reported in 40 patients (30%). Analyses resulted in a 3-variables model for G ≥ 3 OM, including OC EUD with n = 0.05 (OR = 1.02), PG EUD with n = 1 (OR = 1.06), BMI ≥ 30 (OR = 3.8, for obese patients), and a single variable model for mean G ≥ 1.5 OM, i.e. OC EUD with n = 1 (mean dose) (OR = 1.07). Calibration was good in both cases.

CONCLUSION

OC mean dose was found to impact most on OM duration (mean G ≥ 1.5), while G ≥ 3 OM was associated to a synergic effect between PG mean dose and high dose received by small OC volumes, with BMI acting as a dose-modifying factor.

Temporal lobe injury patterns following intensity modulated radiotherapy in a large cohort of nasopharyngeal carcinoma patients

OBJECTIVES

To analyze the correlation between dose-volume-histograms (DVHs) with three patterns (edema, enhancement, and necrosis) of temporal lobe injury (TLI) in patients receiving intensity modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC) and to determine optimal thresholds to predict the incidence of each TLI pattern, with particular emphasis on the relationship between edema volume and the risk of enhancement and necrosis.

MATERIALS AND METHODS

A cohort of 4186 NPC patients treated with IMRT was retrospectively reviewed with TLI presenting in 188 patients. The atlases of complication incidence (ACI) for each pattern were constructed using DVH curves of temporal lobes. Optimal threshold for predicting incidence of each pattern was determined using the point closest to top-left of the plot. The accuracy of using edema volume to predict enhancement and necrosis incidence was evaluated via area under curve (AUC) of receiver operator characteristics (ROC).

RESULTS

All DVH parameters, D_mean, D_max, D_0.25cc, D_0.5cc, D_1cc, D_3cc, D_6cc, V_20Gy, V_30Gy, V_40Gy, V_50Gy, V_60Gy, and V_70Gy, except D_min showed statistically significant differences between subgroups of each pattern (p < 0.05). For predicting incidence of each pattern, optimal DVH thresholds over the range of D_0.25-D_1cc, D_mean and V₂₀-V₇₀ were derived. The optimal thresholds of edema volume for predicting enhancement were 0.96 and 2.2cc and for predicting necrosis were 0.94 and 11.5cc.

CONCLUSION

Optimal DVH thresholds were generated for limiting risk of each injury pattern. Edema volume was a strong predictor for risk of enhancement and necrosis, which could potentially be reduced by lowering edema volume below threshold.

Dosimetric Effects of Head and Neck Immobilization Devices on Multi-field Intensity Modulated Radiation Therapy for Nasopharyngeal Carcinoma

Background: In practice, the dose perturbation effect of head and neck immobilization devices is often overlooked in intensity-modulated radiation therapy (IMRT) for nasopharyngeal carcinoma (NPC). Purpose of this study is to verify and analyze the dosimetric effect of head and neck immobilization devices on NPC multi-field IMRT. Methods: Ten patients with nasopharyngeal carcinoma were randomly selected. Two sets of body contours were established for each patient. One set of body contours did not contain the immobilization device, and the other contour set included the immobilization device. For each patient, dose calculations were conducted for the two sets of contours using the same 9-field IMRT plan, which were recorded as Plan- and Plan+. The dose difference caused by the head and neck immobilization devices was assessed by comparing the dose-volume histogram (DVH) parameter results and by plan subtraction. The gafchromic EBT3 film and anthropomorphic phantom were used to verify the calculated doses. Results: The target coverage and average dose of Plan+ were lower than those of Plan- : the prescription dose coverage rates for PTVnx, PTVnd, PTV1 and PTV2 decreased by 2.4%, 9.9%, 1.5%, and 3.6%, respectively, and the mean doses were reduced by 0.9%, 1.9%, 1.1%, and 1.5%, respectively. Doses in the organs at risk showed no significant differences or slight reductions (the maximum reduction in mean dose was 1.7%). From the EBT3 measurements, the skin dose on the posterior neck was increased by approximately 53%. Conclusion: The attenuation and bolus effects of the head and neck immobilization device reduce dose coverage rate and average dose of the planning target volumes in nasopharyngeal carcinoma and lead to an increase in the skin dose. During treatment planning and dose calculation, the immobilization device should be included within body contour to account for the dose attenuation and skin dose increment.

Successful radiotherapy for endometrial serous carcinoma with local repeated recurrence

The incidence of endometrial serous carcinoma (ESC) has been increasing, and ESC is resistant to treatment. We report a patient with ESC who responded to radiotherapy for multiple recurrences. The first recurrence was detected in the vaginal wall and left internal iliac lymph node 5 months after the initial treatment. Concurrent chemoradiotherapy (CCRT) was administered. Radiation was delivered using the intensity modulated radiation therapy technique. The second recurrent tumor was detected in the right internal iliac lymph node after 4 months, and CCRT was conducted. After 4 months, the third recurrence was detected in the right common iliac node, and CCRT was performed. After 8 months, the fourth recurrence was detected in the horizontal portion of the duodenum, and radiotherapy was administered. After 9 months, the fifth recurrence was detected in the vaginal wall. Interstitial brachytherapy was conducted. Grade 2 gastrointestinal injury, nausea and radiodermatitis were observed. During the subsequent 13-month follow-up, there has been no recurrence. Although ESC is resistant to treatment, radiotherapy could be effective in some cases. Even when multiple recurrences occur, radiotherapy may be considered a treatment option if the irradiation level is permissible.

Ototoxicity and cochlear sparing in children with medulloblastoma: Proton vs. photon radiotherapy

PURPOSE

To compare ototoxicity rates between medulloblastoma patients treated with protons vs. photons.

MATERIALS AND METHODS

The study included 84 children diagnosed with medulloblastoma treated with either passively scattered protons (n = 38) or photons (n = 46). Patients underwent maximal safe resection followed by craniospinal irradiation, posterior fossa and/or tumor bed boost and chemotherapy according to one of 3 multi-institutional trials. Median audiogram follow-up was 56 months for protons and 66 months for photons.

RESULTS

Mean cochlear dose (D_mc) was lower in patients treated with protons for both standard (p < 0.0001) and high-risk disease (p < 0.001). Grade 3 and 4 ototoxicity was seen in 7 of 75 (9.3%) and 9 of 91 (9.9%) ears (Brock, p = 0.91), 13 of 75 (17.3%) and 19 of 91 (20.9%) ears (POG, p = 0.56), and 15 of 75 (20.0%) and 21 of 91 (23.1%) ears (SIOP Boston, p = 0.63) with protons and photons respectively.

CONCLUSIONS

While cochlear doses were lower in the proton group, patients treated with either protons or photons had similar Grade 3 and 4 ototoxicity rates.

Severe lymphopenia during neoadjuvant chemoradiation for esophageal cancer: A propensity matched analysis of the relative risk of proton versus photon-based radiation therapy

BACKGROUND AND PURPOSE

Circulating lymphocytes are exquisitely sensitive to radiation exposure, even to low scattered doses which can vary drastically between radiation modalities. We compared the relative risk of radiation-induced lymphopenia between intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT) in esophageal cancer (EC) patients undergoing neoadjuvant chemoradiation therapy (nCRT).

MATERIAL AND METHODS

EC patients treated with IMRT and PBT were propensity matched based on key clinical variables. Treatment-associated lymphopenia was graded using CTCAE v.4.0. Using matched cohorts, univariate and multivariable multiple logistic regression was used to identify factors associated with increased risk of grade 4 lymphopenia as well as characterize their relative contributions.

RESULTS

Among the 480 patients treated with nCRT, 136 IMRT patients were propensity score matched with 136 PBT patients. In the matched groups, a greater proportion of the IMRT patients (55/136, 40.4%) developed grade 4 lymphopenia during nCRT compared with the PBT patients (24/136, 17.6%, P < 0.0001). On multivariable analysis, PBT was significantly associated with a reduction in grade 4 lymphopenia risk (odds ratio, 0.29; 95% confidence interval, 0.16-0.52; P < 0.0001).

CONCLUSION

PBT is associated with significant risk reduction in grade 4 lymphopenia during nCRT in esophageal cancer.

Suggestions for surveillance and radiation strategy in nasopharyngeal carcinoma treated with IMRT: Based on hazard-rate and patterns of recurrence

OBJECTIVE

The study was designed to appraise the locoregional recurrence patterns using conventional two-dimensional radiotherapy (2D-RT) and intensity modulated radiation therapy (IMRT) in nasopharyngeal carcinoma (NPC) in order to better establish the scenario of the modern radiotherapy and the duration of surveillance.

MATERIALS AND METHODS

We reviewed the institutional database to identify patients with pathologically confirmed, non-metastatic NPC who completed radical 2D-RT or IMRT at our center from 2000 to 2011. We collected data on clinicopathologic features, treatments and outcomes. Statistical analyses were performed using SPSS 20.0 or STATASE 14.0.

RESULTS

The median follow-up was 60.1 months. Of 2315 patients, 1289 (53%) were treated with 2D-RT and 1026 (47%) with IMRT. IMRT group achieved better locoregional control rate, with the 5-year locoregional relapse-free survival (LRRFS) were 84.9% and 87.7% among patients received 2D-RT and IMRT, respectively (P = 0.050). IMRT was superior to 2D technique in terms of local relapse-free survival (LRFS) (88.4% vs 91.1%, P = 0.047) and the advantage was only significant in T3-4 subgroup (81.6% vs 90.2%, P = 0.000). Similar neck control rates were observed using different RT techniques. And the recurrence time appeared to be postponed by IMRT, with peaks accounting for the year 1.5 and year 3-4 compared to which was predominant at the first two years using 2D-RT in nature.

CONCLUSIONS

IMRT provided an improved LRRFS in overall stage and LRFS in advanced T stage for NPC compared with 2D-RT. Annual hazard of recurrence also changed with RT techniques.

Intensity modulated radiation therapy and surgery for Management of Retroperitoneal Sarcomas: a single-institution experience

BACKGROUND

Peri-operative radiation of retroperitoneal sarcomas (RPS) is an important component of multidisciplinary treatment. All retrospective series thus far included patients treated with older radiation therapy (RT) techniques including 2D and 3DRT. Intensity modulated radiation therapy (IMRT) allows for selective dose escalation while sparing adjacent organs. We therefore report the first series of patients with RPS treated solely with IMRT, surgery and chemotherapy. We hypothesized that IMRT would permit safe dose escalation and superior rates of local control (LC) in this high-risk patient population.

METHODS

Thirty patients with RPS treated with curative intent between 2006 and 2015 were included in this retrospective study. RT was administered either pre- or post-operatively and IMRT was used in all patients. Statistical comparisons, LC, distant metastasis (DM), and overall survival (OS) were calculated by Kaplan-Meier analysis and univariate Cox regression.

RESULTS

Median follow-up time after completion of RT was 36 months (range 1.4-112). Median tumor size was 14 cm (range 3.6 - 28 cm). The most prevalent histologies were liposarcoma in 10 (33%) patients and leiomyosarcoma in 10 (33%) with 21 patients (70%) having high-grade disease. Twenty-eight (93%) patients had surgical resection with 47% having positive margins. Chemotherapy was administered in 9 (30%) patients. RT was delivered pre-operatively in 11 (37%) patients, and post-operatively in 19 (63%) with 60% of patients receiving a simultaneous integrated boost. Pre-operative median RT dose to the high-risk area was 55 Gy (range, 43-66 Gy) while median post-operative dose was 60.4 Gy (range, 45-66.6 Gy). There was one acute grade 3 and one late grade 3 toxicity and no grade 4 or 5 toxicities. Three year actuarial LC, freedom from DM, and OS rates were 84%, 64%, and 68% respectively. Positive surgical margins were associated with a higher risk of local recurrence (p = 0.02) and decreased OS (p = 0.04). Pre-operative RT was associated with improved LC (p = 0.1) with a 5-year actuarial LC of 100%. Administration of chemotherapy, timing of RT, histology or grade was not predictive of OS.

CONCLUSIONS

Patients with RPS treated with peri-operative IMRT at our institution had excellent local control and low incidences of toxicity.

Assessing cumulative acute toxicity of chemoradiotherapy in head and neck cancer with or without induction chemotherapy

BACKGROUND

To compare cumulative acute toxicity in head and neck cancer patients treated with concurrent chemoradiotherapy alone (CCRT) versus induction chemotherapy (IC) followed by CCRT (I/CCRT).

METHODS

77 patients underwent definitive CCRT (30 I/CCRT and 47 CCRT). Toxicity was graded using the Common Terminology Criteria for Adverse Events version 4.0. Using the TAME adverse event reporting system, short-term toxicity (T) scores were generated for IC (T_IC), CCRT (T_CCRT), total treatment duration (T_Rx), post-treatment period (T_PT) and an overall score (T_overall) from treatment start to post treatment period.

RESULTS

Acute toxicity other than dysphagia, odynophagia, or dermatitis was reported in 90.0% and 66.0% of I/CCRT and CCRT patients, respectively (P=0.02). Compared to CCRT group, I/CCRT patients reported greater mean T_Rx (T_Rx: 2.11 vs. 2.87, P=0.01) and T_overall (T_overall: 2.60 vs. 3.70, P=0.003).

CONCLUSION

I/CCRT patients reported more cumulative acute toxicity during treatment compared to CCRT patients using the TAME reporting system.

Bilateral diffuse grade 5 radiation pneumonitis after intensity modulated radiation therapy for localized lung cancer

We are reporting a case of fatal radiation pneumonitis that developed six months following chemoradiation for limited stage small cell lung cancer. The patient was a 67-year-old man with a past medical history of Hashimoto’s thyroiditis and remote suspicion for CREST, neither of which were active in the years leading up to treatment. He received 6600 cGy delivered in 200 cGy daily fractions via intensity modulated radiation therapy with concurrent cisplatin/etoposide followed by additional chemotherapy with dose-reduced cisplatin/etoposide and carboplatin/etoposide and then received prophylactic cranial irradiation. The subsequent months were notable for progressively worsening episodes of respiratory compromise despite administration of prolonged steroids and he ultimately expired. Imaging demonstrated bilateral interstitial and airspace opacities. Autopsy findings were consistent with pneumonitis secondary to chemoradiation as well as lymphangitic spread of small cell carcinoma. The process was diffuse bilaterally although his radiation was delivered focally to the right lung and mediastinum.

Is it possible for knowledge-based planning to improve intensity modulated radiation therapy plan quality for planners with different planning experiences in left-sided breast cancer patients?

Background

Knowledge-based planning (KBP) is a promising technique that can improve plan quality and increase planning efficiency. However, no attempts have been made to extend the domain of KBP for planners with different planning experiences so far. The purpose of this study was to quantify the potential gains for planners with different planning experiences after implementing KBP in intensity modulated radiation therapy (IMRT) plans for left-sided breast cancer patients.

Methods

The model libraries were populated with 80 expert clinical plans from treated patients who previously received left-sided breast-conserving surgery and IMRT with simultaneously integrated boost. The libraries were created on the RapidPlan^TM. 6 planners with different planning experiences (2 beginner planners, 2 junior planners and 2 senior planners) generated manual and KBP optimized plans for additional 10 patients, similar to those included in the model libraries. The plan qualities were compared between manual and KBP plans.

Results

All plans were capable of achieving the prescription requirement. There were almost no statistically significant differences in terms of the planning target volume (PTV) coverage and dose conformality. It was demonstrated that the doses for most of organs-at-risk (OARs) were on average lower or equal in KBP plans compared to manual plans except for the senior planners, where the very small differences were not statistically significant. KBP data showed a systematic trend to have superior dose sparing at most parameters for the heart and ipsilateral lung. The observed decrease in the doses to these OARs could be achieved, particularly for the beginner and junior planners. Many differences were statistically significant.

Conclusions

It is feasible to generate acceptable IMRT plans after implementing KBP for left-sided breast cancer. KBP helps to effectively improve the quality of IMRT plans against the benchmark of manual plans for less experienced planners without any manual intervention. KBP showed promise for homogenizing the plan quality by transferring planning expertise from more experienced to less experienced planners.

Validation of the liver mean dose in terms of the biological effective dose for the prevention of radiation-induced liver damage

AIM

The purpose of this study was to determine the optimal mean liver biologically effective dose (BED) to prevent radiation-induced liver disease (RILD) in stereotactic body radiation therapy (SBRT).

BACKGROUND

The actual mean doses appropriate for liver irradiation in modern radiotherapy techniques have not been adequately investigated, although SBRT is sometimes alternatively performed using fractionated regimens.

MATERIALS AND METHODS

SBRT treatment plans for liver tumors in 50 patients were analyzed. All distributions of the physical doses were transformed to BED₂ using the linear-quadratic model. The relationship between physical doses and the BED₂ for the liver were then analyzed, as was the relationship between the mean BED₂ for the liver and the planning target volume (PTV).

RESULTS

A significantly positive correlation was observed between the mean physical dose for the background liver and the mean BED₂ for the whole liver (P < 0.0001, r = 0.9558). Using the LQ model, a mean BED₂ of 73 and 16 Gy for the whole liver corresponded to the hepatic tolerable mean physical dose of 21 and 6 Gy for Child-Pugh A- and B-classified patients, respectively. Additionally, the PTV values were positively correlated with the BEDs for the whole liver (P < 0.0001, r = 0.8600), and the background liver (P < 0.0001, r = 0.7854).

CONCLUSION

A mean BED₂ of 73 and 16 Gy for the whole liver appeared appropriate to prevent RILD in patients with Child-Pugh classes A and B, respectively. The mean BED₂ for the liver correlated well with the PTV.

The role of dentistry other than oral care in patients undergoing radiotherapy for head and neck cancer

The usefulness of dental approaches, such as oral management, has gained recognition among patients treated for head and neck cancer. In particular, oral management plays a very important role before, during, and after treatment in patients undergoing radiotherapy, chemotherapy, or a combination of both. However, specialized dentistry knowledge and techniques that are useful for patients undergoing radiotherapy for head and neck cancer have yet to be reported. Therefore, in this review article, our aim is to introduce dental approaches in radiotherapy for patients with head and neck cancer that have been developed and are currently being used at our institute.

Utility of intraoral stents in external beam radiotherapy for head and neck cancer

AIM

This study aimed to assess the utility and stability of intraoral stent during intensity-modulated radiation therapy (IMRT).

BACKGROUND

The benefits of intraoral stents in radiotherapy are unclear.

MATERIALS AND METHODS

We analyzed 386 setup errors in 12 patients who received IMRT for head and neck cancers without intraoral stents (intraoral stent [-]) and 183 setup errors in 6 patients who received IMRT with intraoral stents (intraoral stent [+]). All patients were matched according to the immobilization method (masks and boards). Setup errors were measured as the distance from the initial setup based on the marking on the skin and mask to the corrected position based on bone matching on cone beam computed tomography.

RESULTS

The mean interfractional setup errors in the right-left, craniocaudal, anterior-posterior (AP), and three-dimensional (3D) directions were -0.33, 0.08, -0.25, and 2.75 mm in the intraoral stent (-) group and -0.37, 0.24, -0.63, and 2.42 mm in the intraoral stent (+) group, respectively (P = 0.50, 0.65, 0.01, and 0.02, respectively). The systematic errors for the same directions were 0.89, 1.46, 1.15, and 0.88 mm in the intraoral stent (-) group and 0.62, 1.69, 0.68, and 0.56 mm in the intraoral stents (+) group, respectively. The random errors were 1.43, 1.43, 1.44, and 1.22 mm in the intraoral stent (-) group and 1.06, 1.11, 1.05, and 0.92 mm in the intraoral stents (+) group, respectively.

CONCLUSION

Setup errors can be significantly reduced in the AP and 3D-directions by using intraoral stents.

Reducing radiation dose to normal brain through a risk adapted dose reduction protocol for patients with favourable subtype anaplastic glioma

AIM

In patients with isocitrate dehydrogenase (IDH) mutated anaplastic glioma determine the dosimetric benefits of delivering radiation therapy using a PET guided integrated boost IMRT technique (ib-IMRT) compared with standard IMRT (s-IMRT) in reducing dose to normal brain.

METHODS

Ten patients with anaplastic glioma, identified as a favourable molecular subgroup through presence of IDH mutation, and managed with radiation therapy using an ib-IMRT were enrolled into a dosimetric study comparing two RT techniques: s-IMRT to 59.4Gy or ib-IMRT with 59.4/54Gy regions. Gross Tumour volume (GTV) and Clinical Target Volumes (CTV) were determined by MRI, 18F-Fluoroethyltyrosine (FET) and 18F-Fluorodeoxyglucose (FDG) PET imaging. A standard risk Planning Target Volume (PTVsr) receiving 59.4Gy (PTV59.4) in the s-IMRT technique was determined by MRI T2Flair and FET PET. For the ib-IMRT technique this PTVsr volume was treated to 54Gy, and the high-risk PTV (PTVhr) receiving 59.4Gy was determined as a higher risk region by FDG PET and MRI gadolinium enhancement. Standard dosimetric criteria and normal tissue constraints based on recent clinical trials were used in target delineation and planning. Normal Brain was defined as Brain minus CTV. Endpoints for dosimetric evaluation related to mean Brain dose (mBrainDose), brain volume receiving 40Gy (Brainv40) and 20Gy (Brainv20). The variation between the dosimetric endpoints for both techniques was examined using Wilcoxon analysis.

RESULTS

The 10 patients had tumours located in temporal (1), parietal (3), occipital (2) and bifrontal (4) regions. In ib-IMRT technique the median volume of PTVhr was 25.5 cm3 compared with PTVsr of 300.0 cm3. For dose to PTVhr the two treatments were equivalent (p = 0.33), and although the ibIMRT had a prescribed 10% dose reduction from 59.4Gy to 54Gy the median reduction was only 5.9%. The ib-IMRT dosimetry was significantly improved in normal brain endpoints specifically mBrainDose (p = 0.007), Brainv40 (p = 0.005) and Brainv20 (p = 0.001), with a median reduction of 9.3%, 19.0 and 10.8% respectively. After a median follow-up of 38 months two patients have progressed, with no isolated relapse in the dose reduction region.

CONCLUSION

An approach using ib-IMRT for anaplastic glioma produces significant dosimetric advantages in relation to normal brain dose compared with s-IMRT plan. This is achieved without a significant reduction to the target volume dose despite the reduction in prescribed dose. This technique has advantages to minimise potential late neurocognitive effects from high dose radiation in patients with favorable subtype anaplastic glioma with predicted median survival beyond ten years.

Impact of waiting time on nodal staging in head and neck squamous-cell carcinoma treated with radical intensity modulated radiotherapy

BACKGROUND AND PURPOSE

To evaluate the influence of delays for radiotherapy on survival, recurrence and upstaging for head and neck squamous-cell carcinoma (HNSCC) with no nodal involvement treated with intensity modulated radiotherapy (IMRT).

MATERIAL AND METHODS

This retrospective study included 63 consecutive patients with HNSCC located in the pharynx and larynx and treated with exclusive IMRT with or without chemotherapy. Survival, loco-regional or distant failure and upstaging were analyzed according to the waiting time.

RESULTS

Mean waiting time for treatment was 62.5 days for the hypopharynx subgroup (range = 37-102), 63 days for the larynx subgroup (range = 19-128) and 58.5 days for the oropharynx subgroup (range = 29-99) (p = 0.725). Nine patients (14%) experienced upstaging. Loco-regional or distant failure occurred in 18 patients. Beyond a delay of 50 days, 19% of patients had local failure, 17% nodal recurrence and 11% distant failure. Within a delay of 50 days, no nodal or distant failure was observed and only 1 patient experienced local recurrence. Upstaging and overall survival were not significantly affected by an increased waiting time.

CONCLUSION

For N0 patients treated with IMRT for HNSCC, waiting time around 50 days after the diagnosis was not significantly associated with an excessive risk of upstaging or recurrence.

Performance of the irregular surface compensator compared with four-field box and intensity modulated radiation therapy for gynecologic cancer

PURPOSE

A retrospective planning study was undertaken to evaluate the dosimetric advantages of the irregular surface compensator (ISC) technique, a forward planning technique with electronic compensation algorithm available on Varian Eclipse treatment planning system. This was extensively compared to the conventional four-field box (4FB) and intensity modulated radiation therapy using 5 fields (IMRT5F) on gynecologic cancer patients.

METHODS

Twenty-two patients were enrolled. The prescribed dose was 50.4Gy in 28 fractions to the primary target including pelvic lymph nodes. 4FB treatment plans were generated, then fluence of anterior and posterior fields were modified to generate ISC plans. IMRT5F were inversely optimized with equally spaced five coplanar fields. Dose-volume parameters were evaluated for the comparison of three planning techniques. The MU and delivery time were also estimated.

RESULTS

In terms of target coverage, the conformity and homogeneity index of ISC (1.67 and 1.03, respectively) were superior to those of 4FB (2.43 and 1.06, respectively) but slightly inferior to those of IMRT5F (1.10 and 1.02, respectively). ISC also illustrated an overall improvement in normal organ saving. Compared to 4FB, the mean dose of the rectum was reduced by about 4.0-5.0Gy with ISC and IMRT5F. The volume receiving large doses was reduced for bladder with statistical significance with ISC and more with IMRT5F relative to 4FB. The mean number of MU per fraction were 200.86 (4FB), 446.09 (ISC) and 895.59 (IMRT5F).

CONCLUSION

The ISC technique has the superior target coverage and healthy tissue sparing in comparison with conventional 4FB and comparable normal organ saving compared to IMRT5F. The ISC can be an available option for gynecologic radiotherapy.

Toxicity and early clinical outcomes in cervical cancer following extended field helical tomotherapy to para-aortic lymph nodes

PURPOSE

To evaluate toxicity and early disease outcome among patients treated for cervical cancer with extended-field helical tomotherapy to the para-aortic nodes.

PATIENTS AND METHODS

Thirty-eight patients (International Federation of Gynecology and Obstetrics [FIGO] stage IB2-IVA) from four institutions received extended-field helical tomotherapy and were retrospectively evaluated. All had nodal disease. Para-aortic lymph nodes were involved in 31 patients. Patients were assessed for toxicity using version 4 of the National Cancer Institute's common terminology criteria for adverse events. Survival curves were plotted using Kaplan-Meier estimates.

RESULTS

All patients underwent radiation to the tumor region (median dose: 45Gy; range: 44-66Gy), pelvic lymph nodes and para-aortic lymph nodes (median dose: 45Gy; range: 44-60Gy). The median dose to positive lymph nodes was 55Gy (range: 45-65Gy). All received platinum-based chemotherapy (31 concurrently). The median follow-up was 15months. Acute toxicity events observed included one patient with grade 5 febrile neutropenia, 11 patients (29%) with grade 3 hematologic complications. Grades 3-4 gastrointestinal and genitourinary toxicities occurred in six (16%) and four (11%) patients, respectively. Three patients had grade 3 pelvic pain (8%). The 6- and 18-month overall survival rates were 94.7 and 63.9%, respectively. The 18-month locoregional control, disease-free survival, and late grade 3 toxicity rates were 60.2, 43.3 and 7.3%, respectively.

CONCLUSION

Extended-field helical tomotherapy was associated with low rates of acute gastrointestinal and genitourinary toxicities with early survival and locoregional control similar to other published series.

Patterns of failure after reirradiation with intensity-modulated radiation therapy and the competing risk of out-of-field recurrences

PURPOSE

To describe patterns of failure (POF) after reirradiation (reRT) with intensity modulated radiation therapy (IMRT) for recurrent/second primary squamous cell carcinoma of the head and neck.

METHODS

From 08/2004-02/2013, 75 consecutive patients received reRT with IMRT. Gross tumor was generally treated with a 5mm planning target volume (PTV) margin. For postoperative cases, a 5mm PTV was added to the clinical target volume which included the postoperative bed. Elective neck coverage was not standard. POF were characterized by correlating the recurrent tumor location on CT-imaging with the reRT IMRT plan.

RESULTS

Patients received definitive reRT (55%) or postoperative reRT (45%) to a median 60Gy (range, 59.4-70Gy). Most patients (88%) received concurrent chemotherapy including induction (16%). The median overall survival was 1.8years. Isolated local-regional recurrence (LRR) was the most common failure-type (2-year cumulative incidence [CI] 22.5% [95% C.I. 13.6-32.7%]), but concurrent LRR and distant-failure occurred frequently (2-year CI LRR+distant-failure 19.6% [95% C.I. 11.3-29.5%]); isolated distant-failure was rare (2-year CI 5.7% [95% C.I. 1.8-12.8%]). The 2-year in-field control was 65% (95% C.I. 52-81%) reflecting encouraging control within the irradiated target. Patients with gross disease were more likely to recur in-field (p=0.02), whereas postoperative patients were more likely to recur out-of-field/marginally than in-field (p=0.02).

CONCLUSIONS

POF after reRT differ when treating gross disease or postoperatively and should be considered when delineating reRT targets. Aggressive local therapy resulted in favorable in-field control, yet there remains a high competing risk of regional and distant micrometastatic disease. Better systemic agents are needed to control clinically occult local-regional and distant disease.

Radiation Oncology--New Approaches in Squamous Cell Cancer of the Head and Neck

The many advances in radiotherapy for squamous cell cancer of the head and neck described in this article will have significant effects on the ultimate outcomes of patients who receive this treatment. The technological and clinical advances should allow one to maintain or improve disease control, while moderating the toxicity associated with head and neck radiation therapy.

Helical tomotherapy and volumetric modulated arc therapy: New therapeutic arms in the breast cancer radiotherapy

AIM

To analyse clinical and dosimetric results of helical tomotherapy (HT) and volumetric modulated arc therapy (VMAT) in complex adjuvant breast and nodes irradiation.

METHODS

Seventy-three patients were included (31 HT and 42 VMAT). Dose were 63.8 Gy (HT) and 63.2 Gy (VMAT) in the tumour bed, 52.2 Gy in the breast, 50.4 Gy in supraclavicular nodes (SCN) and internal mammary chain (IMC) with HT and 52.2 Gy and 49.3 Gy in IMC and SCN with VMAT in 29 fractions. Margins to particle tracking velocimetry were greater in the VMAT cohort (7 mm vs 5 mm).

RESULTS

For the HT cohort, the coverage of clinical target volumes was as follows: Tumour bed: 99.4% ± 2.4%; breast: 98.4% ± 4.3%; SCN: 99.5% ± 1.2%; IMC: 96.5% ± 13.9%. For the VMAT cohort, the coverage was as follows: Tumour bed: 99.7% ± 0.5%, breast: 99.3% ± 0.7%; SCN: 99.6% ± 1.4%; IMC: 99.3% ± 3%. For ipsilateral lung, Dmean and V20 were 13.6 ± 1.2 Gy, 21.1% ± 5% (HT) and 13.6 ± 1.4 Gy, 20.1% ± 3.2% (VMAT). Dmean and V30 of the heart were 7.4 ± 1.4 Gy, 1% ± 1% (HT) and 10.3 ± 4.2 Gy, 2.5% ± 3.9% (VMAT). For controlateral breast Dmean was 3.6 ± 0.2 Gy (HT) and 4.6 ± 0.9 Gy (VMAT). Acute skin toxicity grade 3 was 5% in the two cohorts.

CONCLUSION

HT and VMAT in complex adjuvant breast irradiation allow a good coverage of target volumes with an acceptable acute tolerance. A longer follow-up is needed to assess the impact of low doses to healthy tissues.

Salivary Gland. Photon beam and particle radiotherapy: Present and future

Salivary gland cancers (SGCs) are rare diseases and their treatment depends upon histology, stage and site of origin. Radical surgery is the mainstay of treatment but radiotherapy (RT) plays a key role in both the postoperative and the inoperable setting, as well as in recurrent disease. In the absence of prospective randomized trials, a wide retrospective literature suggests postoperative RT (PORT) in patients with high risk pathological features. SGCs, and adenoid cystic carcinoma (ACC) in particular, are known to be radio-resistant tumors and should therefore respond well to particle beam therapy. Recently, excellent outcome has been reported with radical carbon ion RT (CIRT) in particular for ACC. Both modern photon- and hadron-based treatments are effective and are characterized by a favourable toxicity profile. But it is not clear whether one modality is superior to the other for disease control, due to the differences in patients' selection, techniques, fractionation schedules and outcome measurements among clinical experiences. In this paper, we review the role of photon and particle RT for malignant SGCs, discussing the difference between modalities in terms of biological and technical characteristics. RT dose and target volumes for different histologies (ACC versus non-ACC) have also been taken into consideration.

Intensity modulated radiation therapy with simultaneous integrated boost based dose escalation on neoadjuvant chemoradiation therapy for locally advanced distal esophageal adenocarcinoma

AIM: To evaluate impact of radiation therapy dose escalation through intensity modulated radiation therapy with simultaneous integrated boost (IMRT-SIB).

METHODS: We retrospectively reviewed the patients who underwent four-dimensional-based IMRT-SIB-based neoadjuvant chemoradiation protocol. During the concurrent chemoradiation therapy, radiation therapy was through IMRT-SIB delivered in 28 consecutive daily fractions with total radiation doses of 56 Gy to tumor and 5040 Gy dose-painted to clinical tumor volume, with a regimen at the discretion of the treating medical oncologist. This was followed by surgical tumor resection. We analyzed pathological completion response (pCR) rates its relationship with overall survival and event-free survival.

RESULTS: Seventeen patients underwent dose escalation with the IMRT-SIB protocol between 2007 and 2014 and their records were available for analysis. Among the IMRT-SIB-treated patients, the toxicity appeared mild, the most common side effects were grade 1-3 esophagitis (46%) and pneumonitis (11.7%). There were no cardiac events. The Ro resection rate was 94% (n = 16), the pCR rate was 47% (n = 8), and the postoperative morbidity was zero. There was one mediastinal failure found, one patient had local failure at the anastomosis site, and the majority of failures were distant in the lung or bone. The 3-year disease-free survival and overall survival rates were 41% (n = 7) and 53% (n = 9), respectively.

CONCLUSION: The dose escalation through IMRT-SIB in the chemoradiation regimen seems responsible for down-staging the distal esophageal with well-tolerated complications.