3D Conformal Radiotherapy Research Articles

Pilot study evaluating the tolerability of a 3Gy × 10 daily fraction 3D-conformal palliative radiation therapy protocol plus toceranib for the treatment of measurable carcinomas in the dog.

The use of radiation therapy in conjunction with small molecule inhibitors is an appealing treatment combination for non-resectable carcinomas, which tend to be locally invasive with variable risk of locoregional metastasis. This prospective, pilot study aimed to evaluate the tolerability and adverse event profile of concurrent toceranib and palliative-intent radiation therapy (PRT) in dogs with measurable carcinoma and to secondarily evaluate short-term measurable tumor response. Fifteen dogs with measurable carcinoma received toceranib and 3D-conformal PRT in 3Gy/fraction for 10 daily fractions. Adverse events were graded using standard schemes and tolerability was followed via quality-of-life questionnaires during the 12-week treatment period. Thirteen dogs (87%) experienced acute radiation toxicity, graded as severe in three dogs. All dogs experienced toceranib toxicity, graded as severe in one dog. Seven dogs (47%) completed the 12-week study protocol; four were withdrawn due to toxicity and/or associated poor quality of life and four developed progressive disease. Based on these preliminary results, this 3D-conformal chemoradiation protocol should be considered with caution and only with proper owner education on potential toxicity. More conformal treatment planning techniques or alternative protocols should be investigated for improved tolerability.

Fetal dose estimation for Virtual Tangential-fields Arc Therapy whole breast irradiation by optically stimulated luminescence dosimeters

Breast cancer is the most frequently diagnosed tumor in pregnant women and radiation therapy should carefully be weighted up because of the dose to the fetus. The aim of this study was to investigate fetal dose in a patient treated with Virtual Tangential-fields Arc Therapy (ViTAT), an innovative technique for whole breast irradiation. Optically stimulated luminescence detectors (OSLDs) were calibrated on a Varian TrueBeam linac, with both a 6X and 6XFFF beam quality, and used for out-of-field measurements. Fetal dose related with ViTAT technique was compared to the standard 3D conformal radiation therapy technique (3DCRT). The fetal dose delivered with a ViTAT technique planned with 6XFFF beam was also investigated. Measurements were taken on a phantom composed of Rando Alderson Phantom slices and solid water slabs. OSLDs were placed in a region identified by the height of the fundus from conception to the twentieth week using a custom made PMMA grid. Due to the higher number of monitor units, the peripheral dose of ViTAT delivered with 6X beams is higher than that of 3DCRT. However, nanoDots measurements prove that ViTAT can be used in place of 3DCRT while maintaining similar fetal dose levels if 6XFFF beams are used.

Clinical acceptability of fully automated external beam radiotherapy for cervical cancer with three different beam delivery techniques.

PurposeTo fully automate CT‐based cervical cancer radiotherapy by automating contouring and planning for three different treatment techniques.MethodsWe automated three different radiotherapy planning techniques for locally advanced cervical cancer: 2D 4‐field‐box (4‐field‐box), 3D conformal radiotherapy (3D‐CRT), and volumetric modulated arc therapy (VMAT). These auto‐planning algorithms were combined with a previously developed auto‐contouring system. To improve the quality of the 4‐field‐box and 3D‐CRT plans, we used an in‐house, field‐in‐field (FIF) automation program. Thirty‐five plans were generated for each technique on CT scans from multiple institutions and evaluated by five experienced radiation oncologists from three different countries. Every plan was reviewed by two of the five radiation oncologists and scored using a 5‐point Likert scale.ResultsOverall, 87%, 99%, and 94% of the automatically generated plans were found to be clinically acceptable without modification for the 4‐field‐box, 3D‐CRT, and VMAT plans, respectively. Some customizations of the FIF configuration were necessary on the basis of radiation oncologist preference. Additionally, in some cases, it was necessary to renormalize the plan after it was generated to satisfy radiation oncologist preference.ConclusionApproximately, 90% of the automatically generated plans were clinically acceptable for all three planning techniques. This fully automated planning system has been implemented into the radiation planning assistant for further testing in resource‐constrained radiotherapy departments in low‐ and middle‐income countries.

Quantitative Assessment of the Quality of External Radiotherapy Planning for Patients with Prostate Cancer

Purpose. To quantify the quality of treatment planning for patients with prostate cancer for three different radiotherapy technologies. Materials and methods. The quality of irradiation planning was assessed using the index of homogeneity, conformality and comparison of critical organs doses for 40 patients with prostate cancer using various irradiation technologies: 3D conformal radiation therapy 3DCRT, radiation therapy with intensity modulation IMRT, radiation therapy with intensity modulation in rotation mode RapidArc. The technologies are implemented on conventional electron accelerators of the Clinac iX (Varian, USA), Clinac 2300 CD (Varian, USA) and UniquePower (Varian, USA) models with a nominal photon radiation energy 6 and 18 MeV. Results. The dependences of the homogeneity indices HI, conformality CI within the target, and critical organs doses on the irradiation technology for patients with prostate cancer were obtained. Taking into account the predictive capabilities of the HI index for relapse-free survival, the optimal technology for irradiating patients was chosen. It has been shown that Rapid Arc technology dominates for prostate cancer.

Quantitative Assessment of Distance Radiotherapy Plans for Patients with Uterine Cancer

Purpose: To carry out a quantitative assessment of the quality of planning the remote radiotherapy component of patients with uterine body cancer for three different radiotherapy technologies: 3D conformal radiation therapy 3D-CRT, radiation therapy with intensity modulation IMRT, and with intensity modulation in the rotational mode RapidArc. To determine radiation exposure to critical organs. Material and methods: Radiotherapy plans for 102 patients were calculated using the Eclipse (Varian) planning system. Plans were evaluated using homogeneity and conformity indices from dose-volume histograms. When analyzing dose loads on the rectum, bladder and pelvic bones, a differential dose-volume characteristic was used, which reflects the modal dose D dif . Radiotherapy was carried out on accelerators of the ClinaciX (Varian) model with a photon of 6 MV. Results and conclusion: It turned out that 3D-CRT and IMRT are the most favorable methods for the remote component of radiotherapy. The smallest value of the modal dose D dif for the rectum is achieved with the RapidArc method and is 41 ± 10 Gy. The smallest value of the modal dose D dif for the bladder is also achieved with the RapidArc method and is 45 ± 9 Gy. The dose loads on the femoral heads are approximately the same for all three irradiation methods.

A dosimetric comparison of proton versus photon irradiation for paediatric glomus tumour: a case study

Abstract Background: Intensity-modulated radiation therapy (IMRT) has revolutionised the way head and neck cancers can be treated. It allows for a more conformal treatment plan when compared to 3D conformal radiation therapy. In paediatric patients, however, IMRT continues to deliver higher doses than desirable. Proton beam therapy on the other hand has the potential to further spare organs-at-risk. Methods: A 16-year-old boy with a left-sided paraganglioma of the left base of skull manifested by headaches, neck pain and tongue cramping was simulated, planned and treated with proton therapy with significant contralateral organ-at-risk sparing. Results: For this patient, dosimetric plan comparison between photon and proton plans clearly showed better sparing of contralateral organs-at-risk with protons. The contralateral parotid gland received a mean dose of 386·3 cGy with photons, whereas it received 1·3 cGy (CGE) in the proton plan. Conclusions: The dosimetric advantage of proton beam over photon beam therapy has successfully been demonstrated in this case study for a paediatric patient with a head and neck tumour. Sparing of contralateral structures is especially important in paediatric patients who are at a greater risk of secondary malignancies due to possible long life expectancy.

A nested case-control study on radiation dose-response for cardiac events in breast cancer patients in Germany

BackgroundPrevious studies with the majority of breast cancer (BC) patients treated up to 2000 provided evidence that radiation dose to the heart from radiotherapy (RT) was linearly associated with increasing risk for long-term cardiac disease. RT techniques changed substantially over time. This study aimed to investigate the dose-dependent cardiac risk in German BC patients treated with more contemporary RT. MethodsIn a cohort of 11,982 BC patients diagnosed in 1998–2008, we identified 494 women treated with 3D-conformal RT who subsequently developed a cardiac event. Within a nested case-control approach, these cases were matched to 988 controls. Controls were patients without a cardiac event after RT until the index date of the corresponding case. Separate multivariable conditional logistic regression models were used to assess the association of radiation to the complete heart and to the left anterior heart wall (LAHW) with cardiac events. ResultsMean dose to the heart for cases with left-sided BC was 4.27 Gy and 1.64 Gy for cases with right-sided BC. For controls, corresponding values were 4.31 Gy and 1.66 Gy, respectively. The odds ratio (OR) per 1 Gy increase in dose to the complete heart was 0.99 (95% confidence interval (CI): 0.94–1.05, P = .72). The OR per 1 Gy increase in LAHW dose was 1.00 (95% CI: 0.98–1.01, P = .68). ConclusionsContrary to previous studies, our study provided no evidence that radiation dose to the heart from 3D-conformal RT for BC patients treated between 1998 and 2008 was associated with risk of cardiac events.

LINC-05. Successful response to bevacizumab/irinotecan/temozolomide in a progressive choroid plexus carcinoma: A case report

Choroid plexus carcinomas (CPC) are a rare type of aggressive pediatric brain tumors with poor survival rates, and no standard curative therapy after relapse. We report the case of a 1-year-oldmale, with a right lateral ventricular CPC and disseminated leptomeningeal disease. First line therapy was an initial surgery aborted due to hemorrhage and a second near total resection. After the second surgery six cycles of ICE regimen were applied. The MRI after primary therapy showed progression with a new lesion located on the optic pathway and leptomeningeal disease. At this point a second line therapy consisting of Bebacizumab 10 mg/kg and Irinotecan 125 mg/kg every 2 weeks and Temozolamide 150 mg/m2 every 4 weeks was given. He received up to 24 cycles. His imaging demonstrated 80% primary tumor reduction and improvement of leptomeningeal disease. This treatment gave him the time to turn 3 years old to receive 3D conformational craniospinal radiotherapy as follows: spine 24Gy, overdose 27 Gy to tumor bed and cranial for a total dose 51 Gy. The patient is now 19 months from the end of treatment with stable disease. He is clinically well, with good performance status (Lansky 100%) and attending school. The relevance to present this case is to highlight a safe and effective treatment for a relapsed CPC since there is not a curative therapy for these children.

Dosimetric and radiobiological comparison in head-and-neck radiotherapy using JO-IMRT and 3D-CRT

IntroductionDosimetric and radiobiological evaluations for the Jaws-only Intensity-modulated radiotherapy (JO-IMRT) technique for head and neck jaws-only intensity-modulated radiation therapy (JO-IMRT) and 3D conformal radiation therapy (3D-CRT). To compare the head-and-neck therapeutic approaches utilizing JO-IMRT and 3D-CRT techniques, different radiation dose indices were calculated, including: conformity index (CI), homogeneity index (HI), and radiobiological variables like Niemierko's equivalent uniform dose based tumor control probability (TCP) of planning target volume (PTV), normal tissue complication probability (NTCP) of organs at risk (OAR) (brainstem, spinal cord, and parotid grand). Materials and methodsTwenty-five nasopharynx patients were studied using the Prowess Panther Treatment Planning System (Prowess Inc). The results were compared with the dose distribution obtained using 3D-CRT. ResultsRegarding tumor coverage and CI, JO-IMRT showed better results than 3D-CRT. The average doses received by the PTVs were quite similar: 72.1 ± 0.8 Gy by 3D-CRT and 72.5 ± 0.6 Gy by JO-IMRT plans (p > 0.05). The mean doses received by the parotid gland were 56.7 ± 0.7 Gy by 3D-CRT and 26.8 ± 0.3 Gy by JO-IMRT (p > 0.05). The HI and CI were 0.13 ± 0.01 and 0.14 ± 0.05 and (p > 0.05) by 3D-CRT and 0.83 ± 0.05 and 0.73 ± 0.10 by JO-IMRT (p < 0.05). The average TCP of PTV was 0.82 ± 0.08 by 3D-CRT and 0.92 ± 0.02 by JO-IMRT. Moreover, the NTCP of the parotid glands, brain stem, and spinal cord were lower using the JO-IMRT than 3D-CRT plans. In comparison to the 3D-CRT approach, the JO-IMRT technique was able to boost dose coverage to the PTV, improve the target's CI and HI, and spare the parotid glands. This suggests the power of the JO-IMRT over 3D-CRT in head-and-neck radiotherapy.

Surgical resection, radiotherapy and percutaneous thermal ablation for treatment of stage 1 non-small cell lung cancer: protocol for a systematic review and network meta-analysis

IntroductionNon-small cell lung cancer (NSCLC) makes up the majority of lung cancer cases. Currently, surgical resection is the gold standard of treatment. However, as patients are becoming medically more complex...

Patient reported outcomes for quality of life (QOL) by Expanded Prostate Cancer Index (EPIC) on average 15 years post treatment

Objective/purposePreviously patient reported quality of life (QOL) was reported in men with prostate cancer a mean 2 and 6 years post treatment with open radical prostatectomy (RP), 3D conformal radiation therapy (3D CRT), or 125I low dose rate (LDR) brachytherapy (BT). Herein we update the results 15 years post-treatment QOL. Materials/methodsThe Expanded Prostate Cancer Index (EPIC) domains were scored with differences evaluated at a median 15.8 years follow up based upon mean EPIC summary domains by ANOVA with pairwise post-hoc comparisons adjusted for age. Patient differences of current survey from first cross-section are reported as median change in summary score for each treatment group at median of 2.2 and 6.0, and 15.8 years. ResultsAmong men still alive response rate was 52% in BT, 60% in 3D CRT, and 62% in RP resulting in 30, 41, and 330 QOL questionnaires to evaluate for each corresponding modality at median follow up of 15.8 years. Men were a mean 75.3, 83.6, and 79.3 years of age after RP, 3DCRT, and BT, respectively.At a median of 15.8 years, there were largely persistent differences in EPIC domains without substantial evolution in QoL from middle time points. Persistent worsening in urinary irritative and bowel domain with 3DRT or BT compared to RP. Trend towards worse urinary incontinence with RP were noted without statistical differences within radiotherapy options. ConclusionAs the EPIC patient reported outcomes with the longest follow-up, these data uniquely reveal temporal trends from 2 to 15 years post treatment. However, the treatment modalities of open RP, 3D CRT without image guidance or intensity modulation, and BT without peripheral loading or MRI guidance may not reflect modern techniques.

Effect of dosimetric parameters on postoperative respiratory morbidity in locally advanced esophageal cancer treated with preoperative chemoradiotherapy (CRT).

e16075 Background: Postoperative pulmonary complications are common after neoadjuvant CRT of locally advanced esophageal cancers. Using data from the French multicenter randomized phase II PROTECT trial (NCT02359968), we aimed to evaluate the dosimetric parameters which could be associated with the occurrence of postoperative respiratory morbidities in patients (pts) who underwent preoperative CRT. Methods: Key eligibility criteria for the PROTECT trial were stage II or III resectable adenocarcinoma or squamous cell carcinoma of the esophagus located below the carina. Pts received FOLFOX or Carboplatin-Paclitaxel, combined with radiotherapy (RT): total dose of 41.4 Gy, 5 fractions of 1.8 Gy per week, starting at day 1 of chemotherapy. The patient's position and definition of the target volumes and organs at risk were the same as in the CROSS trial (van Hagen, 2012). Pts were treated using 3D conformal RT or IMRT. Surgery occurred 4 to 8 weeks after completion of CRT through a transthoracic or mini-invasive approach with a two field extended lymphadenectomy. Pts recruited in the PROTECT trial up to Sept. 2019 who underwent surgery after CRT were eligible for this ancillary study. The primary endpoint of our translational study was the occurrence of postoperative respiratory morbidity, of any grade (Clavien-Dindo classification for early morbidity &lt; 31 days; NCI-CTCAE v4 for later events), up to 1 year following surgery, considering disease progression or death as competing events. Cause-specific Cox models were used to model the risk of respiratory morbidity, considering the following factors: performance status, BMI, smoking, histological subtype, tumor site, FEV1, RT technique, time interval between CRT and surgery, and dosimetric parameters derived from the Dose-Volume Histogram analysis (mean lung dose, V10Gy, V20Gy and V30Gy, as other parameters strongly correlated to these 4 ones). Results: Among the 98 pts recruited in the PROTECT trial from Feb. 2015 to Sept. 2019, 78 underwent surgery after CRT and were included in our translational study. Median age was 63.5 years (range 33 to 79). Tumor was located at the middle or lower third of the esophagus for 67% of pts. Mean lung dose was 10.2 Gy (sd = 3.2). Mean PTV volume was 566 cc (sd = 272). A total of 33 pts experienced at least one respiratory morbidity (16 pneumonia, 7 pleural effusion, 4 ARDS, 21 miscellaneous events). The cumulative incidence of respiratory morbidity was 42% one month after surgery (95% CI, 32-54), 44% at 3 months (32-54), and 46% at 6 months (35-57). None of the dosimetric parameters and other studied factors appeared associated with postoperative respiratory morbidity. Conclusions: We did not identify dosimetric factors that could predict the risk of postoperative respiratory morbidity after treatment with preoperative CRT with FOLFOX or Carboplatin-Paclitaxel. Clinical trial information: NCT02359968.

3D Conformal Radiotherapy in Cervical Metastasis to Brain

Background. Cervical cancer is among the commonest malignancies and a top fourth leading cause of cancer death in women worldwide. The five-year survival rate in locally advanced cervical cancer is 91.5%, and only 17.2% — in distant metastasis. Primary cervical cancer metastasis to brain is very rare. Report and analysis of quite rare clinical cases may shed light on this issue, helping formulate relevant therapeutic and diagnostic interventions.Materials and methods. The article describes a case of cervical cancer metastasis to brain. The patient received modern 3D conformal intensity-modulated (IMRT) and image-guided (IGRT) radiation therapies on an Elekta Synergy highenergy linear digital accelerator instrument.Results. Clinical effect has been achieved by end of treatment. Time since diagnosis of primary cervical cancer was 13 months, and 7 months — since diagnosis of brain metastasis.Discussion. The survival rate in brain metastasis is marginal-low and depends on the patient’s age, primary tumour state, presence of extracranial metastases, as well as volume, number and location of metastases in brain parenchyma. An integrated approach including surgery, radiation and chemotherapy is considered superior to improve survival and the quality of life.Conclusion. Despite sheer coverage of therapies available, the mean survival rate in intracranial metastasis remains subtle. Thereby, research and discovery of relapse and metastasis biomarkers of cervical cancer is relevant.

ESTRO ACROP guidelines for external beam radiotherapy of patients with uncomplicated bone metastases

After liver and lungs, bone is the third most common metastatic site (Nystrom et al., 1977). Almost all malignancies can metastasize to the skeleton but 80% of bone metastases originate from breast, prostate, lung, kidney and thyroid cancer (Mundy, 2002). Introduction of effective systemic treatment in many cancers has prolonged patients’ survival, including those with bone metastases.Bone metastases may significantly reduce quality of life due to related symptoms and possible complications, such as pain and neurologic compromise. The most serious complications of bone metastases are skeletal-related events (SRE), defined as pathologic fracture, spinal cord compression, pain, or other symptoms requiring an urgent intervention such as surgery or radiotherapy. In turn, growing access to modern diagnostic tools allows early detection of asymptomatic bone metastases that could be successfully managed with local treatment avoiding development of SRE.The treatment for bone metastases should focus on relieving existing symptoms and preventing new ones. Radiotherapy is the standard of care for patients with symptomatic bone metastases, providing durable pain relief with minimal toxicity and reasonable cost-effectiveness. Historically, the dose was prescribed in one to five fractions and delivered using simple planning techniques. While 3D-conformal radiotherapy is still widely used for treating bone metastases, introduction of highlyconformal radiotherapy techniques such as stereotactic body radiotherapy (SBRT) have opened new therapeutic possibilities that should be considered in selected patients with bone metastases.

Ultra-Hypofractionated vs. Moderate Fractionated Whole Breast Three Dimensional Conformal Radiotherapy during the COVID-19 Pandemic.

Background and Objectives: Reducing time of treatment during COVID-19 outbreaks has been recommended by the leading Radiation Oncology societies. Still minimizing radiation induced tissue toxicity is one of the most important issues in breast cancer patients. The study aimed to investigate compliance, clinical and dosimetry normal tissue toxicity, and cosmetic results between moderated and ultra-fractionated regimes for breast cancer patients during COVID-19 pandemic. Materials and Methods: This pilot prospective randomized study included 60 patients with early breast cancer after preserving surgery, 27 patients advocated to ultra-hypofractionated whole-breast three dimensional (3D) conformal radiotherapy of 26 Gy in 5 fractions over 1 week and 33 patients with moderate fractionated breast 3D conformal radiotherapy patients between March 2020 and July 2020, during the COVID pandemic outbreak. The compliance to treatment, dosimetric parameters, acute and late skin toxicity, subcutaneous tissue toxicity, cosmetic results and clinical follow up for 18 months for the two regimes were analyzed and compared. Results: When two regimes were compared 5 fraction group had significantly lower prevalence of newly infected cases of SARS-CoV-2 and thus delayed/interrupted treatment (p = 0.05), comparable grade 1 CTCAE v5, acute skin toxicity (p = 0.18), Grade 1 Radiation Morbidity Scoring Scheme (RESS) subcutaneous tissue toxicity (p = 0.18), Grade 1 RESS late skin toxicity (p = 0.88) and cosmetic results (p = 0.46). Dosimetric results reveled that patients in 5 fraction group received significantly lower median ipsilateral lung doses (p < 0.01) in addition to left breast cancer patients that received significantly lower median heart dose (p < 0.01) and median left anterior descending artery (LAD) dose (p < 0.01). Conclusion: Ultra-hypofractionated radiotherapy for breast cancer is comparable to moderate hypofractionation regimen regarding grade 1 acute skin toxicity, grade 1 subcutaneous tissue toxicity, late skin toxicity and cosmetic results. Application of ultra-hypofractionated radiotherapy with significantly lower radiation doses for lung and heart could be crucial in reducing the risk of acute/late pulmonary and heart radiation-induced toxicity.

Intensity-Modulated Radiotherapy (IMRT) following Conservative Surgery of the Supraglottic Region: Impact on Functional Outcomes.

Simple SummaryThe present study has been suggested by the previous experience of our group showing that patients treated with conventional radiotherapy (named 3D conformal radiotherapy—3D-CRT) performed after conservative surgery (CS) for tumors of the supraglottic regions experienced a high rate of severe long-term toxicity. Therefore, we reported the toxicity profile of a similar cohort of patients treated with a high-precision radiotherapy technique (named intensity-modulated radiotherapy—IMRT). Moreover, to investigate the advantage of IMRT, we performed a comparison with a historical cohort treated with 3D-CRT. Results showed that patients treated with IMRT achieved a very low toxicity profile and comparison with 3D-CRT was in favor of IMRTs. Therefore, we believe that the results of the present study provide preliminary findings on the potential of IMRT in improving the toxicity profile of patients treated with surgical organ preservation strategies for laryngeal tumors.The aim of the present study was to investigate the role of intensity-modulated radiotherapy (IMRT) on the toxicity profile of patients treated with conservative surgery (CS) of the supraglottic (SG) region. Data on patients treated with CS and postoperative radiotherapy (PORT)-IMRT were prospectively collected. Results. In total, 20 patients were analyzed. Of these, six patients (35%) required the positioning of a temporary tracheostomy. The functional larynx preservation rate was 95%. Females had a higher risk of both endoscopic intervention and chondronecrosis, while the median age was significantly higher in patients requiring enteral nutrition. The incidence of long-term severe toxicities was lower in patients treated with IMRT than in the historical 3D-CRT cohort. Patients who had received PORT-IMRT achieved a lower rate of permanent laryngeal and swallowing dysfunctions. Overall, results from the comparison with the historical 3D-CRT cohort favor the IMRTs.

An Italian survey on “palliative intent” radiotherapy

BackgroundThe aim of this paper is to provide a comprehensive overview of the scenario on radiotherapy (RT) delivered with palliative intent in Italy.Materials and methodsA structured online questionnaire was submitted to Italian radiation oncologists in order to explore the clinical practice in different areas of palliation, namely: bone, lung, brain, liver, and emergencies suitable to RT.Results209 radiation oncologists took part in the study. Stereotactic body irradiation was found to be the preferred technique in lung and liver metastases, whereas 3D conformal RT was registered as the technique of choice for bone and brain metastases. The majority (98%) of participants stated to treat mainly radiotherapy emergencies with 3D conformal RT at doses ranging from 25 to 50 Gy. Re-irradiation is delivered by the majority of respondents, whereas post-treatment follow-up is done only by 51.4% of them.ConclusionsThis nationwide study highlights some heterogeneity among Italian radiation oncologists regarding treatment and follow-up of metastatic cancer patients.

Secondary Malignancy Risk Following Proton vs. X-ray Radiotherapy of Thymic Epithelial Tumors: A Comparative Modeling Study of Thoracic Organ-Specific Cancer Risk.

Simple SummaryProton beam radiotherapy (PBT) offers the possibility to significantly reduce dose to surrounding organs at risk due to their physical advantages compared to X-ray based techniques. The aim of this analysis was to demonstrate whether PBT reduces secondary malignancy risks in patients with thymic malignancies compared to 3D conformal and intensity-modulated radiotherapy with photons. By using two different mechanistic calculation models we could demonstrate significant reductions of secondary malignancy risks with the use of PBT for all independent thoracic organs analyzed with the exception of the thyroid gland. This technology-driven improvement might translate into clinically relevant benefits for patients with thymic malignancies.Background: Proton beam radiotherapy (PBT) offers physical dose advantages that might reduce the risk for secondary malignancies (SM). The aim of the current study is to calculate the risk for SM after X-ray-based 3D conformal (3DCRT) radiotherapy, intensity-modulated radiotherapy (IMRT), and active pencil beam scanned proton therapy (PBS) in patients treated for thymic malignancies. Methods: Comparative treatment plans for each of the different treatment modalities were generated for 17 patients. The risk for radiation-induced SM was estimated using two distinct prediction models—the Dasu and the Schneider model. Results: The total and fatal SM risks estimated using the Dasu model demonstrated significant reductions with the use of PBS relative to both 3DCRT and IMRT for all independent thoracic organs analyzed with the exception of the thyroid gland (p ≤ 0.001). SM rates per 10,000 patients per year per Gy evaluated using the Schneider model also resulted in significant reductions with the use of PBS relative to 3DCRT and IMRT for the lungs, breasts, and esophagus (p ≤ 0.001). Conclusions: PBS achieved superior sparing of relevant OARs compared to 3DCRT and IMRT, leading to a lower risk for radiation-induced SM. PBS should therefore be considered in patients diagnosed with thymic malignancies, particularly young female patients.

Oncological outcomes of patients with salivary gland cancer treated with surgery and postoperative intensity-modulated radiotherapy: a retrospective cohort study.

Salivary gland cancer (SGC) is relatively rare and constitutes a variety of histological subtypes. Previously published studies of SGC patients suggest that postoperative radiation using conventional radiotherapy (RT) or 3-dimensional (3D) conformal radiotherapy may have led to suboptimal oncological outcomes. We identified 60 patients with major SGC treated with surgery followed by postoperative intensity-modulated radiotherapy (IMRT). Data for overall survival (OS), progression-free survival (PFS), locoregional relapse-free survival (LRRFS), distant metastasis-free survival (DMFS), prognostic factors, and treatment-related toxicities were analyzed. Survival was analyzed using the Kaplan-Meier method and compared using the log-rank test. With a median follow-up of 55.5 months, based on Kaplan-Meier analyses, the OS and PFS rates for SGC patients at 3, 5, and 10 years were 90.7%, 85.1%, and 85.1% and 80.1%, 72.7%, and 63.1%, respectively. The LRRFS and DMFS rates at 3, 5, and 10 years were 87.4%, 82.1%, and 82.1% and 85.3%, 78.4%, and 66.1%, respectively. In multivariable analysis (MVA), the node stage (N stage) was an independent predictor of PFS [P=0.047; hazard ratio (HR) =0.089]. A positive margin was a significant prognostic factor for PFS (P=0.036; HR =4.086), LRRFS (P=0.026; HR =5.064), and DMFS (P=0.011; HR =6.367). Major nerve involvement was significantly correlated with PFS (P=0.034; HR =2.394) and DMFS (P=0.008; HR =2.115). The interval from surgery to radiotherapy predicted PFS (P=0.036; HR =3.934) and DMFS (P=0.012; HR =6.231). Adenoid cystic carcinoma (ACC) was the most common histology (n=21; 35%). For ACC, the 5-year OS, PFS, LRRFS, and DMFS were 100%, 67.7%, 76.2%, and 90.2%, respectively. The most common acute toxicities were mucositis and dermatitis, and xerostomia was the most common late adverse event. Lung metastasis was the most common pattern of distant failure. N stage, positive margin, major nerve involvement, and interval from surgery to radiotherapy were important factors associated with PFS, LRRFS, and DMFS. Postoperative IMRT leads to improved survival for SGC patients, with acceptable toxicities.

Re-Irradiation of Recurrent Nasopharyngeal Cancer: A 4-year Follow-up Study of Treatment using 3-Dimensional Conformal Radiotherapy

Introduction: Nasopharyngeal cancer (NPC) is a prevalent diagnosis of head and neck cancers (HNC) in Asia. In Indonesia, it is estimated that there are 12,000 new cases per year. Case Presentation: The author reports a 25-year-old male patient with recurrent NPC. This patient was first diagnosed with NPC stage IVB in 2013 and was treated by chemoradiation. In 2016, he found another mass in his neck. The biopsy result showed the recurrence of the NPC with histopathology of Undifferentiated carcinoma (WHO type III). Re-irradiation was planned, and the patient subsequently received 3D-Conformal Radiotherapy (3D-CRT) at our department. Four years after the completion of re-irradiation, the patient was alive and well with no signs of recurrence but still complained about late toxicities like trismus and fibrotic neck. Conclusions: In this study, we discuss the use of 3D-CRT in the re-irradiation of NPC with its limitation on obtaining optimum dose sculpture compared to more sophisticated and widely spread modalities like intensity-modulated radiotherapy (IMRT). However, with careful planning, we can still obtain optimum tumor dose, minimize organs at-risk (OAR) dose, and subsequently late toxicities that come after. We hope that this study can bring hope to centers with limited facilities, and we suggest further studies on re-irradiation, especially in OAR dose tolerance guidelines.