Intensity-modulated Radiotherapy Group Research Articles

Treatment Related Acute Toxicities Between Treatment with 3D-CRT and IMRT in Localised Prostate Cancer.

To compare the acute toxicities of two radiation treatment techniques, intensity modulated radiation therapy (IMRT), and 3-dimensional conformal radiation therapy (3D-CRT) in localised prostate adenocarcinoma. Descriptive study. Place and Duration of the Study:Department of Oncology, Dr. Ziauddin Hospital, Karachi, Pakistan, from July 2016 to June 2022. Patients with localised prostate adenocarcinoma who underwent treatment using two different advanced radiotherapy techniques i.e., IMRT and 3D-CRT were recruited during the study period. They were followed up for six months for acute gastrointestinal (GI) and genitourinary (GU) adverse events (acute toxicities) related to both treatment modalities according to Modified radiation therapy oncology group (RTOG) criteria. The acute toxicities were assessed at the 2nd, 4th, and 6th week during treatment and at the 3rd and 6th month after treatment. There were 78 patients, with 39 patients in each group. The mean age was 68 ± 10 years in the 3D-CRT and 68 ± 07 years in the IMRT group. Patients in the IMRT group exhibited markedly lower treatment-related acute GI and GU effects at the end of 4th and 6th weeks for anorectal pain (p = 0.04) and (p = 0.01) and burning micturition (p = 0.003) and (p = 0.01), respectively. Furthermore, at 3 months anorectal pain (p = 0.02), loose stools (p = 0.005), and burning micturition (p = 0.01) were present and at 6 months anorectal pain was (p = 0.01) still present. Radiation therapy modalities 3D-CRT and IMRT both showed acceptable toxicity profile in the management of localised prostate cancer, while IMRT group exhibited significantly lower treatment-related acute GI and GU effects. 3D-CRT (3-Dimensional Conformal Radiation Therapy), IMRT (Intensity-Modulated Radiation Therapy), Radiation toxicity.

Comparison of Thyroid Toxicity Profiles in Head and Neck Cancer Patients Irradiated by 3D-Conformal Radiation Therapy and Intensity-Modulated Radiation Therapy

ABSTRACT Background: In spite of recent technical advances in the radiation field, exposure to non-target organs such as the thyroid gland remains unavoidable in locally advanced head and neck cancer (LAHNC) planning, which is associated with late toxicities, and this may affect the lifestyle of cancer survivors. Aim: The purpose of this study was to estimate the incidence of thyroid toxicity in LAHNC patients treated with three-dimensional conformal radiotherapy (3D-CRT) and intensity-modulated radiotherapy (IMRT). To establish its correlation, we have analyzed thyroid profile levels, DVH, and the doses of radiation received by the thyroid volume in both radiotherapy planning methods. Material and Method: Sixty patients with LAHNC enrolled and were divided into two groups treated with 3D-CRT (group A) and IMRT (group B). The patient’s thyroid function test, which consisted of serumT3, T4, and TSH, was done before starting radiotherapy and at 6 months and 12 months follow-up. Absolute thyroid volume, maximum dose, minimum dose, mean dose to the thyroid gland, and percentage of thyroid volume receiving as V10, V20, V30, V40, and V50 were studied. Results: After 6-month post-RT, 6.7% of patients in group A showed biochemical hypothyroidism, whereas biochemical hypothyroidism, sub-clinical hypothyroidism, and hyperthyroidism were observed in 10%, 3.3%, and 10% patients of group B, respectively. After 12 months post-RT, 23.3% of patients in group A showed hypothyroidism. In the 3DCRT group, mean T3 was significantly higher for patients with no hypothyroidism (P < 0.05). Mean T4 was observed to be significantly lower in both the groups in hypothyroid patients (P < 0.05). Mean TSH was significantly higher for hypothyroid patients in the IMRT group (P > 0.01). The difference in thyroid volume and thyroid dose was observed to be statistically significant (P < 0.05). Conclusion: The incidence of thyroid toxicity may be decreased by sparing the volume of the thyroid gland and the thyroid dose kept to a minimum. As per dosimetric parameters, >V40 may predict the risk of developing hypothyroidism after irradiation in LAHNC patients. We recommend regular thyroid function tests on follow-up visits of irradiated patients of LAHNC.

Intensity-modulated radiotherapy alone compared with intensity-modulated radiotherapy plus concurrent chemotherapy in intermediate-risk nasopharyngeal carcinoma : Aprospective multicenter phaseII trial.

This study aimed to investigate the clinical benefit of adding concurrent chemotherapy to intensity-modulated radiotherapy (IMRT) for nasopharyngeal carcinoma (NPC) patients with an intermediate risk (stageII and T3N0M0). Amulticenter phaseII randomized trial was conducted in intermediate-risk NPC patients. Enrolled patients were previously untreated and aged ranged from 18 to 70years without severe coexisting diseases. Patients were randomly assigned to receive IMRT alone or IMRT+concurrent chemotherapy (CC; three cycles of 80 mg/m2 cisplatin every 3weeks). Primary endpoint was defined as 3‑year progression-free survival (PFS). The secondary endpoints were distant metastasis-free survival (DMFS), locoregional relapse-free survival (LRRFS), overall survival (OS), and treatment-associated toxicity. We registered this study with Chinese Clinical Trial Registry (CliCTR1800017132; registered July13, 2018, study start July13, 2018). From November 2015 to July 2019, 42patients with stageII and T3N0M0 NPC were enrolled; 20patients received IMRT alone while 22patients received IMRT+CC. After amedian of 58months of follow-up, we estimated the 3‑year PFS rates as 90% (IMRT group) and 86.4% (IMRT+CC group; hazard ratio 1.387, 95% confidence interval 0.240-8.014; P = 0.719). The 3‑year PFS, OS, and cumulative DMFS and LRRFS showed no significant differences between the two groups (P > 0.05). However, the IMRT group displayed alower incidence of nausea/vomiting, leucopenia, and dry mouth than the IMRT+CC group. Adding CC to IMRT provided no survival benefit but increased treatment-associated toxicities in patients with intermediate-risk NPC.

PD-1 inhibition combined with intensity-modulated radiotherapy, to better serve patients with retroperitoneal lymph node metastases from gastrointestinal cancer.

Gastrointestinal (GI) cancer is the most frequent kind of cancer to involve the retroperitoneal lymph nodes (RPLNs). Radiotherapy (RT) is common treatment of RPLN metastases in patients with GI cancer, while RT is local. Meanwhile, most patients have extra-retroperitoneal metastases. Immunotherapy plus RT have showed effective in advanced non-small cell lung cancer. However, whether the combination therapy is effective on GI cancer with RPLN metastases. In our study, we would estimate the effect of programmed death-1 (PD-1) inhibition in association with intensity modulated radiation therapy (IMRT). Metastatic GI cancer patients with RPLN who were treated at a single institution were retrospectively evaluated from October 2016 to April 2023, who all had measurable lesion and received any therapy of PD-1 inhibitors alone, IMRT alone or PD-1 inhibitors plus IMRT. The follow-ups were assessed by abdominal computed tomography (CT) every 2 or 3 months to progression, dose-limiting toxicity or death. Among the 98 patients, 46 were treated by PD-1 inhibitors combined with IMRT, 26 were by PD-1 inhibitors only and 26 were by IMRT only. Of those, the median age 62 years (range, 25-84 years). Median progression-free survival (PFS) was 7.5 months and median overall survival (OS) was 10.8 months across the 3 therapy groups. Univariate analysis (UVA) indicated that therapy method (P=0.032) and tumor response (P=0.035) were significantly related to PFS. In the PD-1 inhibitors plus IMRT group, 1 patient (2.2%) achieved complete response (CR), 30 (65.2%) had partial remission, and 14 (30.4%) had stable disease. There was no case with CR by IMRT or PD-1 inhibitors alone. Objective response rate (67.4%) and disease control rate (97.8%) were higher in the PD-1 inhibitors combined with IMRT group. In the PD-1 inhibitors plus IMRT and PD-1 inhibitors alone groups, hepatitis B virus (HBV)-positive patients had better OS (P=0.041) on UVA. Meanwhile, in the PD-1 inhibitors plus IMRT group, we observed superior PFS (P=0.041) and OS (P=0.049) in HBV-positive patients on UVA. PD-1 inhibitors plus IMRT may be a better method for advanced GI cancer patients with RPLN metastases. HBV-positive patients can benefit from either PD-1 inhibitors alone or in combination with IMRT.

Acute hospitalizations after proton therapy versus intensity-modulated radiotherapy for locally advanced non-small cell lung cancer in the durvalumab era.

It was hypothesized that use of proton beam therapy (PBT) in patients with locally advanced non-small cell lung cancer treated with concurrent chemoradiation and consolidative immune checkpoint inhibition is associated with fewer unplanned hospitalizations compared with intensity-modulated radiotherapy (IMRT). Patients with locally advanced non-small cell lung cancer treated between October 2017 and December 2021 with concurrent chemoradiation with eitherIMRT or PBT ± consolidative immune checkpoint inhibition were retrospectively identified. Logistic regression was used to assess the association of radiation therapy technique with 90-day hospitalization and grade 3 (G3+) lymphopenia. Competing risk regression was used to compare G3+ pneumonitis, G3+ esophagitis, and G3+ cardiac events. Kaplan-Meier method was used for progression-free survival and overall survival. Inverse probability treatment weighting was applied to adjust for differences in PBT and IMRT groups. Of 316 patients, 117 (37%) received PBT and 199 (63%) received IMRT. The PBT group was older (p<.001) and had higher Charlson Comorbidity Index scores (p=.02). The PBT group received a lower mean heart dose (p<.0001), left anterior descending artery V15Gy (p=.001), mean lung dose (p=.008), and effective dose to immune circulating cells (p<.001). On inverse probability treatment weighting analysis, PBT was associated with fewer unplanned hospitalizations (adjusted odds ratio, 0.55; 95% CI, 0.38-0.81; p=.002) and less G3+ lymphopenia (adjusted odds ratio, 0.55; 95% CI, 0.37-0.81; p=.003). There was no difference in other G3+ toxicities, progression-free survival, or overall survival. PBT is associated with fewer unplanned hospitalizations, lower effective dose to immune circulating cells and less G3+ lymphopenia compared with IMRT. Minimizing dose to lymphocytes may be warranted, but prospective data are needed.

Does intensity-modulated radiation therapy by helical tomotherapy for prostate cancer increase the subsequent risk of bladder cancer? A propensity score-matched analysis.

This study aimed to evaluate the risk of bladder cancer after intensity-modulated radiation therapy (IMRT) using helical tomotherapy for prostate cancer in comparison to the risk post-radical prostatectomy (RP) using propensity score-matched analysis and to assess the risk factors for bladder cancer. This retrospective study included 2067 patients with non-metastatic prostate cancer treated at our institution between June 2007 and December 2016. Of these, 1547 patients were treated with IMRT and 520 underwent RP. The propensity scores were calculated using age, National Comprehensive Cancer Network risk classification, prostate volume, Brinkman index, and follow-up time as matched covariates. A propensity score-matched patient cohort (n = 718; IMRT: 359, RP: 359) was created, and the risk of bladder cancer after treatment was compared. In total, bladder cancer was detected in 33 patients. Five patients in the IMRT group and one in the RP group died of bladder cancer. In the propensity score-matched analysis, the 5-year bladder cancer-free survival rate was significantly lower in the IMRT group than in the RP group (91.7% and 96.2%, respectively; p < 0.001). Multivariate analysis revealed that IMRT and the Brinkman index were the risk factors for bladder cancer in this cohort (odds ratio = 5.085, 95% confidence interval = 1.436-18.008, p = 0.012 and odds ratio = 1.001, 95% confidence interval = 1.000-1.001, p = 0.010, respectively). IMRT for prostate cancer using helical tomotherapy increases the subsequent risk of bladder cancer compared with RP and is an independent risk factor for bladder cancer similar to smoking.

A pooled patient-reported outcomes analysis of moderately hypofractionated proton beam therapy and photon-based intensity modulated radiation therapy for low- or intermediate-risk prostate cancer.

We sought to characterize and compare late patient-reported outcomes (PROs) after moderately hypofractionated intensity modulated radiation therapy (IMRT) and proton beam therapy (PBT) for localized prostate cancer (PC). This multi-institutional analysis included low- or intermediate-risk group PC patients treated with moderately hypofractionated radiation to an intact prostate stratified by treatment modality: IMRT or PBT. The primary outcomes were prospectively collected patient-reported late gastrointestinal (GI) and genitourinary (GU) toxicity assessed by International Prostate Symptom Score (IPSS) and Expanded PC Index Composite (EPIC). Multivariable regression analysis (MVA) controlling for age, race, and risk group tested the effect of time, treatment, and their interaction. 287 IMRT and 485 PBT patients were included. Intermediate risk group (81.2 vs. 68.2%; p < 0.001) and median age at diagnosis (70 vs. 67 years; p < 0.001) were higher in the IMRT group. On MVA, there was no significant difference between modalities. PBT IPSS did not differ from IMRT IPSS at 12 months (odds ratio [OR], 1.19; p = 0.08) or 24 months (OR, 0.99; p = 0.94). PBT EPIC overall GI function at 12 months (OR, 3.68; p = 0.085) and 24 months (OR 2.78; p = 0.26) did not differ from IMRT EPIC overall GI function. At 24 months, urinary frequency was no different between PBT and IMRT groups (OR 0.35; p = 0.096). This multi-institutional analysis of low- or intermediate-risk PC treated with moderately hypofractionated PBT and IMRT demonstrated low rates of late patient-reported GI and GU toxicities. After covariate adjustment, late GI and GU PROs were not significantly different between PBT or IMRT cohorts.

A comparison of the incidence of ≥ grade 2 radiation pneumonitis between intensity-modulated radiotherapy and three-dimensional conformal radiotherapy in patients with unresectable non-small cell lung cancer treated with durvalumab after concurrent chemoradiotherapy.

Intensity-modulated radiation therapy (IMRT) has been increasingly used as a new radiation modality for unresectable non-small cell lung cancer (NSCLC). The risk factors for radiation pneumonitis (RP) during consolidation durvalumab following concurrent chemoradiotherapy (CCRT) using IMRT have not been thoroughly investigated. This retrospective study analyzed medical record data from consecutive patients diagnosed with NSCLC who underwent CCRT and consolidation durvalumab at our institution between April 2018 and September 2022. Since we adopted IMRT for the treatment of NSCLC in April 2020, these patients were categorized into two groups: those treated with IMRT after April 2020 and those treated with three-dimensional conformal radiotherapy (3D-CRT) before April 2020. A total of 31 patients underwent IMRT (the IMRT group), while 25 patients underwent 3D-CRT (the 3D-CRT group). In both groups, the total dose was 60Gy in 30 fractions. The cumulative incidence of ≥ grade 2 RP at 12months was significantly lower in the IMRT group than in the 3D-CRT group (27.0% vs. 64.0%, hazard ratio [HR]: 0.338, 95% confidence interval [CI]: 0.144-0.793, p=0.013). In the multivariable analysis, V20 (≥ 25.6%, HR: 2.706, 95% CI: 1.168-6.269, p=0.020) and radiotherapy technique (IMRT, HR: 0.414, 95% CI: 0.172-0.994, p=0.048) were identified as significant risk factors for ≥ grade 2 RP. IMRT is associated with a lower rate of ≥ grade 2 RP in patients with NSCLC who received CCRT followed by durvalumab.

Combination treatment of transcatheter arterial chemoembolization, intensity-modulated radiotherapy, and sorafenib for hepatocellular carcinoma with macrovascular invasion.

This study evaluated the therapeutic effects and toxic reactions of combining transcatheter arterial chemoembolization (TACE) and intensity-modulated radiotherapy (IMRT) with sorafenib for the treatment of advanced hepatocellular carcinoma (HCC) patients with macrovascular invasion (MVI). We retrospectively analyzed the clinical data of 82 HCC patients with MVI, among whom 35 were treated with TACE plus IMRT alone, and 47 were treated with the combined therapy of TACE, IMRT, and sorafenib. The progression-free survival (PFS), overall survival (OS), and adverse events were assessed. The baseline characteristics were comparable between the 2 groups (all P > .05). In the TACE plus IMRT plus sorafenib group, the median PFS was 17.2 months (95% confidence interval, 14.1-19.9), significantly longer than the 9.4 months (95% confidence interval, 6.8-11.2) observed in the TACE plus IMRT group (P < .001). Additionally, patients treated with the TACE plus IMRT plus sorafenib showed a longer median OS than those treated with TACE plus IMRT alone (24.1 vs 17.3 months; P < .001). The occurrence rates of grade 1 to 2 hand-foot syndrome, other skin reactions, diarrhea, and hair loss were higher in the TACE plus IMRT plus sorafenib group (all P < .05). There were no grade 4 or higher adverse events in either group. The combination of TACE plus IMRT with sorafenib provided substantial clinical benefits in the treatment of HCC patients with MVI, increasing the tumor response rate and prolonging both PFS and OS. This approach demonstrated a tolerable and manageable safety profile.

Clinical Efficacy and Complications of Intensity-modulated Radiation Therapy in Patients With Oropharyngeal Carcinoma: Especially Focus On Osteoradionecrosis

We explored the relative clinical efficacy of intensity-modulated radiation therapy (IMRT) in patients with oropharyngeal cancer (OPC) compared with three-dimensional conformal radiation therapy (3D-CRT). Seventy-four OPC patients treated with definitive IMRT or 3D-CRT between May 2010 and December 2018 were analyzed. Of these, 42 patients were treated with IMRT and 32 with 3D-CRT. We compared clinical benefits and complications. Particular attention was focused on osteoradionecrosis (ORN), which is the most problematic radiation late adverse event, and evaluated the irradiated mandibular volumes. There was no significant difference in the 3-year overall survival (OS), progression free survival (PFS) and locoregional control (LRC) rates between the two groups. However, late Grade 2 xerostomia was lower in the IMRT groups. Four patients (19.0%) developed Grade 3, while no patients developed ORN in the IMRT group (P = 0.003). A comparison of the mandible volumes between the two groups showed that the IMRT group had lower mandibular volumes than the 3D-CRT group in the high-dose range of V40, V50, V60 and V70. In addition, a comparison of the mandibular volumes between ORN and non-ORN showed a significant difference in the V60 and V70. ORN incidence was higher in V60 ≥ 25% and V70 ≥ 15%. A comparison of IMRT and 3D-CRT showed no significant difference in outcomes, however, IMRT led to a significant reduction in late xerostomia and ORN in OPC patients. Reducing of the mandibular V60 and V70 by IMRT seemed to reduce the risk of ORN.

The Outcomes of Intensity Modulated Radiotherapy versus Conventional 2D Radiotherapy in Patients with Oropharyngeal or Hypopharyngeal Squamous Cell Carcinoma. A Case-Control Study

"Introduction: Head and neck cancers’ radiotherapy (RT) is challenging due to the irregular target volumes and the proximity of multiple organs at risk. The purpose of this study is to compare the toxicity, loco-regional control and the pattern of tumour recurrence after intensity modulated radiotherapy (IMRT) or conventional 2D radiotherapy (2D CRT) in patients with squamous cell carcinoma (SCC) oropharyngeal or hypopharyngeal cancers. Material and method: We retrospectively compared the outcomes of SCC oropharyngeal or hypopharyngeal cases treated by IMRT or 2D CRT from 1998 to 2010 in a Canadian Academic Hospital. We matched the patients in the two groups according to primary tumour location and clinical stage. The information on treatment, toxicity and outcomes was retrieved from patients’ medical records. For the patients having a recurrence after IMRT, the CT scan at relapse was fused with the planning CT. For the patients recurring after 2D CRT, we matched the CT images with the relative position of the radiotherapy fields. Statistical analysis was made using GraphPad Prism software. Results: We included a total of 50 patients in the IMRT group and 50 in the 2D CRT group. The median age was 62 and 58 years, respectively, and the median follow-up was 18 and 22.6 months, respectively. Some of the side effects were less frequent on the IMRT group compared to the 2D CRT: xerostomia (16% vs 64%, P=0.0036), mucositis (70% vs 74% P=0.5451), weight loss (18% vs 46% P= 0.0027), radionecrosis/mandibular fracture (0 % vs 2%), fibrosis (0% vs 10%), and telangiectasia (0% vs 4%). However, acute dermatitis and late dysphagia were more frequent in the IMRT group (44% vs 28% P=0.0042; and 14% vs 2% P=0.028; respectively). The overall survival at 2 years was for 74.03% for IMRT and 60% for 2D CRT (P&lt; 0.001) and the 5 years actuarial locoregional control was 89.54 % for IMRT group, and 62.48% for the 2DCRT group (P&lt; 0.001). Three patients from the IMRT group had a local recurrence (2 in-field and 1 marginal), while in the 2D-CRT group, there were 10 patients with a local recurrence (6 in-field and 4 marginal). Conclusion: SCC oropharyngeal and hypopharyngeal patients treated with IMRT and concurrent cisplatin had better outcomes and fewer side effects, when compared to similar cases treated with 2D CRT. The local recurrence had a similar pattern for both techniques."

Proton Beam Therapy (PBT) Versus Intensity-Modulated Radiotherapy (IMRT) for Locally Advanced Non-Small Cell Lung Cancer (LA-NSCLC) in the Era of Immune Checkpoint Inhibitor (ICI) Consolidation: A Retrospective Cohort Study

Patients (pts) with LA-NSCLC treated with concurrent chemoradiation (cCRT) and ICI consolidation are at high risk for treatment-related toxicities and subsequent hospitalization. We hypothesized that PBT is associated with a reduction in acute unplanned hospitalizations as compared to IMRT in the era of ICI consolidation. This single institution, multi-site retrospective study included consecutive pts with LA-NSCLC treated with definitive cCRT with either PBT or IMRT from October 2017 to December 2021. Pts were evaluated for consolidative ICI. Primary endpoint was unplanned treatment-related hospitalization within 90 days of first radiation (RT) treatment. Secondary endpoints included grade 3+ pneumonitis, grade 3+ esophagitis, PFS and OS. Logistic regression was used to assess associations with 90-day hospitalization. Competing risk regression was used for grade 3+ pneumonitis and esophagitis, and Cox regression for PFS and OS. A total of 316 pts were included: 117 (37%) received PBT and 199 (63%) IMRT. Median age was 68.5 yrs; median RT dose 66.6 Gy (IQR 65.9-70.0). PBT group was older (median 71.1 vs 67.2 yrs, p<0.005) and had a higher Charlson comorbidity index (CCI) (median 4 vs 3, p = 0.02). There was no significant difference in ECOG, smoking pack-years, T stage, N stage, target volume size, or receipt of ICI consolidation (66.7% vs 68.3%, p = 0.76). PBT group had lower mean heart dose (5.9 vs 10.8 Gy, p<0.001), LAD V15 (0 vs 6 %, p = 0.001), mean lung dose (14.7 vs 15.7 Gy, p <0.008) and effective dose to immune circulating cells (median 3.7 vs 4.9 Gy, p<0.001) but not mean esophagus dose. PBT was associated with fewer unplanned 90-day hospitalizations (23.9% vs 34.7%); which persisted on multivariable analysis (OR 0.52, 95% CI 0.30-0.90, p = 0.02) after adjusting for CCI, smoking pack-years, T4 tumors and target volume. Reasons for hospitalization in PBT and IMRT groups included progression (1.7% vs 1.5%), definite/probable toxicity from cCRT (11.1% vs 18.6%), possible toxicity from cCRT (7.7% vs 12.6%) or unrelated to cCRT (3.4% vs 2.0%). There was no significant difference between PBT or IMRT groups in G3+ pneumonitis (1-year 6.0% vs 9.1%, p = 0.49), G3+ esophagitis (1-year 6.0% vs 6.5%, p = 0.71), PFS (median 14.4 vs 15.1 months, p = 0.69), or OS (median 34.2 vs 29.4 months, p = 0.41). Among pts with LA-NSCLC treated with cCRT in the era of ICI consolidation, PBT was associated with fewer acute unplanned hospitalizations compared to IMRT. There was no difference in G3+ pneumonitis, G3+ esophagitis, PFS or OS.

[Analysis of risk factors of radiation-induced toxicity in limited-stage small cell lung cancer treated with hypofractionated intensity-modulated radiotherapy].

Objective: To compare the incidence of radiation-related toxicities between conventional and hypofractionated intensity-modulated radiation therapy (IMRT) for limited-stage small cell lung cancer (SCLC), and to explore the risk factors of hypofractionated radiotherapy-induced toxicities. Methods: Data were retrospectively collected from consecutive limited-stage SCLC patients treated with definitive concurrent chemoradiotherapy in Cancer Hospital of Chinese Academy of Medical Sciences from March 2016 to April 2022. The enrolled patients were divided into two groups according to radiation fractionated regimens. Common Terminology Criteria for Adverse Events (CTCAE, version 5.0) was used to evaluate the grade of radiation esophagus injuries and lung injuries. Logistic regression analyses were used to identify factors associated with radiation-related toxicities in the hypofractionated radiotherapy group. Results: Among 211 enrolled patients, 108 cases underwent conventional IMRT and 103 patients received hypofractionated IMRT. The cumulative incidences of acute esophagitis grade ≥2 [38.9% (42/108) vs 35.0% (36/103), P=0.895] and grade ≥ 3 [1.9% (2/108) vs 5.8% (6/103), P=0.132] were similar between conventional and hypofractionated IMRT group. Late esophagus injuries grade ≥2 occurred in one patient in either group. No differences in the cumulative incidence of acute pneumonitis grade ≥2[12.0% (13/108) vs 5.8% (6/103), P=0.172] and late lung injuries grade ≥2[5.6% (6/108) vs 10.7% (11/103), P=0.277] were observed. There was no grade ≥3 lung injuries occurred in either group. Using multiple regression analysis, mean esophageal dose ≥13 Gy (OR=3.33, 95% CI: 1.23-9.01, P=0.018) and the overlapping volume between planning target volume (PTV) and esophageal ≥8 cm(3)(OR=3.99, 95% CI: 1.24-12.79, P=0.020) were identified as the independent risk factors associated with acute esophagitis grade ≥2 in the hypofractionated radiotherapy group. Acute pneumonitis grade ≥2 was correlated with presence of chronic obstructive pulmonary disease (COPD, P=0.025). Late lung injuries grade ≥2 was correlated with tumor location(P=0.036). Conclusions: Hypofractionated IMRT are tolerated with manageable toxicities for limited-stage SCLC patients treated with IMRT. Mean esophageal dose and the overlapping volume between PTV and esophageal are independently predictive factors of acute esophagitis grade ≥2, and COPD and tumor location are valuable factors of lung injuries for limited-stage SCLC patients receiving hyofractionated radiotherapy. Prospective studies are needed to confirm these results.

Clinical treatment considerations in the intensity-modulated radiotherapy era for parotid lymph node metastasis in patients with nasopharyngeal carcinoma

PurposeNo specific irradiation guidelines have been proposed for parotid lymph node (PLN) metastasis in patients with nasopharyngeal carcinoma (NPC). This study aimed to explore the dose prescription and target delineation for PLN metastasis in patients with NPC. MethodsWith the NPC database from a big-data platform, 10,685 patients with primarily diagnosed, non-distant metastatic, histologically proven NPC and treated with intensity modulated radiotherapy (IMRT) at our center from 2008 to 2019 were reviewed and those with PLN metastasis were enrolled in this study. Dosimetry parameters were collected from the dose-volume histograms (DVH). The primary endpoint was overall survival (OS). Least absolute shrinkage and selection operator regression (LASSO) was operated for variable selection. Multivariate Cox regression analysis was applied to identify the independent prognostic factors. ResultsPLN metastases were identified in 275/10685 (2.5%) patients. Of 367 positive PLN, 199 were in superficial intra-parotid, followed by 70 in deep intra-parotid, 54 in subparotid and 44 in subcutaneous pre-auricular. Better survival outcome was observed in PLN-radical IMRT group, compared with PLN-sparing group. In 190 patients received PLN-radical IMRT, multivariate analysis revealed that D95% of level VIII > 55 Gy was an independent beneficial prognostic factor for overall survival (OS), progression-free survival (PFS), distant metastasis-free survival (DMFS), and parotid relapse-free survival (PRFS). ConclusionBased on the distribution pattern of PLN metastasis in NPC and the result of dose-finding study, involving the ipsilateral level VIII into low-risk clinical target volume (CTV2) is recommended for NPC with PLN metastasis.

Acute hospitalizations after proton beam therapy (PBT) versus intensity-modulated radiotherapy (IMRT) for locally advanced non–small-cell lung cancer (LA-NSCLC) in the era of immune checkpoint inhibitor (ICI) consolidation: A retrospective propensity score weighted study.

8573 Background: Prior work found that PBT is associated with fewer acute hospitalizations compared to photons for a variety of cancers. Patients (pts) with LA-NSCLC treated with concurrent chemoradiation (cCRT) and ICI consolidation are at high risk for treatment-related toxicity and acute hospitalizations. We hypothesized that PBT is associated with fewer acute unplanned hospitalizations as compared to IMRT in the era of ICI consolidation. Methods: This single institution, multi-site retrospective study included consecutive pts with LA-NSCLC treated with definitive cCRT with either PBT or IMRT from October 2017 to December 2021. Pts were evaluated for consolidative ICI. Primary endpoint was unplanned hospitalization within 90 days of first radiation (RT) treatment. Secondary endpoints included grade 3+ pneumonitis, grade 3+ esophagitis, PFS, and OS. Logistic regression was used to assess associations with 90-day hospitalization. Competing risk regression was used for grade 3+ pneumonitis and esophagitis and Cox regression for PFS and OS. Inverse probability treatment weighting (IPTW) was applied to adjust for differences in PBT and IMRT groups. Results: 316 pts were included: 117 (37%) received PBT and 199 (63%) IMRT. Median age was 68.5 yrs; median RT dose 66.6 Gy (IQR 65.9-70.0). PBT group was older (median 71.1 vs 67.2 yrs, p &lt; 0.005) and had a higher Charlson comorbidity index (CCI) (median 4 vs 3, p = 0.02). There was no difference in receipt of ICI consolidation (66.7% vs 68.3%, p = 0.76). PBT group had lower mean heart dose (5.9 vs 10.8 Gy, p &lt; 0.001), LAD V15 (0 vs 6%, p = 0.001), mean lung dose (14.7 vs 15.7 Gy, p &lt; 0.008) and effective dose to immune circulating cells (median 3.7 vs 4.9 Gy, p &lt; 0.001) but not mean esophagus dose. PBT was associated with fewer unplanned 90-day hospitalizations (23.9% vs 34.7%; aOR 0.52, 95% CI 0.30-0.90, p = 0.02). This difference persisted on IPTW analysis (OR 0.48, 95% 0.33-0.70, p = 0.0002) after adjusting for CCI, ECOG, smoking pack yrs, T stage, N stage, target volume, concurrent chemotherapy agent and histology. Reasons for hospitalization in PBT and IMRT groups included progression (1.4% vs 1.6%), definite/probable toxicity from cCRT (11.4% vs 18.2%), possible toxicity from cCRT (7.3% vs 12.8%) or unrelated to cCRT (2.5% vs 2.3%). There was no significant difference between PBT and IMRT groups in G3+ pneumonitis (1-year 6.0% vs 9.1%, p = 0.49), G3+ esophagitis (1-year 6.0% vs 6.5%, p = 0.71), PFS (median 14.4 vs 15.1 months, p = 0.69), or OS (median 34.2 vs 29.4 months, p = 0.41); results remained unchanged in IPTW analysis. Conclusions: Among pts with LA-NSCLC treated with cCRT in the era of ICI consolidation, PBT was associated with fewer acute unplanned hospitalizations compared to IMRT.

Clinicopathologic characteristics of second primary squamous cell carcinoma in patients with nasopharyngeal carcinoma after intensity-modulated radiotherapy

To compare the clinicopathologic characteristics of second primary squamous cell carcinoma (SPSCC) in patients with nasopharyngeal carcinoma (NPC) after intensity-modulated radiotherapy (IMRT) with that after radiotherapy (RT). From 49,021 patients with NPC who treated by definitive RT, we were able to identify 15 male patients with SPSCC after IMRT, and 23 male patients with SPSCC after RT. We examined the difference between groups. In IMRT group, 50.33% developed SPSCC within 3 years, whereas 56.52% developed SPSCC after more than 10 years in RT group. Receiving IMRT was related positively to an increased risk of SPSCC (HR = 4.25; P < 0.001). There was no significant correlation between receiving IMRT and the survival of SPSCC (P = 0.051). Receiving IMRT was related positively to an increased risk of SPSCC, and the latency was much shorter. A follow-up protocol, especially in the first three years, should be designed for NPC patients with IMRT.

Dosimetric Comparison of Hypofractionated Regimen in Breast Cancer Using Two Different Techniques: Intensity-Modulated Radiation Therapy (IMRT) and Volumetric-Modulated Arc Therapy (VMAT).

Breast cancer treated with adjuvant hypofractionation radiotherapy with two different techniques, i.e., volumetric-modulated arc therapy (VMAT) and intensity-modulated radiation therapy (IMRT) and their effects in terms of loco-regional control and adverse effects in terms of cutaneous, pulmonary, and cardiac outcomes are compared. This is a prospective non-randomized observational study. VMAT and IMRT plan for 30 breast cancer patients who were supposed to receive adjuvant radiotherapy were prepared using a hypofractionation schedule. The plans were dosimetrically evaluated. Dosimetric comparative analysis of IMRT and VMAT in hypofractionated radiotherapy in breast cancer is done and tested whether VMAT has a dosimetric advantage over IMRT. These patients were recruited for a clinical assessment of toxicities. They were followed up for at least three months. On dosimetric analysis, planning target volume (PTV) coverage (PTV_ V95) of both VMAT (96.41 ± 1.31) and IMRT (96.63 ± 1.56) were similar with significantly lower monitor units required with VMAT plans (1,084.36 ± 270.82 vs 1,181.55 ± 244.50, p = 0.043). Clinically, all patients tolerated hypofractionation through VMAT (n = 8) and IMRT (n = 8) satisfactorily in the short term. No cardiotoxicity or appreciable falls in pulmonary function test parameters were observed. Acute radiation dermatitis poses challenges similar to standard fractionation or any other delivery technique. PVT dose, homogeneity, and conformity indices were similar in both VMAT and IMRT groups. In VMAT, there was high-dose sparing of some critical organs like the heart and lungs at the cost of the low-dose baths to these organs. Increased risk of secondary cancer will require a decade-long follow-up study to indict the VMAT technique. As we move toward precision in oncology, "one-size-fits-all" can never be an acceptable dictum. Each patient is unique and therefore we must offer, and the patient must "choose wisely."

Comparative evaluation of oral mucositis in oral cancer patients undergoing 3-dimensional conformal radiation therapy and intensity modulated radiation therapy with or without chemotherapy.

Oral cancer is a significant cause of death across the world. A combined multimodal approach integrating surgery and radiation therapy (RT) with or without chemotherapy (CT) is commonly employed in advanced oral cancer to prevent recurrences and locoregional spread. Oral mucositis is a common acute toxicity reported in patients undergoing RT and CT. The delivery of optimal cancer therapy protocols is compromised due to morbidity caused by oral mucositis. To compare the severity of oral mucositis in oral cancer patients undergoing 3-Dimensional Conformal Radiation Therapy (3DCRT) and Intensity Modulated Radiation Therapy (IMRT) with or without concomitant CT. This was a prospective, unicentric and longitudinal study conducted in a cancer centre. One hundred four patients with locally advanced oral cancer were enrolled in this study. Fifty-two patients were treated with IMRT and 52 patients with 3DCRT to a dose of >60 Gy, along with concurrent cisplatin weekly CT. Mucositis was recorded before the start, in the end, 1 month, and 3 months post-chemoradiotherapy treatment. Statistical analysis was performed using Statistical Package for Social Sciences (SPSS) software (v. 21.0, Chicago. 2012). Descriptive and frequency statistics were performed for different parameters assessed in 3DCRT and IMRT group. Grade 3 mucositis was the most predominant grade observed in both groups at the end of treatment. Thirty-six patients (69.3%) versus 24 patients (46.1%) developed grade 3 mucositis in 3DCRT and IMRT group, respectively (P = 0.013). Healing was better with IMRT group when compared to 3DCRT group 1 month and 3 months post-RT. Mucositis was severe in patients undergoing concomitant CT. IMRT reduced the incidence of severe mucositis and also improved the treatment-compliance compared to 3DCRT in locally advanced head neck cancer patients treated by chemoradiotherapy.

Endoscopic surgery versus intensity-modulated radiotherapy in locally advanced recurrent nasopharyngeal carcinoma: a multicenter, case-matched comparison

BackgroundThe management of locally advanced recurrent nasopharyngeal carcinoma (rNPC) is challenging. The objective of our study was to compare salvage endoscopic nasopharyngectomy (ENPG) with intensity-modulated radiotherapy (IMRT) in clinical outcomes and complications of locally advanced rNPC.MethodsPatients with histologically confirmed rNPC in rT3-4N0-3M0 stages were retrospectively enrolled between January 2013 and December 2019 in this multicenter, case-matched study. The baseline clinicopathological characteristics of patients were balanced by propensity score matching between the ENPG and IMRT groups. ENPG was performed in patients with easily or potentially resectable tumors. The oncological outcomes as well as treatment-related complications were compared between two groups.ResultsA total of 176 patients were enrolled and 106 patients were matched. The ENPG group (n = 53) and the IMRT group (n = 53) showed comparable outcomes in the 3-year overall survival rate (68.4% vs. 65.4%, P = 0.401), cancer-specific survival rate (80.9% vs. 74.4%, P = 0.076), locoregional failure-free survival rate (36.6% vs. 45.3%, P = 0.076), and progression-free survival rate (27.5% vs. 32.3%, P = 0.216). The incidence of severe treatment-related complications of patients in the ENPG group was lower than that in the IMRT group (37.7% vs. 67.9%, P = 0.002). The most common complications were post perioperative hemorrhage (13.2%) in ENPG group and temporal lobe necrosis (47.2%) in IMRT group, respectively.ConclusionSalvage ENPG exhibits comparable efficacy but less toxicities than IMRT in carefully screened patients with locally advanced rNPC, which may be a new choice of local treatment.Graphical abstract

Toxicity Profile of Intensity Modulated Radiotherapy Vs. 3D-Conformal Radiotherapy in Head and neck cancer: A Retrospective study

Background: Most head and neck patients have historically been treated with photon-based radiation techniques such as intensity modulated radiation therapy (IMRT), there is a growing awareness of the potential clinical benefits of proton therapy over IMRT in the definitive, postoperative and reirradiation settings given the unique physical properties of protons. Aim of the work: to assess toxicity profile of IMRT in comparison to 3D conformal radiotherapy (3DCRT) and to assess predictors for progression free survival and overall survival rates. Patients and Methods: This retrospective cohort study included 131 head and neck cancer patients who were recruited from El Hussein University Hospital over 10 years then they were divided into 2 groups according to the type of radiotherapy. Results: Both groups were comparable regarding age, sex and associated medical disorders except for ischemic heart disease and smoking. Sites of primary tumors were comparable except tongue and nasopharynx. Most of 3DCRT group received TPF as induction chemotherapy and most of IMRT group received concurrent chemotherapy. Dose of irradiation was higher significantly among IMRT group. Grades of early and late toxicity were higher among 3DCRT group. There was no statistically significant difference between both groups regarding response to treatment. Mortality cases were higher significantly among 3DCRT group. Cox regression analysis was performed to assess predictors for progression free survival and overall survival in each group. Conclusion: IMRT provide good choice as radiotherapy technique for head and neck cancers with adequate efficacy similar to other techniques and better toxicity profile.