Simultaneous Integrated Boost Intensity-modulated Radiotherapy Research Articles

Simultaneous integrated boost intensity-modulated radiotherapy post breast-conserving surgery: clinical efficacy, adverse effects, and cosmetic outcomes in breast cancer patients.

Simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) is an innovative technique delivering a higher dose to the tumor bed while irradiating the entire breast. This study aims to assess the clinical outcomes, adverse effects, and cosmetic results of SIB-IMRT following breast-conserving surgery in breast cancer patients. We conducted a retrospective analysis of 308 patients with stage 0-III breast cancer who underwent breast-conserving surgery and SIB-IMRT from January 2016 to December 2020. The prescribed doses included 1.85 Gy/27 fractions to the whole breast and 2.22 Gy/27 fractions or 2.20 Gy/27 fractions to the tumor bed. Primary endpoints included overall survival (OS), local-regional control (LRC), distant metastasis-free survival (DMFS), acute and late toxicities, and cosmetic outcomes. The median follow-up time was 36 months. The 3-year OS, LRC, and DMFS rates were 100%, 99.6%, and 99.2%, respectively. Five patients (1.8%) experienced local recurrence or distant metastasis, and one patient succumbed to distant metastasis. The most common acute toxicity was grade 1-2 skin reactions (91.6%). The most common late toxicity was grade 0-1 skin and subcutaneous tissue reactions (96.7%). Five patients (1.8%) developed grade 1-2 upper limb lymphedema, and three patients (1.1%) had grade 1 radiation pneumonitis. Among the 262 patients evaluated for cosmetic outcomes at least 2 years post-radiotherapy, 96.9% achieved excellent or good results, while 3.1% had fair or poor outcomes. SIB-IMRT after breast-conserving surgery in breast cancer patients demonstrated excellent clinical efficacy, mild acute and late toxicities, and satisfactory cosmetic outcomes in our study. SIB-IMRT appears to be a feasible and effective option for breast cancer patients suitable for breast-conserving surgery.

The Outcomes of Concomitant Hypofractionated Simultaneous Integrated Boost Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin monotherapy for Newly Diagnosed Locally Advanced Cancer Cervix with Positive Lymph Nodes.

The Outcomes of Concomitant Hypofractionated Simultaneous Integrated Boost Intensity-Modulated Radiotherapy Plus Concurrent Weekly Cisplatin monotherapy for Newly Diagnosed Locally Advanced Cancer Cervix with Positive Lymph Nodes.

Definitive chemoradiation for oropharyngeal squamous carcinomas: Outcomes with intensity-modulated radiation therapy using simultaneous integrated boost, in a majorly p16 negative cohort.

The literature on modern-era outcomes of oropharyngeal squamous carcinoma (OPSCC) in India is limited. We analyzed records of consecutive patients with OPSCC treated using a curative SIB IMRT regimen of 66 Gy/30#/6 weeks. One hundred fifteen patients from July 2011 to December 2018 were analyzed. Twenty of 69 patients tested positive for p16. In p16 positive patients, the K-M probability of being disease free and alive at 2 years, with at least one follow-up 3months after treatment, was 83% (median not reached) compared with 48% if p16 was unknown/negative. Patients staged as IVB p16 negative had a 2-year DFS of 25%. Patients unfit for cisplatin and consequently received other agents had 2-year DFS estimated at 20%. Intensity-modulated radiation therapy (IMRT) with simultaneous integrated boost (SIB) and concurrent chemotherapy was feasible, with toxicity and disease control comparable to available literature. AJCC Stage IVB p16 negative disease had notably poor outcome.

Dosimetric comparison of sequential intensity-modulated radiation therapy (IMRT) and simultaneous integrated boost IMRT for lymph node-positive cervical cancer

Abstract Introduction: Nodal boost is being increasingly employed to escalate the dose to involved nodes in node-positive cervical cancer. The study aimed to compare the dosimetric differences between sequential boost intensity-modulated radiation therapy (SeB-IMRT) and simultaneous integrated boost IMRT (SIB-IMRT) in terms of target coverage and organs-at-risk (OARs) with special emphasis on the effect of nodal shrinkage and anatomical change of normal tissues during radiotherapy. Methods: Two computed tomography (CT) datasets (of phase I and phase II) of 40 patients of node-positive cervical cancer treated with SeB-IMRT [planning target volume (PTV) 45/25] followed by SeB to residual nodes (PTV 12·6/7) were utilised. SIB-IMRT1 plan consisted of PTV pelvis and para-aortic nodal region (PTV 45/25) and SIB to gross nodes (PTV 55/25). In order to account for the change in nodal and normal tissue topography during treatment, a third plan (SIB-IMRT2) was generated by utilising the SIB-IMRT1 plan for 44 Gy in 20 fractions and reproducing the plan on the second CT dataset for 11 Gy in 5 fractions. Dosimetric parameters of the three plans were compared using the Friedman test with Bonferroni correction. Results: We observed that the doses to OARs (bowel, rectum and bladder) were significantly higher in SeB-IMRT plan as compared to the SIB-IMRT plans. V40 Gy of bowel for SeB-IMRT, SIB-IMRT1 and SIB-IMRT2 plans were 354·8 cc, 271 cc and 321·8 cc, respectively (p = 0·001), whereas V30 Gy were 687·8 cc, 635·5 cc and 680 cc, respectively (p = 0·001). The target coverage was marginally better in SeB-IMRT plan as compared to SIB-IMRT1 and SIB-IMRT2 plans (V95% = 99·2 versus 97·7 versus 97·9, respectively, p = 0·000) Conclusion: SIB-IMRT led to better sparing of OARs, especially bowel. However, the magnitude of benefit decreases if the change in nodal and normal tissue topography during radiotherapy is not considered implying the need for frequent image guidance when SIB-IMRT is planned for node-positive cervical cancer.

Analysis of the prognostic factors of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in 220 cases of locally advanced squamous esophageal cancer: a retrospective cohort study.

Esophageal cancer is one of the most common malignant tumors in China. Patients with advanced esophageal cancer often cannot be treated by surgery; in these cases, radiation therapy is usually applied. However, there are currently few studies on the clinical efficacy of this treatment method. The present study aimed to investigate and observe the clinical efficacy and related prognostic factors of simultaneous integrated boost-intensity modulated radiation therapy (SIB-IMRT) in esophageal squamous carcinoma, and to provide a reference for clinicians in radiotherapy (RT) departments. The clinical and follow-up data of 220 patients with esophageal squamous carcinoma admitted to the First Affiliated Hospital of Bengbu Medical College from January 2017 to December 2018 were retrospectively analyzed to assess the relevant prognostic factors and analyze their effects on 3-year overall survival (OS) and progression-free survival (PFS). The prognostic influencing factors were analyzed using the log-rank test and Cox multi-factor regression analysis. The median follow-up time was 56.0 months (3.0 to 66.0 months). The 1-, 2-, and 3-year survival rates were 68.6%, 49.1%, and 36.3%, respectively, for the entire cohort, and the 1-, 2-, and 3-year PFS rates were 52.3%, 37.7%, and 25.5%, respectively. The median OS time was 24 months [95% confidence interval (CI): 19.16-28.84 months] and the median PFS time was 15 months (95% CI: 11.04-18.96 months). The multifactorial analysis results showed that gender, RT dose, treatment modality, absolute lymphocyte count (ALC), and gross tumor volume (GTV) were independent prognostic factors affecting 3-year OS (P<0.05); while gender, N-stage, RT dose, and GTV were independent prognostic factors affecting 3-year PFS (P<0.05). In the SIB-IMRT era, the survival of esophageal squamous cell carcinoma (ESCC) patients treated with radical (chemo)radiotherapy is relatively satisfactory. As a single-institution study on radiation therapy for esophageal cancer, this study yielded accurate results that help to provide references for subsequent related studies and clinicians' selection of treatment options.

Dosimetric analysis of Rapid Arc (VMAT) treatment planning in head and neck cancer for quality assurance treatment

The current investigation aimed to compare the treatment plans of simultaneous integrated boost (SIB) fixed intensity modulated radiation therapy (IMRT) and SIB RapidArc (RA) using a number of dosimetric indices. In this study, 29 patients of nasopharyngeal carcinoma (NPC) were considered for treatment plan evaluation of SIB RA and SIB IMRT. The plans were evaluated using conformity index (CI), target coverage (TC), gradient index (GI), external volume Index (EI), homogeneity index (HI), dose heterogeneity index (DHI), standard deviation (SD), and unified dosimetric index (UDI). The dose of each planned target volume (PTV) and organs at risk (OARs) was determined using their respective mean and median doses. In accordance with the results, there is no noticeable difference in the values of CI, TC, GI, EI, and UDI for SIB RA and SIB IMRT. DHI of PTV 54 is better for SIB IMRT as compared to SIB RA and DHI of PTV 60, PTV 70 is same for both techniques. HI, SD and sparing of OARs results in better values for SIB RA as compared to SIB IMRT. However, PTV 54 and PTV 60′s doses indicate over dosage. The dose of PTV 70 is found to be within the limits of prescribed dose for both SIB RA and SIB IMRT. SIB RA homogeneity, sparing of OAR, and SD are observed to be superior to SIB IMRT. In the case of RA, less time and a monitor unit are used. In conclusion, SIB RA is thought to be better than SIB IMRT for the treatment of NPC.

Comparison of Simultaneous Integrated Boost IMRT for Dose Escalation (54 Gy) and Conventional IMRT (45 Gy) Twice Daily Combined with Concurrent Chemotherapy for Limited-Stage Small-Cell Lung Cancer: Analysis of Two Prospective Trials

<h3>Purpose/Objective(s)</h3> Twice-daily thoracic radiotherapy (TRT) with concurrent chemotherapy is standard for limited-stage small-cell lung cancer (LS-SCLC). However, the importance of twice-daily simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) has not been clearly defined in LS-SCLC. Therefore, we conducted a prospective single arm, multicenter phase II study of SIB-IMRT for dose escalation (54 Gy) to the gross tumor volume for LS-SCLC. Here, we compared SIB-IMRT for dose escalation (54 Gy) to the gross tumor volume versus conventional intensity-modulated radiotherapy (IMRT) of standard-dose (45 Gy) twice-daily combined with concurrent chemotherapy in patients with LS-SCLC. <h3>Materials/Methods</h3> Sixty patients with LS-SCLC were entered from 2015 to 2021 in the phase II study of SIB-IMRT, and all 60 patients were treated with SIB-IMRT to the postchemotherapy tumor volume, as the SIB-IMRT group. In the SIB-IMRT group, the prescribed dose was 54Gy at 1.8 Gy twice daily to PGTV, and 45 Gy at 1.5 Gy twice daily to PCTV. We previously conducted a prospective phase III study on thoracic radiotherapy (TRT) target volumes for LS-SCLC (Cancer, 2020, 126(4), 840-849). In that study, from 2012-2017, 85 patients received thoracic IMRT to the postchemotherapy tumor volume, as the IMRT group. In the IMRT group, the prescribed dose was 45 Gy at 1.5 Gy per twice-daily fraction to both the planning gross tumor volume (PGTV) and the planning clinical tumor volume (PCTV). All of the 145 patients in both groups received concurrent chemoradiotherapy (CCRT) after completion of 2 cycles of induction cisplatin-etoposide chemotherapy, and received chemotherapy for 4 to 6 cycles in total. We compared progression free survival (PFS) and overall survival (OS) between the treatment groups by using the Kaplan-Meier method. <h3>Results</h3> Overall, with a median follow-up of 34.6 months, the median PFS and OS were 11.9 and 23.7 months, respectively. The patients in the SIB-IMRT group showed marginal longer PFS than those in the IMRT group (13.3 months versus 11.5 months; <i>p</i> = 0.08). The median OS of the SIB-IMRT and IMRT groups were 35.0 and 20.3 months, with the 2-year OS rate of 66.1% and 38.8%, respectively (<i>p</i> =0.007). For radiotherapy toxicity, grade 2 acute esophagitis was more common in the SIB-IMRT group, but grade≥3 esophagitis and grade≥2 pneumonitis was no difference in both two groups. <h3>Conclusion</h3> For LS-SCLC patients, SIB-IMRT for dose escalation (54 Gy at 1.8Gy twice daily) to PGTV benefited survival greatly. Our results suggest that SIR-IMRT is safe and effective for patients with LS-SCLC and should be further evaluated in a large prospective clinical trial.

Dosimetric comparison of automatically propagated prostate contours with manually drawn contours in MRI-guided radiotherapy: A step towards a contouring free workflow?

BackgroundThe prostate demonstrates inter- and intra- fractional changes and thus adaptive radiotherapy would be required to ensure optimal coverage. Daily adaptive radiotherapy for MRI-guided radiotherapy can be both time and resource intensive when structure delineation is completed manually. Contours can be auto-generated on the MR-Linac via a deformable image registration (DIR) based mapping process from the reference image. This study evaluates the performance of automatically generated target structure contours against manually delineated contours by radiation oncologists for prostate radiotherapy on the Elekta Unity MR-Linac. MethodsPlans were generated from prostate contours propagated by DIR and rigid image registration (RIR) for forty fractions from ten patients. A two-dose level SIB (simultaneous integrated boost) IMRT plan is used to treat localised prostate cancer; 6000 cGy to the prostate and 4860 cGy to the seminal vesicles. The dose coverage of the PTV 6000 and PTV 4860 created from the manually drawn target structures was evaluated with each plan. If the dose objectives were met, the plan was considered successful in covering the gold standard (clinician-delineated) volume. ResultsThe mandatory PTV 6000 dose objective (D98% > 5580 cGy) was met in 81 % of DIR plans and 45 % of RIR plans. The SV were mapped by DIR only and for all the plans, the PTV 4860 dose objective met the optimal target (D98% > 4617 cGy). The plans created by RIR led to under-coverage of the clinician-delineated prostate, predominantly at the apex or the bladder-prostate interface. ConclusionPlans created from DIR propagation of prostate contours outperform those created from RIR propagation. In approximately 1 in 5 DIR plans, dosimetric coverage of the gold standard PTV was not clinically acceptable. Thus, at our institution, we use a combination of DIR propagation of contours alongside manual editing of contours where deemed necessary for online treatments.

Concurrent Weekly Cisplatin and Simultaneous Integrated Boost-IMRT in Locally Advanced Head and Neck Squamous Cell Carcinoma-An Institutional Experience.

Introduction Concurrent chemoradiation with weekly cisplatin in locally advanced head and neck squamous cell carcinoma (LA-HNSCC) is widely practiced in India. Radiation with simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) has the advantage of executing IMRT in single phase with better dose distribution. Material and Methods 150 patients with LA-HNSCC treated between April 2015 and December 2019 were retrospectively evaluated. All patients received 70Gy in 33 to 35 fractions with SIB-IMRT and concurrent weekly cisplatin at a dose of 40 mg/m 2 . Treatment compliance and toxicities were assessed. Overall survival (OS) was evaluated using Kaplan-Meier estimates; univariate and multivariate analysis of prognostic factors were also evaluated. Results Median age was 58.5 years. Forty-five percent had primary oropharyngeal cancer. Sixty-two percent had T3 disease, 41% had N2 disease, and 51% had stage IV disease. All patients received 70Gy dose of RT. Median chemotherapy cycles were six, 84.7% received 200 mg/m 2 . Acute grade 2 xerostomia was seen in 79%, grade 3 neutropenia, mucositis and pharyngitis were seen in 11, 15, and 21%, respectively. Complete response was seen in 66.6%. At median follow-up of 21.4 months (3-71) OS was 60% and median OS was 33.2 months. Estimated 2 and 3 year OS was 56 and 48%. On univariate analysis, absence of node, N0-N1, stage III, cisplatin use, dose per fraction 2.12Gy ,and complete response showed good OS ( p <0.05). On multivariate analysis dose per fraction 2.12Gy and complete response showed good OS ( p <0.05). Conclusion Definitive chemoradiation with weekly cisplatin and SIB-IMRT in LA-HNSCC is well tolerated with good clinical outcomes.

SIB-IMRT combined with apatinib for unresectable hepatocellular carcinoma in patients with poor response to transarterial chemoembolization

Radiotherapy combined with apatinib exhibits synergistic anti-tumor effect, while the application of simultaneous integrated boost intensity modulated radiotherapy (SIB-IMRT) combined with apatinib in HCC patients is scarce. Hence, this study aimed to explore the treatment response, survival, and safety profile of the SIB-IMRT combined with apatinib in unresectable HCC (uHCC) patients. A total of 19 uHCC patients with deficient response to transarterial chemoembolization (TACE), who scheduled for SIB-IMRT combined with apatinib treatment were enrolled. The SIB-IMRT was applied at the following dose: 95% planning target volume (PTV) at 30-50Gy/2-2.5Gy/15-20f and 90% Boost of 45-72Gy/3-4.5Gy/15-20f at 5 times per week with cone beam computerized tomography validation. During and after radiotherapy, the apatinib was administrated orally with the initial dose of 500mg per day. The complete response, partial response, stable disease, and progressive disease rates were 31.6%, 36.8%, 21.1% and 10.5%, respectively. Consequently, the objective response rate and disease control rate were 68.4% and 89.5%, respectively. During a median follow-up duration of 9.0 months, the median progression-free survival (PFS) was 6.0 (95% confidential interval (CI): 4.9-7.1) months with 1-year PFS rate of 42.1%; the median overall survival (OS) was not reached with 1-year OS rate of 54.6%. The safety profile was acceptable with the most common adverse events including myelosuppression (42.1%), skin reaction (36.8%), and albuminuria (26.3%). SIB-IMRT combined with apatinib exhibits a good efficacy and tolerable safety profile, which could be considered as a potential treatment choice for uHCC patients who have deficient response to TACE.

Twice-daily thoracic radiotherapy by intensity-modulated radiation therapy (IMRT) compared with simultaneous integrated boost IMRT (SIB-IMRT) with concurrent chemotherapy for patients with limited-stage small cell lung cancer. A propensity-score matched analysis

BackgroundConcurrent chemoradiotherapy is the standard treatment for limited-stage small-cell lung cancer patients (SCLC). However, the optimal dose and schedule of thoracic radiotherapy (TRT) has not been established. MethodsWe retrospectively reviewed the clinical records of limited-stage SCLC patients treated with twice-daily TRT and concurrent chemotherapy between December 2009 and December 2017. Patients were divided into two groups according to radiotherapy dose: the intensity modulated radiotherapy (IMRT) group [45 Gy to the planning target volume (PTV)] and the simultaneous integrated boost IMRT (SIB-IMRT) group (57 Gy to the gross tumour volume, 51 Gy to the clinical target volume, and 45 Gy to PTV). A 1:1 propensity score matching (PSM) was applied to balance the observable potential confounding factors between the two groups. Primary endpoint was progression-free survival (PFS). ResultsA total of 112 patients were enrolled in our study, including 71 patients in the IMRT group and 41 patients in the SIB-IMRT group. After PSM, the clinical features were well balanced between the groups, including 37 patients each. The median PFS was 17.54 months in the IMRT group versus 34.92 months in the SIB-IMRT group (P = 0.047). The median overall survival (OS) was 38.52 months in the IMRT group versus 63.41 months in the SIB-IMRT group (P = 0.261). ConclusionsCompared with IMRT, a high dose of twice-daily TRT by the SIB-IMRT approach with concurrent chemotherapy for limited-stage SCLC patients may improve PFS without increasing toxicities. However, PFS improvement failed to result in significant advantages in OS.

Dose-escalation by hypofractionated simultaneous integrated boost IMRT in unresectable stage III non-small-cell lung cancer

BackgroundTo explore the maximum tolerated dose (MTD) and evaluate the safety of dose escalation using hypofractionated simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) concurrent with chemotherapy for unresectable stage III non-small cell lung cancer (NSCLC).MethodsFour escalating radiation dose levels were used. This study included 25 patients with previously untreated NSCLC who received six concurrent weekly chemotherapy cycles comprising cisplatin and docetaxel. Dose-limiting toxicity (DLT) was defined as any acute toxicity that interrupted radiotherapy for more than 1 week. MTD was defined as the highest dose level that didn’t induce DLT or grade 5 toxicity in two patients.ResultsAll 25 patients received the prescribed escalating radiation dose from the start dose up to LEVEL 4. Two patients experienced DLT at dose LEVEL 4. One patient died because of upper gastrointestinal hemorrhage within 6 months after radiotherapy, whereas another patient among the additional five patients died because of grade 5 radiation pneumonitis within 2 months after radiotherapy. Dose LEVEL 3 was defined as MTD. The 1- and 2-year local controls were 82.8 and 67.8%, respectively. The median progression-free survival was 15.4 months, whereas the median overall survival was 27.3 months.ConclusionsDose escalation was safely achieved up to LEVEL 3 [the planning gross target volume (PTVG) 60.5 Gy/22 Fx, 2.75 Gy/Fx; the planning clinical target volume (PTVC) 49.5 Gy/22 Fx] using SIB-IMRT concurrently with chemotherapy for unresectable stage III NSCLC, and the acute toxicities were generally well tolerated. Further prospective studies on long-term outcomes and late toxicities are warranted.Trial registrationRetrospective registration, ChiCTR1900027290(08/11/2019).

Comparison of efficacy and safety between simultaneous integrated boost intensity-modulated radiotherapy and standard-dose intensity-modulated radiotherapy in locally advanced esophageal squamous cell carcinoma: a retrospective study

ObjectiveThis study aimed to evaluate the efficacy and safety of simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT) versus standard-dose intensity-modulated radiotherapy (SD-IMRT) in the treatment of locally advanced esophageal squamous cell carcinoma.MethodsFrom July 2003 to March 2014, 1748 patients in a single center who received definitive chemoradiotherapy were included in the analysis. A total of 109 patients who underwent SIB-IMRT and fulfilled all inclusion and exclusion criteria were identified as the study group. A total of 266 patients who underwent SD-IMRT (60 Gy/30 fractions, 2 Gy/fraction, 1 time/day, 5 times/week) during the same period were selected as the control group. Propensity score matching (PSM) was used to balance the baseline characteristics. Survival status, treatment failure mode, and the occurrence of adverse events were compared between the two groups.ResultsThere were more women and more cervical and upper thoracic cancers (P = 0.038, < 0.001, respectively) in the SIB-IMRT group before case matching. The median progression-free survival (PFS) in the SD-IMRT and SIB-IMRT groups was 22 and 19 months, respectively, and the median overall survival duration was 24 and 22 months, respectively, with χ2 = 0.244 and P = 0.621. After PSM of 1:1, 138 patients entered the final analysis (69 cases from each group). The median PFS of the SD-IMRT group and the SIB-IMRT group was 13 and 18 months, respectively, with χ2 = 8.776 and P = 0.003. The 1‑, 3‑, and 5‑year overall survival rates were 66.7, 21.7, and 8.7% and 65.2, 36.2, and 27.3%, respectively, and the median overall survival duration was 16 and 22 months, respectively, with χ2 = 5.362 and P = 0.021. Treatment failure mode: 5‑year local regional recurrence rates of SD-IMRT and SIB-IMRT were 50.7 and 36.2%, respectively, with χ2 = 2.949 and P = 0.086. The 5‑year distant metastasis rates of the two groups were 36.2 and 24.6%, respectively, with χ2 = 2.190 and P = 0.139. Adverse events: 3 patients experienced grade 4–5 toxicity (2.2%), including one case of grade 4 radiation esophagitis and two cases of grade 5 radiation pneumonitis, all in the SD-IMRT group; 14 patients experienced grade 3 adverse events (10.1%), primarily including radiation esophagitis, radiation pneumonitis, and hematological toxicity.ConclusionThe technique of SIB-IMRT was safe and reliable compared with SD-IMRT. In addition, SIB-IMRT had locoregional control advantages and potential survival benefits.

Evaluation of target autocrop function in nasopharyngeal carcinoma SIB IMRT plan.

A new target autocrop function was introduced in the Varian Eclipse™ treatment planning software (version 15.5 above) (Lohynská in Klin Onkol 33(4):288-294, 2020). The study aimed to evaluate this new target autocrop impact on nasopharyngeal carcinoma (NPC) plan quality and delivery efficiency. Randomly 66 approved NPC simultaneous integrated boost (SIB) intensity-modulated radiation therapy (IMRT) treatment plans were retrospectively studied. The manual cropping-based plans served as reference and were designed using sliding-window IMRT. Reference plans were re-optimized with identical plan parameters following the institutional clinical protocol, except for the redundant optimization objective of the manual cropping targets deleted. Additionally, each target within 5mm of another had one minimum objective at 100% volume and one maximum objective at 0% volume for the autocrop plans. Plan quality was assessed based on selected parameters, including TCP (tumor control probability), NTCP (normal tissue complication probability), conformality index (CI), homogeneity index (HI), and dose-volume characteristics. Additionally, the delivery efficiency, the total plan treatment time defined as a sum of monitor units (MUs) for each treated field, and delivery accuracy, γ passing rate of treatment plan quality assurance (QA) also were compared. Both the manual cropping plans and the autocrop plans could be approved by an experienced oncologist. Overall, the autocrop plans could provide approximately a 13% reduction in linac MU while maintaining comparable plan quality, radiobiological ranking, and accuracy to the manual cropping plans. The new target autocrop tip facilitated the SIB IMRT plans for nasopharyngeal cancer patients. The autocrop could guarantee the quality and delivery accuracy of the radiotherapy plan and improved the planning efficiency, treatment efficiency, and reduced machine wear and tear. It was a promising tool for optimal plan selection for NPC SIB IMRT.

Twice-Daily Thoracic Radiotherapy by Intensity-Modulated Radiation Therapy (IMRT) or Simultaneous Integrated Boost (SIB) IMRT With Concurrent Chemotherapy for Limited-Stage Small Cell Lung Cancer Patients? A Propensity-Score Matched Analysis

<h3>Purpose/Objective(s)</h3> Concurrent chemoradiotherapy is the standard treatment for limited-stage small-cell lung cancer patients (SCLC), but the optimal dose and schedule of radiotherapy have not been established. <h3>Materials/Methods</h3> We retrospectively reviewed the clinical records of limited-stage SCLC patients treated with twice-daily thoracic radiotherapy by intensity modulated radiotherapy (IMRT) or Simultaneous integrated boost IMRT (SIB-IMRT) with concurrent chemotherapy between December 2009 to December 2017. The patients were divided into two groups according to the radiotherapy dose. The patients of SIB-IMRT group received 57Gy at 1.9Gy twice-daily to the gross tumor volume (GTV), 51Gy at 1.7Gy twice-daily to the clinical target volume (CTV) and 45Gy at 1.5Gy twice-daily to the planning target volume (PTV), and the patients of IMRT group received 45Gy at 1.5Gy twice-daily to PTV. A 1:1 propensity score matching (PSM) was applied to balance observable potential confounding factors between two groups. Primary endpoint was progression-free survival (PFS). Overall survival (OS), objective tumor response (ORR) and treatment-related toxicities were also evaluated. Statistical analyses were conducted using SPSS version 22.0 and statistical significance was defined as <b>P</b> < 0.05. <h3>Results</h3> A total of 112 patients were enrolled in our study, including 71 patients in IMRT group and 41 patients in SIB-IMRT group. After PSM, the clinical features were well balanced between two groups included 37 patients each. ORR in IMRT group and SIB-IMRT group were 94.6% (35/37) and 97.3% (36/37), respectively. Median PFS was 17.54 months in IMRT group <b>vs</b> 34.92 months in SIB-IMRT group (<b>P</b> = 0.047). Median OS was 38.52 months in IMRT group <b>vs</b> 63.41 months in SIB-IMRT group (<b>P</b> = 0.261). The incidence of grade 3-4 treatment-related toxicities was 43.24% (32/74), and there was no significant difference between two groups (<b>P</b> = 0.639). <h3>Conclusion</h3> Compared with IMRT, the high dose of twice-daily thoracic radiotherapy by SIB-IMRT approach with concurrent chemotherapy for the patients with limited-stage SCLC were well-tolerated and may improve PFS, but PFS improvement didn't result in significant advantage in OS.

The feasibility of a dose painting procedure to treat prostate cancer based on mpMR images and hierarchical clustering

BackgroundWe aimed to assess the feasibility of a dose painting (DP) procedure, known as simultaneous integrated boost intensity modulated radiation Therapy (SIB-IMRT), for treating prostate cancer with dominant intraprostatic lesions (DILs) based on multi-parametric magnetic resonance (mpMR) images and hierarchical clustering with a machine learning technique.MethodsThe mpMR images of 120 patients were used to create hierarchical clustering and draw a dendrogram. Three clusters were selected for performing agglomerative clustering. Then, the DIL acquired from the mpMR images of 20 patients were categorized into three groups to have them treated with a DP procedure being composed of three planning target volumes (PTVs) determined as PTV1, PTV2, and PTV3 in treatment plans. The DP procedure was carried out on the patients wherein a total dose of 80, 85 and 91 Gy were delivered to the PTV1, PTV2, and PTV3, respectively. Dosimetric and radiobiologic parameters [Tumor Control Probability (TCP) and Normal Tissue Complication Probability (NTCP)] of the DP procedure were compared with those of the conventional IMRT and Three-Dimensional Conformal Radiation Therapy (3DCRT) procedures carried out on another group of 20 patients. A post-treatment follow-up was also made four months after the radiotherapy procedures.ResultsAll the dosimetric variables and the NTCPs of the organs at risks (OARs) revealed no significant difference between the DP and IMRT procedures. Regarding the TCP of three investigated PTVs, significant differences were observed between the DP versus IMRT and also DP versus 3DCRT procedures. At post-treatment follow-up, the DIL volumes and apparent diffusion coefficient (ADC) values in the DP group differed significantly (p-value < 0.001) from those of the IMRT. However, the whole prostate ADC and prostate-specific antigen (PSA) indicated no significant difference (p-value > 0.05) between the DP versus IMRT.ConclusionsThe results of this comprehensive clinical trial illustrated the feasibility of our DP procedure for treating prostate cancer based on mpMR images validated with acquired patients’ dosimetric and radiobiologic assessment and their follow-ups. This study confirms significant potential of the proposed DP procedure as a promising treatment planning to achieve effective dose escalation and treatment for prostate cancer.Trial registration: IRCT20181006041257N1; Iranian Registry of Clinical Trials, Registered: 23 October 2019, https://en.irct.ir/trial/34305.

Long-term efficacy and safety of simultaneous integrated boost radiotherapy in non-operative esophageal squamous cell carcinoma: a multicenter retrospective data analysis (3JECROG R-05)

Objective: To analyze the survival benefits and treatment related toxic effects of simultaneous integrated boost intensity-modulated radiotherapy (SIB-RT) for non-operative esophageal squamous cell carcinoma patients. Methods: The data of 2 132 ESCC patients who were not suitable for surgery or rejected operation, and underwent radical radiotherapy from 2002 to 2016 in 10 hospitals of Jing-Jin-Ji Esophageal and Esophagogastric Cancer Radiotherapy Oncology Group (3JECROG) were analyzed. Among them, 518 (24.3%) cases underwent SIB (SIB group) and 1 614 (75.7%) cases did not receive SIB (No-SIB group). The two groups were matched with 1∶2 according to propensity score matching (PSM) method (caliper value=0.02). After PSM, 515 patients in SIB group and 977 patients in No-SIB group were enrolled. Prognosis and treatment related adverse effects of these two groups were compared and the independent prognostic factor were analyzed. Results: The median follow-up time was 61.7 months. Prior to PSM, the 1-, 3-, and 5-years overall survival (OS) rates of SIB group were 72.2%, 42.8%, 35.5%, while of No-SIB group were 74.3%, 41.4%, 31.9%, respectively (P=0.549). After PSM, the 1-, 3-, and 5-years OS rates of the two groups were 72.5%, 43.4%, 36.4% and 75.3%, 41.7%, 31.6%, respectively (P=0.690). The univariate survival analysis of samples after PSM showed that the lesion location, length, T stage, N stage, TNM stage, simultaneous chemoradiotherapy, gross tumor volume (GTV) and underwent SIB-RT or not were significantly associated with the prognosis of advanced esophageal carcinoma patients who underwent radical radiotherapy (P<0.05). Cox model multivariate regression analysis showed lesion location, TNM stage, GTV and simultaneous chemoradiotherapy were independent prognostic factors of advanced esophageal carcinoma patients who underwent radical radiotherapy (P<0.05). Stratified analysis showed that, in the patients whose GTV volume≤50 cm(3), the median survival time of SIB and No-SIB group was 34.7 and 30.3 months (P=0.155), respectively. In the patients whose GTV volume>50 cm(3), the median survival time of SIB and No-SIB group was 16.1 and 20.1 months (P=0.218). The incidence of radiation esophagitis and radiation pneumonitis above Grade 3 in SIB group were 4.3% and 2.5%, significantly lower than 13.1% and 11% of No-SIB group (P<0.001). Conclusions: The survival benefit of SIB-RT in patients with locally advanced esophageal carcinoma is not inferior to non-SIB-RT, but without more adverse reactions, and shortens the treatment time. SIB-RT can be used as one option of the radical radiotherapy for locally advanced esophageal cancer.

The promising outcome with simultaneous integrated boost intensity modulated radiotherapy in confined nasal extranodal NK/T-cell lymphoma

The study aimed to retrospectively analyze the prognosis of patients with stage IE nasal extranodal natural killer/T-cell lymphoma (ENKTL) with dose reduction to clinical target volume (CTV) by using simultaneous integrated boost intensity-modulated radiotherapy (SIB-IMRT). Forty-four patients were reviewed retrospectively. The prescribed dose was 45 Gy/25 fractions for extended involved-field site and 50–55 Gy/25 fractions for primary tumor site by using SIB-IMRT. The 5-year overall survival (OS), local control (LC) and progression-free survival (PFS) were 81.2%, 93.0%, and 78.8%, respectively. The complete response (CR) rate was 85.4% (37/44). Three patients (6.8%) patients had local failure and 3 (6.8%) patients developed systemic failure. There was only one patient had grade 3 mucositis and 2 patients had grade 3 or grade 4 hematologic toxicities. For patients with stage IE nasal ENKTL, appropriate dose reduction to CTV by SIB-IMRT strategy is feasible and safe with a promising outcome.

P-68 Concurrent Weekly Cisplatin and Simultaneous Integrated Boost-Intensity Modulated Radiotherapy (SIB-IMRT) in Locally Advanced Head and Neck Squamous Cell Carcinoma (LA-HNSCC)

P-68 Concurrent Weekly Cisplatin and Simultaneous Integrated Boost-Intensity Modulated Radiotherapy (SIB-IMRT) in Locally Advanced Head and Neck Squamous Cell Carcinoma (LA-HNSCC)

Definitive Simultaneous Integrated Boost Versus Conventional-Fractionated Intensity Modulated Radiotherapy for Patients With Advanced Esophageal Squamous Cell Carcinoma: A Propensity Score-Matched Analysis.

BackgroundThe aim of this study was to compare the effects of simultaneous integrated boost–intensity modulated radiotherapy (SIB-IMRT) and conventional fractionated-IMRT (CF-IMRT) for patients with esophageal squamous cell carcinoma (ESCC).MethodsThe data of 1173 patients treated with either CF-IMRT or SIB-IMRT for a curative intent from 2005 to 2016 were retrospectively reviewed. Propensity score matching (PSM) was used to create a well-balanced cohort of 687 patients at 1:2 ratio (237 patients in SIB-IMRT group and 450 patients in CF-IMRT group). Overall survival (OS), progression-free survival (PFS), recurrence pattern, and toxicity profiles were evaluated and compared between the two groups after PSM.ResultsAfter a median follow-up time of 42.3 months (range, 3.0-153.2 months) for surviving patients, survival results were comparable in the two groups. After PSM, the 1-year, 2-year and 4-year OS rates in the SIB-IMRT and CF-IMRT groups were 70.0% vs. 66.4%, 41.9% vs. 41.7% and 30.2% vs. 27.6%, respectively (p = 0.87). The 1-year, 2-year and 4-year PFS rates were 48.4% vs. 49.1%, 31.2% vs. 29.4%, and 26.1% vs. 17.9%, respectively (p = 0.64). Locoregional recurrence (p = 0.32) and distant metastasis (p = 0.54) rates were also comparable between two groups. The toxicity profile was similar in the two groups. Multivariate analyses in the matched samples showed that female, concurrent chemotherapy and earlier clinical stage were independently associated with longer OS and PFS.ConclusionsSIB-IMRT appears to be equivalent to CF-IMRT in treatment efficacy and safety, and could become an alternative option for definitive radiotherapy of ESCC.