Conformal Radiotherapy In Patients Research Articles

Post-operative intensity-modulated vs 3D conformal radiotherapy after conservative surgery for laryngeal tumours of the supraglottic region: a dosimetric analysis on 20 patients.

To perform a dosimetric comparison between intensity modulated radiotherapy (IMRT) and 3D conformal radiotherapy in patients with locally advanced (stage III and IV) tumours of the supraglottic region treated with conservative surgery and post-operative radiotherapy. An in-silico plan using a 3D conformal shrinking field technique was retrospectively produced for 20 patients and compared with actually delivered IMRT plans. Eighteen structures (arytenoids, constrictor muscles, base of tongue, floor of mouth, pharyngeal axis, oral cavity, submandibular glands and muscles of the swallowing functional units [SFU]) were considered. IMRT allowed a reduction of maximum and mean doses to 9 and 14 structures, respectively (p < .05). IMRT achieved a reduction of unnecessary dose to the remnant larynx and the majority of surrounding SFUs. Further prospective analyses and correlations with functional clinical outcomes are required to confirm these dosimetric findings.

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.

Comparison of Acute Gastrointestinal Toxicity of Intensity-Modulated Radiotherapy Versus Three-Dimensional Conformal Radiotherapy in Patients of Carcinoma Cervix.

Introduction Cervical cancer is the most common gynaecological malignancy worldwide, with a higher prevalence in middle- and low-income countries. Chemoradiotherapy, followed by intracavitary brachytherapy, is the treatment of choice in locally advanced cervical cancer. The most common acute side effect of external beam radiotherapy (EBRT) is bowel toxicity in the form of diarrhoea and abdominal cramps. The treatment techniques of EBRT were revolutionised with the advent of intensity modulation. This study aims to prospectively analyse whether the dosimetric advantage of intensity-modulated radiotherapy (IMRT) over three-dimensional conformal radiotherapy (3DCRT) is translated clinically into a decrease in acute toxicity. Method Twenty-four patients were randomised into two groups: the 3DCRT and the IMRT. Acute gastrointestinal (GI) toxicity was assessed during treatment using radiation therapy oncology group grading. The factors under consideration were age, stage of the disease, treatment technique, chemotherapy, and the intention of therapy (radical or adjuvant). The mean bowel bag dose of the two techniques was analysed. Result Among the factors under consideration, it was found that the treatment technique was the only factor that had a significant association with acute bowel toxicity in both univariate (p = 0.036) and multivariate analyses (p = 0.028). The mean V25 (the volume receiving 25 Gy), V45, and V50 of the bowel bag in the IMRT arm were significantly less than the 3DCRT arm. Grades 2 and 3 acute bowel toxicities were also higher in the 3DCRT arm. Conclusion The treatment technique is essential to determining acute GI toxicity during pelvic radiotherapy. With IMRT, the dose to the bowel bag and, in turn, the acute bowel toxicity can be reduced.

Investigating the Radiation Dose Received by the Heart and Its Electrocardiographic Changes after Three-dimensional Conformal Radiation Therapy in Patients with Left Breast Cancer

Background and Objective: Breast cancer is one of the most common cancers and the fifth leading cause of cancer deaths in Iran. The present study aimed to investigate the absorbed dose received by the heart and its relationship with cardiac complications in radiotherapy of patients with left breast cancer using a three-dimensional conformal radiotherapy technique. Materials and Methods: A total of 181 women with left breast cancer who received radiotherapy after surgery were included in the study. Dosimetric parameters were obtained using dose-volume histograms for the heart, whole lung, left lung, and clinical target volume. Electrocardiography tests were performed for all patients before and one year after the radiotherapy. Results: The mean doses of heart, left lung, whole lung, and clinical target volume were 6.3±3.1, 13.3±4.5, 6.9±3.7, and 47.3±6.4 Gray (Gy), respectively. A significant reduction in T-wave amplitude was observed in 57% of patients three months after radiotherapy. T-wave amplitude decreased from 3.03±0.92 mm to 1.56±0.83 mm. The reduction in the T-wave amplitude displayed a significant relationship with the mean dose of the heart (β = 2.653; P= 0.019). Conclusion: In women with left-sided breast cancer, cardiac complications are frequent, for which electrocardiographic tests can be used for cardiac evaluation after radiotherapy. Based on the obtained results, the most frequent side effect caused by radiotherapy in these patients was an abnormality in T-wave

Reduced Risk of Lymphedema With Intensity-modulated Radiation Therapy Compared With 3-dimensional Conformal Radiation Therapy in Patients With Cervical Cancer Who Received Postoperative Pelvic Radiation Therapy.

To compare the long-term adverse events of intensity-modulated radiation therapy (IMRT) with those of 3-dimensional conformal radiation therapy (3D-CRT) in patients with intermediate-risk and high-risk uterine cervical cancer who underwent postoperative pelvic radiation therapy (PORT). We reviewed the medical records of 177 patients with cervical cancer who underwent radical surgery and PORT. IMRT and 3D-CRT were administered to 93 and 84 patients, respectively. Follow-up and toxicity assessments were then carried out. The median follow-up period was 63 months (range: 3 to 177). There was a significant difference in the follow-up period between the IMRT and 3D-CRT cohorts (median: 59 vs. 112mo, P <0.0001). The crude incidences of acute grade 2+ and grade 3+ gastrointestinal toxicities were significantly lower with IMRT than with 3D-CRT (22.6% vs. 48.1%, P =0.002, and 3.2% vs. 11.1%, P =0.04, respectively). The Kaplan-Meier estimates of late toxicities revealed that IMRT significantly reduced grade 2+ genitourinary (GU) toxicity and lower-extremity lymphedema ([LEL] requiring intervention) compared with 3D-CRT ([6.8% vs. 15.2% at 5-year, P =0.048] and [3.1% vs. 14.6% at 5-year, P =0.0029], respectively). IMRT was the only significant predictor of reducing LEL risk. The risks of acute gastrointestinal toxicity, late GU toxicity, and LEL from PORT for cervical cancer were reduced by IMRT. Lower inguinal doses may have contributed to a lower risk of developing LEL, which should be validated in future studies.

Dosimetric analysis of 3 dimensional conformal radiotherapy with volumetric modulated arc therapy in patients with carcinoma oesophagus – Prospective study

: To study the dosimetry and treatment plan of Volumetric Modulated Arc Therapy and 3 Dimensional Conformal Radiotherapy in patients with carcinoma oesophagus. : A prospective study was taken up in Department of Radiotherapy, from October 2017 to June 2019. A total 20 patients who achieved eligibility criteria was taken into study and both 3D CRT (3D Conformal Radiation Therapy)and VMAT(Volumetric Modulated Arc Therapy ) plans was done in all patients. Dosimetric comparison is done between these two techniques. Dose to spinal cord is significantly reduced with VMAT technique when compared to 3D CRT. VMAT plans in this study showed significantly reduced doses to heart, when compared to 3D CRT plans. VMAT plans decrease volume of lung receiving high dose(v20,dmean,v30,v40) compared to 3D CRT but at a cost of delivering low dose to more volume of lung (v5, v10, v15) resulting in serious complications like radiation pneumonitis. VMAT plans are advisable in carcinoma oesophagus patients to achieve reduced doses to OARs(Organs at Risk) like Spinal Cord, Heart &amp; Lung and better target coverage particularly in cervical esophagus where higher doses are planned.

Volumetric Intensity-Modulated Arc Stereotactic Radiosurgery Boost in Oligometastatic Patients with Spine Metastases: a Dose-escalation Study

AimsTo report the final results of a dose-escalation study of volumetric intensity-modulated arc stereotactic radiosurgery (VMAT-SRS) boost after three-dimensional conformal radiation therapy in patients with spine metastases. Materials and methodsOligometastatic cancer patients bearing up to five synchronous metastases (visceral or bone, including vertebral ones) and candidates for surgery or radiosurgery were considered for inclusion. 25 Gy was delivered in 10 daily fractions (2 weeks) to the metastatic lesion, affected vertebrae and adjacent ones (one cranial and one caudal vertebra). Sequentially, the dose to spinal metastases was progressively increased (8 Gy, 10 Gy, 12 Gy) in the patient cohorts. Dose-limiting toxicities were defined as any treatment-related non-hematologic acute adverse effects rated as grade ≥3 or any acute haematological toxicity rated as ≥ 4 by the Radiation Therapy Oncology Group scale. ResultsFifty-two lesions accounting for 40 consecutive patients (male/female: 29/11; median age: 71 years; range 40–85) were treated from April 2011 to September 2020. Most patients had a primary prostate (65.0%) or breast cancer (22.5%). Thirty-two patients received 8 Gy VMAT-SRS boost (total BED α/β10: 45.6 Gy), 14 patients received 10 Gy (total BED α/β10: 51.2 Gy) and six patients received 12 Gy (total BED α/β10: 57.6 Gy). The median follow-up time was over 70 months (range 2–240 months). No acute toxicities > grade 2 and no late toxicities > grade 1 were recorded. The overall response rate based on computed tomography/positron emission tomography–computed tomography/magnetic resonance was 78.8%. The 24-month actuarial local control, distant metastases-free survival and overall survival rates were 88.5%, 27.1% and 90.3%, respectively. ConclusionA 12 Gy spine metastasis SRS boost following 25 Gy to the affected and adjacent vertebrae was feasible with an excellent local control rate and toxicity profile.

Conformal Radiation Therapy in Patients With Cardiovascular Implantable Electronic Devices: Proposed Practical Implementation of the 2019 American Association of Physicists in Medicine Task Group No. 203 Risk-Stratified Interrogation Schedule

PurposeRadiation therapy (RT) in patients with cardiac implantable electronic devices (CIED) carries a risk of device malfunction from radiation exposure. We sought to evaluate the incidence of CIED malfunction in a cohort of patients treated with modern RT techniques. Methods and MaterialsA retrospective analysis of 193 CIED patients treated with RT between 2000 and 2018 was conducted. All patients underwent pre-, intra-, and post-RT CIED interrogations. Patient demographics, CIED details, RT details, including total dose, modality, treatment site, CIED distance from RT field, treatment planning system maximum dose and in vivo dose estimates, and CIED malfunction data were analyzed. ResultsCIEDs in use were mainly pacemakers (single-chamber 10%, dual-chamber 49%) and defibrillators (35%). Patients received a median RT dose of 50 Gy (range, 7-80 Gy), treated with 3-dimensional CRT (47%), intensity modulated RT/volumetric modulated arc therapy (38%), and stereotactic body radiation therapy (10%). Neutron producing energies were used in 13% of the treatments. A strong correlation was noted between treatment planning system estimated maximum dose and in vivo estimated CIED dose when the CIED distance from the treatment field was >3 cm. However, in vivo measurements provide a lower estimated absorbed dose for CIED devices <3 cm from the RT field. During a median follow-up of 24 months (range, 7-64 months), 2 adverse CIED-related events were recorded: a spontaneous defibrillator discharge and a pacemaker malfunction subsequently causing ventricular tachycardia. Both patients received stereotactic body radiation therapy to the thorax, with CIED dose of 5 and 19.2 cGy, respectively. Both events occurred 2 years posttreatment without any intra- or post-RT CIED interrogations changes noted. ConclusionsIn this series of patients treated with modern RT techniques, we observed a CIED malfunction rate of 1.04%. These low event rates establish the safety of delivering modern RT in CIED patients with the possibility of reducing the burden of intra- and posttreatment CIED monitoring.

First experience of using combination of conformal radiation therapy with intraarterial administration of gemcitabine and nanostabilized paclitaxel in patients with locally advanced pancreatic cancer complicated by persistent chronic pain

Introduction. Locally advanced pancreatic cancer (LAPC) is accompanied by a diverse clinical picture, one of the leading symptoms is chronic pain syndrome (CPS), which occurs in 30 % of patients in the early stages of the disease and in 80 % of patients with advanced pancreatic cancer. The basic method of treating CPS is analgesic therapy. However, the widespread use of painkillers is limited due to the short and incomplete analgesic effects, as well as side effects of painkillers. The use of chemoradiotherapy (CRT) contributes to the relief of CPS, however, it is accompanied by adverse events (AE) and a short analgesic effect. Aim. The aim of the study was to evaluate the first experience of using of intra-arterial administration of a combination of gemcitabine at a dose of 1,000 mg/m2 and nano-stabilized paclitaxel at a dose of 125 mg/m 2 in combination with conformal radiation therapy in patients with LAPC with CPS. Materials and methods . A controlled open, single-center, non-randomized, retrospective study included 17 patients who received combined treatment - a single selective intra-arterial administration of gemcitabine at a dose of 1,000 mg/m 2 and nano-stabilized paclitaxel at a dose of 125 mg/m 2 , followed by conformal radiation therapy with beam of 51 Gr in medium fractionation mode. The dynamics of CPS was assessed by the intensity, severity, localization and characteristics of the applied analgesic therapy using the BPi-SF-Russian-2001 questionnaire when the patient was admitted before treatment, on the 24th and 54th days of combination therapy. Results. Complications associated with angiography and radiation therapy have not been reported. There were no pronounced (more than Grade 1) immediate and distant AEs of intra-arterial chemotherapy in patients. An analysis of CPS and its associated indicators showed a decrease in the severity of pain, which ultimately was an important component of the quality of life of patients. Significant decrease in CPS occurred on the 24th day before treatment. The analgesic effect was reliably maintained on the 54th day. The maximum analgesic effect of the combined treatment was noted on the 24th day. Thus, the duration of anesthesia was recorded up to 54 days. The analgesic effect significantly contributed to improving mood, the ability to contact with others, and also affected the quality and duration of sleep and the ability to enjoy life in patients of the study group. Conclusion. The use of intra-arterial chemotherapy with gemcitabine and nano-stabilized paclitaxel in combination with radiation therapy can effectively affect on CPS and the quality of life in patients with LAPC.

Relationship Between Changes in Myocardial F-18 Fluorodeoxyglucose Uptake and Radiation Dose After Adjuvant Three-Dimensional Conformal Radiotherapy in Patients with Breast Cancer.

This study aimed to assess the relationship between radiation dose and changes in the irradiated myocardial F-18 fluorodeoxyglucose (FDG) uptake after radiotherapy (RT) in breast cancer patients. The data of 55 patients with left and 48 patients with right breast cancer who underwent curative surgical resection and adjuvant three-dimensional conformal RT and staging (PET1), post-adjuvant chemotherapy (PET2), post-RT (PET3), and surveillance (PET4) FDG positron emission tomography/computed tomography (PET/CT) were retrospectively reviewed. The median interval between PET1 and curative surgical resection, between the end of adjuvant chemotherapy and PET2, between the end of RT and PET3, and between the end of RT and PET4 were five days, 13 days, 132 days, and 353 days, respectively. The myocardial-to-blood pool uptake ratio was measured in all patients. For patients with left breast cancer, the 30 Gy- (30 Gy) and 47.5 Gy-irradiated myocardium-to-low-irradiated myocardium (47.5 Gy) FDG uptake ratios were additionally measured. There were no differences in the myocardial-to-blood pool uptake ratios between left and right breast cancer on all PET scans. For left breast cancer, higher 30 Gy and 47.5 Gy uptake ratios were observed on PET3 than on PET1 and PET2. Both uptake ratios decreased on PET4 compared to PET3, but, were still higher compared to PET1. On PET3 and PET4, the 47.5 Gy were higher than the 30 Gy uptake ratios, while there were no differences between them on PET1 and PET2. Although the whole myocardium FDG uptake showed no significant change, the irradiated myocardium FDG uptake significantly increased after RT and was related to radiation dose to the myocardium in breast cancer patients. These results might be an imaging evidence that supports the increased risk of heart disease after RT in patients with left breast cancer.

Intensity-Modulated Radiation Therapy versus 3D Conformal Radiation Therapy in Patients Undergoing Regional Nodal Irradiation/Postmastectomy Radiation Therapy for Breast Cancer: Looking Beyond Dosimetric Outcomes

Prospective data and meta-analyses support the use of adjuvant regional nodal irradiation (RNI)/postmastectomy radiation therapy (PMRT) for the majority of women with axillary lymph node positive breast cancer. However, RNI increases dose to the heart and lung compared resulting in increased toxicity. Inverse-planned intensity modulated radiation therapy (IMRT) has the ability to reduce high dose to the heart/lung compared to traditional 3D conformal radiation therapy (3DCRT). Early concerns with IMRT were that it may be too conformal resulting in increased risk of local-regional failures (LRF). To date, clinical outcomes with IMRT have not been well studied in patients receiving RNI/PMRT. We have used planning target volume (PTV)-based, dose-volume analysis driven RNI/PMRT planning since 2013 using primarily 3DCRT but IMRT as needed to meet heart/lung planning objectives. We hypothesize that toxicity and LRF rates are similar between patients treated with IMRT and 3DCRT. We identified patients that received RNI/PMRT from 2013-2016. Patients received conventional fractionation (200 cGy/day) to the breast/chestwall, axillary, supraclavicular (SCV), and internal mammary chain (IMC) PTVs. We divided the cohort into 2 groups (IMRT vs. 3DCRT). We collected patient and disease characteristics, acute toxicity, LRF, and distant metastases (DM) events. Differences in characteristics were evaluated with the t-test or Chi-square test. The primary endpoint was the cumulative incidence of LRF as a first failure. We also evaluated the cumulative incidence of DM. We included 241 patients (69 IMRT, 172 3DCRT): 60% had stage III disease; 60% (ER+ or PR+)/HER2-; 20% triple-negative; 20% HER2+. IMRT group had higher rates of left-sided (65% vs. 47%, p=0.009) and grade 3 (58% vs. 43%, p=0.04) disease. The IMCs were irradiated in 97%. Treatment was well tolerated: grade 3 dermatitis 6% in each group with no other grade 3 toxicities. Grade 2 pneumonitis occurred in 2 (0.83%), both 3DCRT. Median follow-up is 3.5 years. There were 5 LRF events (2 IMRT, 3 3DCRT): 2 patients with isolated LRF (iLRF) and 3 patients with simultaneous LRF+DM resulting in 4-year LRF=2.1% (4.1% IMRT vs. 1.4% 3DCRT, p=0.55) and 4-yr iLRF=1.1% (1.5% vs. 0.8%, p=0.43). The iLRF (1 IMRT, 1 3DCRT) both occurred in the SCV region. The other LRF+DM event in the IMRT group was a chestwall/axillary/IMC recurrence post-mastectomy. The additional 2 LRF+DM events in the 3DCRT group included: ipsilateral SCV and level V nodes post-lumpectomy; and a lumpectomy bed recurrence. Most failures were DM: 4-year rate=15% (21.0% IMRT vs. 13.2% 3DCRT, p=0.58). In this modern cohort of patients receiving RNI/PMRT with a PTV-based approach, we saw rare high-grade toxicity, and we found no difference in LRF and DM rates between IMRT and 3DCRT patients. These data should provide reassurance that IMRT does not compromise disease outcomes and that IMRT can safely be used when needed to meet normal tissue constraints.

Comparison of clinical efficacy and prognosis of intensity-modulated radiotherapy and three dimensional conformal radiotherapy in patients with stage II/III esophageal cancer: a multi-center retrospective analysis in Beijing, Tianjin and Hebei province (3JECROG R-06)

Objective To compare the therapeutic effects between three-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) in patients with stage Ⅱ/Ⅲ esophageal cancer and investigate the prognostic factors. Methods Medical record of 2 132 patients with stage Ⅱ/Ⅲ esophageal cancer who underwent definitive radiotherapy with/without chemotherapy in 10 hospitals from January 2002 to December 2016 from were retrospectively analyzed. Among these patients, 37.9% of them were aged≥70 years, 33.9% with neck and upper esophageal tumors and 66.1% with middle and lower esophageal and borderline tumors. The median gross tumor volume (GTV) and lymph node gross tumor volume (GTVnd) was 41.6 cm3.Among them, 32% were stage Ⅱ and 68% were stage Ⅲ.A total of 723 patients received 3DCRT and 1 409 cases received IMRT.Patients received an equivalent dose in 2 Gy (EQD2) ≥ 60 Gy accounted for 86.1%, and 41.1% of them received concurrent chemoradiotherapy. Results The median follow-up time was 60.8 months. The 1-, 3-and 5-year overall survival (OS) of all patients was 73.9%, 41.7% and 32.6%, and the 1-, 3-and 5-year progression-free survival (PFS) was 62.2%, 37.3% and 32%, respectively. Multivariate analysis demonstrated that age, primary tumor location, clinical stage, tumor target volume, EQD2 and concurrent chemoradiotherapy were the independent prognostic factors for OS.Age, primary tumor location, clinical stage, tumor target volume and EQD2 were the independent prognostic factors for PFS.The OS and PFS did not significantly differ among the low-risk, low-/moderate-risk, moderate-/high-risk and high-risk groups according to age≥70 years, tumor diameter>5 cm, tumor volume≥41.6 cm3 and stage Ⅲ(P<0.001). After the propensity score matching (PSM) method, neither 3DCRT nor IMRT yielded significant advantages in OS or PFS (P=0.971; P=0.658). However, IMRT tended to yield survival benefits in low-risk patients (P=0.125). Conclusions Both 3DCRT and IMRT yield relatively high OS rate in patients with stage Ⅱ/Ⅲ esophageal cancer. The prognosis model established in this investigation can properly predict the survival of patients. Low-risk patients tend to obtain survival benefits from IMRT. Key words: Esophageal neoplasm/three-dimensional conformal radiotherapy; Esophageal neoplasm/intensity-modulated radiotherapy; Prognosis

A Randomized Comparison of Radiation Therapy Techniques in the Management of Node-Positive Breast Cancer: Primary Outcomes Analysis

Although inverse-planned intensity modulated radiotherapy (IMRT) and deep inspiration breath hold (DIBH) may allow for more conformal dose distributions, it is unknown whether using these technologies reduces cardiac or pulmonary toxicity of breast radiotherapy. A randomized controlled trial compared IMRT-DIBH versus standard, free-breathing, forward-planned, three-dimensional conformal radiotherapy in patients with left-sided, node-positive breast cancer in whom the internal mammary nodal region was targeted. Endpoints included dosimetric parameters and changes in pulmonary and cardiac perfusion and function, measured by single photon emission computed tomography (SPECT) scans and pulmonary function testing performed at baseline and 1year post treatment. Of 62 patients randomized, 54 who completed all follow-up procedures were analyzed. Mean doses to the ipsilateral lung, left ventricle, whole heart, and left anterior descending coronary artery were lower with IMRT-DIBH; the percent of left ventricle receiving ≥5Gy averaged 15.8% with standard radiotherapy and 5.6% with IMRT-DIBH (P<.001). SPECT revealed no differences in perfusion defects in the left anterior descending coronary artery territory, the study's primary endpoint, but did reveal statistically significant differences (P=.02) in left ventricular ejection fraction (LVEF), a secondary endpoint. No differences were found for lung perfusion or function. The small but statistically significant benefit in preservation of cardiac LVEF observed here should motivate future studies that include LVEF as a potentially meaningful endpoint. Future studies should disaggregate the impact of IMRT from that of DIBH. Clinical practice should recognize the importance of minimizing cardiac dose, even when already low in comparison to historical levels.

Tomotherapy Versus 3D Conformal Radiation Therapy in Patients With Head And Neck Cancer Treated With Definitive (Chemo) Radiation Therapy

Since the introduction of Tomotherapy in our center, it has not been possible to treat all head and neck cancer (HNC) patients on it due to logistic reasons. It was a unique situation where HNC patients were treated simultaneously by the same specialists using two different radiation therapy techniques in the same institute. The objective of this study is to evaluate the efficacy and toxicity of two techniques, i.e. Tomotherapy and 3D conformal radiation therapy in HNC patients treated with definitive (chemo)radiation therapy. Between March 2009 to February 2013, 165 consecutive patients with a biopsy proven squamous cell carcinoma of head and neck region treated with definitive radiation therapy 65 Gy in 30 fractions ± weekly cisplatin/cetuximab chemo(bio)therapy were included. The data was collected retrospectively, log-rank test was used for survival analysis; chi-square and Fisher’s exact test were used for group analysis. Ninety-seven patients received 3D conformal radiation therapy (3D CRT group) and 68 patients were treated with Tomotherapy (Tomo group). Median age was 63 years (range: 37-89) in 3DCRT and 58 years (range: 19-77) in the Tomo group. In both groups, oropharynx was the most common primary subsite (54% in 3D CRT and 63% in Tomo). Majority of the patients in both groups were of stage (TNM 7th edition) IVa (54% in 3D CRT and 66% in Tomo) followed by stage IVb (10% in each group). Of the patients in 3D CRT, 56.7% received concurrent chemotherapy (95% cisplatin, 5% cetuximab) while 86.8% of Tomo group received chemotherapy (92% cisplatin, 8% cetuximab). In 3D CRT, 67.3% of the patients completed all 6 cycles of chemotherapy compared to that 74.6% in Tomo group. Response was achieved in 93.8% cases in 3D CRT and 97.1% cases in Tomo group. In 3D CRT, 17 patients recurred locally and 8 developed distant metastases as compared to 14 and 10 respectively in Tomo group. With a median follow up of 42 months (range: 1-83), 1-year and 5-year disease-free survival were 80% and 63.7% in 3D CRT vs 88.1% and 77.1% in Tomo group. One-year overall survival and 5-year survival were 85.5% and 54.2% in 3D CRT group vs 85.3% and 62.1% in Tomo group. The incidence of acute toxicities was higher in Tomo group given the higher percentage of patients received concurrent chemotherapy. However, there was a trend of lower incidence of late toxicities in the Tomo group: bone necrosis (7 patients in 3D CRT vs 3 in Tomo, P=.52), complete xerostomia (18 vs 8, P=.24), and laryngeal cartilage necrosis (5 vs 1, P=.40). A significant difference was observed in late swallowing dysfunction requiring intervention (27 in 3D CRT vs 5 in Tomo, P=.02). There was no statistical difference in DFS and OS between two groups; however, we observed a trend of lower incidence of late toxicities in patients treated with Tomotherapy, with a significant difference in late swallowing dysfunction.

MS 06.05 The Use of Adjuvant IMRT after Pleurectomy/Decortication

MS 06.05 The Use of Adjuvant IMRT after Pleurectomy/Decortication

Intensity-modulated radiotherapy has superior outcomes to three-dimensional conformal radiotherapy in patients with stage IE-IIE extranodal nasal-type natural killer/T-cell lymphoma.

We compared the treatment outcomes, toxicities and prognoses of patients with stage IE-IIE extranodal natural killer/T-cell lymphoma (ENKTL) treated with intensity-modulated radiotherapy (IMRT) or three-dimensional conformal radiotherapy (3DCRT). Newly diagnosed early-stage ENKTL patients (N = 173) were enrolled and received extended involved-field radiotherapy following induction chemotherapy. Patients were treated with 3DCRT (n = 98) or IMRT (n = 75). One-to-one matching of the IMRT and 3DCRT groups was performed through propensity score matching, which yielded 23 pairs of patients. The two groups achieved similar complete remission rates before and after radiotherapy (P > 0.05). All patients were followed up for a median of 41 months. The rates of local recurrence-free survival (LRFS, P < 0.001), progression-free survival (PFS, P = 0.003) and overall survival (OS, P = 0.003) were longer in the IMRT than 3DCRT group. In the matched patients, IMRT was still associated with superior LRFS (P = 0.024), but not with improved PFS (P = 0.113) or OS (P = 0.115). Multivariate analysis also suggested IMRT was a favorable independent factor for LRFS (HR = 2.230, P = 0.043), but not for PFS (P = 0.195) or OS (P = 0.116). Equivalent acute toxicities were observed for 3DCRT and IMRT; however, among stage II patients who had received cervical irradiation, the rate of late xerostomia was lower in the IMRT than 3DCRT group (38.5% vs. 66.7%, P = 0.046). Overall, IMRT yielded a better treatment response and local control than 3DCRT, and tended to reduce late xerostomia in patients with cervical irradiation, but failed to enhance OS. Thus, IMRT is recommended for the treatment of stage IE-IIE ENKTL patients.

Clinical Outcome of CT-Based Image Guided Adaptive Brachytherapy Combined With Conformal Radiation Therapy in Patients With Uterine Cervical Cancer

Clinical Outcome of CT-Based Image Guided Adaptive Brachytherapy Combined With Conformal Radiation Therapy in Patients With Uterine Cervical Cancer

O.3 - Dosimetric comparison of intensity-modulated radiotherapy versus 3D conformal radiotherapy in patients with head-and-neck cancer

O.3 - Dosimetric comparison of intensity-modulated radiotherapy versus 3D conformal radiotherapy in patients with head-and-neck cancer

Weekly kilovoltage cone-beam computed tomography for detection of dose discrepancies during (chemo)radiotherapy for head and neck cancer

ABSTRACTBackground. Use of highly conformal radiotherapy in patients with head and neck carcinoma may lead to under-/overdosage of gross target volume (GTV) and organs at risk (OAR) due to changes in patients’ anatomy. A method to achieve more effective radiation treatment combined with less toxicity is dose-guided radiotherapy (DGRT). The aim of this study was to evaluate discrepancies between planned and actually delivered radiation dose in head and neck patients and to identify predictive factors.Methods. In this retrospective analysis, 20 patients with cT2-4 N0-3 M0 carcinoma originating from oropharynx, oral cavity, larynx and hypopharynx (Cohort 1), and seven patients with cT1-4 N0-3 M0 nasopharyngeal carcinoma (Cohort 2) treated with primary (chemo)radiotherapy and undergoing weekly kV-CBCT scans were included. Radiation dose was recalculated on 184 kV-CBCT images, which was quantified by D95% (GTV), Dmean (parotid and submandibular glands) and D2% (spinal cord). Predictive factors investigated for changes in these dose metrics were: gender, age, cT/N-stage, tumor grade, HPV-status, systemic therapy, body mass index at start of treatment, weight loss and volume change over the duration of the radiotherapy.Results. There was no significant difference between the planned and delivered dose for GTV and OARs of Week 1 to subsequent weeks for Cohort 1. In Cohort 2, actually delivered Dmean to parotid glands was significant higher than planned dose (1.1 Gy, p = 0.002). No clinically relevant correlations between dose changes and predictive factors were found.Conclusion. Weekly dose calculations do not seem to improve dose delivery for patients with tumors of the oral cavity, oropharynx, larynx and hypopharynx. In patients with nasopharyngeal carcinoma, however, mid-treatment imaging may facilitate DGRT.

Role of thoracic conformal radiotherapy in patients with extensive-stage small cell lung cancer

Objective To evaluate the role of thoracic three-dimensional conformal radiotherapy (3DCRT) in patients with extensive-stage small cell lung cancer (ES-SCLC).Methods A total of 171 patients with ES-SCLC admitted from 2004 to 2009 were included in the study.Eighty-six patients received thoracic 3DCRT and systemic chemotherapy (CT),while 85 patients received systemic CT alone.3DCRT was delivered at 1.5 Gy/fraction twice daily or 2.0 Gy/fraction once daily,with a total dose ranging from 40 to 62 Gy.The CT regimen consisted of carboplatin/cisplatin and etoposide.The survival time and survival rate were calculated by the Kaplan-Meier method,and the log-rank test was used for univariate prognostic analysis;the Cox model was used for multivariate prognostic analysis.Results The follow-up rate was 100％.The median overall survival (OS) time and the 2-and 5-year OS rates were 15 months,31.5％,and 2.4％,respectively,for all patients;they were 18 months,35.3％,and 2.4％,respectively,for the CT/3DCRT group,versus 12 months,14.5％,and 2.4％ for the CT group (P =0.023).The median progression-free survival (PFS) time and the 1-and 2-year PFS rates were 8 months,27.5％,and 2.4％,respectively,for all patients;they were 9 months,35.4％,and 6.0％,respectively,for the CT/3DCRT group,versus 6 months,20.5％,and 6.0％ for the CT group (P =0.004).In the CT/3DCRT group,the 22 patients who received 45 Gy at 1.5 Gy/fraction twice daily had a median PFS time of 11 months,versus 9 months for the 26 patients who received 60 Gy at 2.0 Gy/fraction once daily (P =0.037).Multivariate analysis revealed that receiving ≥ 4 cycles of CT (P =0.001) and 3DCRT (P =0.008) were favorable prognostic factors for OS.Conclusions Thoracic 3DCRT can improve the OS and PFS in patients with EDSCLC,and it has good efficacy when delivered with a total dose of 45 Gy at 1.5 Gy/fraction twice daily.Thoracic 3DCRT and receiving ≥4 cycles of CT are independent favorable prognostic factors for OS. Key words: Lung neoplasms/radiotherapy; Radiotherapy, three-dimensional conformal; Radiotherapy, hyperfraction; Prognosis