Conformal Radiotherapy Techniques Research Articles

Angle of concavity in planning target volume can be adopted as selection criteria for intensity-modulated radiation therapy or three-dimensional conformal radiotherapy technique in brain tumors.

With innovation of medical imaging, radiotherapy attempts to conform the high dose region to the planning target volume (PTV). The present work aimed to assess the angle of concavity in PTV can be adopted as selection criteria for intensity-modulated radiation therapy (IMRT) or three-dimensional conformal radiotherapy (3DCRT) technique in Brain tumors. Thirty previously irradiated patients with brain tumors were replanned with both 3DCRT and IMRT technique. Angle of concavity (dip) in the PTV near the organs at risk was measured in the contoured structure set images of each patient. These cases were divided into three groups where angles were 0°, >120° and <120°. Dose of 60 Gy/30# was fixed. In Group 1, the IMRT plan had better TV95% as compared to 3DCRT respectively with significant P value (P = 0.002). Mean of conformity index (CI) and Homogeneity Index (HI) were comparable. For Group 2 (angle >120°), the IMRT plan had better TV95% as compared to 3DCRT respectively with a significant P value (P = 0.021). HI and CI were not significant. For Group 3 (<120°), IMRT plan had better TV95% as compared to 3DCRT respectively with a significant P value (P = 0.001). HI and CI were better in IMRT arm with significant P value. The results from this study showed that the angle of concavity can be considered as an additional objective tool for selection criteria whether tumor can be treated with IMRT or 3DCRT. Tumors where angle of concavity was <120°, HI and CI provided more uniformity and conformity of dose distribution inside PTV with significant P values.

Gated radiation therapy for patients with breast cancer to reduce the dose to the lung and heart: A comparative cross-sectional study

ABSTRACT JOURNAL/crsat/04.03/02201859-202306020-00005/figure1/v/2023-08-03T140821Z/r/image-tiff Background: Deep inspiratory breath hold (DIBH) is an established technique to treat left breast cancer with fewer side-effects to the surrounding organs at risk (OARs). However, studies assessing DIBH in resource-poor settings, especially in a government setup, are scarce. Objectives: Our primary objective was to assess and compare the dosimetric changes in the DIBH technique compared to the free breathing technique among patients with left-sided breast cancer undergoing radiation therapy. Materials and Methods: This was a comparative cross-sectional study conducted in the Department of Radiation Oncology, Kidwai Memorial Institute of Oncology (Bengaluru, India), over a period of 24 months. A total of 65 patients were treated with the three-dimensional conformal radiation therapy (3D-CRT) technique either using DIBH or free breathing as per the standard protocol. The dosimetric comparisons for the surrounding OARs, in terms of mean percentage volume receiving 15 Gy (V15Gy) and 20 Gy (V20Gy) in the left lung, V25Gy, V30Gy, V5Gy in the heart the mean dose in Gy received by 25% (V25%) and 40% (V40%) of the heart, V10% and V30% of the left anterior descending artery (LAD) and mean values of Dmean dose (Gy) received by the left lung, heart, and LAD artery were compared between both the techniques. Results: Among 65 patients, 25 (38.4%) were treated by the free breathing technique and 40 (61.6%) by DIBH. Various dosimetric parameters that were significantly lower in the DIBH compared to free breathing techniques included the mean percentage volume of left lung receiving 20 Gy (V20 Gy) (29.5% vs. 23.5%), heart receiving 25 Gy (V25Gy) (6.7% vs. 2.9%) and 30 Gy (12.8% vs. 2.0%), mean values of Dmean received by the heart (7.8 Gy vs. 4.5 Gy) and LAD artery (31.3 Gy vs. 16.9 Gy), mean dose received by 10% volume of LAD (V10%) (36.3 Gy vs. 29.0 Gy) and 30% of LAD artery (V30%) (34.3 Gy vs. 22.2 Gy) (P &lt; 0.001). Conclusion: DIBH significantly decreases the radiation dose delivered to the heart, left lung, and LAD artery. Thus, in patients with left-sided breast cancer, DIBH leads to a lower radiation dose to the OARs, leading to potentially less side-effects.

Stereotactic body radiation therapy for colorectal cancer liver metastases.

The management of colorectal cancer liver metastases requires a multidisciplinary approach, which may incorporate systemic therapy, surgery, or local ablative therapies. Stereotactic body radiation therapy (SBRT) is a non-invasive highly conformal radiation technique that enables the delivery of large doses of radiation in a few fractions to well-defined targets using image-guidance and motion management. For selected patients with colorectal cancer liver metastases, stereotactic body radiation therapy can be delivered safely, with excellent long-term local control and overall survival. The purpose of this clinical practice review is to review the background, indications, and treatment details of stereotactic body radiation therapy for the treatment of colorectal liver metastases. SBRT for colorectal cancer liver metastases may be considered for patients with oligometastatic colorectal cancer in combination with surgery or other locally ablative therapies; for patients who are not candidates for surgical resection; or after failure of resection or other ablative therapies. When planning SBRT both a computed tomography and magnetic resonance imaging simulation may be obtained, where feasible, for target delineation. One or 3 fraction SBRT can be considered for lesions away from the central liver and luminal organs at risk, whereas 5 fraction SBRT is preferred otherwise. Image-guidance and motion management strategies are essential components of liver SBRT and will guide the creation of relevant internal and planning target volume margins. For lesions in close proximity to or overlapping with organs-at-risk, the balance between adequate local control and potential for cure with potential acute and late toxicity must be carefully considered.

Hypofractionated radiotherapy in postmastectomy locally advanced breast cancer: an interim report on acute toxicities and dosimetry.

There is a growing interest in the use of hypofractionation in the setting of post-mastectomy radiation therapy (PMRT). Here, we present an interim report on the acute toxicities and the dosimetry of a 15-day hypofractionated regimen. Patients aged 18-75 years who underwent mastectomy and had pathological stage IIB-IIIC or any clinical stage who had received neoadjuvant chemotherapy were treated with PMRT at a dose of 43.5 Gy in 15 fractions. Acute toxicities were scored using Common Terminology Criteria for Adverse Events (CTCAE) version 4.0. Between September 2020 and September 2021, 92 patients were enrolled in the study. Majority experienced grade 1 dermatitis during the course of treatment. Skin toxicities peaked two weeks after PMRT in which 57 patients (62%) had grade 2 dermatitis and 6 patients (7%) had grade 3 dermatitis. Most resolved one month after treatment, with all resolving at three months. Grade 2 fatigue occurred in 4 patients (4%). There were no grade 3 fatigue or pneumonitis of any grade. The average V95% for the chest wall, axilla, and supraclavicular fossa were 91.5%, 99.3%, and 97.5%, respectively. Average ipsilateral lung V17 was 43.6%, while the mean heart dose averaged at 3.46 Gy. This interim report showed that hypofractionated PMRT is associated with a low incidence of clinically significant acute toxicities. With the use of the 3-dimensional conformal radiotherapy technique and volume-based planning, adequate target volume coverage and acceptable heart doses were achieved, although with a slightly higher ipsilateral lung dose.

A Comparison of Intensity-Modulated Radiotherapy With Simultaneous Integrated Boost With Three-Dimensional Conformal Radiotherapy With Sequential Boost for Locally Advanced Cervical Cancer: A Dosimetric Study.

Objective The aim of this study was to compare the dosimetric criteria between the intensity-modulated radiation therapy (IMRT) technique with a simultaneous integrated boost (SIB) and the three-dimensional conformal radiation therapy (3DCRT) technique with a sequential boost (SB) plans for patients with locally advanced cervical cancer (LACC). Materials and methods A retrospective dosimetric comparison was performed in 15 patients with locally advanced cervical cancer who had previously been treated with fractions of 1.8 Gy up to doses of 45, 54-55.8, and 59.4 Gy in 28-33 sessions using the three-dimensional conformal radiation therapy (3DCRT) technique with a sequential boost (SB)and who had a new planning that was made using the intensity-modulated radiation therapy (IMRT) technique with a simultaneous integrated boost (SIB) in 25 sessions.The conformity index, quality of coverage, homogeneity index, mean doses, maximum doses, and different organ at risk (OAR) dose constraints were calculated for the dosimetric comparison of treatment plans. Descriptive analysis was performed using measures of central tendency and dispersion for the quantitative variablesand absolute and relative frequencies for the qualitative variables. The comparison was made using the Wilcoxon signed rank sum test for a type I error level of 0.05. The statistical softwareStata 11 (StataCorp LLC, College Station, Texas, USA) was used in the analysis. Results The mean age of the patients was 52 years, 33% were stage IIIB, and 67% had squamous cell carcinomas. The conformity index was 0.74 and 0.46 (difference: 0.28; p<0.01), the quality of coverage was 0.84 and 0.94 (difference: -0.10; p<0.01), and the homogeneity index was 0.12 and 0.070 (difference: 0.052; p<0.01) for IMRT-SIB and 3DCRT-SB, respectively. When the mean doses of the OARs were compared, all were lower with the IMRT-SIB technique, with statistically significant differences in the rectum and bladder. Conclusions The IMRT-SIB technique achieves a greater conformation of the doses on the treatment volumes with a significant reduction of the doses on the bladder and rectum.

Cardiac Morbidity Following Chemoradiation in Stage III Non-small Cell Lung Cancer Patients: A Population-Based Cohort Study

AimsTo assess the risk of cardiac toxicity following radical radiotherapy in advanced lung cancer patients. Materials and methodsPatients with a diagnosis of stage III non-small cell lung cancer (NSCLC) receiving chemoradiotherapy were extracted from a population-based cohort in Ontario, Canada. The primary outcome of cardiac toxicity, defined as cardiac events or congestive heart failure, was assessed at 1 and 5 years following chemoradiotherapy. Secondary outcomes included overall survival, survival in relationship to post-treatment cardiac events and the effect of radiotherapy technique on cardiac toxicity. ResultsIn total, 2031 NSCLC patients were included. The cumulative incidence of cardiac toxicity at 5 years was 20.3% (18.4–22.3). The median survival was 13.7 months in NSCLC patients who had a cardiac event post-chemoradiotherapy compared with 23.4 months in those who did not (P = 0.012). There was a trend towards increased cumulative cardiac toxicity (hazard ratio 3.37, P = 0.14) with three-dimensional conformal radiotherapy compared with intensity-modulated or volumetric arc radiotherapy techniques. ConclusionThe risk of cardiac events and congestive heart failure 5 years after radical thoracic radiotherapy appears high and survival is inferior at 1 year in those patients who experience a cardiac event post-treatment. More conformal radiotherapy techniques may help reduce cardiac toxicity. Further studies should investigate adaptive treatment planning and close monitoring and intervention in this high-risk group after chemoradiotherapy.

Moderne definitive Radiochemotherapie – State of the Art-Umsetzung und neue Konsolidierungsstrategien

BackgroundIn locally advanced non-small-cell lung cancer (NSCLC), the addition of chemotherapy to radiotherapy and consolidation with durvalumab leads to a significant increase in overall survival and represents the most profound innovation of the last decade.ObjectivesAnalysis of new possibilities for the state-of-the-art implementation of definitive radiochemotherapy concepts.Materials and methodsEvaluation of prospective and randomised studies regarding improvements in treatment outcomes.ResultsOverall survival benefit of consolidating checkpoint inhibitor therapy after combined radiochemotherapy with durvalumab is 43% (95% confidence interval 38–47%) versus 33% (27–40%) in the placebo group in an updated analysis of the PACIFIC trial for 5‑year survival; stratified hazard ratio for death is 0.72 (95% CI 0.59–0.89, p = 0.0025). In the dose escalation studies, increased pulmonary and oesophageal side effects were observed, so no immediate clinical benefit could be derived from the increase in local efficacy. Improved imaging before and during therapy and optimised possibilities of dose application, especially by using intensity-modulated radiotherapy (IMRT), allow selective sparing of healthy structures, which increases the ability to safely intensify radiotherapy also in connection with new immunomodulatory substance combinations.ConclusionThe integration of immunotherapy, the stringent use of fluorodeoxyglucose positron emission tomography (FDG-PET) in staging and radiation planning, the widespread use of highly conformal radiation techniques (IMRT; volumetric modulated arc therapy, VMAT) and the consistent application of image-guided radiotherapy have led to significant improvements in treatment outcomes.

Local control results in extremity soft tissue sarcomas

Aim: The aim of this study is to investigate local control results and effective predictive factors in local control of extremity soft tissue sarcomas, retrospectively. Material and Method: 51 patients underwent postoperative adjuvant radiotherapy (RT) in Dr. Abdurrahman Yurtaslan Ankara Oncology Training and Research Hospital between October 2008-January 2022. Patients who underwent post-operative adjuvant RT were treated with 60-68 Gy in 2 phases from 2 Gy /day using conformal radiotherapy technique. IMA chemotherapy protocol was applied to 31.4% of the patients after radiotherapy. Results: The median follow up time was 46 months range (1-135). Recurrence was detected in 5 of the patients and the mean time of recurrence was 11.6 months (min: 3-max: 27). 10 patients developed metastasis at follow-up, the mean time until metastasis was 27 months (min: 18- max: 46). The mean overall survival (OS) was 103 (min:4-max:139) months and the OS of 2, 5 and 10 years were 93%, 65% and 60%, respectively. Disease-free survival (DFS) was 97 (min:4-max:139) months; 2, 5 and 10 years of DFS were 77%, 65% and 60%, respectively. The OS in patients aged ≥65 years old was significantly lower than in patients &amp;lt;65 years old (p=0.02). Overall and disease-free survival was significantly lower in patients undergoing chemotherapy (p=0.037 for overall survival, p=0.013 for disease-free survival). The occurrence of recurrence, metastasis or death within 3 years after the operation was significantly higher than after 3 years (p&amp;lt;0.001). Local failure was significantly higher in grade 3 tumors (p=0.05). All patients who recurred had grade 3 tumors. Metastasis and excitus were significantly higher in the follow-up of patients who underwent chemotherapy at one point during their treatment (p=0.027 for metastasis, p=0.042). Conclusion: While favorable local control results are obtained with adjuvant high dose-conformal radiotherapy in extremity sarcomas, close follow up is important for distant metastasis and local recurrence, especially in the first 3 years.

Disparities in Specialized Radiation Treatment Modalities for Grade Group 2, Intermediate-Risk Prostate Cancer

<h3>Purpose/Objective(s)</h3> Men with Grade Group 2 (GG2) intermediate risk (IR) prostate cancer (PCa) have multiple curative radiation (RT) options. Compared to conventional external beam photon RT (XRT), including 3D-conformal RT (3DCRT) and IMRT, highly conformal RT techniques may provide less integral RT dose to normal tissue, including brachytherapy (BT), SBRT, and proton beam radiation therapy (PBT). These treatments require either advanced equipment and/or specialized training. Here we analyzed national trends in utilization of XRT, BT monotherapy, SBRT, and PBT, and assessed potential factors associated with receiving each technique. We hypothesize that socioeconomic and/or racial disparities are associated with differences in utilization of these specialized techniques. <h3>Materials/Methods</h3> Men diagnosed with favorable IR PCa cancer, defined as Gleason 3+4 disease, PSA < 20 and clinical stage T1-T2 N0 M0, between 2004-2017 were identified in the National Cancer Database. Cohorts were defined as: XRT (3DCRT+IMRT, hypofractionated (HF) or standard fractionation (SF)), BT monotherapy (HDR, LDR), SBRT (5 fx) and PBT (HF or SF). Trends in utilization were examined. Associations between technique and patient, clinical disease, and sociodemographic characteristics were assessed by multivariable logistic regression, with <i>P</i><0.05 considered significant. <h3>Results</h3> 71,140 patients met inclusion criteria of which 72.4% received standard XRT and 27.6 % received specialized radiation modalities (18.5% brachytherapy, 6.0% SBRT, & 3.1% PBT). Utilization of XRT and BT declined from 71.0% (XRT) and 27.5% (BT) in 2004 to 69.7% (XRT) and 17.2% (BT) in 2017. Receipt of SBRT and PBT increased from 0% (SBRT) and 1.45% (PBT) in 2004 to 9.9% (SBRT) and 3.3% (PBT) in 2017, respectively. On multivariable logistic regression, Black patients were less likely to receive BT (adjusted OR 0.79; 95%CI 0.74-0.83), SBRT (adjusted OR 0.77; 95%CI 0.70-0.85), or PBT (adjusted OR 0.39; 95%CI 0.33-0.47) compared to XRT (all <i>P</i><0.0001). Socially disadvantaged seniors (SDS; age >65 years with Medicaid insurance) were less likely to receive specialized RT (adjusted OR 0.45; 95%CI 0.31-0.60; P<0.0001). Factors associated with increased likelihood of receiving BT, SBRT, or PBT included: treatment at Academic/Research center, treatment at a metropolitan facility, younger age, lower Charlson-Deyo Comorbidity Score, and lower PSA at presentation (all P < 0.01). <h3>Conclusion</h3> Trends in utilization of RT modalities have dramatically changed in recent years with a sharp decline in BT, a doubling of PBT, and rapid adoption of SBRT, as coded in the NCDB. Compared to White patients with GG2 IR PCa, there are disparities in utilization of BT, SBRT, and PBT for Black patients and for SDS. It is unclear whether similar disparities exist for other prostate cancer grade groups for which BT and SBRT are being utilized. Future efforts should address access-to-care challenges for the use of these specialized techniques as they are expanded into higher GG.

Postoperative radiotherapy with modern techniques does not improve survival for operable stage IIIA-N2 non–small cell lung cancer

ObjectivesThis study aims to evaluate whether postoperative radiotherapy using newer techniques (intensity-modulated radiotherapy [IMRT]) is associated with improved survival for patients with stage IIIA-N2 non–small cell lung cancer (NSCLC) who underwent complete resection. MethodsThe overall survival of patients with stage IIIA-N2 NSCLC who received postoperative IMRT versus no postoperative IMRT following induction chemotherapy and lobectomy in the National Cancer Database from 2010-2018 was assessed via Kaplan-Meier analysis, Cox proportional hazards analysis and propensity score-matched analysis. Additional survival analyses were also conducted in patients with completely resected stage IIIA-pN2 NSCLC who had upfront lobectomy (without induction therapy) followed by adjuvant chemotherapy alone or adjuvant chemotherapy with postoperative IMRT. Only patients receiving IMRT, which is a newer, more conformal radiotherapy technique, were included. Patients with positive surgical margins were excluded. ResultsA total of 3203 patients with stage IIA-N2 NSCLC who underwent lobectomy were included. Five hundred eighty-eight (18.4%) patients underwent induction chemotherapy followed by lobectomy, and 2615 (82%) underwent lobectomy followed by chemotherapy. In unadjusted, multivariable-adjusted, and propensity score--matched analyses, there were no significant differences in overall survival between the patients who also received postoperative IMRT versus those who did not. ConclusionsIn this national analysis, the use of postoperative IMRT was not associated with improved survival in patients with completely resected stage IIIA-N2 NSCLC with or without induction chemotherapy.

Simulasi dosis serap kanker payudara dengan empat sudut penyinaran menggunakan teknik radioterapi konformal tiga dimensi

Cancer treatment using radiotherapy has several techniques. This study uses a three-dimensional conformal technique with four radiation directions at angles of 0°, 60°, 180°, and 240°. This study aims to determine the absorbed dose of breast cancer tissue using a three-dimensional conformal radiotherapy technique with the addition of a multileaf collimator (MLC) using a linear accelerator radiotherapy machine. The MLC is modeled in the form of a beam with 24 rods made in duplicate which is inserted in the middle of an empty space in the form of a cylinder with a diameter of 1.3 cm. The cancer tissue was modeled as a ball with a diameter of 3 cm located in the center of the left breast. The method used is the Monte Carlo method using the MCNPX Visual Editor software. The combined absorption dose for the four radiation directions showed the largest absorption dose was in cancer tissue at 2 Gy, while the organ that received the least absorption dose was the liver at 0.0054 Gy.

Quality of Life in Locally Advanced Head and Neck Cancer Patients with Different Radiotherapy Techniques after Definitive Chemo Radiotherapy - A Real-World Data Study with Indian Patients

BACKGROUND&#x0D; The standard of care in non-resectable locally advanced head and neck cancer with squamous cell histology is radical radiotherapy (RT) along with concurrent chemotherapy. Previously, these patients were treated with conventional radiotherapy techniques. Such conventional techniques can lead to morbidity with an impact on quality-of-life (QOL) in long-term survivors. Conformal radiotherapy experiences significant improvements in QOL domains versus conventional techniques. Radiotherapy planning and treatment with conformal techniques require advanced and relatively expensive equipment. Our study is aimed at evaluating the feasibility of conventional radiotherapy techniques in terms of quality of life in locally advanced head and neck cancer patients in comparison to the conformal technique in the Indian setting.&#x0D; METHODS&#x0D; Sixty patients with locally advanced head and neck cancer who received chemo-radiation therapy and came for follow-up after a minimum of two years were scheduled to complete the QOL questionnaire (QLQ-C30 and QLQ-H&amp;N35 scores). These scores were compared between the patients who were treated with conventional and conformal techniques.&#x0D; RESULTS&#x0D; Results showed that when comparing EORTC QLQ–C30 scoring, patients who were treated with conventional RT had a significantly higher median score for emotional QOL and lower median scores for fatigue, pain, appetite loss, and financial difficulties as compared to the conformal RT group. But only the financial difficulties scale showed a significant p-value. When comparing EORTC QLQ–H&amp;N35 scores, all QLQ-HN35 scores did not show any significant difference, except for speech problems. Patients treated with the conventional technique had a significantly lower median score for speech problems compared to the conformal RT group.&#x0D; CONCLUSIONS&#x0D; Based on these results, it is concluded that conventional radiotherapy techniques can be advised to locally advanced head and neck cancer patients when conformal radiotherapy techniques are not available, especially in developing or underdeveloped countries.

Locoregional failure after postoperative flank irradiation for nephroblastoma: Results from the French cohort of the SIOP-2001 trial.

To describe locoregional failure (LRF) after postoperative flank radiotherapy (RT) among French patients with nephroblastoma included in the Société Internationale d'Oncologie Pédiatrique (SIOP)-2001 protocol. In selected SIOP-2001 patients, planning with simulation computed tomography (CT) scan and posttreatment CT scan demonstrating LRF were registered and analyzed. LRF was contoured and classified as in-field, marginal or out-of-field according to dose distribution. Total 316 French SIOP-2001 patients were treated with postoperative RT. Three patients with nephroblastoma developed LRF after flank RT. All failures were located within the retroperitoneum. In two patients, the relapse was within the RT field and in one it was classified as marginal. LRF after postoperative flank RT for nephroblastoma was rare and exclusively situated in the retroperitoneum. These results point out this region as the most at risk of local relapse. A prospective evaluation of a target volume restricted to the retroperitoneum allowing the use of modern and highly conformal radiation techniques in order to decrease dose to normal tissues shall be encouraged.

Dosimetric comparison between intensity modulated radiotherapy and three-dimensional conformal radiotherapy in adjuvant setting after radical cystectomy in high-risk urothelial bladder cancer

Objective: To compare the 4-field 3D conformal radiotherapy technique (3DCRT) to the intensity-modulated radiotherapy (IMRT) 9-field technique for adjuvant radiotherapy post radical cystectomy in high-risk urothelial bladder cancer cases. Patients and Methods: A dosimetric analysis of 11 urothelial bladder cancer patients who underwent radical cystectomy was performed. These patients were presented to the radiotherapy department, National Cancer Institute, Cairo, between 2018 and 2020 with adjuvant radiotherapy using the IMRT technique. Two plans were designed for each patient, one using 9-field IMRT and the second using 4-field 3DCRT. The two techniques were compared, including the PTV, bowel bag, rectum, neobladder, and pelvic bone marrow. Results: Comparing different DVHs, the planning target volume (PTV) was adequately covered in both plans, while the 9-field IMRT technique delivered significantly lower doses to OARs (bowel, rectum, and pelvic bone marrow). Conclusion: The IMRT technique incredibly spared the OARs more than that obtained by the 3DCRT technique, while both techniques covered the PTV adequately. The IMRT technique, through sparing OARs, was expected to decrease early and late radiation side effects.

Experiences and Outcomes in Olfactory Neuroblastoma Over A Decade at a Tertiary Cancer Center.

Background Olfactory neuroblastoma is a rare epithelial malignancy arising from the odorant receptors in the nasal mucosa or along the cribriform plate of the ethmoid bone. Clinical presentation includes nasal stuffiness, local pain, epistaxis, anosmia, visual impairment, proptosis, headache, and seizures. Radiologic imaging with CT or MRI, an ophthalmic evaluation, and histopathologic confirmation with immunohistochemistry are parts of the initial diagnostic workup. Although surgery, chemotherapy, and radiation have an equally important role in the management, earlier stages may preferably be treated with surgery or radiotherapy and the later stages with a multimodality approach. Materials and Methods We conducted a retrospective review of 13 patients diagnosed with olfactory neuroblastoma, registered at Mehdi Nawaz Jung Regional Cancer Center over a decade (2010-2019). We analyzed the age and sex distribution, performance status at presentation, clinical symptomatology, and the Kadish stage. In addition, the therapeutic aspects of patients were studied. Results The most common presentation noted was nasal stuffiness, followed by epistaxis and proptosis. The majority of patients had good performance status at presentation. Ten patients presented with a Kadish stage C, while the remaining patients presented with Kadish stage B. Cervical nodal metastasis was seen in three patients, four patients received multimodality treatment with neoadjuvant chemoradiotherapy followed by surgery, two patients received neoadjuvant chemotherapy followed by radiation, two patients received only surgery, and one patient received surgery followed by adjuvant radiation. Conformal radiation techniques were used to deliver doses as high as 50 to 66 Gy in 2 Gy per fraction. Two patients presented with distant metastasis during follow-up, one with bone metastasis, and the other with retroperitoneal nodal metastasis; they received palliative chemotherapy and conformal radiation to the primary site. Conclusion This study concludes that neoadjuvant chemotherapy followed by radiation gives the best outcomes. It has been observed that in multi-modality treatment, radiotherapy played a significant role in improving overall survival and better outcomes. Multidisciplinary discussions provide a better sequencing of management.

Three-dimensional conformal radiotherapy (3D-CRT) vs. volumetric modulated arc therapy (VMAT) in deep inspiration breath-hold (DIBH) technique in left-sided breast cancer patients-comparative analysis of dose distribution and estimation of projected secondary cancer risk.

The purpose of this study was to compare two techniques of irradiation of left-sided breast cancer patients who underwent breast-conserving surgery, three-dimensional conformal radiotherapy technique (3D-CRT) and volumetric modulated arc therapy (VMAT), in terms of dose distribution in the planning target volume (PTV) and organs at risk (OARs). The second aim of the study was estimation of the projected risk of radiation-induced secondary cancer for both radiotherapy techniques. For 25patients who underwent CT simulation in deep inspiration breath-hold (DIBH), three treatment plans were generated: one using athree-dimensional conformal radiotherapy technique and two using volumetric modulated arc therapy. First VMAT-DIBH geometry consisted of three partial arcs (ARC-DIBH 3A) and second consisted of four partial arcs (ARC-DIBH 4A). Cumulative dose-volume histograms (DVHs) were used to compare dose distributions within the PTV and OARs (heart, left anterior descending coronary artery [LAD], ipsilateral and contralateral lung [IL, CL], and contralateral breast [CB]). Normal tissue complication probabilities (NTCPs) and organ equivalent doses (OEDs) were calculated using the differential DVHs. Excess absolute risks (EARs) for second cancers were estimated using Schneider's full mechanistic dose-response model. All plans fulfilled the criterium for PTV V95% ≥ 95%. The PTV coverage, homogeneity, and conformity indices were significantly better for VMAT-DIBH. VMAT showed asignificantly increased mean dose and V5Gy for all OARs, but reduced LAD Dmax by 15 Gy. For IL, CL, and CB, the 3D-CRT DIBH method achieved the lowest values of EAR: 28.38 per 10,000PYs, 2.55 per 10,000PYs, and 4.48 per 10,000PYs (p < 0.001), compared to 40.29 per 10,000PYs, 15.62 per 10,000PYs, and 23.44 per 10,000PYs for ARC-DIBH 3A plans and 41.12 per 10,000PYs, 15.59 per 10,000PYs, and 22.73 per 10,000PYs for ARC-DIBH 4A plans. Both techniques provided negligibly low NTCPs for all OARs. The study shows that VMAT-DIBH provides better OAR sparing against high doses. However, the large low-dose-bath (≤ 5 Gy) is still aconcern due to the fact that alarger volume of normal tissues exposed to lower doses may increase aradiation-induced risk of secondary cancer.

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

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

Comparison of Breast Cancer Radiotherapy Techniques Regarding Secondary Cancer Risk and Normal Tissue Complication Probability - Modelling and Measurements Using a 3D-Printed Phantom.

BackgroundRadiotherapy after breast-conserving therapy is a standard postoperative treatment of breast cancer, which can be carried out with a variety of irradiation techniques. The treatment planning must take into consideration detrimental effects on the neighbouring organs at risk—the lung, the heart, and the contralateral breast, which can include both short- and long-term effects represented by the normal tissue complication probability and secondary cancer risk.Patients and MethodsIn this planning study, we investigate intensity-modulated (IMRT) and three-dimensional conformal (3D-CRT) radiotherapy techniques including sequential or simultaneously integrated boosts as well as interstitial multicatheter brachytherapy boost techniques of 38 patients with breast-conserving surgery retrospectively. We furthermore develop a 3D-printed breast phantom add-on to allow for catheter placement and to measure the out-of-field dose using thermoluminescent dosimeters placed inside an anthropomorphic phantom. Finally, we estimate normal tissue complication probabilities using the Lyman–Kutcher–Burman model and secondary cancer risks using the linear non-threshold model (out-of-field) and the model by Schneider et al. (in-field).ResultsThe results depend on the combination of primary whole-breast irradiation and boost technique. The normal tissue complication probabilities for various endpoints are of the following order: 1%–2% (symptomatic pneumonitis, ipsilateral lung), 2%–3% (symptomatic pneumonitis, whole lung), and 1%–2% (radiation pneumonitis grade ≥ 2, whole lung). The additional relative risk of ischemic heart disease ranges from +25% to +35%. In-field secondary cancer risk of the ipsilateral lung in left-sided treatment is around 50 per 10,000 person-years for 20 years after exposure at age 55. Out-of-field estimation of secondary cancer risk results in approximately 5 per 10,000 person-years each for the contralateral lung and breast.ConclusionsIn general, 3D-CRT shows the best risk reduction in contrast to IMRT. Regarding the boost concepts, brachytherapy is the most effective method in order to minimise normal tissue complication probability and secondary cancer risk compared to teletherapy boost concepts. Hence, the 3D-CRT technique in combination with an interstitial multicatheter brachytherapy boost is most suitable in terms of risk avoidance for treating breast cancer with techniques including boost concepts.

Comparison of Dosimetric Parameters in Dysphagia Aspiration-Related Structures and Clinical Correlation in Head and Neck Cancer Patients Treated With Radiotherapy.

IntroductionChemoradiotherapy plays a major role in the treatment of head and neck cancer (HNC). Persistent dysphagia following primary chemoradiotherapy for head and neck cancers can have a devastating effect on a patient’s quality of life. Many studies have shown that the dosimetric sparing of critical structures which were included in swallowing such as the pharyngeal constrictor muscle and larynx can provide improved functional outcomes and better quality of life. However, there are no current randomized studies confirming the benefits of such swallowing-sparing strategies. The aim is to evaluate late dysphagia after chemoradiotherapy for head and neck cancer and to examine its correlation with clinical and dosimetric parameters.Materials and methodsThe period of this prospective study was from November 2018 to March 2020. Patients were divided randomly in 1:1 ratio into two groups, group 1 and group 2, each with 25 patients. Group 1 was planned by three-dimensional conformal radiotherapy (3D-CRT) technique and group 2 was planned by intensity-modulated radiotherapy technique (IMRT) technique. Treatment was delivered after approval of radiotherapy plan. To evaluate the dose to dysphagia aspiration-related structures (DARS), these structures were contoured and dose-volume histograms were generated. Various dosimetric parameters of DARS were evaluated. Swallowing status was clinically evaluated based on the Radiation Therapy Oncology Group and the Common Terminology Criteria for Adverse Events, version 5.ResultsA significant advantage was seen with intensity-modulated radiotherapy technique (IMRT) in comparison to three-dimensional conformal radiotherapy (3D-CRT) in terms of mean dose delivered to the pharyngeal constrictor muscles (66.03 Gy vs 68.77 Gy, p=0.003). The mean dose delivered to the combined dysphagia/aspiration-related structures (DARS) was statistically significantly lower in IMRT compared to 3D-CRT (66.15 Gy vs. 70.09 Gy, p<0.001). Other dose-volumes were also reduced in IMRT group (V30: {98.64% vs. 99.88%, p=0.05}; V50: {90.49% vs. 99.02%, p=0.0002}; V60: {83.92% vs. 95.04, p=0.0002}; D50: {70 Gy vs. 71.16 Gy, p=0.001); and D80: {61.18 Gy vs. 67.39 Gy, p=0.01}. Futhermore, the clinical worsening of dysphagia was less common in IMRT group (48% vs. 80%, p=0.039).ConclusionIMRT can reduce the high-dose volumes received by the DARS receiving high doses by sparing these structures through optimization. This may provide a significant additional benefit that could improve dysphagia and hence the quality of life of patients with head and neck cancer.

Radioterapi Linac Energi 6 MV Terhadap Kanker Serviks Pada Organ Rektum Menggunakan Teknik 3DCRT dan IMRT Di RSUP Sanglah Denpasar

Cervical cancer radiotherapy on the Linac aircraft uses a 6 MV energy photon beam with 3 Dimension Conformal Radiotherapy (3DCRT) and Intensity Modulation Radiation Therapy (IMRT) techniques. Radiotherapy planning on the 3DCRT and IMRT techniques is then compared by analyzing the dose distribution or planning target volume (PTV) coverage through the Conformity Index (CI) and Homogeneity Index (HI) and Organ At Risk (OAR) where the risk organ that is considered is the rectum. In this study, 30 data on cervical cancer patients were used at the Radiotherapy Installation at Sanglah Hospital Denpasar with a plan using a box system on the 3DCRT technique and the IMRT technique with rotation angles of 00, 900, 1800, and 2700 and a radiation dose of 5000 cGy. Comparison of these two techniques is done by analyzing the Dose Volume Histogram (DVH) curve on PTV coverage on the Treatment Planning System (TPS) computer. The results of this study indicate that the average CI value in the 3DCRT technique is 1.017542 while the IMRT technique is 1.019668, with the Mann Whitney test (Asymp.Sig = 0.492). Likewise, the HI value, where the 3DCRT technique averaged 0.089494 while the IMRT technique was 0.093126 with Mann Whitney test (Asymp.Sig = 0.487), both CI and HI values were not significant. While the percentage of the average dose of the rectum on both the 3DCRT and IMRT irradiation techniques are 96% and 87%, respectively. Cervical cancer radiotherapy using IMRT technique can minimize the absorbed dose in OAR (rectum).