Pelvic Radiotherapy In Patients Research Articles

Impact of pelvic radiation therapy in patients with early neuroendocrine cervical carcinoma and no residual disease in the radical hysterectomy specimen: a NeCTuR study

ObjectiveThe impact of adjuvant pelvic radiation therapy on the rate and location of recurrences was evaluated in patients with early-stage (IA1–IB2) neuroendocrine cervical carcinoma who underwent prior conization or polypectomy...

A ferroptosis-targeting ceria anchored halloysite as orally drug delivery system for radiation colitis therapy

Radiation colitis is the leading cause of diarrhea and hematochezia in pelvic radiotherapy patients. This work advances the pathogenesis of radiation colitis from the perspective of ferroptosis. An oral Pickering emulsion is stabilized with halloysite clay nanotubes to alleviate radiation colitis by inhibiting ferroptosis. Ceria nanozyme grown in situ on nanotubes can scavenge reactive oxygen species, and deferiprone was loaded into the lumen of nanotubes to relieve iron stress. These two strategies effectively inhibit lipid peroxidation and rescue ferroptosis in the intestinal microenvironment. The clay nanotubes play a critical role as either a medicine to alleviate colitis, a nanocarrier that targets the inflamed colon by electrostatic adsorption, or an interfacial stabilizer for emulsions. This ferroptosis-based strategy was effective in vitro and in vivo, providing a prospective candidate for radiotherapy protection via rational regulation of specific oxidative stress.

Feasibility of hypofractionated pelvic radiotherapy with parametrial and nodal simultaneous integrated boost for locally advanced cervical cancers: dummy run for the HYACINCT trial

Objectives The HYACINCT trial will investigate the role of dose-adapted hypofractionated pelvic radiotherapy in patients with locally advanced cervical cancer who are ineligible for cisplatin. This dummy run evaluated the feasibility of the protocol treatment planning objectives using intensity-modulated radiotherapy (IMRT) and volumetric arc therapy (VMAT). Material and Methods The HYACINCT protocol defines a set of guidelines for image acquisition, target and organ delineation, and treatment planning objectives. Fifteen dummy cases were prepared, five each for three levels of dose requirements: 40 Gy without boost, and with boost to 45 Gy and to 48 Gy. IMRT and VMAT plans were prepared for each case, evaluated and assigned penalty and compliance scores according to planning objectives, and subjected to quality control. IMRT and VMAT plans were compared in terms of treatment plan quality (target coverage, penalty, and compliance scores), and treatment delivery. Tumor extent (T-stage, T-score), nodal status, and PTV volumes (in cc) were examined as potential determinants of penalty and compliance scores. Results IMRT was able to meet the planning objectives for all but one case; and VMAT, for all cases. All plans passed the quality control check. IMRT and VMAT were equivalent in terms of target coverage and penalty and compliance scores, but the latter was associated with better treatment delivery. T-score was a determinant for the penalty score. Conclusion The HYACINCT radiotherapy protocol is feasible with either IMRT or VMAT. VMAT may be beneficial in more extensive cases, as measured by the T-score. Trial Registration Number NCT05210270

SynthRAD2023 Grand Challenge dataset: Generating synthetic CT for radiotherapy.

Medical imaging has become increasingly important in diagnosing and treating oncological patients, particularly in radiotherapy. Recent advances in synthetic computed tomography (sCT) generation have increased interest in public challenges to provide data and evaluation metrics for comparing different approaches openly. This paper describes a dataset of brain and pelvis computed tomography (CT) images with rigidly registered cone-beam CT(CBCT) and magnetic resonance imaging (MRI) images to facilitate the development and evaluation of sCT generation for radiotherapy planning. The dataset consists of CT, CBCT, and MRI of 540 brains and 540 pelvic radiotherapy patients from three Dutch university medical centers. Subjects' ages ranged from 3 to 93 years, with a mean age of 60. Various scanner models and acquisition settings were used across patients from the three data-providing centers. Details are available in a comma separated value files provided with the datasets. The data is available on Zenodo (https://doi.org/10.5281/zenodo.7260704, https://doi.org/10.5281/zenodo.7868168) under the SynthRAD2023 collection. The images for each subject are available in nifti format. This dataset will enable the evaluation and development of image synthesis algorithms for radiotherapy purposes on a realistic multi-center dataset with varying acquisition protocols. Synthetic CT generation has numerous applications in radiation therapy, including diagnosis, treatment planning, treatment monitoring, and surgical planning.

Comprehensive dose evaluation of a Deep Learning based synthetic Computed Tomography algorithm for pelvic Magnetic Resonance-only radiotherapy

Background and PurposeMagnetic Resonance (MR)-only radiotherapy enables the use of MR without the uncertainty of MR–Computed Tomography (CT) registration. This requires a synthetic CT (sCT) for dose calculations, which can be facilitated by a novel Zero Echo Time (ZTE) sequence where bones are visible and images are acquired in 65 seconds. This study evaluated the dose calculation accuracy for pelvic sites of a ZTE-based Deep Learning sCT algorithm developed by GE Healthcare. Materials and MethodsZTE and CT images were acquired in 56 pelvic radiotherapy patients in the radiotherapy position. A 2D U-net convolutional neural network was trained using pairs of deformably registered CT and ZTE images from 36 patients. In the remaining 20 patients the dosimetric accuracy of the sCT was assessed using cylindrical dummy Planning Target Volumes (PTVs) positioned at four different central axial locations, as well as the clinical treatment plans (for prostate (n = 10), rectum (n = 4) and anus (n = 6) cancers). The sCT was rigidly and deformably registered, the plan recalculated and the doses compared using mean differences and gamma analysis. ResultsMean dose differences to the PTV D98% were ≤ 0.5% for all dummy PTVs and clinical plans (rigid registration). Mean gamma pass rates at 1%/1 mm were 98.0 ± 0.4% (rigid) and 100.0 ± 0.0% (deformable), 96.5 ± 0.8% and 99.8 ± 0.1%, and 95.4 ± 0.6% and 99.4 ± 0.4% for the clinical prostate, rectum and anus plans respectively. ConclusionsA ZTE-based sCT algorithm with high dose accuracy throughout the pelvis has been developed. This suggests the algorithm is sufficiently accurate for MR-only radiotherapy for all pelvic sites.

24P A phase II trial of docetaxel/cisplatin chemotherapy followed by pelvic radiation therapy in patients with high-risk endometrial carcinoma after staging surgery

The purpose of this study was to evaluate the efficacy of docetaxel/cisplatin chemotherapy followed by pelvic radiation therapy after staging surgery in high-risk endometrial cancer patients. This was a prospective, phase 2, multicenter clinical trial. Eligible patients included surgically staged stage I-II endometrial cancer with high-risk factors and stage III-IV endometrial cancer. Three cycles of chemotherapy consisting of docetaxel (70 mg/m2) and cisplatin (60mg/m2) was started within 5 weeks after staging surgery. Pelvic radiation therapy (45-50.4Gy) was started within 4 weeks after chemotherapy. The primary endpoint was progression-free survival (PFS). A total of 67 patients were enrolled but 9 were excluded. Median age was 54 years (range, 31-73 years). Forty patients (69%) had endometrioid adenocarcinoma. Stage was IIIC in 9 (15%), IVA in 15 (26%), and IVB in 11 patients (19%). Staging surgery was performed by open surgery in 27 patients (46%), laparoscopic surgery in 23 patients (40%), and robotic surgery in 8 patients (14%). Grade 3 and 4 hematologic toxicity was reported in 26 and 43 patients, grade 3 non-hematologic toxicity was reported in 13 patients. After a median follow-up of 58 months (range, 2-101 months), 11 patients had recurrence and 2 of them died of disease. PFS (± SE) was 90% (± 4%), 84.3% (± 4.8 %), 79.9% (± 5.5 %) at 1, 3, and 5 year, respectively. Overall survival (± SE) was 98.3% (± 1.7%), 96.2%, (± 2.6%), 96.2 (± 2.6%) at 1, 3, and 5 year, respectively. Endometrial cancer with high risk factors could benefit from adjuvant chemotherapy using docetaxel/cisplatin followed by radiation therapy with manageable toxicities. Further studies are needed with the incorporation of biological agents to estimate the real benefit of these treatment strategy.

A machine learning model for grade 4 lymphopenia prediction during pelvic radiotherapy in patients with cervical cancer.

Background/purposeSevere lymphopenia during pelvic radiotherapy (RT) predicts poor survival in patients with cervical cancer. However, the risk of severe lymphopenia has not been well predicted. We developed a machine learning model using clinical and dosimetric information to predict grade 4 (G4) lymphopenia during pelvic RT in patients with cervical cancer.MethodsThis retrospective study included cervical cancer patients treated with definitive pelvic RT ± induction/concurrent chemotherapy. Clinical information and a set of dosimetric parameters of external beam radiotherapy plan were collected. G4 lymphopenia during RT, which was also referred to as G4 absolute lymphocyte count (ALC) nadir, was defined as ALC nadir <0.2 × 109 cells/L during RT according to Common Terminology Criteria for Adverse Events (CTCAE) v4.03. Elastic-net logistic regression models were constructed for the prediction of G4 lymphopenia during pelvic RT using a repeated cross-validation methodology.ResultsA total of 130 patients were eligible, and 43 (33.1%) patients had G4 lymphopenia during RT. On multivariable analysis, G4 ALC nadir was associated with poor overall survival (OS) [hazard ratio (HR), 3.91; 95% confidence interval (CI), 1.34–11.38, p = 0.01]. Seven significant factors [Eastern Cooperative Oncology Group (ECOG) performance score, pre-RT hemoglobin, pre-RT lymphocytes, concurrent chemotherapy, gross tumor volume of regional lymphadenopathy (GTV_N volume), body volume, and maximum dose of planning target volume receiving at least 55 Gy (PTV_5500 Dmax)] were obtained by elastic-net logistic regression models and were included in the final prediction model for G4 ALC nadir. The model’s predicting ability in test set was area under the curve (AUC) = 0.77 and accuracy = 0.76. A nomogram of the final predicting model was constructed.ConclusionsThis study developed and validated a comprehensive model integrating clinical and dosimetric parameters by machine learning method, which performed well in predicting G4 lymphopenia during pelvic RT for cervical cancer and will facilitate physicians to identify patients at high risk of G4 lymphopenia who might benefit from modified treatment approaches.

Systematic Review of Comparisons Between Plastic and Silicone Dilators: Revealing a Knowledge Gap.

Vaginal stenosis is a distressing side effect of radiation therapy that can impair quality of life. Dilator therapy is an option for patients undergoing pelvic radiotherapy to mitigate vaginal stenosis. Currently, the dilators given to patients by most hospitals are made of plastic, compared to silicone dilators which are available on the market for purchase. We conducted a systematic literature review to find information to guide clinical recommendations to pelvic radiotherapy patients on potential differences regarding the use of plastic vs silicone dilators with regard to efficacy, cost, and patient preferences. A systematic literature review was conducted in Embase, MEDLINE, and PubMed using Emtree terms. To be included in the review, papers needed to: focus on female patients undergoing radiation therapy, assess a vaginal dilator, measure any dilator intervention outcome, and specifically compare plastic vs silicone dilators for any measured outcome (either qualitative or quantitative). The initial search yielded 195 articles. Two area experts, with a third expert for arbitration, read each article and found that none met all review inclusion criteria. No studies were found that compared silicone to plastic dilators with regard to efficacy in treating vaginal stenosis due to radiation therapy, no studies were found that compared cost or cost-effectiveness of the 2 dilator types, and no studies were found comparing patient preferences or experiences (eg, comfort, adherence, ease of use) between the 2 dilator types. The materials used to create dilators have never been rigorously compared in the context of radiotherapy-related vaginal stenosis. Institutions and patients have no data to guide their choice. Significantly more research at the patient and institutional level is needed to explore the potential long-term quality of life and cost benefits of improved adherence with silicone dilator use, and to guide shared decision-making regarding dilator choice.

A nodal risk cutoff for whole pelvic radiotherapy for prostate cancer?

In their recent Review paper in The Lancet Oncology, Gert De Meerleer and colleagues take a comprehensive look at evidence for pelvic irradiation in patients with prostate cancer.1 Specifically, for clinically node-negative prostate cancer, the value of elective whole pelvic radiotherapy (WPRT) has been discussed at length. For patients with Roach nodal risk of at least 20%, the POP-RT trial showed significant improvement in biochemical control, disease-free survival, and metastasis-free survival with WPRT.

Sonographic Imaging of Surgically Transpositioned Ovaries in the Treatment of Rectal Carcinoma

Pelvic radiation therapy in patients with advanced rectal carcinoma improves oncological outcomes, but often raises infertility concerns in reproductive-age patients. Laparoscopic ovarian transposition is a surgical method which may offer preservation of ovarian function during and after cancer treatment. Sonographic evaluation of the ovaries post transposition gives insight into their condition and the efficacy of ovarian transposition in the continuation of ovarian function after radiation. This case describes how sonography was used to identify and evaluate surgically transpositioned ovaries in a patient with rectal adenocarcinoma.

646TiP A randomized phase III, factorial design, of cabazitaxel and pelvic radiotherapy in patients with localized prostate cancer and high-risk features of relapse: The PEACE 2 trial from Unicancer

Although prostate cancer-related death is almost systematically due to metastatic dissemination, nowadays most prostate cancer patients have localized disease at diagnosis. Compared to radiotherapy (RT) alone, combining androgen deprivation therapy (ADT) with RT improves survival of patients with high-risk localized prostate cancer. Adding ADT plus docetaxel before prostate RT improves failure-free survival. Cabazitaxel, a second-generation taxane, is active against several docetaxel-resistant cell lines and is better tolerated than docetaxel from a patient standpoint.

Elective nodal radiotherapy in prostate cancer.

In patients with prostate cancer who have a high risk of pelvic nodal disease, the use of elective whole pelvis radiotherapy is still controversial. Two large, randomised, controlled trials (RTOG 9413 and GETUG-01) did not show a benefit of elective whole pelvis radiotherapy over prostate-only radiotherapy. In 2020, the POP-RT trial established the role of elective whole pelvis radiotherapy in patients who have more than a 35% risk of lymph node invasion (known as the Roach formula). POP-RT stressed the importance of patient selection. In patients with cN1 (clinically node positive) disease or pN1 (pathologically node positive) disease, the addition of whole pelvis radiotherapy to androgen deprivation therapy significantly improved survival compared with androgen deprivation therapy alone, as shown in large, retrospective studies. This patient population might increase in the future because use of the more sensitive prostate-specific membrane antigen PET-CT will become the standard staging procedure. Additionally, the SPORTT trial suggested a benefit of whole pelvis radiotherapy in biochemical recurrence-free survival in the salvage setting. A correct definition of the upper field border, which should include the bifurcation of the abdominal aorta, is key in the use of pelvic radiotherapy. As a result of using modern radiotherapy technology, severe late urinary and intestinal toxic effects are rare and do not seem to increase compared with prostate-only radiotherapy.

PO-1668 Impact of immobilization devices on planning target volume for pelvic radiotherapy patients

PO-1668 Impact of immobilization devices on planning target volume for pelvic radiotherapy patients

The effect of patient positioning (prone or supine) on the dose received by small bowel in pelvic radiotherapy in rectal cancer patients

PurposeThe small bowel is a main dose-limiting organ in pelvic radiotherapy in the patients with rectal cancer. Conventionally, pelvic radiotherapy of patients with rectal cancer is performed in the prone position. Material and MethodsThirty-nine patients underwent CT planning scan in the treatment position (20 patients in prone position group and 19 patients in supine position group). After radiation treatment planning optimization, the volumes of the irradiated small intestines were investigated. ResultsThe volume of irradiated small bowel was higher in the supine position (mean difference; 36,274 cm3). However, it was not statistically significant (P value=0.187) ConclusionSupine position could be accepted for the patients undergoing preoperative rectal cancer chemo-radiation.

Association of bowel radiation dose-volume with skeletal muscle loss during pelvic intensity-modulated radiotherapy in cervical cancer.

Radiation-induced bowel damage may compromise nutrient absorption and digestion and affect body composition during pelvic radiotherapy in patients with locally advanced cervical cancer (LACC). This study aimed to evaluate the relationship between bowel radiation dose-volume and body composition changes during pelvic radiotherapy. Data of 301 LACC patients treated with chemoradiotherapy were analyzed. Changes in skeletal muscle index (SMI) and density (SMD), and total adipose tissue index (TATI) were measured from computed tomography images at the L3 vertebral level. A reduction in SMI, SMD, or TATI of ≥10% was classified as "loss." Bowel V45 indicates the bowel volume (mL) receiving a radiation dose of ≥45 Gy. The relationship between body composition and bowel V45 was analyzed using logistic regression models. After treatment, 61 (20.3%), 81 (26.9%), and 97 (32.2%) patients experienced SMI, SMD, and TATI loss, respectively. Increased bowel V45 was independently associated with increased odds of SMI loss (odds ratio [OR]: 1.012; 95% confidence interval [CI]: 1.007-1.018; p<0.001) and TATI loss (OR: 1.006; 95% CI: 1.001-1.010; p=0.01), but not with SMD loss (OR: 1.005; 95% CI: 1.000-1.009; p=0.054). The cut-off value with the highest accuracy for predicting SMI loss was V45 ≥222 mL; a higher rate of SMI loss was noted in 40.0% of patients with V45 ≥222 mL than in 13.7% of patients with V45 <222 mL (p<0.001). Higher bowel dose-volume was significantly associated with muscle loss during pelvic radiotherapy. Bowel dose-volume consideration is required in individualized nutritional counseling and supportive care in clinical practice.

A199 SEVERE COLITIS FOLLOWING PELVIC RADIOTHERAPY: CASE REPORT AND REVIEW OF THE LITERATURE

Abstract Background Mild-to-moderate proctocolitis is a well-known complication of pelvic radiation therapy, occurring in 43% and 6% of patients following external beam radiotherapy (EBRT) and brachytherapy (BT), respectively. This typically presents as recurrent painless rectal bleeding, diarrhea, urgency, and/or iron-deficiency anemia. Severe ulcerating proctocolitis is a less common complication of pelvic radiotherapy and is rare following BT. We report two cases of severe ulcerating proctocolitis mimicking inflammatory bowel disease (IBD) following pelvic radiotherapy in patients without known IBD, including an elderly male undergoing EBRT, and an elderly female undergoing vaginal vault BT. Aims To describe two cases of severe ulcerating proctocolitis, mimicking IBD, following pelvic radiotherapy. Methods Case descriptions and literature review. Results A 71-year-old male without antecedent gastrointestinal disease developed bloody diarrhea 3 months following EBRT for treatment of prostate cancer. Infectious work-up was negative. Blood work showed anemia and an elevated CRP. CT scan showed distal large bowel inflammation concerning for proctocolitis. Flexible sigmoidoscopy revealed severe proctosigmoiditis with circumferential thickening and nodularity of the mucosa and multiple ulcers. Biopsies showed ulcer tissue with fibrinopurulent exudate. He was treated with systemic corticosteroids and symptoms gradually resolved. Repeat colonoscopy 8 months later showed healed inflammation with scarring and residual radiation proctosigmoiditis. A 74-year-old female without antecedent gastrointestinal disease developed watery diarrhea 2 weeks after initiating low dose vaginal vault BT for treatment of endometrial cancer. Infectious work-up was negative. Blood work showed an elevated CRP and CT scan revealed proctocolitis extending to the descending colon. Flexible sigmoidoscopy revealed severe ulcerating proctosigmoiditis with tram tracks of denuded mucosa. Biopsies showed moderate diffuse chronic active colitis with crypt abscesses and apoptotic bodies. She was treated with systemic corticosteroids followed by infliximab and methotrexate, with mild symptomatic improvement. However, repeat endoscopy revealed persistent severe ulceration. Unfortunately, she developed a sigmoid perforation with pelvic abscess, leading to bacteremia and fungemia, and subsequently passed. Conclusions While rare, severe ulcerating proctocolitis mimicking IBD can occur following pelvic radiotherapy, including BT. The decision to manage these patients as IBD using immunosuppressive therapy should be weighed against the risks of these therapies, considering a patient’s age and underlying health, and in collaboration with a patient’s health care team. Careful assessment for risk factors and pathological findings from biopsy specimens may help in predicting the likelihood of IBD in such patients. Funding Agencies None

Retrospective audit of inter-fraction motion for pelvic node radiotherapy in prostate cancer patients

IntroductionPelvic lymph nodes move independently to the prostate. When delivering radiotherapy to prostate and pelvic lymph nodes, daily inter- and intra-fraction anatomical changes need to be accounted for. Planning target volume (PTV) margins, grown from the pelvic lymph node clinical target volume need to be determined, to account for this variation in position. MethodsTwenty patients who had daily online image guided radiotherapy to prostate and pelvic lymph nodes between April and December 2018 were selected. Ten pre-treatment verification images using cone beam CT from each patient were registered to pelvic bone anatomy, prostate soft tissue or fiducial markers and pelvic lymph node soft tissue to assess the accuracy of treatment delivery. Population systematic and random errors and PTV margins were calculated. ResultsPTV margins of 0.4 cm, 0.4 cm and 0.7 cm left–right (LR), superior–inferior (SI) and anterior–posterior (AP) respectively were derived for the pelvic lymph nodes when registering to prostate. PTV margins of 0.3 cm, 0.2 cm and 0.4 cm LR, SI and AP respectively were derived for the pelvic lymph nodes when registering to bone. There was a posterior systematic shift of the prostate during the treatment course. ConclusionThere is differential motion of pelvic lymph nodes to prostate and in the era of prostate and pelvic radiotherapy for patients with node positive prostate cancer; there is increasing importance in the accuracy of dose delivery to the involved lymph node. Hence, this group of patients may benefit from personalised radiotherapy PTV margins, especially if the involved pelvic lymph node is within the anterior part of the clinical target volume. Implications for practiceOptimisation of dose delivery to the pelvic lymph nodes when prioritising the prostate in prostate and pelvic lymph node image guided radiotherapy.

Risk factors associated with Para-Aortic Lymph Node Failure after pelvic irradiation in patients with Cervical Cancer.

Objective: Previous studies have shown that prophylactic extended-field irradiation can reduce para-aortic lymph node failure (PALNF) rates in patients with cervical cancer. As such, this type of irradiation may particularly benefit patients with a high risk of PALNF. In the present study, we analyzed the risk factors for PALNF in patients with cervical cancer treated with pelvic irradiation in order to identify potential indications of prophylactic extended-field irradiation.Methods: We evaluated patients with 2018 FIGO stage IB3-IIIC1 cervical cancer who were treated with definitive pelvic radiotherapy or concurrent chemoradiotherapy at our institution between 2011 and 2014. Univariate and multivariate analyses were performed to identify risk factors for PALNF.Results: We included 572 patients in the study. The median follow-up period was 37.9 months. Eighteen patients (3.1%) first site of tumor relapse was the para-aortic lymph nodes, and thus showed PALNF. Using multivariate Cox regression analysis, we identified two significant risk factors for PALNF: tumor extension to the pelvic wall (hazard ratio, HR 3.60, p=0.026) and ≥ 2 pelvic MLNs (HR 5.30, p=0.005). For patients with and without risk factors, the 3-year overall survival, disease-free survival, and PALNF rates were 77.3% and 90.1% (p<0.001), 56.4% and 83.1% (p<0.001), and 12.0% and 2.3% (p<0.001), respectively.Conclusion: Tumor extension to the pelvic wall and ≥ 2 pelvic MLNs are positively associated with PALNF after pelvic irradiation in patients with cervical cancer. Further trials will be required to validate whether patients with these two risk factors may benefit from prophylactic extended-field irradiation.

A service evaluation of immobilisation devices for pelvic radiotherapy patients: could a hand held grip ring provide the link between patient comfort and geometric accuracy?

Keywords: Immobilisation, Grip ring, patient experience, pelvic radiotherapy Introduction: For many departments the standard set up for pelvis patients is to have the patients hands placed on their chest in a position which is comfortable for them to maintain during treatment. To improve the patient experience by providing ways of relaxing the patient, making them more comfortable for treatment, and also creating a more reproducible position for geometric accuracy a service evaluation was completed. A service evaluation was undertaken to ascertain how to increase patient comfort and their ability to relax, thus enhancing their experience, whilst creating a more reproducible position to improve geometric accuracy. Method and Materials:•Sample size of 40 randomised patients•All undergoing pelvic radiotherapy•All selected patients treated with and without the grip ring for a comparison•Each patient completed a survey relating to comfort/relaxation•Data from survey was sourced and divided into positive and negative responses•Data from daily CBCT images acquired from 10 patients in both set ups (10 with grip ring, 10 without grip ring) Results: Data from 40 separate surveys revealed 77% of patients felt more comfortable and relaxed while holding the grip ring, 6% disliked the grip ring and 17% felt no change. Only 20% of patients had errors outside the tolerance band whilst holding the ring compared to 40% of those who did not. This was based on images with directional errors of >0.3cm being out of tolerance. Conclusion and Discussion: A high percentage of patients found the grip ring made treatment more comfortable and relaxed. These results are indicating that the grip ring leads to an improvement in patient position which leads to a more accurate setup. Introducing a more comfortable method of immobilisation that helps to relax the patient could also be used as a tool to help relax dementia patients. The findings from this service evaluation shows the grip ring to be a low cost piece of immobilisation that enhances the patient experience and comfort whilst also improving immobilisation and geometric accuracy. Numerical

Toxicity and Efficacy Outcomes of Preoperative Pelvic Radiation Therapy in Patients with Inflammatory Bowel Disease and Rectal Cancer

Toxicity and Efficacy Outcomes of Preoperative Pelvic Radiation Therapy in Patients with Inflammatory Bowel Disease and Rectal Cancer