Moderate Hypofractionation Research Articles

Impact of dose fractionation regimen of adjuvant radiotherapy on cosmetic outcomes after immediate breast reconstruction

Background. Evidence for the safety of using the hypofractionation (HF) regimen after immediate breast reconstruction (IBR) in patients with breast cancer is not well documented. the purpose of the study was a retrospective analysis of surgical treatment with IBR and postoperative radiation therapy (RT) in conventional fractionated (CF) and hypofractionated (HF) regimens in breast cancer patients. Material and Methods. a retrospective analysis of treatment outcomes was carried out in 219 breast cancer patients who underwent mastectomy with IBR using permanent implant or tissue expander. all patients received postoperative RT: 97 received CF RT (22–25 fractions of 2 Gy) and 122 HF RT (15–16 fractions of 2.66–2.7 Gy). Cosmetic complications were represented by reconstructive failure (RF). all patients underwent an analysis of the incidence of reconstructive failures (RF) or capsular contracture (CC) (Baker III–IV). Results. CF RT was performed in 97 women: 55 – after IBR using tissue expander and 42 using permanent implant. the median follow-up time was 61 months. Complications were observed in 37 women (35.1 %): RF in 22 cases (22.7 %) and CC in 12 (12.4 %) cases. the median time to RF was 8 months, CC – 48.5 months. after RT to the tissue expander, CC rate was 0 %, RF – 25.5 %. after RT to the implants, CC was revealed in 28.6 %, RF in 19 % cases. In patients who received HF RT, cosmetic complications were detected in 51 (41.8 %) of 122 patients. the median follow-up time was 34 months. RF was revealed in 22.1 % cases, the median time was 9 months. CC was observed in 24 women (19.7 %) with the median time of 27 months. after HF RT to the expander, CC was observed in 4.9 %, RF in 39 % of cases. After RT to the implant, CC was detected in 27.2 %, RF in 13.6 % of cases. no significant differences in the risk of complication between patients who received conventional or hypofractionated RT were found (р=0.19). after RT to the expander, no differences (р=0.18 and р=0.12). After RT to the implant, there were also no differences in the frequency of CC and RF (р=0.52 and р=0.42). Conclusion. There were no significant differences in the frequency of cosmetic complications after postoperative radiotherapy in conventional fractionation or moderate hypofractionation regimens.

Implant-based reconstruction and adjuvant radiotherapy in breast cancer patients-current status and DEGRO recommendations.

The aim of this review is to give an overview of the results of prospective and retrospective studies using allogenic reconstruction and postmastectomy radiotherapy (PMRT) in breast cancer and to make recommendations regarding this interdisciplinary approach. APubMed search was conducted to extract relevant articles from 2000 to 2024. The search was performed using the following terms: (breast cancer) AND (reconstruction OR implant OR expander) AND (radiotherapy OR radiation). Data from the literature on allogenic breast reconstruction and radiation are presented and discussed in relation to toxicity and cosmesis. Breast reconstruction is also feasible if PMRT is necessary. Patients need to be informed about the relevant risk of capsular fibrosis and implant failure. Aplanned reconstruction is no reason to forgo PMRT nor is an indication for PMRT areason to forego implant-based breast reconstruction if desired by the patient. It is important to provide detailed information here to enable shared decision-making. There is still no clear consensus regarding implant-based reconstruction (IBR) and PMRT. However, in clinical practice, both aone-stage (immediate "implant-direct" IBR) procedure with PMRT up to the final implant and atwo-stage (immediate-delayed IBR) procedure with PMRT up to the tissue expander (TE) and later exchange of the TE are used; both approaches have their specific advantages and disadvantages. Depending on patient-specific factors and the surgeon's experience and estimates, both IBR procedures are also possible in combination with PMRT. When using aTE/implant approach, completing skin stretching by adequately filling the expander before PMRT may be favorable. This approach is particularly practical when adjuvant chemotherapy is planned but may lead to postponement of radiotherapy when primary systemic therapy is given. According to the latest data, moderate hypofractionation also appears to be safe in the context of the IBR approach. It is important to have aclosely coordinated interdisciplinary approach and to fully inform patients about the increased rate of potential side effects.

Quantifying non-clinical outcomes of ultra-hypofractionated breast radiotherapy in Western NSW-A narrative review.

Ultra-Hypofractionated Whole Breast Radiotherapy (U-WBRT) has been proven to be a viable treatment option for breast cancer patients receiving radiation therapy, however, due to its novelty our understanding of its non-clinical benefits is still evolving. With increasing U-WBRT selection during COVID and in rural and regional settings such as the Western New South Wales Local Health District (WNSWLHD), it's important to quantify the savings when compared to other fractionation schedules (e.g. Conventional fractionation (C-WBRT) involving 25 fractions and Moderate hypofractionation (M-WBRT) with 15 fractions.) Using literature sourced from Medline, Embase, Pubmed and reports from relevant websites and organisations this narrative review investigates quantifiable methods of assessing non-clinical benefits of U-WBRT in rural settings according to the triple bottom line philosophy. This review was able to identify a standard set of quantifiable metrics that can compare the non-clinical benefits of various fractionation schedules, with relevance to a rural setting. These include: fractionation trends, financial subsidy, average linear accelerator (Linac) minutes, hospital visits, travel time and distance, Linac energy consumption, travel and Linac carbon emissions. By identifying these metrics, non-clinical benefits between the fractionation schedules can easily be quantified and compared.

Prospective Observational Study on Moderate Hypofractionated Radiotherapy for Localized Prostate Cancer in Rwanda: Acute Toxicity in Patients.

Moderate hypofractionation (MHF) offers logistical and financial advantages, and has become standard in Western countries but not yet in Africa. This study assessed GI and genitourinary (GU) acute toxicity in Rwandan men undergoing MHF (20 × 3 Gy) treatment. Since 2021, patients with prostate cancer at the Rwanda Cancer Centre have been informed about the study on MHF treatment and could participate by signing an informed consent. The study included patients with confirmed prostate adenocarcinoma (any T, any prostate-specific antigen any Gleason score, N0M0), excluding those with inflammatory bowel disease, previous pelvic irradiation, or previous prostatectomy. Participants received 20 fractions of 3 Gy over 4 weeks using the volumetric modulated arc radiotherapy (RT) technique with a 6 megavoltage linear accelerator. GI and GU acute toxicity was evaluated at week 2, at the end of RT, and 3 months after treatment using the Radiation Therapy Oncology Group (RTOG) acute toxicity grading system. Fifty consecutive patients with localized prostate cancer were included. The median patient age was 70 years. Most patients (86%) had high-risk disease and 94% received androgen-deprivation therapy. The cost and treatment time were reduced by 50%. The distribution of maximum acute RTOG toxicity scores were for GI 10% grade 0, 70% grade 1, 20% grade 2, 0% grade 3, and for GU scores were 0%, 40%, 54%, and 6%, respectively. By 3 months, RT symptoms had returned to baseline levels for most patients. MHF (20 × 3 Gy) was well tolerated in men treated for prostate cancer in Rwanda, showing that MHF is feasible in an African setting. However, further research on acute and late toxicity for more patients is warranted.

Investigating the Uptake of Hypofractionation for Breast and Prostate Cancer in Sub-Saharan Africa: A Qualitative Study of Physician and Medical Physicist Perspectives

In prostate and breast cancer, moderate hypofractionation (HF) has demonstrated comparable, if not greater, efficacy than conventional fractionation. There is a stark disparity in the uptake of HF between North America and Africa. Using the Consolidative Framework for Implementation Research, we evaluated barriers and facilitators for implementing HF in Sub-Saharan Africa (SSA). Radiation oncologists and medical physicists working in SSA were recruited via the AORTIC Radiation Oncology Special Interest Group and subsequent snowball sampling. Interviews were conducted virtually between November 2022 and January 2023. Transcripts were analyzed using directed content analysis guided by a Consolidative Framework for Implementation of research interview domains and constructs. In total, 19 interviewees (17 radiation oncologists and 2 medical physicists) from 11 SSA countries participated, of which 94% noted the use of HF (40.05 Gy/15fx or 42.67 Gy/16fx) in breast cancer clinics and 38% in prostate cancer clinics (60-66 Gy/20fx). While nearly all participants identified the benefits of HF for both clinics and patients, many also noted that the lack of long-term data within an African population created discomfort in using HF. Many participants believed in the utility of HF but expressed a lack of confidence in its use caused by uncertainty about the safety of the technique, especially in centers with cobalt or 3-dimensional conformal radiation therapy-only capabilities. In breast HF, participants expressed concern regarding breast size and ideal eligibility criteria for patients. In prostate HF, on-treatment imaging and lack of fiducials were identified as barriers. Key facilitators in adopting HF included hands-on training, partnerships with disease-site-specific individuals with HF experience, and consensus on patient eligibility and technique requirements. HF is regarded as a valuable tool for breast and prostate cancer in SSA, and breast HF is widely used. Attention to the use of 3-dimensional conformal radiation therapy with HF, long-term toxicity data in African populations, and training sessions may facilitate further use of HF for prostate cancer.

Image-guided Hypofractionated Radiotherapy as an Alternative to Radical Prostatectomy in Localized Prostate Cancer in Elderly Patients with Low Life Expectancy.

Radical prostatectomy is appropriate for any patient whose cancer appears clinically localised to prostate. However because of potential perioperative morbidity, radical prostatectomy is generally reserved for patients whose life expectancy is more than ten years. Moderate hypofractionation for localized prostate cancer is safe and effective. There is a growing body of evidence in support of extreme hypofractionation for localized prostate cancer. Hypofractionation for prostate cancer was originally carried out in the pursuit of efficiency and convenience, but has now attracted greatly renewed interest based upon a hypothesis that prostate cancers have a higher sensitivity to fraction size, reflected in a low α/β ratio, then do late responding organs at risk such as the rectum or bladder. From January 2017 to December 2020 we treated 112 patients of localised Prostate Cancer with Image Guided Radiotherapy (IGRT). They were in range of 75-85 years. They were of stage T1-T3, N0 or N1. There were significant comborbidities. ECOG performance status was 0-1. They were given 3 months of Androgen Deprivation Therapy (ADT) before starting IGRT. Patients were immobilised with casts and subject to CT simulation. CBCT was taken daily. Dose was 70 Gy @ 250 cGy per fraction at a frequency of 5 fractions per week. Complete blood counts were done weekly for assessment of haematological toxicity. Androgen Deprivation Therapy was continued post IGRT. All the patients were able to complete the treatment. Evaluation was done at one month, three month and six months post treatment. 104 out of 112 patients achieved complete response. Other 8 had near complete response. There were no acute grade 3-4 toxicities. Grade 1-2 toxicities like skin desquamation, diarrhoea, burning micturition were managed conservatively. Late toxicity was rectal bleeding seen after one year of completion of treatment and was managed with steroid enemas. 23 patients required argon plasma laser therapy. Image guided radiotherapy is well tolerated, easy to implement and an effective alternative to radical prostatectomy in elderly patients with comorbidities and low life expectancy.

Randomised controlled trials on radiation dose fractionation in breast cancer: systematic review and meta-analysis with emphasis on side effects and cosmesis

ObjectiveTo provide a comprehensive assessment of various fractionation schemes in radiation therapy for breast cancer, with a focus on side effects, cosmesis, quality of life, risks of recurrence, and survival...

Setting the Stage: Feasibility and Baseline Characteristics in the PARTIQoL Trial Comparing Proton Therapy Versus Intensity Modulated Radiation Therapy for Localized Prostate Cancer

Men with localized prostate cancer may receive either photon-based intensity modulated radiation therapy (IMRT) or proton beam therapy (PBT). The PARTIQoL trial (NCT01617161) demonstrates the feasibility of performing a large, multicenter phase 3 randomized trial comparing IMRT with PBT for localized prostate cancer. Here, we report baseline features of patients enrolled on this trial and present strategies to improve feasibility of other similar trials. Patients with low- or intermediate-risk prostate cancer were randomly assigned to either PBT or IMRT with stratification by institution, age, use of rectal spacer, and fractionation schedule (conventional fractionation: 79.2 Gy in 44 fractions vs moderate hypofractionation: 70.0 Gy in 28 fractions). The primary endpoint is a change from baseline bowel health using the Expanded Prostate Index Composite score 24 months after radiation therapy. Secondary objectives include treatment-related differences in urinary and erectile functions, adverse events, and efficacy endpoints. Between July 2012 and November 2021, 450 patients were successfully accrued. Patients were randomly assigned to either PBT (N = 226) or to IMRT (N = 224); 13 were ineligible or withdrew before treatment. The median age of 437 analyzed patients was 68 years (range, 46-89 years). A total of 41% of patients had low-risk and 59% had intermediate-risk disease. In total, 49% of patients were treated with conventional fractionation and 51% with moderately hypofractionation. 48% of patients used a rectal spacer. For patients receiving PBT, pencil beam scanning was used in 48%. PBT and IMRT arms were balanced for baseline variables. Despite significant challenges, the PARTIQoL trial demonstrated that, with targeted recruitment approaches, multicenter collaboration, payer engagement, and protocol updates to incorporate contemporary techniques, it is feasible to perform a large phase 3 randomized clinical trial to assess whether PBT improves outcomes. We will separately report primary results and continue to monitor participants for longer follow-up and secondary endpoints.

CHHiP vs PROFIT for Localized Prostate Cancer: A Retrospective Dosimetric Comparison of Organs at Risk

ABSTRACT Objectives Moderate hypofractionation for localized prostate cancer has become a standard of care in many radiation therapy centers worldwide. Several fractionation and planning protocols exist, with CHHiP and PROFIT (60 Gy in 20 fractions) being 2 of the most commonly used. We retrospectively compared the doses received by organs at risk (OARs) using these 2 protocols. Materials and Methods We retrospectively reviewed the charts of 25 randomly selected de-identified patients treated with intensity-modulated radiation therapy (IMRT) for prostate cancer in a single tertiary care center. For each patient, we generated 2 sets of contours for target volumes and OARs in accordance with both CHHiP and PROFIT protocols. A total of 50 IMRT plans, using Prowess Panther software version 5.10, were generated and achieved the respective planning targets and normal tissue constraints. The related-samples Wilcoxon signed-rank test was used to compare the mean dose, V60, V50, and V40 of each of the bladder, rectum, and penile bulb. Results Patients had a mean age of 73 years, average prostate-specific antigen level of 9.8 ng/mL, mostly a Gleason score of 7, and a clinical stage that ranged from T1c to T2c. In the CHHiP plans, the rectum averaged a significantly lower V60 (0.5% vs 4.5%, P < .001) and V50 (13.1% vs 15.7%, P = .026) than with PROFIT. Similarly, the bladder in CHHiP averaged a significantly lower V60 (1.9% vs 7.7%, P < .001) and V50 (13.2% vs 15.5%, P = .035). The penile bulb received a lower mean dose (21.9 Gy vs 30.5 Gy, P < .001), V50 (5.6% vs 14.4%, P = .037), and V40 (11.4% vs 35.2%, P < .001) on average in the CHHiP plans as well. Conclusion In our dosimetric comparison, CHHiP spared the OARs to a greater degree than PROFIT. While contouring and planning using the CHHiP protocol are usually more demanding, we expect that greater sparing of OARs will minimize clinical toxicity in patients with prostate cancer receiving moderately hypofractionated radiation therapy.

Multi-institutional questionnaire-based survey on online adaptive radiotherapy performed using commercial systems in Japan in 2023.

In this study, we aimed to conduct a survey on the current clinical practice of, staffing for, commissioning of, and staff training for online adaptive radiotherapy (oART) in the institutions that installed commercial oART systems in Japan, and to share the information with institutions that will implement oART systems in future. A web-based questionnaire, containing 107 questions, was distributed to nine institutions in Japan. Data were collected from November to December 2023. Three institutions each with the MRIdian (ViewRay, Oakwood Village, OH, USA), Unity (Elekta AB, Stockholm, Sweden), and Ethos (Varian Medical Systems, Palo Alto, CA, USA) systems completed the questionnaire. One institution (MRIdian) had not performed oART by the response deadline. Each institution had installed only one oART system. Hypofractionation, and moderate hypofractionation or conventional fractionation were employed in the MRIdian/Unity and Ethos systems, respectively. The elapsed time for the oART process was faster with the Ethos than with the other systems. All institutions added additional staff for oART. Commissioning periods differed among the oART systems owing to provision of beam data from the vendors. Chambers used during commissioning measurements differed among the institutions. Institutional training was provided by all nine institutions. To the best of our knowledge, this was the first survey about oART performed using commercial systems in Japan. We believe that this study will provide useful information to institutions that installed, are installing, or are planning to install oART systems.

44 Ultrahypofractionated Versus Moderately Hypofractionated and Conventionally Fractionated Pelvic Radiotherapy for Prostate Cancer: Outcomes from 3 Prospective Clinical Trials

44 Ultrahypofractionated Versus Moderately Hypofractionated and Conventionally Fractionated Pelvic Radiotherapy for Prostate Cancer: Outcomes from 3 Prospective Clinical Trials

Sequential Moderate Hypofractionated Boost in Breast Cancer Patients: A Monoinstitutional Analysis of Late Side Effects.

In breast cancer (BC) patients who have received breast-conserving surgery, moderate hypofractionation is standard of care for whole-breast irradiation (HF-WBI). On the other hand, the fractionation schedule for the boost is less well defined. A previous prospective study of our group aimed at evaluating acute and late cutaneous and subcutaneous side effects related to a sequential hypofractionated boost (HB) in patients who had received HF-WBI. The present study aimed at evaluating late side effects at a longer follow-up. From 2014 to 2015, 219 BC patients received moderate HF-WBI (42.4 Gy in 16 fractions) at the Radiation Oncology Section of the University of Perugia. Patients with negative prognostic factors received a HB (2.65 Gy for 4 or 5 fractions). Late side effects were assessed using the Common Terminology Criteria for Adverse Events v5.0. Univariate and multivariate analyses estimated predictive factors for late toxicity. Median follow-up was 8.6 years (range=6.7-9.6). One hundred and sixty-five patients were evaluable in the present analysis; HB was administered to 47.3% of them. Late cutaneous and subcutaneous side effects occurred in 26/165 patients (15.8%); and all were G1. In univariate analysis ≥10 excised lymph nodes and HB administration emerged as risk factors for late side effects (p=0.003 and p=0.041, respectively). In multivariate analysis only ≥10 excised lymph nodes were confirmed as a risk factor for side effects (OR=3.431; 95%CI=1.209-9.737). HB after HF-WBI was safe and well-tolerated, even at a long-term follow-up; consequently, it can be used in routine practice.

PTCOG international survey of practice patterns and trends in utilization of proton therapy for breast cancer

Purpose/objectivesThe indications, techniques, and extent to which proton beam therapy (PBT) is employed for breast cancer are unknown. We seek to determine PBT utilization for breast cancer. Materials/methodsThe Particle Therapy Co-Operative Group (PTCOG) Breast Subcommittee developed an IRB-approved 29-question survey and sent it to breast cancer radiation oncologists at all active PBT centers worldwide in June 2023. Descriptive statistics were used to summarize responses, and comparisons by continent were performed using Fisher’s exact tests. ResultsOf 79 surveys distributed, 28 recipients submitted responses (35 % response rate) representing fifteen U.S., 8 European, and 5 Asian centers (continent response rate 50 %, 38 %, and 18 %, respectively). Overall, 93 % reported treating breast cancer patients with PBT; 13 (50 %) have treated ≥100 breast cancer patients at their center since opening. Most (89 %) have pencil beam scanning technology. Nearly half (46 %) use moderate hypofractionation (15–20 fractions) for regional nodal irradiation and 42 % conventional fractionation (25–30 fractions). More European centers prefer hypofractionation (88 %) vs. Asian (50 %) and U.S. (21 %) centers (p = 0.003). Common patient selection methods were practitioner determination/patient preference (n = 16) and comparative plan evaluation (n = 15). U.S. centers reported the most experience with breast PBT, with 71 % having treated ≥100 breast cancer patients vs. 38 % in Europe and none in Asia (p = 0.001). Of respondent centers, 39 % enrolled ≥75 % of breast PBT patients on a research study. ConclusionUtilization, patient selection methods, and dose-fractionation approaches for breast cancer PBT vary worldwide. These survey data serve as a benchmark from which successor surveys can provide insight on practice pattern evolution.

Acute toxicity patterns and their management after moderate and ultra- hypofractionated radiotherapy for prostate cancer: A prospective cohort study

ObjectiveHypofractionation has become the new clinical standard for prostate cancer. We investigated the management of acute toxicity in patients treated with moderate hypofractionation (MHF) or Ultrahypofractionation (UHF). MethodsIn a prospective cohort setting, patients (N=316) received either MHF (20 fractions of 3/3.1 Gy, 5 fractions per week, N=156) or UHF (7 fractions of 6.1 Gy, 3 fractions per week, N=160) to the prostate +/- (base of the) seminal vesicles between 2019 and 2023. UHF was not indicated in case of significant lower urinary tract symptoms (LUTS) or T3b disease. Patient-reported outcomes (PRO) were online distributed at baseline, end of treatment (aiming at last fraction +/- 3 days), 3 months. Acute toxicity rates, management, and associations with baseline factors were analysed using Chi-square test and logistic regression. CTCAE scores (version 5) were calculated. ResultsTreatment for acute urinary complaints was prescribed in 46 % (MHF) and 29 % (UHF). Taking into consideration baseline LUTS, MHF and UHF showed similar rates of PROs and management. Medication for acute gastrointestinal (GI) symptoms was prescribed for 21.1 % (MHF) and 14.1 % (UHF) with more loperamide for diarrhea in MHF (9.0 %) vs UHF (1.9 %, p = 0.005). Grade ≥ 2 (MHF / UHF) was scored in 40 % / 28 % for GI (p = 0.03) and 50 % / 31 % for GU (p < 0.01). PROs for GI reported after last fraction of UHF were significantly worse compared to before last fraction. ConclusionUHF was safe with respect to acute toxicity risks in the selected population. MHF is associated with risks of significant diarrhea which needs further investigation. Furthermore, optimal registration of acute toxicity for UHF requires measurements up to 1–2 weeks after the last fraction.

Characterizing Compromised Target Coverage With Hypofractionated Radiation Therapy for Pancreatic Cancer.

Introduction Proximity of organs at risk (OAR) hinders radiation dose escalation for the treatment of pancreatic cancer. To address this limitation, there is interest in protracted-fractionation (PF: 15 to 25 fractions) courses employing moderate hypofractionation (MHF: 3-4 Gy/fraction). However, there persists underdosing where tumor interfaces with OAR. The significance of compromised tumor coverage and dose heterogeneity on tumor control remains unknown. Here, we report our initial planning experience with PF-MHF in pancreatic cancer. Methods We retrospectively reviewed radiation courses for locally advanced or recurrent pancreatic cancer with a PF-MHF approach: 45 Gy in 25 fractions (1.8 Gy/fraction) to PTV with 75 Gy (3 Gy/fraction) as an integrated boost to the GTV. We reviewed dosimetric parameters for the GTV: percentage overlap with planning OAR volume (PRV-GTV overlap), D99.9%, D0.1cc, Dmean, V75Gy, and V60Gy. We also calculated the GTV's generalized equivalent uniform dose (gEUD) valueusing two differentavalues (-5 and -15). Lastly, we reoptimized two plans with two approaches: increasing gEUD or relaxing the maximum dose constraint. Results A total of 26 plans were included in our analysis: 14 locally advanced and 12 locally recurrent pancreatic cancer cases. While the D0.1cc median value was 81.7 Gy, target volume coverage was relatively low (V75Gy median 71%). Median gEUD were 71 Gy (a = -5) and 62.8 Gy (a = -15) and inversely correlated with PRV-GTV overlap. On reoptimized plans, both approaches yielded similar results, but an increase in target coverage and gEUD were seen only when there was limited PRV-GTV overlap. Conclusion Although radiation dose can be escalated within the GTV, there continues to be low coverage by the prescription dose, especially with high PRV-GTV overlap. Relaxing the maximum dose constraint in planning allows for meaningful improvement in tumor coverage in limited PRV overlap scenarios. Continued refinement of the PF-MHF approach is needed.

Uptake of ultra-hypofractionated radiation therapy following breast-conserving surgery among patients with early-stage breast cancer: a multi-institutional questionnaire survey.

In patients with early-stage breast cancer following breast surgery, ultra-hypofractionated (UHF) breast/chest wall radiation therapy (RT) has been shown to be non-inferior to a moderate-hypofractionated (MHF) regimen, with a minimal risk of breast induration, in the FAST-Forward trial, and UHF is now becoming the standard regimen in Europe. Herein, we aimed to investigate Japanese patients' attitudes toward the UHF regimen. A questionnaire-based survey was conducted at 13 RT centers in nine prefectures across Japan. All patients underwent breast-conserving surgery, followed by either conventional fractionation (2Gy/fr) or MHF (2.66Gy/fr) whole-breast irradiation (WBI) with or without a tumor bed boost. The questionnaire consisted of 13 questions mainly addressing quality-of-life during RT. Key questions included an 11-point scale (0-10) for rating the patients' enthusiasm for the UHF regimen and prioritization of the following treatment-related effects: treatment efficacy, acute/late adverse effects, physical/emotional/financial burden, and breast cosmesis. The patient and treatment characteristics were assessed by a physician. In total, 247 questionnaires were administered between November 2022 and June 2023. The age distribution was as follows: < 50:50s:60s: ≥ 70 = 59 (24%):76 (30%):63 (26%):49 (20%). Sixty-nine percent of patients rated their enthusiasm for the UHF regimen at ≥ 6 out of 10 points (45% rated 10/10). Treatment efficacy was the highest priority for most patients (89%), whereas breast cosmesis the lowest priority (53%). Patients' enthusiasm for UHF-WBI was observed across the cohort. These results could motivate researchers and clinicians to introduce UHF regimens in clinical practice.

Acute Toxicity in Moderate Hypofractionation Over Three Weeks for Localized Prostate Cancer Without Marker Implantation

Purpose: prospective observational study of patients with localized prostate cancer referred for radiotherapy using a hypofractionation scheme without marker implantation with the advantages offered by shorter treatments in lower-middle-income countries. Our objective was to establish the acute genitourinary and gastrointestinal toxicity using hypofractionation radiotherapy scheme of 15 fractions. Methods and Materials: From March to November 2022, patients with low- to intermediate-risk prostate cancer received 54 Gy in 15 fractions (3.6 Gy per fraction) for 3 weeks using VMAT without intraprostatic fiducial markers or a rectal hydrogel spacer. Were evaluated through rectal examination, prostate-specific antigen (PSA) levels, and diagnostic imaging such as computed tomography (CT), magnetic resonance imaging (MRI), bone scan, or positron emission tomography (PET/CT) with PSM, the cumulative incidence of late grade ≥2 genitourinary and gastrointestinal toxicities were analyzed. Results: Thirty-six patients were enrolled in this prospective observational study; all of them were treated with highly hypofractionated VMAT with intermediate to high risk. The follow-up period was 3 months for evaluated acute toxicity. In terms of genitourinary toxicity, 8% of patients experienced grade 2 toxicity, which included urinary frequency, urgency, and dysuria. There were no cases of grade 3 or higher genitourinary toxicity. Regarding gastrointestinal toxicity, 5% of patients experienced grade 2 toxicity, which included diarrhea and rectal bleeding. No grade 3 or higher gastrointestinal toxicity was observed. Conclusions: Highly hypofractionated VMAT delivering 54 Gy in 15 fractions for 3 weeks for prostate cancer without intraprostatic fiducial markers facilitated favorable oncological outcomes without severe complications. These findings support the feasibility and safety of this treatment option and highlight the potential advantages of hypofractionation, further studies are needed to confirm these findings and evaluate the long-term oncological outcomes of moderate hypofractionation for localized prostate cancer.

3395: Acute toxicity from PACE-C comparing Stereotactic Body Radiotherapy (SBRT) with moderate hypofractionation (MHRT)

3395: Acute toxicity from PACE-C comparing Stereotactic Body Radiotherapy (SBRT) with moderate hypofractionation (MHRT)

2485: Moderate hypofractionation with simultaneous integrated boost after conservative surgery for BCa

2485: Moderate hypofractionation with simultaneous integrated boost after conservative surgery for BCa

1063: The impact of moderate hypofractionation on costs and travel burden in breast cancer patients

1063: The impact of moderate hypofractionation on costs and travel burden in breast cancer patients