Hypofractionated Radiotherapy Schedule Research Articles

Comprehensive 3DCRT Hypofractionated Radiotherapy Schedule for Localized Prostate Adenocarcinoma in the Era of IMRT: Dosimetric and Endoscopic Analysis.

Background: Moderate hypofractionated radiotherapy (MHRT) has emerged as the preferred treatment modality for localized prostate cancer based on randomized controlled studies regarding efficacy and toxicity using contemporary radiotherapy techniques. In the setting of MHRT, available data on dosimetric parameters and late rectal toxicity are limited. Aim: To present the effects of MHRT on late rectal toxicity while conducting an extensive dosimetric analysis in conjunction with rectoscopy results. Methods: This is a prospective study including patients with intermediate-risk prostate adenocarcinoma. All patients were treated with MHRT 44 Gy in 16 fractions to the seminal vesicles and to the prostate, followed by a sequential boost to the prostate alone of 16.5 Gy in 6 fractions delivered with three-dimensional conformal radiation therapy (3DCRT). Acute and late toxicity were assessed. Endoscopy was performed at baseline, every 3 months post-therapy for the first year, and every 6 months for the year after. The Vienna Rectoscopy Score (VRS) was used to assess rectal mucosal injury related to radiotherapy. Dosimetric analysis for the rectum, rectal wall, and its subsegments (upper, mid, and low 1/3) was performed. Results: Between September 2015 and December 2019, 20 patients enrolled. Grade 1 late gastrointestinal toxicity occurred in 10% of the patients, whereas 5% had a grade ≥2. Twelve months post radiotherapy: 4 (20%) patients had VRS 1; 2 (10%) patients had VRS 2; 1(5%) patient had VRS 3. 24 months post radiotherapy, VRS 1 was observed in 4 patients (20%) and VRS 2 in 3 (15%) patients. The dosimetric analysis demonstrated noticeable variations between the rectum, rectal wall, and rectal wall subsegments. The dosimetric analysis of the rectum, rectal wall, and its mid and low segments with respect to rectoscopy findings showed that the higher dose endpoints V52.17Gy and V56.52Gy are associated with rectal mucosal injury. Conclusions: A thorough delineation of the rectal wall and its subsegments, together with the dosimetric analysis of these structures, may reduce late rectal toxicity. Dosimetric parameters such as V52.17Gy and V56.52Gy were identified to have a significant impact on rectal mucosal injury; additional dose endpoint validation and its relation to late GI toxicity is needed.

TO STUDY PALLIATION OF SYMPTOMS BY A HYPOFRACTIONATED RADIOTHERAPY SCHEDULE IN ADVANCED INOPERABLE SQUAMOUS CELL CARCINOMAS OF THE ORAL CAVITY

Introduction: Decisions regarding optimal integration of surgery, radiation, and chemotherapy should be made on a case to case basis in a multidisciplinary tumor board setting. Treatment planning of advanced oral cavity cancers is derived from trials that included a heterogeneous group of patients which included all head and neck sites and observational data from the oral cavity cancer patient series. Aim: The aim of the study was to study palliation of symptoms and improvements in quality of life (QoL) in inoperable squamous cell cancers of the oral cavity with a hypofractionated radiotherapy schedule. Methods: It is a prospective and observational study in patients with locally advanced squamous cell cancers of the oral cavity attending the outpatient clinic who have been deemed inoperable after discussion in a multidisciplinary team were considered. The data was tested using Friedman’s test for the significance in QoL. Results: All of the functional scales were found significant in this study with physical functioning, emotional functioning and cognitive functioning (CF) being significant at 1% alpha level while role functioning (RF) and social functioning (SF) are significant at 5% alpha level. RF was assessed based on the capabilities of the patient to finish daily activities. The median score remained at 33 but the interquartile range (IQR) was showing an increasing trend. Both pain and head-and-neck specific pain had significantly reduced over time. Fatigue had shown a constant reduction during radiation and during the first follow-up as well. The increase in nausea, vomiting, and constipation during radiation can be attributed to the use of morphine during radiation for pain control and as an effect of radiation itself. There was weight loss during radiation which improved during subsequent follow-up visits. Conclusions: In patients diagnosed with inoperable oral cavity cancer, hypofractionated radiotherapy delivering 50 Gy in 20 fractions over 4 weeks is a well-tolerated and safe regimen. In our study, statistically significant QoL improvement in global health score, SF, and CF lasting for a minimum of 6 weeks was attained after completion of treatment with this regimen.

Predictive Value of Tumor Volume on Local Control in Hepatocellular Carcinoma Treated with Image Guided Hypofractionated Radiation Treatment

External beam radiation treatment (EBRT) is an important local treatment in liver-confined hepatocellular carcinoma (HCC) patients who are not candidates for curative therapy. EBRT dose, technique and prognostic factors are evolving. We hypothesized that tumor volume to liver volume ratio can be a predictor of local control (LC) in patients treated with hypo-fractionated radiation (HFRT) in HCC MATERIALS/METHODS: We retrospectively reviewed 50 patients of HCC treated with HFRT at our institution. HFRT schedule was chosen such that the radiation dose to the remaining liver and other organs at risk (OAR) met the standard dosimetric constraints. Image guided techniques were used for motion management, internal target volume (ITV) and planning target volume (PTV) delineation. Tumor to Liver Ratio (TLR) was defined as ratio of PTV volume to whole liver volume. TLR ≤ 0.3 was considered as low volume disease and TLR > 0.3 was considered as high-volume disease. The radiation dose ranged from 45 Gy to 67.5 Gy in 5 - 15 fractions. The biologically equivalent dose (BED) for tumor ranged from 58.5 Gy10 to 100 Gy10. Local control (LC) was evaluated by Kaplan-Meier analysis, with log-rank test for groups stratified as per TLR. Multivariate Cox regression analysis was performed to identify additional prognostic factors. The mean duration of follow-up was 24 months. The median age was 69 years (range 50 - 90) and 76% were males. 32 patients had CP-A class cirrhosis while 17 had CP-B and 1 had CP-C class. BCLC stage A, B, C and D was seen in 2, 14, 33 and 2 patients, respectively. Portal vein thrombosis was present in 9 patients and prior trans-arterial chemo embolization (TACE) was done in 23 patients. The median volume of PTV was 551 cc (range 52 - 1990 cc). The TLR ranged from 0.04 - 0.67 with a median of 0.29. The median BED radiation dose was 78.4 Gy10 (range - 58.5 Gy10 to 100 Gy10). Nine patients had local recurrence with overall LC rate of 82%. The LC was better in low volume tumors, with the TLR cut-off of 0.3 as a significant factor associated with LC (p = 0.007). The 1-year actuarial LC with TLR ≤ 0.3 was 88% as compared 61% in TLR of > 0.3 (p = 0.007). BED ≥60 Gy10 was associated with better 1 year LC as compared to BED < 60 Gy10 (89% vs 62%; p = 0.11). ALBI grade 1 was associated with better 1 year LC as compared to ALBI grade 2 (80% versus 75%; p = 0.40). On multivariate analysis, high volume disease and TLR >0.3 were significant prognostic factor for LC. HFRT has good 1-year local control of 82% in carefully selected unresectable HCC. Radiation with BED greater than 60 Gy10 and ALBI grade 1 showed a trend towards better LC. Smaller tumors had better LC with a PTV to liver ratio (TLR) of < 0.3. This information can help in identifying the poor responders, intensifying the radiation treatment and adding additional therapy to improve the oncological outcomes.

Outcome of Hypofractionated Radiotherapy for Localized Gastric Mucosa-associated Lymphoid Tissue Lymphoma.

With the prevalence of COVID-19, the importance of short-course radiotherapy (RT) in many cancers has been discussed. The aim of this study was to evaluate the results of hypofractionated schedule RT for localized gastric mucosa-associated lymphoid tissue (MALT) lymphoma. We assessed 45 patients with localized gastric MALT lymphoma who underwent RT between 2005 and 2019. The total RT dose ranged from 24-36 Gy in 10-18 fractions (median of 28 Gy/14 fractions). Patients were divided into three groups according to the dose fractionation: Group A, 30-36 Gy in 15-18 fractions; Group B, 26-28 Gy in 13-14 fractions; and Group C, 24-25 Gy in 10 fractions. All the patients achieved complete remission without local recurrence. The 5-year overall, cause-specific, and progression-free survival rates were 97.5%, 100%, and 97.5%, respectively, with a median follow-up period of 82 months. Among the dose fractionation groups, there were no statistically significant differences in local control or incidence of grade 2 or worse adverse events. Results of RT for localized gastric MALT lymphoma showed excellent local control and survival with no serious adverse events, regardless of dose fractionation. In situations where short-term RT is required, a hypofractionated RT schedule of 24-25 Gy in 10 fractions could be an option for RT schedules.

Influence of physical and radiobiological models on evaluation of radiotherapy treatment fractionation schedules for GBM brain tumours

This study aims to evaluate the radiotherapy planning performance considering the clinical results of glioblastoma multiforme (GBM)-treated patients from both physical and radiobiological perspectives. Radiotherapy plans are done for 20 patients with GBM tumors who have received radical VMAT treatment on Eclipse-13.5. Dosimetric and radiobiological evaluation metrics are estimated to compare the two plans in terms of TCP, NTCP, and P+ in the context of the evaluated physical metrics. Both conventional and hypofractionation give better dose homogeneity and conformity to the tumour. In addition, hypofractionation schedule coverage targets cells with radiation doses higher than conventional schemes. However, both schedules are at acceptable and safe levels. Statistically, the calculated metrics showed good significance between conventional and hypofractionated radiotherapy schedules. The results have led to the safe use of hypofractionated radiotherapy that can be extended for different tumours, which helps in breaking down the waiting list of patients in many hospitals, especially in cases of pandemics such as COVID-19.

Challenges and Opportunities With the Use of Hypofractionated Radiation Therapy in Cancer Care: Regional Perspectives From South Korea, Japan, Singapore, and Australia

Hypofractionated radiotherapy schedules provide higher per-fraction radiation doses delivered in fewer fractions than conventional schedules. This novel delivery method is supported by a large body of clinical trial evidence across various cancer sites in both curative and palliative settings. Hypofractionation is associated with benefits such as lower costs, improved patient access and increased treatment precision, which has led to its inclusion in various treatment guidelines. Despite this, utilization is not uniform across cancer sites and geographic regions due to reasons such as reimbursement models, nuances in healthcare systems, and professional culture. Key factors to ensure patients benefit from access to high quality radiotherapy include publishing clinical evidence, cross-country collaboration to fill knowledge gaps, reviewing reimbursement models, and improving patient advocacy in treatment decision-making.

Moderate hypofractionated radiation therapy and pathologic response for soft tissue sarcomas (STS) of limbs and trunk: experience from a tertiary cancer center.

Preoperative radiation therapy following by limb-sparing or conservative surgery is a standard approach for limb and trunk STS. Data supporting hypofractionated radiotherapy schedules are scarce albeit biological sensitivity of STS to radiation would justify it. We sought to evaluate the impact of moderate hypofractionation on pathologic response and its influence on oncologic outcomes. From October 2018 to January 2023, 18 patients with limb or trunk STS underwent preoperative radiotherapy at a median dose of 52.5Gy (range 49.5-60Gy) in 15 fractions of 3.5Gy (3.3-4Gy) with or without neoadjuvant chemotherapy. A favorable pathologic response (fPR) was considered as ≥ 90% tumor necrosis on specimen examination. All patients completed planned preoperative radiotherapy. Eleven patients (61.1%) achieved a fPR, and 7 patients (36.8%) a complete pathologic response with total disappearance of tumor cells. Nine patients (47%) developed grade 1-2 acute skin toxicity, and 7 patients (38.8%) had wound complications on follow-up. With a median follow-up of 14months (range 1-40), no cases of local relapse were observed, and actuarial 3-year overall survival (OS) and distant metastases-free survival (DMFS) are 87% and 76.4%, respectively. In the univariate analysis, the presence of a favorable pathologic response (fPR) was associated with improved 3-year OS (100% vs. 56.03%, p = 0.058) and 3-year DMFS (86.91% vs. 31.46%, p = 0.002). Moreover, both complete or partial RECIST response and radiological stabilization of the tumor lesion showed a significant association with higher rates of 3-year distant metastasis-free survival (DMFS) (83% vs. 83% vs. 56%, p < 0.001) and 3-year overall survival (OS) (100% vs. 80% vs. 0, p = 0.002). Preoperative moderate hypofractionated radiation treatment for STS is feasible and well tolerated and associates encouraging rates of pathologic response that could have a favorable impact on final outcomes.

A Hypofractionated Radiotherapy Schedule with a Simultaneous Integrated Boost for Breast Cancer: Outcomes including Late Toxicity and Health Quality.

Introduction: This study aimed to evaluate the long-term adverse effects on the physical appearance and overall well-being of breast cancer patients who receive hypofractionated radiotherapy as whole breast and simultaneous integrated boost (SIB) treatment, utilizing intensive modulated radiotherapy (IMRT), volumetric modulated arc therapy (VMAT), or a hybrid therapy approach. Material/Methods: This investigation involved administering hypofractionated SIB-VMAT therapy to individuals diagnosed with early-stage breast cancer. Treatment was carried out over a three-week period in which a total dose of 48.06 Gy was given to the entire breast and 54 Gy was given to the tumor bed. Data on skin toxicity and cosmetic outcomes were analyzed both during the acute phase and during the three-month and five-year follow-up periods after treatment. Results: A total of 125 patients treated between December 2014 and December 2016 were included in the study. The data of these patients with at least 5 years of follow-up were analyzed. Conclusions: Considering these long-term results, hypofractionated SIB-VMAT can be considered a viable treatment choice, even for patients with unfavorable conditions.

244P Alternate-day hypofractionated radiotherapy for radical treatment of head & neck cancer during the COVID-19 pandemic: A single institute experience

Managing head and neck squamous cell carcinoma (HNSCC) requires a prolonged course of concurrent chemoradiotherapy and other supportive care measures. Such a multidisciplinary approach was significantly hampered during the emergence of the COVID-19 pandemic which necessitated divergence of health resources towards treating the infected patients thereby compromising cancer care. Therefore, we adopted an alternate-day hypofractionated radiotherapy (ADH RT) schedule, aiming to decrease patients’ hospital visits daily without compromising the oncological outcomes.

Effectiveness of hypofractionated and normofractionated radiotherapy in a triple‐negative breast cancer model

Breast cancer (BC) is one of the most diagnosed malignant carcinomas in women with a triple-negative breast cancer (TNBC) phenotype being correlated with poorer prognosis. Fractionated radiotherapy (RT) is a central component of breast cancer management, especially after breast conserving surgery and is increasingly important for TNBC subtype prognosis. In recent years, moderately hypofractionated radiation schedules are established as a standard of care, but many professionals remain skeptical and are concerned about their efficiency and side effects. In the present study, two different triple-negative breast cancer cell lines, a non-malignant breast epithelial cell line and fibroblasts, were irradiated daily under normofractionated and hypofractionated schedules to evaluate the impact of different irradiation regimens on radiation-induced cell-biological effects. During the series of radiotherapy, proliferation, growth rate, double-strand DNA break-repair (DDR), cellular senescence, and cell survival were measured. Investigated normal and cancer cells differed in their responses and receptivity to different irradiation regimens, indicating cell line/cell type specificity of the effect. At the end of both therapy concepts, normal and malignant cells reach almost the same endpoint of cell count and proliferation inhibition, confirming the clinical observations in the follow-up at the cellular level. These result in cell lines closely replicating the irradiation schedules in clinical practice and, to some extent, contributing to the understanding of growth rate or remission of tumors and the development of fibrosis.

Bladder preservation in older adults with muscle-invasive bladder cancer: A retrospective study with concurrent chemotherapy and twice-daily hypofractionated radiotherapy schedule

IntroductionBladder cancer occurs mainly in older adults and surgery is not always possible when there are geriatric conditions and comorbidities. Trimodal treatment (TMT) combining trans-urethral resection of bladder tumour (TURBT) followed by concurrent chemoradiation (CRT) would be a curative alternative in such patients. Materials and MethodsAll consecutive patients 75 years of age and older with non-metastatic muscle-invasive bladder cancer (MIBC) treated with TMT by Georges Pompidou European Hospital team were retrospectively analysed. Induction CRT combined hypofractionated twice-daily radiotherapy targeting bladder and pelvis to a total dose of 24 Gy (Gy) with concurrent platinum salt and 5-fluorouracil. Consolidation CRT to a total dose of 44 Gy was proposed to patients with biopsy-proven complete response after induction phase and those with persistent tumour underwent salvage cystectomy. We assessed using Kaplan-Meier method overall survival (OS), cancer specific survival (CSS), invasive recurrence-free survival (IRFS), metastasis-free survival (MFS), survival with bladder preserved (SBP), and toxicities. With a Cox model for OS and the Fine Gray method of competing risk for secondary endpoints, we analysed in univariate (u) and multivariate (m) analysis the impact of tumour characteristics and patient profiles: gender, age, age-adjusted Charlson comorbidity index, polypharmacy, and malnutrition. ResultsFrom 1988 to 2017, 85 patients were included. After induction, complete response rate was 83.5%. With a median follow-up of 63 months, 5 year-OS, CSS, IRFS, MFS and SBP were 61.0%, 77.6%, 71%, 82.9%, and 70.2% respectively. A persistent tumour after induction impacted SBP (SHRm 3.61; p = 0.004), CSS (SHRm 3.27; p = 0.023), and MFS (SHRm 3.68; p = 0.018). Late grade 3 urinary and gastrointestinal toxicities were 3.5% and 1.2%. DiscussionWe report here the largest series of bladder preservation over 75 years in a curative intent. Outcomes and tolerance in selected older adults compared favourably with surgical series and with CRT studies using classical fractionation.

Radiation dose and schedule influence the abscopal effect in a bilateral murine CT26 tumor model

Radiotherapy (RT) can induce immune-mediated responses in local irradiated tumors, and non-irradiated distant metastasis is termed the abscopal effect. Here, we aimed to evaluate the impact of different RT doses and fractions on anti-tumor responses within local irradiated and distance non-irradiated tumor microenvironments. In mice bearing CT26 tumors, the primary tumor was irradiated with three different RT doses (16 Gy × 1F, 10 Gy × 2F, and 3 Gy × 10F) with the same biologically effective dose. Tumor volumes and immune cells changes were assessed in irradiated and non-irradiated tumors. Survival times were evaluated over 90 days. Only 16 Gy × 1F radiation increased CD8 + T cells number in the irradiated (p = 0.043) and non-irradiated (p = 0.047) tumors compared to the untreated group. A high frequency of tumor-associated macrophages-1 (TAM-1) and low TAM-2 was found in 16 Gy × 1F irradiated mice.Moreover, 16 Gy × 1F significantly induced interferon gamma (IFNγ)-producing CD8 + cells in the spleen compared to controls (p = 0.021). Hypofraction regimens (16 Gy × 1F, 10 Gy × 2F) caused a reduction in myeloid-derived suppressor cells in the irradiated tumors. We detected A modest growth delay in both flank tumors and long-term survival after hypofraction treatments (16 Gy × 1F, 10 Gy × 2F). A single high RT dose increased CD8 + cells number in irradiated (p = 0.000) and non-irradiated (p = 0.002) tumors approximal up to 2 points along with significant induction of IFN-γ production by CD8 + cells in the spleen when combined with anti- programmed death ligand-1 (PDL-1) (p = 0.000). Combination therapy was also associated with bilateral tumor growth control and increased life span in mice. Hypofractionated RT schedules, especially single high dose, seem the most effective regimen for inducing an abscopal effect. Immune checkpoint inhibitors could promote RT-induced systemic effects.

Once daily (OD) versus twice-daily (BID) chemoradiation for limited stage small cell lung cancer (LS-SCLC): A meta-analysis of randomized clinical trials

ObjectivesAssess Once daily (OD) chemoradiation effectiveness for LS-SCLC compared with twice daily (BID) chemoradiation. Methods and materialsFollowing the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guideline, eligible randomized clinical trials (RCT) comparing OD and BID were identified on electronic databases. A meta-analysis was performed to compare overall survival (OS), progression-free survival (PFS), and toxicity. A metaregression analysis was conducted to explore the influence of fractionation, biological effective dose (BED), the proportion of patients treated with prophylactic cranial irradiation (PCI), elective nodal irradiation (ENI), and the start of radiotherapy (week 1 or week 4). ResultsFive RCTs with a total of 1941 patients (OD vs. BID) were included. The relative risk (RR) for OS and PFS was 0.97 (CI95% 0.8–1.1, p = 0.731) and 0.90 (CI95% 0.7–1.1, p = 0.20) at 3-years. In the metaregression analysis, hypofractionated radiotherapy schedules were associated with an improvement in overall survival (p = 0.03). The start of radiotherapy (W1 or W4), BED, and ENI had no significant effect on OS and PFS. The complete response rate partial response and overall response rate for BID vs OD were 40% vs. 33% (p = 0.97), 50% vs. 57% (p = 0.94), and 89% vs. 93% (p = 0.99). The rate of completed planned RT 96% vs. 94% (p = 0.66), and the % of ≥4 chemotherapy cycles received 74% vs. 74% (p = 0.99), did not differ between OD and BID. The local and distant failure rates were not significantly different between OD and BID 40% vs. 33% (p = 0.88) and 36% vs. 36% (p = 0.99). No difference in grade 2 or grade 3 pneumonitis and esophagitis was observed among the groups (p = NS). ConclusionFor LS-SCLC, OD conventional chemoradiation results in similar outcomes to BID chemoradiation. In contrast, hypofractionated radiotherapy was associated with a better OS and PFS than BID. Additional randomized phase III trials exploring hypofractionation with systemic therapy are warranted to validate our findings.

Evaluation of the Clinical Outcomes of Altered Fractionated Radiotherapy in Node Positive Breast Cancer (A Retrospective Study)

Abstract Background Hypofractionated radiotherapy schedules provide alternative shorter courses of radiotherapy of more than 2 Gy per fraction and lower total doses compared to the conventionally fractionated schedule of 1.8–2.0 Gy per fraction in 25 fractions. Hypofractionated radiotherapy offers the advantage of improving patients’ convenience and reducing cost and resource requirements. Aim To evaluate the efficacy and toxicity of hypofractionated radiotherapy compared to the conventional schedule. Methods In this retrospective study, the clinical data of 140 patients of node positive breast cancer patients were analyzed. Radiation toxicities and locoregional recurrence were compared between patients who received conventionally fractionated radiation schedule and those who received hypofractionated radiation schedules. Results After a median follow-up of 48 months, the incidence of loco-regional recurrence was comparable between the conventional and hypofractionated arms; 4% vs 3.1%, respectively (P-value = 0.769). Documented acute skin toxicity with ≥ grade 3 was found in 10.6% of the conventional group and in 5.6% of the hypofractionated group (p = 0.409). Grade 1 late lung toxicity was manifested in 6.1% of the conventional group and 7.5% of the hypofractionated group and G2 lung toxicity was found in one case only (1.9%) in the hypofractionated group (p = 0.596). Cardiac toxicity was documented in five cases; 9.4% and 5.1% in the conventional group and hypofractionated groups, respectively (pvalue=0.486). Conclusion Hypofractionated radiotherapy is comparable to conventional radiotherapy regarding locoregional tumor control and treatment toxicities.

Long Term Arm and Shoulder Toxicities in Breast Cancer Patients Receiving Hypofractionated Radiation Therapy

&#x0D; Aim: The purpose of this study is to evaluate the late toxicities in hypo fractionated radiation schedule in breast cancer patients with regional nodal irradiation (RNI), limited to axilla and supraclavicular regions. Late effects on arm and shoulder were noted as follows: skin edema (lymphedema), restricted shoulder movements (brachial plexus injury) and localised pain.Material and Methods: In this study we randomly enrolled 100 breast cancer post mastectomy cases in the year 2018. All cases were previously asymptomatic after surgery. They were prospectively treated with hypo fractionated local and regional nodal irradiation by 2.67 gray / fraction dose, total 15 fractions (total dose-40 gray). Evaluation was done at 12 months after completion of radiation therapy. Assessment was done by RTOG, LENT- SOMA scales. Results: Significant lymphedema was observed in 17 (17%) cases. Restricted arm mobility was seen in 14 (14%) of patients. Pain (moderate/severe) in arm and shoulder was most commonly seen, in 25 (25%) cases. Conclusions: As hypo fractionated regimes in breast cancer treatment have become new standard; its late term effects are significant and comparable to other conventional radiation therapy regimes. These studies need further and longer duration of evaluation.&#x0D; &#x0D;

Infection Control and Modified Workflow Strategies in Radiation Oncology Department during COVID 19 Crisis: An Institutional Experience

Purpose: To build safe environment for cancer fighters and radiation personnel during COVID-19 pandemic by focusing on infection control, workflow and radiotherapy dose schedules modification strategies in radiation oncology departments. Material and Methods: A meeting was called post lock down in radiation oncology department to prepare infection control policies and workflow strategies in time of COVID-19 Pandemic.Results: Strategies and policies were formed during COVID-19 crises taking following points into consideration 1) Infection control policies 2) CT simulation policies 3) Day care admission and chemotherapy administration policies 4) Radiation treatment plan modification and delivery strategies 5) Brachytherapy delivery strategies.Conclusion: Management of cancer patients is an issue running parallel to the present condition of COVID-19 pandemic. Further randomized trial on hypofractionated radiotherapy schedules should be encouraged. Positivity, awareness and systematic approach are most important step in balancing the current scenario.

Synchronous bilateral breast cancer treated with a 3-week hypofractionated radiotherapy schedule: clinical and dosimetric outcomes.

Background and purposeSynchronous bilateral breast cancer (SBBC) accounts for 1–3.5% of breast cancer patients. The aim of this study was to evaluate dosimetric issues, clinical outcomes, and acute toxicities for SBBC patients receiving synchronous bilateral hypofractionated radiotherapy (SBHRT) and to compare them with patients treated with synchronous bilateral normofractionated RT schedule (SBNRT).Materials and methodsFrom April 2016 to March 2020, 39 SBBC patients were referred to our institution. Patients were divided according to their prescription dose: Group A: 50 Gy/25fx (fractions), B: 60–64 Gy/25fx, C: 40.05 Gy/15fx; D: 48 Gy/15fx. Toxicity was evaluated using Common Terminology Criteria for Adverse Events (CTCAE)v.5.0.Results34 patients were finally evaluated. Median follow-up was 24 months for NF schedule and 9 months for HF schedule. In the HF schedule, no acute side-effects > G2 were observed and no dermatitis was reported in 6th month´s assessments. 95% of patients have no evidence of disease and only 1 patient presented local relapse in the first mammography after RT. No distant failures or deaths were observed. Regarding dosimetric issues, the inter-patient average Dmean for the heart was: Group A: 5.0 Gy (4.6–5.5), Group B: 4.4 Gy (4.1–5.4), Group C: 4.8 Gy (4.5–5.1) and Group D: 5.3 Gy (4.4–5.6). For the lungs, the inter-patient average Dmean was: Group A: 10.8 Gy (9.8–12.2), Group B: 11.5 Gy (11.3–12), Group C: 9.8 Gy (9.3–10.5) and Group D: 10.5 Gy (10–11.3).ConclusionsThis is the first study reporting the safety, feasibility, and tolerability of 40.05 Gy/15fx over 3 weeks for the treatment of SBBC patients. Further study with larger accrual is mandatory.

Moderate hypofractionated post-prostatectomy radiation therapy is feasible and well tolerated: experience from a single tertiary cancer centre.

Conventional post-prostatectomy radiation therapy comprises 6.5-8weeks of treatment, therefore, hypofractionated and shortened schemes arouse increasing interest. We describe our experience regarding feasibility and clinical outcome of a post-prostatectomy moderate hypofractionated image-guided radiotherapy schedule MATERIALS AND METHODS: From Oct 2015-Mar 2020, 113 patients, median age of 62years-old (range 45-76) and prostate adenocarcinoma of low risk (30%), intermediate risk (49%) and high risk (21%) were included for adjuvant (34%) or salvage radiation therapy (66%) after radical prostatectomy (RP). All patients underwent radiotherapy with image-guided IMRT/VMAT to a total dose of 62.5Gy in 2.5Gy/fraction in 25 fractions. Sixteen patients (14%) received concomitant androgen deprivation therapy. With a median follow-up of 29months (range 3-60months) all patients but three are alive. Eleven patients (10%) developed exclusive biochemical relapse while 19 patients (17%) presented macroscopically visible relapse: prostatectomy bed in two patients (2%), pelvic lymph nodes in 13 patients (11.5%) and distant metastases in four patients (4%). The 3years actuarial rates for OS, bFRS, and DMFS were 99.1, 91.1 and 91.2%, respectively. Acute and late tolerance was satisfactory. Maximal acute genitourinary (AGU) toxicity was G2 in 8% of patients; maximal acute gastrointestinal (AGI) toxicity was G2 in 3.5% of patients; maximal late genitourinary (LGU) toxicity was G3 in 1% of patients and maximal late gastrointestinal (LGI) toxicity was G2 in 2% of patients. There were no cases of severe acute or late toxicity. No relationship was found between acute or late GI/GU adverse effects and dosimetric parameters, age, presence of comorbidities or concomitant treatments. Hypofractionated radiotherapy (62.5Gy in 25 2.5Gy fractions) is feasible and well tolerated with low complication rates allowing for a moderate dose-escalation that offers encouraging clinical results for biochemical control and survival in patients with prostate cancer after radical prostatectomy.

Ten Daily Fractions for Whole Breast Cancer Irradiation: Long Term Results

To report the feasibility and oncological outcomes in breast cancer patients treated with a short hypofractionated radiotherapy schedule. We evaluated 380 breast cancer patients treated with ten daily fractions of radiotherapy up to 39 Gy on tumor bed. Primary endpoint was local relapse rate (LRR). Secondary endpoints were overall survival (OS) and metastasis-free survival (MFS). The median follow up was 5.0 years. Two- and 5-year LRR rates were 0.2 and 2%, respectively. Two- and 5-year MFS rates were 96.1% and 90.5%, respectively. Two and 5-year OS rates were 97.4% and 95%, respectively. This short schedule may represent an alternative option to standard mild hypofractionated radiotherapy in breast cancer patients due to its excellent feasibility and very low recurrence rate.

Abstract PO-034: Prospective planning of radiation treatment at new patient conference during the COVID-19 Pandemic: The University of Mississippi Medical Center experience

Abstract Objective: To evaluate patterns of patient management in an academic Radiation Oncology department between 3/17/20 and 5/8/20 during the COVID-19 pandemic. Background: As a response to the worldwide COVID-19 pandemic, our Radiation Oncology department instituted a number of measures to limit spread of the disease to our patients and staff. This included prospectively evaluating all new referrals for radiation treatment and determining an appropriate course of action, which if appropriate included delaying the start of radiation, hypofractionation, or using other modalities of treatment prior to start of radiation. Methods: We analyzed data for 82 patients between 3/17/20-5/8/20 to evaluate patterns of management. The chi-squared test was used to evaluate the descriptive characteristics of the study population, with P values ≤ 0.05 considered statistically significant. One sample t-test was used to compare the statistical mean difference between sample variables. Data were analyzed using SPSS 24.0 software (IBM, Armonk, NY, USA). Results: The data set comprised 38% Caucasians and 59% African Americans. An age breakdown revealed 12.3% below age 30, 42% between ages 30-60, and 45.7% over age of 60. When the data were analyzed by gender, we noted a significant difference by site of treatment (p=0.005) and whether immediate treatment was required or not (p=0.029). This likely reflects gender-driven differences in cancer site with patients diagnosed with prostate cancer getting LHRH agonist therapy prior to start of radiation. Hypofractionated radiation schedules were used in 2 patients with cord compression early during the study period compared to 3 patients who received standard fractionation later, and one person elected to go straight to hospice care (p=0.002). Of patients for heterotopic ossification prophylaxis, 3/14 declined radiation and one was over the weight limit of the radiation table (p=0.000). 41% of patients were inpatients. No patients developed COVID-19 during our study period. Conclusion: A prospective evaluation of new patient referrals may have helped mitigate the spread of COVID-19 at our Radiation Oncology facility. This is one of several prospective measures that our department took to protect patients and staff. Citation Format: Sanjay Joseph, Mary Nittala, Paul Roberts, Maurice King, Hiba Ahmed, Ashley Albert, Toms Thomas, Robert Allbright, Satyaseelan Packianathan, Eswarkumar Mundra, Srinivasan Vijayakumar. Prospective planning of radiation treatment at new patient conference during the COVID-19 Pandemic: The University of Mississippi Medical Center experience [abstract]. In: Proceedings of the AACR Virtual Meeting: COVID-19 and Cancer; 2020 Jul 20-22. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(18_Suppl):Abstract nr PO-034.