Short-course Radiotherapy Research Articles

Hypofractionated short-course radiation therapy for recurrent ovarian cancer: A retrospective cohort study

Hypofractionated short-course radiation therapy for recurrent ovarian cancer: A retrospective cohort study

Preventive efficacy of hydrocortisone enema for radiation proctitis in rectal cancer patients undergoing short-course radiotherapy: a phase II randomized placebo-controlled clinical trial.

This study aimed to investigate the efficacy of hydrocortisone enema in preventing radiation proctitis in patients with rectal cancer undergoing short-course radiotherapy (SCRT). This phase II randomized controlled trial enrolled patients with newly diagnosed locally advanced rectal cancer (clinically staged T3-4 and/or N1-2M0). Participants received a median of 4 cycles of neoadjuvant chemotherapy (capecitabine plus oxaliplatin) followed by 3-dimensional conformal SCRT (25 Gy in 5 fractions). Patients were randomly assigned to receive either a hydrocortisone enema (n=50) or a placebo (n=51) once daily for 5 consecutive days during SCRT. The primary endpoint was the incidence and severity of acute proctitis. Of the 111 eligible patients, 101 were included in the study. Baseline characteristics, including sex, age, performance status, and tumor location, were comparable across the treatment arms. None of the patients experienced grade 4 acute gastrointestinal toxicity or had to discontinue treatment due to treatment-related adverse effects. Patients in the hydrocortisone arm experienced significantly less severe proctitis (P<0.001), diarrhea (P=0.023), and rectal pain (P<0.001) than those in the placebo arm. Additionally, the duration of acute gastrointestinal toxicity following SCRT was significantly shorter in patients receiving hydrocortisone (P<0.001). Hydrocortisone enema was associated with a significant reduction in the severity of proctitis, diarrhea, and rectal pain compared to placebo. Additionally, patients treated with hydrocortisone experienced shorter durations of gastrointestinal toxicity following SCRT. This study highlights the potential benefits of hydrocortisone enema in managing radiation-induced toxicity in rectal cancer patients undergoing radiotherapy.

Comparative analysis of hypofractionated short-course versus standard radiation therapy in elderly patients with glioblastoma: analysis of nationwide database.

Hypofractionated short-course radiation therapy (SCRT) is an alternative treatment option for elderly or frail patients with newly diagnosed glioblastoma (GBM) post-surgery. This study compares survival outcomes and treatment costs between patients receiving SCRT and those undergoing standard long-course radiation therapy (LCRT). This retrospective study utilized health insurance claims and national cancer registry data from Korea to compare overall survival (OS) and treatment costs between patients receiving SCRT and LCRT across all ages and sub-group analysis within the subgroup of cases aged 65 and older from 2016 onwards, a period when intensity-modulated radiotherapy (IMRT) was widely adopted. A total of 1,598 patients were included. Median OS since the first day of radiation therapy was 10.4 months (95% CI [9.6; 12.8]) for SCRT (n = 197) versus 16.2 months (95% CI [15.5; 16.9]) for LCRT (n = 1401) respectively. Subgroup analysis using stabilized inverse probability of treatment weighting (S-IPTW) showed indicating non-inferiority in elderly patients in median OS for elderly patients (≥ 65) with 10.6 months (95% CI [8.9; 14.0]) for SCRT (n = 147) versus 13.2 months (95% CI [8.9; 14.0]) for LCRT (n = 541). The median treatment cost of SCRT is about 6,000 USD lower, 25% less than LCRT. Compliance with the standard TMZ regimen post-radiation improved OS across all age groups. Considering comparable OS and shorter treatment duration, SCRT offers a viable, cost-effective option for elderly GBM patients. Adhering to standard TMZ also contributes to OS improvement. Further research reflecting key prognostic factors is essential to refining the role of SCRT.

Short-Course TNT Improves Rectal Tumor Downstaging in a Retrospective Study of the US Rectal Cancer Consortium.

The RAPIDO trial showed promising rates of pathologic complete response (pCR) after neoadjuvant short-course radiation with consolidation chemotherapy (total neoadjuvant therapy [SC TNT]) for rectal cancer. Only single-center reviews comparing tumor downstaging between SC TNT and long-course chemoradiation (LCRT) have been published in the United States. We reviewed our multi-institutional experience with both. The US Rectal Cancer Consortium database (2007-2018) including data from six high-volume rectal cancer care centers was reviewed. Patients with nonmetastatic, rectal adenocarcinoma who had neoadjuvant LCRT alone or SC TNT before excision or definitive nonoperative management were included. The primary outcome was the rate of complete response (CR), including pCR or durable (12 month) clinical complete response. Of 857 included patients, 175 (20%) received SC TNT and 682 (80%) received LCRT. The LCRT group had more low tumors (51.8% vs. 37.1%, p < 0.0001) and more clinically node-negative disease (31.8% vs. 22.3%, p < 0.0001). The CR rate was higher after SC TNT (34.1% vs. 20.3%, p = 0.0001). SC TNT was a predictor of CR (OR: 2.52, CI: 1.68-3.78). SC TNT patients completing 5-6 months of consolidation chemotherapy had a CR rate of 42.9%. There was no difference in 3-year PFS. SC TNT increases CR rate when compared to LCRT. For patients seeking nonoperative options or fewer radiation treatments, SC TRT should be preferred over LCRT alone.

Node-sparing modified short-course Radiotherapy Combined with CAPOX and Tislelizumab for locally Advanced MSS of Middle and low rectal Cancer (mRCAT): an open-label, single-arm, prospective, multicentre clinical trial

BackgroundNeoadjuvant chemoradiotherapy followed by total mesorectal excision is a standard treatment for locally advanced rectal cancer. Mismatch repair-deficient locally advanced rectal cancer (LARC) was highly sensitive to PD-1 blockade. However, most rectal cancers are microsatellite stable (MSS) or mismatch repair-proficient (pMMR) subtypes for which PD-1 blockade is ineffective. Radiation can trigger the activation of CD8 + T cells, further enhancing the responses of MSS/pMMR rectal cancer to PD-1 blockade. Radioimmunotherapy offers a promising therapeutic modality for rectal cancer. Progenitor T exhausted cells are abundant in tumour-draining lymph nodes and play an important role in immunotherapy. Conventional irradiation fields include the mesorectum and regional lymph nodes, which might cause considerable damage to T lymphocytes and radiation-induced fibrosis, ultimately leading to a poor response to immunotherapy and rectal fibrosis. This study investigated whether node-sparing modified short-course irradiation combined with chemotherapy and PD-1 blockade could be effective in patients with MSS/ pMMR LARC.MethodsThis was a open-label, single-arm, multicentre, prospective phase II trial. 32 LARC patients with MSS/pMMR will receive node-sparing modified short-course radiotherapy (the irradiated planned target volume only included the primary tumour bed but not the tumour-draining lymph nodes, 25 Gy/5f, 5 Gy/f) followed by CAPOX and tislelizumab. CAPOX and tislelizumab will be started two days after the completion of radiotherapy: oxaliplatin 130 mg/m2 intravenous infusion, day 1; capecitabine 1000 mg/m2 oral administration, days 1–14; and tislelizumab 200 mg, intravenous infusion, day 1. There will be four 21-day cycles. TME will be performed at weeks 14–15. We will collect blood, tumour, and lymphoid specimens; perform flow cytometry and in situ multiplexed immunofluorescence detection; and analyse the changes in various lymphocyte subsets. The primary endpoint is the rate of pathological complete response. The organ preservation rate, tumour regression grade, local recurrence rate, disease-free survival, overall survival, adverse effects, and quality of life will also be analysed.DiscussionIn our research, node-sparing modified radiotherapy combined with immunotherapy probably increased the responsiveness of immunotherapy for MSS/pMMR rectal cancer patients, reduced the occurrence of postoperative rectal fibrosis, and improved survival and quality of life. This is the first clinical trial to utilize a node-sparing radiation strategy combined with chemotherapy and PD-1 blockade in the neoadjuvant treatment of rectal cancer, which may result in a breakthrough in the treatment of MSS/pMMR rectal cancer.Trial registrationThis study was registered at www.clinicaltrials.gov. Trial registration number: NCT05972655. Date of registration: 31 July 2023.

Early outcomes of pre-operative short course radiotherapy with simultaneous integrated boost and response-adapted chemotherapy for advanced rectal cancer

Background and purposeLimited evidence exists for dose escalation in neoadjuvant short course radiotherapy (SCRT) for rectal cancer. With enhanced imaging and radiotherapy techniques over the past decades along with the valuable endpoint of pathological complete response (pCR), we believe SCRT with simultaneous integrated boost could potentially provide deeper pathological responses and improve local control. Methods and MaterialsBetween Jan-2020 to Dec 2022, Locoregional advanced rectal cancer patients that were treated with neoadjuvant SCRT with SIB up to 5.5-6Gy per fraction with 5 daily fractions followed by response adapted chemotherapy was retrospectively reviewed. pCR rates, R0 resection rates, tumour down staging, toxicities and early pattern of recurrence are reported. ResultsAmong the 76 patients, 67 (88%) were able to undergo curative intent surgery. R0 resection was achieved in 99% (n = 66) of patients with pCR rates of 28% (n = 19). 46% (n = 31) of patients had significant pathological down staging (ypT2N0) and 55% (n = 37) of patients had both T and N down staging. Most common grade 3 or above radiotherapy related side effects were proctitis, rectal pain and dermatitis found in 5% (n = 4), 3% (n = 2) and 3% (n = 2) of patients respectively. Grade 3 or above surgical complications were observed in 15% (n = 10) of patients. There was no treatment related deaths. With a median follow up of 27 months, only 6% (n = 4) had local recurrence after surgery. ConclusionNeoadjuvant short course radiotherapy with simultaneous boost for rectal cancer is feasible with no added toxicities. Patients who underwent surgery achieve a high R0 resection and pCR rates. Early data suggests low rates of locoregional recurrence. Further follow up and research is needed to validate and optimize the dose, method, and schedule of dose escalation.

Predicting Pathologic Complete Response in Locally Advanced Rectal Cancer with [68Ga]Ga-FAPI-04 PET, [18F]FDG PET, and Contrast-Enhanced MRI: Lesion-to-Lesion Comparison with Pathology.

Neoadjuvant therapy in patients with locally advanced rectal cancer (LARC) has achieved good pathologic complete response (pCR) rates, potentially eliminating the need for surgical intervention. This study investigated preoperative methods for predicting pCR after neoadjuvant short-course radiotherapy (SCRT) combined with immunochemotherapy. Methods: Treatment-naïve patients with histologically confirmed LARC were enrolled from February 2023 to July 2023. Before surgery, the patients received neoadjuvant SCRT followed by 2 cycles of capecitabine and oxaliplatin plus camrelizumab. 68Ga-labeled fibroblast activation protein inhibitor ([68Ga]Ga-FAPI-04) PET/MRI, [18F]FDG PET/CT, and contrast-enhanced MRI were performed before treatment initiation and before surgery in each patient. PET and MRI features and the size and number of lesions were also collected from each scan. Each parameter's sensitivity, specificity, and diagnostic cutoff were derived via receiver-operating-characteristic curve analysis. Results: Twenty eligible patients (13 men, 7 women; mean age, 60.2 y) were enrolled and completed the entire trial, and all patients had proficient mismatch repair or microsatellite-stable LARC. A postoperative pCR was achieved in 9 patients (45.0%). In the visual evaluation, both [68Ga]Ga-FAPI-04 PET/MRI and [18F]FDG PET/CT were limited to forecasting pCR. Contrast-enhanced MRI had a low sensitivity of 55.56% to predict pCR. In the quantitative evaluation, [68Ga]Ga-FAPI-04 change in SULpeak percentage, where SULpeak is SUVpeak standardized by lean body mass, had the largest area under the curve (0.929) with high specificity (sensitivity, 77.78%; specificity, 100.0%; cutoff, 63.92%). Conclusion: [68Ga]Ga-FAPI-04 PET/MRI is a promising imaging modality for predicting pCR after SCRT combined with immunochemotherapy. The SULpeak decrease exceeding 63.92% may provide valuable guidance in selecting patients who can forgo surgery after neoadjuvant therapy.

Management of Locally Advanced Rectal Cancer: ASCO Guideline.

ASCO Guidelines provide recommendations with comprehensive review and analyses of the relevant literature for each recommendation, following the guideline development process as outlined in the ASCO Guidelines Methodology Manual. ASCO Guidelines follow the ASCO Conflict of Interest Policy for Clinical Practice Guidelines.Clinical Practice Guidelines and other guidance ("Guidance") provided by ASCO is not a comprehensive or definitive guide to treatment options. It is intended for voluntary use by providers and should be used in conjunction with independent professional judgment. Guidance may not be applicable to all patients, interventions, diseases or stages of diseases. Guidance is based on review and analysis of relevant literature, and is not intended as a statement of the standard of care. ASCO does not endorse third-party drugs, devices, services, or therapies and assumes no responsibility for any harm arising from or related to the use of this information. See complete disclaimer in Appendix 1 and 2 (online only) for more.PURPOSETo provide evidence-based guidance for clinicians who treat patients with locally advanced rectal cancer.METHODSA systematic review of the literature published from 2013 to 2023 was conducted to identify relevant systematic reviews, phase II and III randomized controlled trials (RCTs), and observational studies where applicable.RESULTSTwelve RCTs, two systematic reviews, and one nonrandomized study met the inclusion criteria for this systematic review. Expert Panel members used available evidence and informal consensus to develop evidence-based guideline recommendations.RECOMMENDATIONSFollowing assessment with magnetic resonance imaging, for patients with microsatellite stable or proficient mismatch repair locally advanced rectal cancer, total neoadjuvant therapy (TNT; ie chemoradiation [CRT] and chemotherapy) should be offered as initial treatment for patients with tumors located in the lower rectum and/or patients who are at higher risk for local and/or distant metastases. Patients without higher-risk factors may discuss chemotherapy with selective CRT depending on extent of response, TNT, or neoadjuvant long-course CRT or short-course radiation. For patients who are candidates for TNT, the preferred timing for chemotherapy is after radiation, and neoadjuvant long-course CRT is preferred over short-course radiation therapy (RT), however short-course RT may also be a viable treatment option depending on circumstances. Nonoperative management may be discussed as an alternative to total mesorectal excision for patients who have a clinical complete response to neoadjuvant therapy. For patients whose tumors are microsatellite instability-high or mismatch repair deficient, immunotherapy is recommended.Additional information is available at http://www.asco.org/gastrointestinal-cancer-guidelines.

[Prognostic and Predictive Value of a Modified Diagnostic Biopsy-Adapted Immunoscore in Patients with Rectal Cancer After Neoadjuvant Treatment- a translational study from the STELLAR trial]

BackgroundThe purpose of this study was to assess the prognostic significance of the modified diagnostic biopsy-adapted immunoscore (mISb) in determining the outcomes for patients with locally advanced rectal cancer (LARC) in a neoadjuvant setting. MethodsWe included 181 LARC patients from a single subcenter of a prospective study comparing total neoadjuvant therapy (TNT) based on short-course radiotherapy with long-term chemoradiotherapy (CRT). Tumor biopsies at baseline were stained for CD8+ and CD3+ T-cell densities. The mISb was developed using mean percentile of CD8+ T-cell density and CD8/CD3 ratios. Patients were classified into low (0%-25%), intermediate (>25%-70%), and high (>70%-100%) in both groups. The relativity among different lymphocytes and their correlation with survival were illustrated. Survival analyses and Cox regression models were used to compare the prognostic value of mISb and ISb for survival outcomes, and to assess the role of mISb in TNT and CRT subgroups respectively. ResultsIn this study, 151 (83.4%) patients received surgery and 30 (16.6%) followed a watch and wait strategy. A strong correlation was found between CD8+ and CD3+ T-cell densities (R=0.86, P<0.001), while a weak correlation witnessed between CD8+ and CD8/CD3 ratio (R=0.45). The 3-year disease-free survival (DFS) for the entire cohort was 69.9%, with 57.2%, 68.6%, and 85.5% for the low, intermediate, and high mISb groups respectively (P=0.01), while ISb failed to distinguish survival outcomes. Multivariate analysis revealed mISb to be an independent prognostic factor for DFS in surgically treated patients (P=0.01). Specifically, patients with high mISb score showed longer PFS than other subgroups in the TNT cohort (P=0.049), but no significant difference was found in the CRT population. ConclusionsIn this study, mISb demonstrates significant prognostic value in LARC patients receiving preoperative therapies, especially in the TNT subgroup. These findings may help tailor the intensity of neoadjuvant therapy for patients.

The impact of preoperative treatments on the immune environment of rectal cancer.

To improve local disease control, the use of preoperative radiotherapy either alone or combined with chemotherapy has become standard practice in rectal cancer, but it is unclear how these treatments modify the antitumoral immune response. We aimed to evaluate tumor histopathologic features and the prognostic effect of host immune response in rectal cancer with variable treatment modalities. Ninety-five rectal cancers with short-course radiotherapy (SRT), 97 with long-course chemoradiotherapy (CRT), and 154 without preoperative treatments, were evaluated for histopathologic features including Crohn's-like reaction (CLR). CD3+ and CD8+ immunohistochemistry and tumor cells were analyzed from tumor tissue microarray samples to calculate T-cell densities and G-cross function values to estimate cancer cell-T-cell co-localization (proximity score). We found that lymphocyte densities were diminished after SRT, but CLR was scarcer after CRT. Proximity score and CLR density were prognostic for survival in cancer without preoperative treatments and could be combined into an enhanced prognostic score (immune grade). In the irradiated tumors, CLR density remained prognostic while the impact of T-cell infiltration was insufficient alone. In multivariable analysis, the immune grade proved to be an independent prognostic factor for survival. In conclusion, the immune contexture of rectal cancer harbors prognostic significance even after preoperative radiotherapy.

A Review of Neoadjuvant Therapy and the Watch-and-Wait Protocol in Rectal Cancer: Current Evidence and Future Directions.

The treatment of rectal cancer underwent a significant change with the introduction of total mesorectal excision (TME), which substantially improved recurrence rates. However, TME is associated with complications such as fecal incontinence and poor bladder control, especially in tumors located near the anal verge. The watch-and-wait (WW) protocol has emerged as an alternative for patients achieving a clinical complete response (cCR) following neoadjuvant radiochemotherapy. This narrative review, developed according to the Scale for the Assessment of Narrative Review Articles guidelines, evaluates neoadjuvant treatments and the WW protocol for rectal cancer. Literature was sourced from the PubMed database using specific search terms related to neoadjuvant therapy and the WW protocol, resulting in 63 articles selected for discussion. Neoadjuvant treatment, including chemoradiation and short-course radiotherapy, is indicated for T3 and T4 rectal adenocarcinomas. Studies like the German Rectal Cancer Study Group and the PRODIGE 23 trial have shown the benefits of preoperative treatment, including improved disease-free survival and reduced local recurrence rates. However, challenges in adopting the WW protocol include the risk of local regrowth and distant metastasis. Immune checkpoint inhibitors have shown promise in mismatch repair-deficient patients, yet the data are insufficient to fully endorse WW for these cases. The WW protocol is viable for selected rectal cancer patients, with ongoing debates regarding criteria for inclusion. Key challenges include accurately identifying cCR and managing patients with near-complete responses. MRI and endoscopic evaluation are crucial for assessing treatment response, although achieving a pathological complete response remains uncertain. The WW strategy offers a potential organ-preserving approach in rectal cancer management but requires careful patient selection and comprehensive risk-benefit discussions. Further research is needed to refine criteria for inclusion and optimize treatment protocols, enhancing outcomes while minimizing invasive interventions.

Dose tracking assessment for magnetic resonance guided adaptive radiotherapy of rectal cancers

BackgroundMagnetic resonance-guided adaptive radiotherapy (MRgART) at MR-Linac allows for plan optimisation on the MR-based synthetic CT (sCT) images, adjusting the target and organs at risk according to the patient’s daily anatomy. Conversely, conventional linac image-guided radiotherapy (IGRT) involves rigid realignment of regions of interest to the daily anatomy, followed by the delivery of the reference computed tomography (CT) plan. This study aims to evaluate the effectiveness of MRgART versus IGRT for rectal cancer patients undergoing short-course radiotherapy, while also assessing the dose accumulation process to support the findings and determine its usefulness in enhancing treatment accuracy.MethodsNineteen rectal cancer patients treated with a 1.5 Tesla MR-Linac with a prescription dose of 25 Gy (5 Gy x 5) and undergoing daily adapted radiotherapy by plan optimization based on online MR-based sCT images, were included in this retrospective study. For each adapted plan (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{\ ext{T}\ ext{P}}_{\ ext{a}\ ext{d}\ ext{a}\ ext{p}}$$\\end{document}), a second plan (\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{\ ext{T}\ ext{P}}_{\ ext{I}\ ext{G}\ ext{R}\ ext{T}}$$\\end{document}) was generated by recalculating the reference CT plan on the daily MR-based sCT images after rigid registration with the reference CT images to simulate the IGRT workflow. Dosimetry of \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{\ ext{T}\ ext{P}}_{\ ext{a}\ ext{d}\ ext{a}\ ext{p}}$$\\end{document} and\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:\\:{\ ext{T}\ ext{P}}_{\ ext{I}\ ext{G}\ ext{R}\ ext{T}}$$\\end{document}was compared for each fraction. Cumulative doses on the first and last fractions were evaluated for both workflows. The dosimetry per single fraction and the cumulative doses were compared using dose-volume histogram parameters.ResultsNinety-five fractions delivered with MRgART were compared to corresponding simulated IGRT fractions. All MRgART fractions fulfilled the target clinical requirements. IGRT treatments did not meet the expected target coverage for 63 out of 94 fractions (67.0%), with 13 fractions showing a V95 median point percentage decrease of 2.78% (range, 1.65-4.16%), and 55 fractions exceeding the V107% threshold with a median value of 15.4 cc (range, 6.0-43.8 cc). For the bladder, the median \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{\ ext{D}}_{15\ ext{c}\ ext{c}}$$\\end{document} values were 18.18 Gy for the adaptive fractions and 19.60 Gy for the IGRT fractions. Similarly the median \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\:{\ ext{D}}_{5\ ext{c}\ ext{c}}$$\\end{document} values for the small bowel were 23.40 Gy and 25.69 Gy, respectively. No statistically significant differences were observed in the doses accumulated on the first or last fraction for the adaptive workflow, with results consistent with the single adaptive fractions. In contrast, accumulated doses in the IGRT workflow showed significant variations mitigating the high dose constraint, nevertheless, more than half of the patients still did not meet clinical requirements.ConclusionsMRgART for short-course rectal cancer treatments ensures that the dose delivered matches each fraction of the planned dose and the results are confirmed by the dose accumulation process, which therefore seems redundant. In contrast, IGRT may lead to target dose discrepancies and non-compliance with organs at risk constraints and dose accumulation can still highlight notable dosimetric differences.

Organ preservation after neoadjuvant long-course chemoradiotherapy versus short-course radiotherapy

Potential differences in organ preservation between total neoadjuvant therapy (TNT) regimens integrating long-course chemoradiotherapy (LCCRT) and short-course radiotherapy (SCRT) in rectal cancer remain undefined. This natural experiment arose from a policy change in response to the COVID-19 pandemic during which our institution switched from uniformly treating patients with LCCRT to mandating that all patients be treated with SCRT. Our study includes 323 locally advanced rectal adenocarcinoma patients treated with LCCRT-based or SCRT-based TNT from January 2018 to January 2021. Patients who achieved clinical complete response were offered organ preservation with watch-and-wait (WW) management. The primary outcome was 2-year organ preservation. Additional outcomes included local regrowth, distant recurrence, disease-free survival (DFS), and overall survival (OS). Patient and tumor characteristics were similar between LCCRT (n= 247) and SCRT (n= 76) cohorts. Median follow-up was 31 months. Similar clinical complete response rates were observed following LCCRT and SCRT (44.5% versus 43.4%). Two-year organ preservation was 40% [95% confidence interval (CI) 34% to 46%] and 31% (95% CI 22% to 44%) among all patients treated with LCCRT and SCRT, respectively. In patients managed with WW, LCCRT resulted in higher 2-year organ preservation (89% LCCRT, 95% CI 83% to 95% versus 70% SCRT, 95% CI 55% to 90%; P= 0.005) and lower 2-year local regrowth (19% LCCRT, 95% CI 11% to 26% versus 36% SCRT, 95% CI 16% to 52%; P= 0.072) compared with SCRT. The 2-year distant recurrence (10% versus 6%), DFS (90% versus 90%), and OS (99% versus 100%) were similar between WW patients treated with LCCRT and SCRT, respectively. While WW eligibility was similar between cohorts, WW patients treated with LCCRT had higher 2-year organ preservation and lower local regrowth than those treated with SCRT, yet similar DFS and OS. These data support induction LCCRT followed by consolidation chemotherapy as the preferred TNT regimen for patients with locally advanced rectal cancer pursuing organ preservation.

570P A phase II clinical study of fruquintinib (Fru) combined with toripalimab (Tor) and short-course radiotherapy (SCRT) as neoadjuvant therapy for locally advanced rectal cancer (LARC)

570P A phase II clinical study of fruquintinib (Fru) combined with toripalimab (Tor) and short-course radiotherapy (SCRT) as neoadjuvant therapy for locally advanced rectal cancer (LARC)

564P Short-course radiotherapy combined with chemotherapy and PD-1 inhibitor in proficient mismatch repair or microsatellite stable (pMMR/MSS) low-lying early rectal cancer: Preliminary findings from a prospective, multi-center, phase II trial (TORCH-E)

564P Short-course radiotherapy combined with chemotherapy and PD-1 inhibitor in proficient mismatch repair or microsatellite stable (pMMR/MSS) low-lying early rectal cancer: Preliminary findings from a prospective, multi-center, phase II trial (TORCH-E)

Protocol amendment for ENSEMBLE study: A multicenter, randomized, phase III trial to test the superiority of consolidation irinotecan, capecitabine and oxaliplatin vs capecitabine and oxaliplatin following short course radiotherapy as total neoadjuvant therapy in patients with locally advanced rectal cancer—Changing the irinotecan dosage.

TPS99 Background: Total neoadjuvant therapy (TNT) presents a promising approach for treating patients (pts) with locally advanced rectal cancer (LARC). TNT not only enhances outcomes for LARC pts but also contributes to improving their quality of life by offering non-operative management (NOM) for patients with complete clinical response (cCR) or near-complete clinical response (nCR). We are currently conducting a phase III trial, the ENSEMBLE study, which was presented at ASCO Breakthrough 2023. At this stage, we have modified the protocol for this study. Additionally, we are conducting translational research (TR) to establish clear criteria for NOM following TNT. Methods: In the ENSEMBLE study, the experimental treatment group received short-course radiotherapy (SCRT) (5×5 Gy) followed by six cycles of CAPOXIRI (capecitabine 800 mg/m2 [orally, twice daily, days 1-14], oxaliplatin 130 mg/m2 [intravenously, day 1], and irinotecan 200 mg/m2 [intravenously, day 1, every 3 weeks]). The standard-of-care group received SCRT (5×5 Gy) followed by six cycles of CAPOX (capecitabine 1000 mg/m2 [orally, twice daily, days 1-14], oxaliplatin 130 mg/m2 [intravenously, day 1, every 3 weeks]). However, the experimental treatment group experienced a higher rate of adverse events due to the high starting dose of irinotecan. After consulting the data and safety monitoring committee (DSMC), it was recommended to reduce the starting dose of irinotecan. Results: Enrollment for the ENSEMBLE study commenced in November 2022. By August 2023, severe adverse events necessitating emergency reporting had occurred in the experimental treatment group. In response to these adverse events, the DSMC was consulted, leading to the reduction of the starting dose of irinotecan to 150 mg/m2. Following this adjustment, no severe adverse events requiring emergency reporting were observed during the experimental treatment with CAPOXIRI. We are currently continuing the ENSEMBLE study to advance treatment options for LARC pts. The TR component of the ENSEMBLE study involves genomic profiling through whole genome plus RNA sequencing of tissue and blood samples, as well as circulating nucleic acid sequencing (cNAS). Additionally, all imaging data (MRI, CT, and colonoscopy) and clinical information are being collected to develop criteria for NOM. Conclusions: A starting dose of irinotecan at 150 mg/m2 appears to be feasible after SCRT in the ENSEMBLE study. Furthermore, the ENSEMBLE study aims to establish clear NOM criteria through deep learning with TR. Clinical trial information: NCT05646511 / jRCTs031220342 .

Circulating tumor DNA for predicting radiographic and pathologic response to total neoadjuvant therapy in locally advanced rectal cancer: ENSEMBLE-1.

71 Background: Total neoadjuvant therapy (TNT) has dramatically shifted the treatment paradigm for locally advanced rectal cancer (LARC), prolonging survival with high rates of pathologic complete response (pCR) and introducing opportunities for nonoperative management (NOM). However, there is a need for robust predictive biomarkers of TNT efficacy, local cancer regrowth in NOM, and overall prognosis. Circulating tumor DNA (ctDNA) is a minimally invasive biomarker used to detect molecular residual disease (MRD) and predict recurrence in colorectal cancer after curative resection. The effectiveness of ctDNA MRD status specifically as a predictive biomarker for TNT was evaluated in the Phase II TNT study, ENSEMBLE-1 (jRCTs051200113), conducted in Japan. Methods: Patients with LARC undergoing TNT were enrolled in ENSEMBLE-1. Protocol treatment was defined as short-course radiotherapy (SCRT: 25Gy) followed by six cycles of CAPOX and total mesorectal excision (TME). NOM was allowed if a clinical complete response (cCR) was achieved after TNT. ctDNA was measured by SignateraTM (Natera, Inc.) at the following time points: baseline (pre-treatment), after SCRT, after 4 cycles of CAPOX, before TME, and post operatively at 4w, 12w, 24, 36 and 48w in the GALAXY trial (UMIN000039205). Results: A total of 30 patients were enrolled in the study. After completing TNT, TME and NOM were performed in 20 and 7 patients, respectively. ctDNA was measured in 26 patients (TME: 19 patients, NOM: 7 patients). ctDNA was detected in 100% (25/25) at baseline, 81% (21/26) after SCRT, 31% (8/26) after 4 cycles of CAPOX, and 45% (9/20) after TNT. The attached table shows the results of statistical analyses of the correlation between ctDNA status, clinical response, TME or NOM, and pathologic complete response (pCR). It was found that ctDNA status after SCRT and after 4 cycles of CAPOX was associated with cCR or non cCR (p=0.007 and p=0.007, respectively). Additionally, ctDNA status after TNT was associated with pCR or non pCR (p=0.029). Conclusions: Our study demonstrates that ctDNA-based MRD may predict TNT response in LARC patients. Negative ctDNA during treatment correlates with favorable responses and may be an aid in NOM decision making. Clinical trial information: jRCTs051200113 . [Table: see text]

Efficacy and safety of combining short-course neoadjuvant chemoradiotherapy with envafolimab in locally advanced rectal cancer patients with microsatellite stability: A phase II PRECAM experimental study.

Conventional neoadjuvant chemoradiotherapy (nCRT) yields a pathologic complete response (pCR) rate of 15%-30% for locally advanced rectal cancer (LARC). This study ventures to shift this paradigm by incorporating short-course nCRT with immunotherapy, specifically Envafolimab, to achieve improved treatment efficacy and possibly redefine the standard of care for LARC. The PRECAM study is a prospective, single-arm, phase 2 clinical trial for LARC in patients with microsatellite stable (MSS) tumors. Participants received short-course radiotherapy (25Gy/5f), followed by two cycles of CAPEOX chemotherapy and six weekly doses of Envafolimab, a PD-L1 antibody, before total mesorectal excision surgery. The primary endpoint was the pCR rate. From April to December 2022, 34 patients were enrolled, of whom 32 completed the study, each diagnosed with an MSS rectal adenocarcinoma. All patients underwent preoperative CRT combined with Envafolimab. Remarkably, a pCR rate of 62.5% (20/32) was attained, and a significant pathologic response rate of 75% (24/32) was achieved. Additionally, 21 of 32 participants achieved a neoadjuvant rectal (NAR) score below 8, suggesting an effective treatment response. Common adverse events included tenesmus (78.1%), diarrhea (62.5%), and leukocyte decrease (40.6%). Two Grade 3 adverse events were noted, one related to liver function abnormality and the other to a decrease in platelet count. Surgical procedures were performed in all cases, with minor complications, including ileus, infections, and anastomotic leakage. As of this report, there have been no reported cases of recurrence or death during the follow-up period, ranging from 12 to 20 months. In LARC patients exhibiting MSS tumors, combining short-course nCRT with Envafolimab demonstrated favorable efficacy, leading to a significant pCR rate. Minor adverse effects and surgical complications were observed. These preliminary but promising results underscore the potential of this approach and call for further exploration and validation through a randomized controlled trial.

71262 - Surgical outcomes after TNT in rectal cancer with short-course radiotherapy using protons or photons: Early results from the randomised PRORECT trial

71262 - Surgical outcomes after TNT in rectal cancer with short-course radiotherapy using protons or photons: Early results from the randomised PRORECT trial

Electronic patient-reported outcome-based surveillance system to evaluate safety and efficacy of preoperative immunochemotherapy with or without short-term chemoradiation in patients with esophageal squamous cell carcinoma (ePRO-PICCRT): protocol for a prospective, single-arm, phase II study.

Radiation-associated adverse events (ADEs) in patients with esophageal squamous cell carcinoma (ESCC) remain a problem. Recent research has focused on reducing radiation-associated ADEs while maintaining efficacy, particularly through the combination of immune checkpoint inhibitors (ICIs) with chemotherapy. Patient-reported outcomes (PROs) have also emerged as reliable measures for monitoring treatment effectiveness and quality of life (QoL). This trial aims to investigate the feasibility of using patient-reported dysphagia relief to assess pathological response following neoadjuvant immunochemotherapy, as well as the safety and efficacy of neoadjuvant immunochemotherapy combined with short-course radiotherapy for patients with locally advanced ESCC. This study is designed as a prospective, single-arm, phase II study. Eligible ESCC patients will be invited to participate in this study. All participants will receive paclitaxel (albumin-bound) (260 mg/m2, day 1), carboplatin [area under the curve (AUC) 5; 5 mg/mL/min, day 1] or cisplatin [60 mg/m2, intravenous drip (ivdrip), day 1], and tislelizumab (200 mg, day 1) in the first treatment cycle. Early remission of dysphagia is defined as relief greater than 70% according to the dysphagia symptom score in the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire esophagus-specific questionnaire (EORTC OES-18). The early remission group (Group A) will continue with the same regimen for two treatment cycles. The latent remission group will continue with one treatment cycle followed by neoadjuvant immunochemotherapy combined with short-course radiotherapy (radiotherapy 30 Gy/10 F). The primary objective is the pathological complete response (pCR) rate. Research data collection, storage, and management will be conducted in a web-based Real-World-Data Management Platform (RWDMP). Longitudinal data will be conducted by a linear mixed model with treatment effects, baseline factors influencing the endpoint as fixed effects, and the center as a random effect. This study will provide evidence for using patient-reported dysphagia relief to evaluate pathological response after neoadjuvant immunochemotherapy in early remission (Group A) and to evaluate the safety and efficacy of combining immunochemotherapy with short-course radiotherapy in latent remission (Group B) among patients with ESCC. Limitations include the single-arm study design, small sample size, and the need for further exploration of the specific mechanism and mediator of early dysphagia remission's effect on immunochemotherapy effectiveness. This study is registered at Clinicaltrials.gov (NCT05596890).