Short-course Preoperative Radiotherapy Research Articles

Preoperative short-course radiotherapy followed by chemotherapy and PD-1 inhibitor administration for locally advanced rectal cancer: A study protocol of a randomized phase II/III trial (STELLAR II study).

For patients with locally advanced rectal cancer, previous STELLAR studies have shown that a new adjuvant treatment paradigm of short-course radiotherapy followed by neoadjuvant chemotherapy can achieve pathological complete response rates superior to those of standard care; however, the 3-year DFS is inferior to neoadjuvant concurrent radiotherapy. Recent studies have shown that immune checkpoint inhibitors may improve the prognosis of rectal cancer and have good synergy with radiotherapy. Therefore, neoadjuvant chemotherapy combined with immune checkpoint inhibitors after a short course of radiotherapy has the potential to further improve complete response rates and prognosis. The STELLAR II study is a multicentre, open label, two-arm randomized, phase II/III trial of short-course radiotherapy followed by neoadjuvant chemotherapy concurrent with immunotherapy for locally advanced rectal cancer. A total of 588 patients with locally advanced rectal cancer (LARC) will be randomly assigned to the experimental and control groups. The experimental group will receive short-course radiotherapy and neoadjuvant chemotherapy in combination with sindilizumab, while the control group will receive short-course radiotherapy and neoadjuvant chemotherapy. Both groups will subsequently receive either total rectal mesenteric resection or a watch & wait (W&W) strategy. The phase II primary endpoint is the complete remission rate, and the secondary endpoints include grade 3-4 adverse events, perioperative complications, R0 resection rate, overall survival, local recurrence rate, distant metastasis rate and quality of life score. A seamless phase II/III randomized controlled design will be used to investigate the effectiveness and safety of the TNT strategy with the addition of immunotherapy. The trial opened, and the first patient was recruited on 31 August 2022. Trial registration number and date of registration: ClinicalTrials.gov NCT05484024, 29 July 2022. The STELLAR II trial will prospectively evaluate the efficacy of TNT treatment strategies that incorporate immune checkpoint inhibitors. The trial will yield important information to guide routine management of patients with local advanced rectal cancer.

3214: Preoperative short-course radiation therapy: data from clinical practice for protons and photons

3214: Preoperative short-course radiation therapy: data from clinical practice for protons and photons

A prospective multicenter phase II trial of total neoadjuvant therapy for locally advanced rectal cancer in JAPAN: ENSEMBLE-1 study.

123 Background: The short- and long-term prognosis of total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC) is elucidated in the world. We evaluated the feasibility and safety of TNT for patients with LARC in Japan. Methods: This prospective, multicenter, open-label, single-arm phase II trial was conducted at five institutions. The key eligibility criteria were age ≥20 years, LARC within 12 cm from the anal verge, and cT3-4N0M0 or TanyN+M0 at the time of diagnosis that enabled curative resection. Preoperative short-course radiation therapy (SCRT) 5 Gy × 5 days (total 25 Gy) + CAPOX (6 courses) followed by total mesorectum excision (TME) was the treatment protocol. Non-operative management (NOM) was allowed if clinical complete response (cCR) was obtained in the preoperative evaluation. The primary endpoint was the pathological complete response (pCR) rate. With a pCR rate threshold of 5%, an expected value of 28%, a one-sided significance level of 5%, and a power of at least 80%, the sample size required by the exact binomial distribution method would be ≥19 patients. Considering a few dropouts, ineligible cases, and patients in which resection was not performed, the target sample size was set to 27 patients. Results: Thirty patients (male, n=26; female, n=4; median age, 62.5 [44-74] years; cT [T2, n=1; T3, n=25; T4, n=4]; cN [N0, n=13; N1, n=13; N2, n=4]) were enrolled. The final analysis included 30 patients in total. The completion rates were 100% for SCRT and 83% for CAPOX. TME and NOM were performed in 20 and seven patients, respectively. pCR was observed in six patients (30% [95% CI 14.0%–50.8%]). The primary endpoint was met. pCR+cCR was observed in 13 (43.3%) patients at TME or restaging. There were no treatment-related deaths. Grade ≥3 (CTCAE ver. 5.0) adverse events (≥20%), including diarrhea (23.3%) and neutropenia (23.3%). The median follow-up period was 21.8 (10.9-29.6) months. Recurrences in three patients (10.0%) were observed. In NOM, regrowth (28.6%) in two patients occurred, of which one patient was performed TME and one patient is on chemotherapy. Conclusions: ENSEMBLE-1 demonstrated satisfactory pCR and cCR, and well-tolerated safety of TNT for patients with LARC in JAPAN. Further long-term prognosis observation is required. A phase III trial, ENSEMBLE (NCT05646511/jRCTs031220342) is currently ongoing in JAPAN. Clinical trial information: jRCT s051200113 .

Preoperative Short-Course Radiotherapy with Delayed Surgery Versus Long-Course Chemoradiotherapy for Locally Advanced Rectal Cancer

Preoperative Short-Course Radiotherapy with Delayed Surgery Versus Long-Course Chemoradiotherapy for Locally Advanced Rectal Cancer

Short-course preoperative radiotherapy increases pelvic fracture risk in rectal cancer

Short-course preoperative radiotherapy increases pelvic fracture risk in rectal cancer

Total neoadjuvant therapy with short-course radiotherapy Versus long-course neoadjuvant chemoradiotherapy in Locally Advanced Rectal cancer, Korean trial (TV-LARK trial): study protocol of a multicentre randomized controlled trial

BackgroundFor locally advanced rectal cancer (LARC), total neoadjuvant therapy (TNT) may enhance tumour response, reduce recurrence, and improve patient compliance compared to upfront surgery. Recent studies have shown that chemoradiotherapy (CRT) followed by consolidation chemotherapy leads to higher rate of pathologic complete response (pCR) than induction chemotherapy followed by CRT. However, an optimal TNT regimen that maximise the pCR rate and minimise toxicity has not been established. Therefore, the aim of this trial was to investigate whether preoperative short-course radiotherapy followed by chemotherapy with four cycles of CAPOX can double the pCR rate compared to a standard schedule of long-course preoperative CRT in patients with LARC.MethodsThis is a multi-centre, prospective, open label, randomised controlled trial. Patients with clinical primary tumour stage 3 and higher or regional node-involved rectal cancer located within 10 cm from the anal verge were randomly assigned equally to short-course radiotherapy (25 Gy in 5 fractions over 1 week) followed by four cycles of CAPOX (intravenous oxaliplatin [130 mg/m2, once a day] on day 1 and capecitabine [1,000 mg/m2, twice a day] from days 1 to 14) (TNT) or CRT (50.4 Gy in 28 fractions over 5 weeks, concurrently with concomitant oral capecitabine 825 mg/m2 twice a day). After preoperative treatment, total mesorectal excision was performed 2–4 weeks in the TNT group and 6–10 weeks in the CRT group, followed by optional additional adjuvant chemotherapy. The primary endpoint is the pCR rate, and secondary endpoints include disease-related treatment failure, quality of life, and cost-effectiveness. Assuming a pCR rate of 28% and 15% in the TNT and CRT groups, respectively, and one-side alpha error rate of 0.025 and power of 80%, 348 patients will be enrolled considering 10% dropout rate.DiscussionThe TV-LARK trial will evaluate the superiority of employed TNT regimen against the standard CRT regimen for patients with LARC. We aimed to identify a TNT regimen that will improve the pCR rate and decrease systemic recurrence in these patients.Trial registrationCris.nih.go.kr ID: KCT0007169 (April 08, 2022). The posted information will be updated as needed to reflect the protocol amendments and study progress.

Short-term outcomes of a prospective multicenter phase II trial of total neoadjuvant therapy for locally advanced rectal cancer in Japan (ENSEMBLE-1).

To evaluate the feasibility and safety of total neoadjuvant therapy (TNT) in patients with locally advanced rectal cancer (LARC) in Japan. This prospective, multicenter, open-label, single-arm phase II trial was conducted at five institutions. The key eligibility criteria were age ≥ 20 years, LARC within 12 cm from the anal verge, and cT3-4N0M0 or TanyN+M0 at the time of diagnosis that enabled curative resection. Preoperative short-course radiation therapy (SCRT) 5 Gy × 5 days (total 25 Gy) + CAPOX (six courses) followed by total mesorectum excision (TME) was the treatment protocol. Non-operative management (NOM) was allowed if clinical complete response (cCR) was obtained in the preoperative evaluation. The primary endpoint was the pathological complete response (pCR) rate. Thirty patients (male, n = 26; female, n = 4; median age, 62.5 [44-74] years; cT [T2, n = 1; T3, n = 25; T4, n = 4]; cN [N0, n = 13; N1, n = 13; N2, n = 4]) were enrolled. The final analysis included 30 patients in total. The completion rates were 100% for SCRT and 83% for CAPOX. TME and NOM were performed in 20 and seven patients, respectively. pCR was observed in six patients (30% [95% CI 14.0%-50.8%]). The primary endpoint was met. pCR+cCR was observed in 13 (43.3%) patients. There were no treatment-related deaths. Grade ≥3 (CTCAE ver. 5.0) adverse events (≥20%), including diarrhea (23.3%) and neutropenia (23.3%). The median follow-up period was 15.6 (10.5-22.8) months, with no recurrence or regrowth in NOM. ENSEMBLE-1 demonstrated satisfactory pCR and cCR, and well-tolerated safety of TNT for patients with LARC in Japan.

Neoadjuvant short-course radiotherapy followed by chemotherapy plus camrelizumab versus long-course chemoradiotherapy followed by chemotherapy for patients with locally advanced rectal cancer: A randomized, multicenter, open-label phase 3 trial (Union).

TPS3638 Background: Short-course preoperative radiotherapy (SCPRT) and long-course chemoradiotherapy (LCCRT) are standard neoadjuvant treatments for locally advanced rectal cancer (LARC). Further, the RAPIDO trial found that SCPRT combined with consolidation chemotherapy produced better short- and long-term outcomes than SCPRT alone for patients with high-risk LARC. A phase 2, single-arm trial of neoadjuvant SCPRT followed by camrelizumab (an anti-PD-1 antibody) plus chemotherapy demonstrated promising short-term outcomes in patients with LARC. The Union trial is evaluating the efficacy and safety of neoadjuvant SCPRT followed by camrelizumab plus chemotherapy versus LCCRT followed by chemotherapy in patients with LARC. Methods: The Union trial is enrolling patients aged 18-75 with histologically confirmed clinical stage T3-4/N+ adenocarcinoma of the rectum, Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1, and a tumor inferior margin less than 10 cm above the anal verge. Eligible patients are randomized in a 1:1 ratio to either arm A or arm B. Patients in arm A receive neoadjuvant treatment with SCPRT (a total of 25 Gy in 5 days) followed by camrelizumab (200 mg/m2 intravenous drip on day 1, every 3 weeks for 2 cycles) plus CAPOX (oxaliplatin 130 mg/m2 intravenous infusion over 2 hours on day 1, capecitabine 1000 mg/m2 oral twice daily, days 1–14, every 3 weeks for 2 cycles), surgery, and adjuvant treatment with camrelizumab plus CAPOX (6 cycles) followed by camrelizumab until the medication duration of camrelizumab reaches one year. Patients in arm B receive neoadjuvant treatment with LCCRT (capecitabine 825 mg/m2 twice daily, 5 days a week, combined with a total dose of 50.4 Gy in 28 days) followed by CAPOX (2 cycles), surgery, and adjuvant treatment with CAPOX (6 cycles). Randomization is stratified by clinical T stage (≤T3 vs T4) and clinical N stage (N0 vs N+). The primary endpoint is pathologic complete response (pCR). The secondary endpoints are 3-year event-free survival rate, overall survival, R0 resection rate, completion rate of neoadjuvant treatment, 3-year disease-free survival rate, tumor regression grading, safety, and quality of life. pCR is evaluated per the AJCC 8th Edition TRG scoring system as assessed by the blinded independent central review. Adverse events are graded by the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Quality of life is assessed by the European Organization for the Research and Treatment of Cancer Quality of Life Questionnaire Core 30. This study began enrollment in July 2021 with a planned enrollment of 230 patients. Clinical trial information: NCT04928807 .

Selecting a TNT Schedule in Locally Advanced Rectal Cancer: Can We Predict Who Actually Benefits?

Many consider the standard of care for locally advanced rectal cancer (LARC) to be preoperative chemoradiotherapy, radical surgery involving a total mesorectal excision, and post-operative adjuvant chemotherapy based on the pathology of the specimen. The poor impact on distant control is a major limitation of this strategy, with metastasis rates remaining in the 25-35% range and recovery after radical surgery leading to reluctance with prescription and inconsistent patient compliance with adjuvant chemotherapy. A second limitation is the low rate of pathologic complete response (pCR) (around 10-15%) despite multiple efforts to potentiate preoperative chemoradiation regimens, which in turn means it is less effective at achieving non-operative management (NOM). Total neoadjuvant treatment (TNT) is a pragmatic approach to solving these problems by introducing systemic chemotherapy at an early timepoint. Enthusiasm for delivering TNT for patients with LARC is increasing in light of the results of published randomized phase III trials, which show a doubling of the pCR rate and a significant reduction in the risk of subsequent metastases. However, there has been no demonstrated improvement in quality of life or overall survival. A plethora of potential chemotherapy schedules are available around the radiotherapy component, which include preoperative induction or consolidation with a range of options (FOLFOXIRI, FOLFOX, or CAPEOX,) and a varying duration of 6-18 weeks, prior to long course chemoradiation (LCCRT) or consolidation NACT following short-course preoperative radiation therapy (SCPRT) using 5 × 5 Gy or LCCRT using 45-60 Gy, respectively. The need to maintain optimal local control is a further important factor, and preliminary data appear to indicate that the RT schedule remains a crucial issue, especially in more advanced tumors, i.e., mesorectal fascia (MRF) invasion. Thus, there is no consensus as to the optimum combination, sequence, or duration of TNT. The selection of patients most likely to benefit is challenging, as clear-cut criteria to individuate patients benefiting from TNT are lacking. In this narrative review, we examine if there are any necessary or sufficient criteria for the use of TNT. We explore potential selection for the individual and their concerns with a generalized use of this strategy.

Treatment of locally advanced rectal cancer and synchronous liver metastases: multicentre comparison of two treatment strategies.

Management of locally advanced rectal cancer (LARC) has been optimized during recent times through (beyond) total mesorectal excision surgery and, more recently, the introduction of total neoadjuvant treatment (TNT)1–4. For patients with synchronous liver metastases, the optimal treatment strategy is less clear, with high variability among institutions worldwide5. In the Netherlands, two specific treatment sequences have mainly been used for treating LARC and synchronous liver metastases: the liver-first approach (LFA) and the M1 schedule6–8. The LFA consists of induction systemic chemotherapy, subsequent local treatment of the liver metastases, followed by long-course (chemo)radiotherapy and resection of the primary tumour. The rationale behind LFA is to treat the rectal tumour locally only when control of synchronous liver metastases has been established. Radiotherapy and primary tumour resection can be avoided in patients with disease progression during the first phase of the schedule9. The M1 schedule starts with preoperative short-course pelvic radiotherapy (5 × 5 Gy), followed by systemic therapy, and subsequent surgical treatment of both the liver and rectum (either simultaneously, liver first or primary tumour first). The advantage of starting with radiotherapy is the immediate downstaging effect on the primary tumour. This strategy has been proven safe and effective, and leads to excellent local control10.

Efficacy and safety of neoadjuvant preoperative short-course radiation followed by envafolimab plus CAPEOX in microsatellite stable (MSS)/mismatch repair proficient (pMMR) locally advanced rectal cancer.

134 Background: Chemoradiation is the standard neoadjuvant treatment for locally advanced rectal cancer. Microsatellite stable (MSS)/ mismatch repair proficient (pMMR) rectal cancer rarely responds to immune checkpoint inhibitor monotherapy, but combination with chemoradiation may improve sensitivity of MSS/pMMR tumors by inducing immune-stimulatory effects. Therefore, we aimed to investigate the efficacy and safety of patients treated with neoadjuvant preoperative short-course radiation followed by envafolimab plus CAPEOX for MSS/pMMR locally advanced rectal cancer. Methods: This is an open-label, single-center, phase ¢ò study. Patients (pts) with locally advanced rectal adenocarcinoma with MSS/pMMR were eligible. MMR protein expression was tested by immunohistochemistry (IHC) £¬and MSI status was confirmed by NGS (next generation sequencing). All pts included in this study underwent neoadjuvant short-course radiation (total dose of 5¡Á5Gy) in the first week after enrollment, then followed by 6 cycles of envafolimab (anti-PD-L1 inhibitor,150mg, d1, subcutaneous injection, QW) plus 2 cycles of CAPEOX in the next six weeks, and subsequently underwent total mesorectal excision (TME) in the ninth week. The primary endpoint is pathological complete response rate. Secondary endpoints include tumor regression grade (TRG), 3 year disease free survival, overall survival, toxicity, and quality of life (QoL). Results: This study intends to recruit 32 pts, and a total of 21 pts were enrolled from January 2022 to September 2022. Overall median age was 67 (42-79) years. 12 pts completed study designed treatment protocol (envafolimab plus CAPOX) followed with TME procedures, and 9 pts are still undergoing neoadjuvant treatment. All 12 pts achieved major partial response (MPR) evaluated by diffusion-weighted magnetic resonance imaging (DW-MRI), and 8 pts (8/12,76.6%) achieved pCR. During neoadjuvant treatment period, 20 pts (20/21, 95.2%) presented with treatment-related AEs (TRAEs) of any grade, 18 pts (18/21, 85.7%) had grade 1-2 and one each pts had grade 3 and 4 thrombocytopenia (2/21, 9.5%). The most common TRAEs were sensation of rectal tenesmus. Conclusions: Neoadjuvant preoperative short-course radiation followed by envafolimab plus CAPEOX in MSS/pMMR locally advanced rectal cancer achieved a promising pathologic response. Meanwhile, this combination neoadjuvant therapy is safe and worthy of application to clinical practice. (Funded by Sir Run Run Shaw Hospital Zhejiang University School of Medicine.) Clinical trial information: NCT05216653 .

The safety of an MRI simulation-guided boost after short-course preoperative radiotherapy for unresectable rectal cancer (SUNRISE): interim analysis of a randomized phase II trial

PurposeThe safety of an MRI simulation-guided boost after short-course preoperative radiotherapy (SCPRT) for unresectable rectal cancer is assessed with a planned interim analysis.Methods and materialsPatients diagnosed with clinical stage T3-4 or regional lymph node-positive disease with positive mesorectal fascia or T4b disease evaluated by pelvic MRI were randomly assigned to the SCPRT-boost group (25 Gy in 5 fractions plus 4 Gy delivered to the gross tumor volume, followed by four cycles of chemotherapy) or preoperative chemoradiotherapy group (50 Gy in 25 fractions with concurrent chemotherapy). Then, patients received total mesorectal excision surgery after preoperative treatment. The primary endpoint was the R0 resection rate. The interim analysis was performed when 42 patients completed their assigned treatments.ResultsFrom October 2018 to November 2019, a total of 43 patients were enrolled, and 42 patients were included in the interim analysis. During preoperative therapy, grade 3 or above toxicities were observed in 10/21 (47.6%) patients in the experimental group, and 4/21 (19.0%) patients in the control group. A total of 17 (81.0%) and 13 (61.9%) patients in the experimental group and control group underwent surgery, respectively. Overall, 65.1% of the patients achieved R0 resection in the intention-to-treat analysis. Surgery-related adverse complications were observed in 2 patients (11.8%) in the experimental group and 1 patient (7.7%) in the control group.ConclusionOur results show that the toxicity of an MRI simulation-guided boost after SCPRT for unresectable rectal cancer is acceptable. Thus, this clinical trial will be continued as planned.

Preoperative short-course radiation therapy with PROtons compared to photons in high-risk RECTal cancer (PRORECT): Initial dosimetric experience

Background and purposeNeoadjuvant short-course radiotherapy(SCRT) followed by full-dose systemic chemotherapy is an established treatment modality in locally advanced rectal cancer (LARC). Until recently, SCRT has been exclusively delivered with photons. Proton beam therapy (PBT) may minimize acute toxicity, which in turn likely impacts favorably on the tolerability to subsequent chemotherapy. The aim of this study is a dosimetric comparison between SCRT with photons and protons in the randomized phase II trial PRORECT (NCT04525989). Materials and methodsFrom June 2021 to June 2022, twenty consecutive patients with LARC have been treated according to study protocol. For each patient, both a VMAT and a PBT treatment plans have been generated and compared pairwise. ResultsDose-volume histogram (DVH) analysis revealed that SCRT with protons significantly reduced radiation dose to pelvic organs at risk including bladder, bones, and bowel in comparison to SCRT with photons. Photon and proton treatment plans had equivalent conformity and homogeneity indexes. ConclusionPreoperative SCRT with protons offers a significant reduction of radiation dose to normal tissues compared with current photon-based radiotherapy technique. Demonstrated dosimetric advantages may translate into measurable clinical benefits in patients with LARC. Clinical implications of the dosimetric superiority of SCRT with protons will be presented in the coming reports from the PRORECT trial.

Short-course radiotherapy as part of total neoadjuvant therapy for locally advanced rectal cancer – a new standard?

Selection of optimal perioperative treatment for rectal cancer remains a subject of controversy. Recently established new rationales for the use of short-course preoperative radiotherapy (SCRT – 25 Gy in 5 fractions), instead of standard long-course preoperative radio-chemotherapy (LCRT-CT), are presented and discussed in the present review. New data suggest that short-course radiotherapy combined with 6 cycles of CAPOX, or 9 of FOLFOX4, at present may be considered the best option for perioperative treatment of high-risk rectal cancer. However, there is a clear need to further optimize preoperative treatment using rapidly evolving markers of treatment response, including microsatellite instability and targetable or predictive tumour mutations.

The Impact of Postoperative Complications on Short- and Long-Term Health-Related Quality of Life After Total Mesorectal Excision for Rectal Cancer

BackgroundSurvival for rectal cancer patients has improved over the past decades. In parallel, long-term health-related quality of life (HRQoL) is gaining interest. This study focuses on the effect of complications following rectal cancer surgery on HRQoL and survival. MethodsThe TME-trial (1996-1999) randomized patients with operable rectal cancer between surgery with preoperative short-course radiotherapy and surgery. Questionnaires including the Rotterdam Symptom Checklist were sent at 6 time points within the first 24 months and after 14 years the EORTC QLQ-C30 and EORTC QLQ-CR29 questionnaires. Differences in HRQoL and survival between patients with and without complications were analyzed. ResultsA total of 1207 patients were included, of which 482 (39.9%) patients experienced complications, surgical complications occurred in 177 (14.6%) patients, non-surgical complications in 197 (16.3%) and 108 patients (8.9%) had a combination of both types of complications. Three months after surgery, patients with a combination of surgical- and non-surgical complications, especially patients with anastomotic leakage, had the worst HRQoL. Twelve months postoperative HRQoL returned to a similar level as before surgery, regardless of complications. In patients who survived 14 years, no significant differences in HRQoL were seen between patients with and without complications. However, patients with complications did have lower overall survival. ConclusionThis study shows that survival and short-term HRQoL are negatively affected by complications. Twelve months after surgery HRQoL had returned to the preoperative level regardless, of complications. Also, in patients that survived 14 years, there was no effect of complications on HRQoL detected.

430P Prediction of pathologic complete response to preoperative (chemo)radiotherapy and/or chemotherapy in rectal cancer using clinical and imaging parameters

Complete pathological response (pCR) is achieved in 10-20% of rectal cancers when treated with preoperative short-course radiotherapy (scRT) or long-course chemoradiotherapy (CRT) and in 28% with total neoadjuvant therapy (TNT) including scRT/CRT with chemotherapy. pCR is linked to better outcome. Which clinical or imaging factors predict pCR?.

Study protocol of a phase II study to evaluate safety and efficacy of neo-adjuvant pembrolizumab and radiotherapy in localized rectal cancer

BackgroundReshaping the tumor microenvironment by novel immunotherapies represents a key strategy to improve cancer treatment. Nevertheless, responsiveness to these treatments is often correlated with the extent of T cell infiltration at the tumor site. Remarkably, microsatellite stable rectal cancer is characterized by poor T cell infiltration and, therefore, does not respond to immune checkpoint blockade. To date, the only available curative option for these patients relies on extensive surgery. With the aim to broaden the application of promising immunotherapies, it is necessary to develop alternative approaches to promote T cell infiltration into the tumor microenvironment of these tumors. In this regard, recent evidence shows that radiotherapy has profound immunostimulatory effects, hinting at the possibility of combining it with immunotherapy. The combination of long-course chemoradiotherapy and immune checkpoint inhibition was recently shown to be safe and yielded promising results in rectal cancer, however short-course radiotherapy and immune checkpoint inhibition have never been tested in these tumors.MethodsOur clinical trial investigates the clinical and biological impact of combining pembrolizumab with short-course radiotherapy in the neo-adjuvant treatment of localized rectal cancer. This phase II non-randomized study will recruit 25 patients who will receive short-course preoperative radiotherapy (5 Gy × 5 days) and four injections of pembrolizumab starting on the same day and on weeks 4, 7 and 10. Radical surgery will be performed three weeks after the last pembrolizumab injection. Our clinical trial includes an extensive translational research program involving the transcriptomic and proteomic analysis of tumor and blood samples throughout the course of the treatment.DiscussionOur study is the first clinical trial to combine short-course radiotherapy and immune checkpoint inhibition in rectal cancer, which could potentially result in a major breakthrough in the treatment of this cancer. Additionally, the translational research program will offer insights into immunological changes within the tumor and blood and their correlation with patient outcome. Taken together, our work will help optimizing future treatment combinations and, possibly, better selecting patients.Trial registrationThis study was registered with www.clinicaltrial.gov: NCT04109755. Registration date: June, 2020.

Preoperative radiotherapy for rectal cancer: A bibliometric analysis of the 100 most-cited research articles.

Preoperative long-course radio-chemotherapy (LC-RCHT) or preoperative short-course radiotherapy (SC-RT) are widely used in the treatment of locally advanced rectal cancer (LARC). This study aimed to evaluate the 100 most-cited research articles focused on preoperative radiotherapy for rectal cancer to reveal existing academic trends and the direction of therapeutic research. This was a retrospective study based on publicly accessible data. The Web of Science database was used to identify the 100 most-cited articles. The median values for total citation and average citation per year (CPY) were 240.50 (range, 150-3787) and 17.32 (5.03-222.76), respectively. Randomized (median: 24.88 vs 13.32, P = 0.001) and funded (median: 27.33 vs 14.73, P = 0.002) studies had more CPY than those with opposite characteristics. No significant difference was found between studies using SC-RT and LC-RCHT, in terms of average CPY (median: 15.27 for SC-RT vs 18.36 for LC-RCHT, P = 0.303). In terms of the primary aim of the investigation, studies investigating non-operative treatment strategies had higher CPY than those investigating other subcategories (p = 0.029). Randomized studies, funded studies, and studies investigating non-operative treatment were associated with more CPY. There remains equal interest in preoperative SC-RT and LC-RCHT for rectal cancer.

The Evolving Neoadjuvant Treatment Paradigm for Patients with Locoregional mismatch Repair Proficient Rectal Cancer.

The standard of care for locally advanced rectal cancer (LARC) has included preoperative chemoradiation, total mesorectal excision surgery and post operative adjuvant chemotherapy based on histopathology. The current therapeutic landscape in LARC has many different options with different directions of travel - depending on the goal of treatment. Enthusiasm for delivering total neoadjuvant therapy (TNT) for patients with locally advanced rectal cancer (LARC) is increasing in the light of recently published randomised phase III trials - RAPIDO and PRODIGE-23. There is a wide diversity of different potential schedules and a multitude of approaches, which include induction neoadjuvant chemotherapy (NACT) with a range of chemotherapy options (CAPEOX, FOLFOX, FOLFOXIRI) and a varying duration of 6-18 weeks, or consolidation NACT. These schedules either precede or follow short-course preoperative radiation therapy (SCPRT) using 5 × 5Gy or long-course chemoradiation (LCCRT) using 45-60Gy respectively. The different strategies of induction and consolidation neoadjuvant chemotherapy have been compared and have similar long-term outcomes, but consolidation chemotherapy may facilitate organ-sparing. The results are driving novel paradigms with both intensification and de-intensification treatment strategies. The ideal combination, sequence or duration of such a TNT approach remains undefined. As yet, there are no robust clinical, genetic, molecular, immune or imaging features (alone or integrated), which either direct or aid these choices. Currently, the selection of neoadjuvant treatment is driven by the impact on avoidance or feasibility of surgery or reducing the risk of metastases rather than prevention of local recurrence. Most believe that TNT will improve overall survival, despite the present lack of evidence. Both the inherent heterogeneity in LARC and the observed range of different responses underline the need for response biomarkers to individually tailor therapy rather than 'a one size fits all' approach.

A PROSPECTIVE COMPARATIVE STUDY ON LOCALLY ADVANCED RECTAL CARCINOMA TREATED WITH PRE-OPERATIVE SHORT-COURSE RADIOTHERAPY VERSUS LONG-COURSE RADIOTHERAPY WITH CONCOMITANT CHEMOTHERAPY

Objective: In locally advanced non-metastatic rectal carcinoma, pre-operative radiotherapy is an acceptable alternative over post-operative radiation to improve locoregional control after radical surgery. There are two regimens of pre-operative radiotherapy – short-course radiotherapy (25 Gy/5 fractions/1 week) and long-course chemoradiotherapy (CRT) (50.4 Gy/28 fractions/5.5 weeks). Our study aimed to compare the pathological response, margin negative surgery rates, and treatment-related acute toxicities between these two approaches. Methods: Patients with histologically proven locally advanced, non-metastatic rectal adenocarcinoma were randomized into study group and control group – the study group received short-course radiotherapy (25 Gy/5 fractions/1 week) followed by surgery after 7–10 days of completion of radiotherapy and the control group received long-course radiotherapy (50.4 Gy/28 fractions/5.5 weeks) with concurrent capecitabine followed by surgery after 4–6 weeks of completion of radiotherapy. Histopathology reports were studied in both groups for the determination of pathological response of tumor and surgical margin status. All patients received adjuvant chemotherapy for 6 months with oxaliplatin and capecitabine. For the assessment of treatment-related acute toxicities, patients were examined during the entire course of treatment. Results: Overall pathological response (complete response+partial response) was 81.25% in the study arm and 86.66% in the control arm. Complete response rate was 15% in the study arm and 25% in the control arm. Margin negative surgery rates were higher in long-course CRT than short-course radiotherapy (90% vs. 82%), but it was statistically insignificant. Radiation-induced acute skin reactions (less than Grade 2) were significantly higher in long-course CRT arm (p=0.003). Conclusion: There is no significant difference between pre-operative short-course radiotherapy and long-course concomitant CRT in terms of efficacy and acute toxicity profile. Thus, with our limited resources and huge patient load, short-course radiotherapy can be used as an acceptable alternative to long-course CRT.