Optimal fractionation of preoperative radiotherapy and timing to surgery for rectal cancer (Stockholm III): a multicentre, randomised, non-blinded, phase 3, non-inferiority trial

OUP accepted manuscript

Purpose

Methods

Results

Conclusion

Could Five Be the New Twenty-Five? Long-term Oncologic Outcomes from a Phase II, Prospective, 5-Fraction Pre-operative Radiation Therapy Trial in Patients with Localized Soft Tissue Sarcoma

Purpose

Management of adult soft tissue sarcomas entails a multidisciplinary approach with surgery and radiation therapy with or without chemotherapy. The use of preoperative irradiation has been well established, and although conventional fractionation involves daily treatments over the course of 5 weeks, higher doses per fraction may be beneficial due to the radiobiologic profile of sarcoma. In this study we report long-term oncologic outcomes from a single-institution, phase II study evaluating a 5-fraction hypofractionated course of preoperative radiation.

Methods and materials

Preoperative hypofractionated radiation therapy was administered to 35 Gy in 5 fractions every other day followed by resection 4 to 6 weeks later. If given, chemotherapy consisted of a doxorubicin-ifosfamide-based regimen delivered neoadjuvantly. The primary endpoint was local control. Additional survival and pathologic outcomes, including overall and distant metastasis-free survival, tumor, and treatment-related pathology, as well as acute and late toxicity were examined.

Results

Thirty-two patients were enrolled in this prospective, single-arm phase II trial. At a median follow-up of 36.4 months (range, 3-56), no patient developed a local recurrence, and the 3-year overall and distant metastasis-free survival was 82.2% and 69%, respectively. Major acute postoperative wound complications occurred in 25% of patients. Grade 2 and 3 fibrosis occurred in 21.7% and 13% of patients, respectively. The 2-year median and mean Musculoskeletal Tumor Society score for all patients was 28 and 27.4, respectively.

Conclusions

A condensed course of preoperative hypofractionated radiation therapy leads to excellent rates of local control and survival with acceptable toxicity profiles. Potential studies ideally with phase II or III randomized trials would help corroborate these findings and other preoperative hypofractionated results in soft tissue sarcomas.

Tumor Microenvironment Modifications Recorded With IVIM Perfusion Analysis and DCE-MRI After Neoadjuvant Radiotherapy: A Preclinical Study

PURPOSE

Neoadjuvant radiotherapy (NeoRT) improves tumor local control and facilitates tumor resection in many cancers. Some clinical studies demonstrated that both timing of surgery and RT schedule influence tumor dissemination, and subsequently patient overall survival. Previously, we developed a pre-clinical model demonstrating the impact of NeoRT schedule and timing of surgery on metastatic spreading. We report on the impact of NeoRT on tumor microenvironment by MRI.

METHODS

According to our NeoRT model, MDA-MB 231 cells were implanted in the flank of SCID mice. Tumors were locally irradiated (PXI X-Rad SmART) with 2x5Gy and then surgically removed at different time points after RT. Diffusion-weighted (DW) and Dynamic contrast enhancement (DCE) MRI images were acquired before RT and every 2 days between RT and surgery. IntraVoxel Incoherent Motion (IVIM) analysis was used to obtain information on intravascular diffusion, related to perfusion (F: perfusion factor) and subsequently tumor vessels perfusion. For DCE-MRI, we performed semi-quantitative analyses.

RESULTS

With this experimental model, a significant and transient increase of the perfusion factor F [50% of the basal value (n=16, p<0.005)] was observed on day 6 after irradiation as well as a significant increase of the WashinSlope with DCE-MRI at day 6 (n=13, p<0.05). Using immunohistochemistry, a significant increase of perfused vessels was highlighted, corresponding to the increase of perfusion in MRI at this same time point. Moreover, Tumor surgical resection during this peak of vascularization results in an increase of metastasis burden (n=10, p<0.05).

CONCLUSION

Significant differences in perfusion-related parameters (F and WashinSlope) were observed on day 6 in a neoadjuvant radiotherapy model using SCID mice. These modifications are correlated with an increase of perfused vessels in histological analysis and also with an increase of metastasis spreading after the surgical procedure. This experimental observation could potentially result in a way to personalize treatment, by modulating the time of surgery guided on MRI functional data, especially tumor perfusion.

Debating Pros and Cons of Total Neoadjuvant Therapy in Rectal Cancer

Simple Summary

Rectal cancers represent one third of all colorectal tumours. Patients diagnosed with localised colon cancer undergo surgery upfront, likely followed by adjuvant chemotherapy. Those diagnosed with localised rectal cancer, however, frequently benefit from neoadjuvant treatments with either radiotherapy or chemoradiotherapy before undergoing surgery. On the other hand, the benefit of adjuvant chemotherapy in this setting is more controversial. The main challenges in treating patients affected by rectal cancer encompass: decreasing the risks of local relapse and distant metastases, preserving the sphincter and minimising treatment-associated functional sequelae, and improving overall survival. Some of these fuelled the concept of total neoadjuvant therapy, namely giving all available treatments including radiotherapy and systemic chemotherapy before surgery. Here, we critically review the pros and cons of such a treatment strategy, but also discuss the biological rational to support neoadjuvant treatment intensification.

Abstract

Recently, two large, randomised phase III clinical trials of total neoadjuvant therapy (TNT) in locally advanced rectal cancer were published (RAPIDO and PRODIGE 23). These two trials compared short-course radiotherapy (SCRT) followed by chemotherapy with standard chemoradiotherapy (CRT) and chemotherapy followed by CRT with standard CRT, respectively. They showed improvement in some of the outcomes such as distant recurrence and pathological complete response (pCR). No improvement, however, was observed in local disease control or the de-escalation of surgical procedures. Although it seems lawful to integrate TNT within the treatment algorithm of localised stage II and III rectal cancer, many questions remain unanswered, including which are the optimal criteria to identify patients who are most likely to benefit from this intensive treatment. Instead of providing a sterile summary of trial results, we put these in perspective in a pros and cons manner. Moreover, we discuss some biological aspects of rectal cancer, which may provide some insights into the current decision-making process, and represent the basis for the future development of alternative, more effective treatment strategies.

Rectal cancer radiotherapy

We present the updated recommendations of the French society of oncological radiotherapy for rectal cancer radiotherapy. The standard treatment for locally advanced rectal cancer consists in chemoradiotherapy followed by radical surgery with total mesorectal resection and adjuvant chemotherapy according to nodal status. Although this strategy efficiently reduced local recurrences rates below 5% in expert centres, functional sequelae could not be avoided resulting in 20 to 30% morbidity rates. The early introduction of neoadjuvant chemotherapy has proven beneficial in recent trials, in terms of recurrence free and metastasis free survivals. Complete pathological responses were obtained in 15% of tumours treated by chemoradiation, even reaching up to 30% of tumours when neoadjuvant chemotherapy is associated to chemoradiotherapy. These good results question the relevance of systematic radical surgery in good responders. Personalized therapeutic strategies are now possible by improved imaging modalities with circumferential margin assessed by magnetic resonance imaging, by intensity modulated radiotherapy and by refining surgical techniques, and contribute to morbidity reduction. Keeping the same objectives, ongoing trials are now evaluating therapeutic de-escalation strategies, in particular rectal preservation for good responders after neoadjuvant treatment, or radiotherapy omission in selected cases (Greccar 12, Opera, Norad).

[Complete response after neoadjuvant therapy of rectal cancer: implications for surgery]

For (locally advanced) rectal cancer, a multimodal therapy concept comprising neoadjuvant radiotherapy/chemoradiotherapy, radical surgical resection with partial/complete mesorectal excision and subsequent adjuvant chemotherapy represents the current international standard of care. Further developments in neoadjuvant therapy concepts, such as the principle of total neoadjuvant therapy, lead to an increasing number of patients who show a complete clinical response in restaging after neoadjuvant therapy without clinically detectable residual tumor. In view of the risk associated with radical surgical resection in terms of perioperative morbidity and a potentially non-continence-preserving procedure, the question of the oncological justifiability of an organ-preserving procedure in the case of a complete clinical response under neoadjuvant therapy is increasingly being raised. The therapeutic principle of watch and wait, defined by refraining from immediate radical surgical resection and inclusion in a close-meshed, structured follow-up program, currently appears to be oncologically justifiable based on the current study situation; however, for the initial evaluation of the extent of the clinical response and for the structuring of the close-meshed follow-up program, further optimization and standardization based on broadly designed studies appear necessary in order to be able to provide this concept to a clearly defined patient collective as an oncologically equivalent therapy principle also outside specialized centers.

Concurrent use of statins and neoadjuvant chemoradiotherapy for rectal cancer: a systematic review and meta-analysis

PURPOSE

Statins are used primarily in patients with cardiovascular disease. More recently, they have demonstrated benefit in oncology patients. In vitro models have shown decreased rectal tumor cell viability in cells receiving chemoradiation and statin therapy. In vivo models have been less clear. This study aims to elucidate the impact of concurrent use of statins on the efficacy of neoadjuvant therapy for rectal cancer.

METHODS

Search of Medline, EMBASE, and CENTRAL was performed. Articles were included if they reported complete pathological response (pCR), long-term oncologic outcomes, or chemoradiotherapy-induced toxicity in patients with rectal cancer receiving concurrent statin and neoadjuvant therapy. A pairwise meta-analyses was performed using inverse variance random effects.

RESULTS

From 1564 citations, six studies with 726 patients on statin therapy (24.5% female, age: 63.6 years) and 1863 patients not on statin therapy (35.6% female, age: 60.9 years) were included. There was no significant difference in pCR rate between patients on statin therapy and patients not on statin therapy (RR 1.23, 95%CI 0.98-1.54, p = 0.08). Similarly, no difference existed between groups in long-term oncologic outcomes (5-year overall survival: RR 1.03, 95%CI 0.86-1.24, p = 0.75; 5-year disease-free survival: RR 1.04, 95%CI 0.85-1.26, p = 0.73). Chemoradiotherapy-induced toxicities were similar between groups.

CONCLUSION

The concurrent use of statin and neoadjuvant therapy did not significantly impact short- or long-term oncologic outcomes in patients with rectal cancer. Yet, despite pooling of data, this study remained inadequately powered. Larger, prospective studies are required to further elucidate the impact of statins on patients undergoing neoadjuvant therapy for rectal cancer.

Management of colorectal cancer during the COVID-19 pandemic: Recommendations from a statewide multidisciplinary cancer collaborative

COVID‐19 has resulted in significant disruptions in cancer care. The Illinois Cancer Collaborative (ILCC), a statewide multidisciplinary cancer collaborative, has developed expert recommendations for triage and management of colorectal cancer when disruptions occur in usual care. Such recommendations would be applicable to future outbreaks of COVID‐19 or other large‐scale disruptions in cancer care.

Radiotherapy regimens for rectal cancer: long-term outcomes and health-related quality of life in the Stockholm III trial

BACKGROUND

The Stockholm III trial randomly assigned 840 patients to short-course radiotherapy of 5 × 5 Gy with surgery within 1 week (SRT), short-course radiotherapy of 5 × 5 Gy with surgery after 4-8 weeks (SRT-delay), or long-course radiotherapy of 25 × 2 Gy with surgery after 4-8 weeks (LRT-delay). This study details the long-term oncological outcomes and health-related quality of life (HRQoL).

METHODS

Patients with biopsy-proven resectable adenocarcinoma of the rectum were included. Primary outcome was time to local recurrence (LR), and secondary endpoints were distant metastases (DMs), overall survival (OS), recurrence-free survival (RFS), and HRQoL. Patients were analysed in a three-arm randomization and a short-course radiotherapy comparison.

RESULTS

From 1998 to 2013, 357, 355, and 128 patients were randomized to the SRT, SRT-delay, and LRT-delay groups respectively. Median follow-up time was 5.7 (range 5.3-7.6) years. Comparing patients in the three-arm randomization, the incidence of LR was three of 129 patients, four of 128, and seven of 128, and DM 31 of 129 patients, 38 of 128, and 38 of 128 in the SRT, SRT-delay, and LRT-delay groups respectively. In the short-course radiotherapy comparison, the incidence of LR was 11 of 357 patients and 13 of 355, and DM 88 of 357 patients and 82 of 355 in the SRT and SRT-delay groups respectively. No comparisons showed statistically significant differences. Median OS was 8.1 (range 6.9-11.2), 10.3 (range 8.2-12.8), and 10.5 (range 7.0-11.3) years after SRT, SRT-delay, and LRT-delay respectively. Median OS was 8.1 (range 7.2-10.0) years after SRT and 10.2 (range 8.5-11.7) years after SRT-delay. There were no statistically significant differences in HRQoL.

CONCLUSION

After a follow-up of 5 years, delaying surgery for 4-8 weeks after radiotherapy treatment with 5 × 5 Gy was oncologically safe. Long-term HRQoL was similar among the treatment arms.

TRIAL REGISTRATION NUMBER

NTC00904813.

Current State of Neoadjuvant Radiotherapy for Rectal Cancer

Colorectal cancer is the third most commonly diagnosed cancer, with rectal cancer accounting for 30% of cases. The current standard of care curative treatment for locally advanced rectal cancer is (chemo)radiotherapy followed by surgery and adjuvant chemotherapy. Although neoadjuvant radiotherapy has reduced the risk of local recurrence to less than 10%, the risk of distant metastasis remained high at 30% affecting patient survival. In addition, there is a recognition that there is heterogeneity in tumor biology and treatment response with good responders potentially suitable for treatment de-escalation. Therefore, new treatment sequencing and regimens were investigated. Here, we reviewed the evidence for current neoadjuvant treatment options in patients with locally advanced rectal adenocarcinoma, and highlight the new challenges in this new treatment landscape.

Phase II, single-arm trial of preoperative short-course radiotherapy followed by chemotherapy and camrelizumab in locally advanced rectal cancer

Background

In locally advanced rectal cancer (LARC), preoperative short-course radiotherapy (SCRT) with delayed surgery has been shown to be as effective as long-course chemoradiotherapy, with only modest benefits. This study aimed to evaluate the efficacy and safety of preoperative SCRT combined with subsequent CAPOX (capecitabine and oxaliplatin) and the anti-PD-1 antibody camrelizumab in patients with LARC.

Methods

This was a prospective, single-arm, phase II trial. Treatment-naïve patients with histologically confirmed T3-4N0M0 or T1-4N+M0 rectal adenocarcinoma received 5×5 Gy SCRT with two subsequent 21-day cycles of CAPOX plus camrelizumab after 1 week, followed by radical surgery after 1 week. The primary endpoint was pathological complete response (pCR) rate. Biomarker analysis was performed to identify a potential predictor of pCR to treatment.

Results

From November 7, 2019 to September 14, 2020, 30 patients were enrolled, and 27 patients received at least one dose of CAPOX plus camrelizumab. Surgery was performed in 27 (100%) patients. The pCR (ypT0N0) rate was 48.1% (13/27), including 46.2% (12/26) for proficient mismatch repair (MMR) tumors and 100% (1/1) for deficient MMR tumors. Immune-related adverse events were all grade 1–2, with the most common being reactive cutaneous capillary endothelial proliferation (81.5%). No grade 4/5 adverse events occurred. Biomarker analysis showed patients without FGFR1–3 deletions had a better tendency for pCR.

Conclusions

SCRT combined with subsequent CAPOX plus camrelizumab followed by delayed surgery showed a favorable pCR rate with good tolerance in patients with LARC, especially in the proficient MMR setting. A randomized controlled trial is ongoing to confirm these results.

Trial registration number

ClinicalTrials.gov identifier: NCT04231552.

Dietary Fiber and the Hippocampal Neurogenic Niche in a Model of Pelvic Radiotherapy

We sought to determine whether radiation to the colorectum had an impact on parameters of hippocampal neurogenesis and, if so, whether it could be modulated by a fiber-rich diet. Male C57BL/6J mice were fed a diet containing bioprocessed oat bran or a fiber-free diet, starting two weeks before colorectal irradiation with 4 fractions of 8 Gray or sham-irradiation. Diets were then continued for 1, 6 or 18 weeks, whereafter parameters of hippocampal neurogenesis were analyzed and correlated to serum cytokine levels. No statistically significant changes in neuronal markers or cell proliferation were found at one week post-irradiation. Six weeks post-irradiation there was a decreased cell proliferation in the subgranular zone that appeared slightly more pronounced in irradiated animals on a fiber-free diet and increased numbers of immature neurons per mm² dentate gyrus in the irradiated mice, with a statistically significant increase in mice on a fiber-rich diet. Microglial abundancy was similar between all groups. 18 weeks post-irradiation, a fiber-free diet had reduced the number of immature neurons, whereas irradiation resulted in an increase. Despite this, the population of mature neurons was stable. Analysis of serum cytokines revealed a negative correlation between MIP1-α and the number of immature neurons one week after irradiation, regardless of diet. Our findings show that pelvic radiotherapy has the potential to cause a long-lasting impact on hippocampal neurogenesis, and dietary interventions may modulate this impact. More in-depth studies on the relationship between irradiation-induced intestinal injury and brain health are warranted.

Development and Assessment of a Clinical Calculator for Estimating the Likelihood of Recurrence and Survival Among Patients With Locally Advanced Rectal Cancer Treated With Chemotherapy, Radiotherapy, and Surgery

IMPORTANCE

Predicting outcomes in patients receiving neoadjuvant therapy for rectal cancer is challenging because of tumor downstaging. Validated clinical calculators that can estimate recurrence-free survival (RFS) and overall survival (OS) among patients with rectal cancer who have received multimodal therapy are needed.

OBJECTIVE

To develop and validate clinical calculators providing estimates of rectal cancer recurrence and survival that are better for individualized decision-making than the American Joint Committee on Cancer (AJCC) staging system or the neoadjuvant rectal (NAR) score.

DESIGN, SETTING, AND PARTICIPANTS

This prognostic study developed risk models, graphically represented as nomograms, for patients with incomplete pathological response using Cox proportional hazards and multivariable regression analyses with restricted cubic splines. Because patients with complete pathological response to neoadjuvant therapy had uniformly favorable outcomes, their predictions were obtained separately. The study included 1400 patients with stage II or III rectal cancer who received treatment with chemotherapy, radiotherapy, and surgery at 2 comprehensive cancer centers (Memorial Sloan Kettering [MSK] Cancer Center and Siteman Cancer Center [SCC]) between January 1, 1998, and December 31, 2017. Patients from the MSK cohort received chemoradiation, surgery, and adjuvant chemotherapy from January 1, 1998, to December 31, 2014; these patients were randomly assigned to either a model training group or an internal validation group. Models were externally validated using data from the SCC cohort, who received either chemoradiation, surgery, and adjuvant chemotherapy (chemoradiotherapy group) or short-course radiotherapy, consolidation chemotherapy, and surgery (total neoadjuvant therapy with short-course radiotherapy group) from January 1, 2009, to December 31, 2017. Data were analyzed from March 1, 2020, to January 10, 2021.

EXPOSURES

Chemotherapy, radiotherapy, chemoradiotherapy, and surgery.

MAIN OUTCOMES AND MEASURES

Recurrence-free survival and OS were the outcome measures, and the discriminatory performance of the clinical calculators was measured with concordance index and calibration plots. The ability of the clinical calculators to predict RFS and OS was compared with that of the AJCC staging system and the NAR score. The models for RFS and OS among patients with incomplete pathological response included postoperative pathological tumor category, number of positive lymph nodes, tumor distance from anal verge, and large- and small-vessel venous and perineural invasion; age was included in the risk model for OS. The final clinical calculators provided RFS and OS estimates derived from Kaplan-Meier curves for patients with complete pathological response and from risk models for patients with incomplete pathological response.

RESULTS

Among 1400 total patients with locally advanced rectal cancer, the median age was 57.8 years (range, 18.0-91.9 years), and 863 patients (61.6%) were male, with tumors at a median distance of 6.7 cm (range, 0-15.0 cm) from the anal verge. The MSK cohort comprised 1069 patients; of those, 710 were assigned to the model training group and 359 were assigned to the internal validation group. The SCC cohort comprised 331 patients; of those, 200 were assigned to the chemoradiotherapy group and 131 were assigned to the total neoadjuvant therapy with short-course radiotherapy group. The concordance indices in the MSK validation data set were 0.70 (95% CI, 0.65-0.76) for RFS and 0.73 (95% CI, 0.65-0.80) for OS. In the external SCC data set, the concordance indices in the chemoradiotherapy group were 0.71 (95% CI, 0.62-0.81) for RFS and 0.72 (95% CI, 0.59-0.85) for OS; the concordance indices in the total neoadjuvant therapy with short-course radiotherapy group were 0.62 (95% CI, 0.49-0.75) for RFS and 0.67 (95% CI, 0.46-0.84) for OS. Calibration plots confirmed good agreement between predicted and observed events. These results compared favorably with predictions based on the AJCC staging system (concordance indices for MSK validation: RFS = 0.69 [95% CI, 0.64-0.74]; OS = 0.67 [95% CI, 0.58-0.75]) and the NAR score (concordance indices for MSK validation: RFS = 0.56 [95% CI, 0.50-0.63]; OS = 0.56 [95% CI, 0.46-0.66]). Furthermore, the clinical calculators provided more individualized outcome estimates compared with the categorical schemas (eg, estimated RFS for patients with AJCC stage IIIB disease ranged from 7% to 68%).

CONCLUSIONS AND RELEVANCE

In this prognostic study, clinical calculators were developed and validated; these calculators provided more individualized estimates of the likelihood of RFS and OS than the AJCC staging system or the NAR score among patients with rectal cancer who received multimodal treatment. The calculators were easy to use and applicable to both short- and long-course radiotherapy regimens, and they may be used to inform surveillance strategies and facilitate future clinical trials and statistical power calculations.

Oral microbiota affects the efficacy and prognosis of radiotherapy for colorectal cancer in mouse models

Radiotherapy is inevitably intertwined with various side effects impairing the quality of life of cancer patients. Here, we report the possibility that alterations of the oral microbiota influence the therapeutic efficacy and prognosis of radiotherapy for primary rectal cancer and colorectal cancer (CRC) liver metastases that pathologically disrupt gastrointestinal integrity and function. 16S rRNA sequencing shows that oral microbiota alterations change the gut bacterial composition within tumors but not in adjacent peritumor tissues in CRC mouse models. Specifically, buccal Fusobacterium nucleatum migrates to the CRC locus and impairs the therapeutic efficacy and prognosis of radiotherapy. Administration of a specific antibiotic, metronidazole, abrogates the adverse effects of oral microbiome fluctuation on radiotherapy for CRC. The oral microbiota were also associated with radiation-induced intestinal injury via intestinal microbes. Our findings demonstrate that the oral microbiome in synergy with its intestinal counterparts impinges on the efficacy and prognosis of radiotherapy for CRC.

Efficacy of endoscopic surveillance in the detection of local recurrence after radical rectal cancer surgery is limited? A retrospective study

Background

Rectal cancer, one of most common neoplasms, is characterized by an overall survival rate exceeding 60%. Nonetheless, local recurrence (LR) following surgery for rectal cancer remains a formidable clinical problem. The aim of this study was to assess the value of postoperative endoscopic surveillance (PES) for the early detection of LR in rectal cancer after radical anterior resection with sigmoid-rectal anastomosis.

Methods

We performed an anterior resection in 228 patients with stages I‑III rectal cancer who had undergone surgery from 2001 to 2008 in the Oncology Center in Bydgoszcz, Poland. Of these patients, 169 had perioperative radiotherapy or radiochemotherapy. All patients underwent PES with abdominal and pelvic imaging (abdominal ultrasound, computed tomography, magnetic resonance) and clinical examination. Sensitivities, specificities, positive likelihood ratios, negative likelihood ratios, and receiver operating characteristic curves were calculated to compare the value of colonoscopy versus imaging techniques for the diagnosis of LR.

Results

During the 5-year follow-up, recurrences occurred in 49 (21%) patients; of these, 15 (6%) had LR, which was most often located outside the intestinal lumen (n = 10, 4%). Anastomotic LR occurred in 5 (2%) patients. The mean time to anastomotic LR was 30 months after initial surgery, similar to that of other locations (29 months). Both imaging and endoscopy were shown to be efficient techniques for the diagnosis of LR in anastomotic sites. In the study group, endoscopy did not provide any additional benefit in patients who were receiving radiation therapy.

Conclusions

The benefit of PES for the detection of LR after curative treatment of rectal cancer is limited and not superior to imaging techniques. It remains a useful method, however, for the histopathological confirmation of suspected or confirmed recurrence.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12957-021-02413-0.

Preoperative radiotherapy 5 × 5 Gy and short versus long interval between surgery for resectable rectal cancer: 10-Year follow-up of the randomised controlled trial

BACKGROUND

Studies on short-course preoperative radiotherapy in combination with total mesorectal excision for rectal cancer reported improved local control without clear survival benefits. The optimal fractionation and interval between radiotherapy and surgery are still under debate. We, therefore, aimed to report 10-year results of a randomized clinical trial (RCT, NCT01444495) comparing different time intervals between irradiation and surgery for rectal cancer.

MATERIAL AND METHODS

Data from the RCT conducted at a single academic centre were reviewed based on regular control visits with the median follow-up of 12 years. Patients with rectal cancer were randomly assigned to short-course preoperative radiotherapy (5 × 5 Gy) followed by surgery 7-10 days (short interval) or 4-5 weeks (long interval) after the end of irradiation. The primary endpoint was the local recurrence rate at 5 years. The secondary endpoints included overall survival, disease-free survival, systemic recurrence rate, and downstaging.

RESULTS

A total of 154 patients were randomly assigned to short (n = 77) or long interval (n = 77) surgery. The cumulative incidence of local recurrence at 10 years was 1.3% and 11.7% in the short and long-interval groups, respectively (p = 0.031). Accordingly, the incidence of systemic relapse was 14.3% versus 9.1% (p = 0.0319). There were no differences in the overall 10-year survival between patients subject to short and long-interval surgery (58% vs 61%, p = 0.754). However, patients with downstaging after radiotherapy had significantly better 10-year survival rates than non-responders.

CONCLUSIONS

Short-course preoperative radiotherapy with delayed surgery demonstrated an increased risk of local relapse over a 10-year follow-up.

Clinical Complete Response in Patients With Rectal Adenocarcinoma Treated With Short-Course Radiation Therapy and Nonoperative Management

PURPOSE

This study aimed to determine the clinical efficacy and safety of nonoperative management (NOM) for patients with rectal cancer with a clinical complete response (cCR) after short-course radiation therapy and consolidation chemotherapy.

METHODS AND MATERIALS

Patients with stage I-III rectal adenocarcinoma underwent short-course radiation therapy followed by consolidation chemotherapy between January 2018 and May 2019 (n = 90). Clinical response was assessed by digital rectal examination, pelvic magnetic resonance imaging, and endoscopy. Of the patients with an evaluable initial response, those with a cCR (n = 43) underwent NOM, and those with a non-cCR (n = 43) underwent surgery. The clinical endpoints included local regrowth-free survival, regional control, distant metastasis-free survival, disease-free survival, and overall survival.

RESULTS

Compared with patients with an initial cCR, patients with initial non-cCR had more advanced T and N stage (P = .05), larger primary tumors (P = .002), and more circumferential resection margin involvement on diagnostic magnetic resonance imaging (P < .001). With a median follow-up of 30.1 months, the persistent cCR rate was 79% (30 of 38 patients) in the NOM cohort. The 2-year local regrowth-free survival was 81% (95% confidence interval [CI], 70%-94%) in the initial cCR group, and all patients with local regrowth were successfully salvaged. Compared with those with a non-cCR, patients with a cCR had improved 2-year regional control (98% [95% CI, 93%-100%] vs 85% [95% CI, 74%-97%], P = .02), distant metastasis-free survival (100% [95% CI, 100%-100%] vs 80% [95% CI, 69%-94%], P < .01), disease-free survival (98% [95% CI, 93%-100%] vs 71% [95% CI, 59%-87%], P < .01), and overall survival (100% [95% CI, 100%-100%] vs 88% [95% CI, 79%-98%], P = .02). No late grade 3+ gastrointestinal or genitourinary toxicities were observed in the patients who underwent continued NOM.

CONCLUSIONS

Short-course radiation therapy followed by consolidation chemotherapy may be a feasible organ preservation strategy in rectal cancer. Additional prospective studies are necessary to evaluate the safety and efficacy of this approach.

Transanal Drainage Tube Use for Preventing Anastomotic Leakage After Laparoscopic Low Anterior Resection in Patients With Rectal Cancer: A Randomized Clinical Trial

Importance

Preventing anastomotic leakage (AL) is crucial for colorectal surgery. Some studies have suggested a positive role of transanal drainage tubes (TDTs) in AL prevention after low anterior resection, but this finding is controversial.

Objective

To assess the effect of TDTs in AL prevention after laparoscopic low anterior resection for rectal cancer.

Design, Setting, and Participants

This multicenter randomized clinical trial with parallel groups (TDT vs non-TDT) was performed from February 26, 2016, to September 30, 2020. Participants included patients from 7 different hospitals in China who were undergoing laparoscopic low anterior resection with the double-stapling technique for mid-low rectal cancer; 576 patients were initially enrolled in this study, and 16 were later excluded. Ultimately, 560 patients were randomly divided between the TDT and non-TDT groups.

Interventions

A silicone tube was inserted through the anus, and the tip of the tube was placed approximately 5 cm above the anastomosis under laparoscopy at the conclusion of surgery. The tube was fixed with a skin suture and connected to a drainage bag. The TDT was scheduled for removal 3 to 7 days after surgery.

Main Outcomes and Measures

The primary end point was the postoperative AL rate within 30 days.

Results

In total, 576 patients were initially enrolled in this study; 16 of these patients were excluded. Ultimately, 560 patients were randomly divided between the TDT group (n = 280; median age, 61.5 years [IQR, 54.0-68.8 years]; 177 men [63.2%]) and the non-TDT group (n = 280; median age, 62.0 years [IQR, 52.0-69.0 years]; 169 men [60.4%]). Intention-to-treat analysis showed no significant difference between the TDT and non-TDT groups in AL rates (18 [6.4%] vs 19 [6.8%]; relative risk, 0.947; 95% CI, 0.508-1.766; P = .87) or AL grades (grade B, 14 [5.0%] and grade C, 4 [1.4%] vs grade B, 11 [3.9%] and grade C, 8 [2.9%]; P = .43). In the stratified analysis based on diverting stomas, there was no significant difference in the AL rate between the groups, regardless of whether a diverting stoma was present (without stoma, 12 [5.8%] vs 15 [7.9%], P = .41; and with stoma, 6 [8.3%] vs 4 [4.5%], P = .50). Anal pain was the most common complaint from patients in the TDT group (130 of 280, 46.4%). Accidental early TDT removal occurred in 20 patients (7.1%), and no bleeding or iatrogenic colonic perforations were detected.

Conclusions and Relevance

The results from this randomized clinical trial indicated that TDTs may not confer any benefit for AL prevention in patients who undergo laparoscopic low anterior resection for mid-low rectal cancer without preoperative radiotherapy.

Trial Registration

ClinicalTrials.gov Identifier: NCT02686567.

Neoadjuvant short-course radiotherapy with consolidation chemotherapy for locally advanced rectal cancer: a systematic review and meta-analysis

BACKGROUND

Short-course radiotherapy with consolidation chemotherapy (SCRT-CCT) has emerged as a promising alternative to the long course chemoradiotherapy (LCRT) regimen in locally advanced rectal cancer management. The systematic review and meta-analysis is aimed at summarizing current evidence on SCRT-CCT and comparing it to LCRT.

MATERIAL AND METHODS

Electronic databases of MEDLINE, Web of Science, and Cochrane library were searched using a predefined search strategy returning 3314 articles. This review included 11 studies (6 randomized trials and 5 non-randomized studies) on SCRT-CCT regimen based on seven different cohorts. Weighted arithmetic means and forest plots were generated to determine summary estimates.

RESULTS

The probability of achieving pathological complete response (pCR) was higher with SCRT-CCT compared to LCRT (risk ratio [RR] = 1.75, 95% confidence interval [CI]: 1.41-2.19). No statistically significant difference in 3-year overall survival (OS) was observed between the two groups (RR= 1.06, 95% CI: 0.98-1.14). The weighted arithmetic mean of 3-year OS and pCR was 83.6% versus 80.9%, and 24.5% versus 13.6% for SCRT-CCT and LCRT, respectively. R0 resection and T-downstaging rates ranged from 69.2-100% to 47-75% for SCRT-CCT, and 71-92.3% and 41-75% for LCRT, respectively. The regimens had similar compliance, postoperative, and late toxicity, however, acute toxicity rates varied primarily due to differences in treatment protocols.

CONCLUSIONS

This review highlights the ability of SCRT-CCT to produce improved tumor response with comparable OS, R0 resection, and T-downstaging at the cost of increased acute toxicity. However, heterogeneity in treatment protocols across studies makes it difficult to provide definitive conclusions regarding the regimen. Several ongoing trials are expected to provide further evidence confirming the findings of RAPIDO trial and detail appropriate SCRT-CCT protocols to improve oncological outcomes, minimize toxicity, and determine its effectiveness as the standard-of-care for locally advanced rectal cancer patients.

Total neoadjuvant therapy in patients with locally advanced rectal cancer: A tertiary medical center experience

The current standard of care for locally advanced rectal cancer (LARC) includes preoperative chemoradiation, followed by total mesorectal excision and adjuvant chemotherapy. This multimodality treatment improves local control but is associated with low compliance rates without clear beneficial effects on overall survival (OS) and distant metastasis. In this retrospective study, the charts of patients diagnosed with cT3/4 or cT2-node-positive rectal cancer between January 2011 and June 2019 were reviewed. The chemoradiation therapy (CRT) group received a long course of CRT with capecitabine followed by surgery and adjuvant chemotherapy. The total neoadjuvant therapy (TNT) group received 6 cycles mFOLFOX and a short course of radiation therapy followed by surgery. A total of 81 patients were included, among which 55 (67.9%) received CRT and 26 (32.1%) received TNT. In the CRT group, 15 (27.3%) patients achieved pathologic complete response (pCR) compared with 10 (38.5%) in the TNT group (P=0.22). A total of 19 (35.8%) cases in the CRT group downstaged to pT0N0 or pT1N0 compared with 11 (42.3%) in the TNT group (P=0.33). The 2-year disease-free survival (DFS) rate was 81.0% in the TNT group and 84.0% in the CRT group (P=0.15). Out of 55 patients in the CRT group, 30 patients received adjuvant chemotherapy, 22 (40.0% of CRT cases) of which completed a full course. All 26 patients in the TNT group received neoadjuvant chemotherapy, where 22 (84.6%) patients took a full course (P<0.001). In conclusion, the present study revealed that patients treated with TNT were more compliant to chemotherapy than those treated with CRT. A numerically higher pCR rate, and nodal and tumor downstaging were noted in the TNT group without significance. No difference was noted in the 2-year DFS. Longer follow-up is required.

Comparison of guidelines on rectal cancer: exception proves the rule?

The standard of care for early or locally advanced rectal cancer is promoted by multiple clinical practice guidelines globally, but the considerable differences between the guidelines may cause confusion. We compared the latest updated clinical practice guidelines from five professional societies/authorities: National Comprehensive Cancer Network, American Society of Colorectal Surgeons, European Society of Medical Oncology, Chinese National Health Commission, and Chinese Society of Clinical Oncology. Key evidence is discussed for a better understanding of some seemingly contradictory recommendations.

Brazilian society of surgical oncology: Guidelines for the surgical treatment of mid-low rectal cancer

BACKGROUND

Colorectal cancer (CRC) is the third leading cause of cancer in North America, Western Europe, and Brazil, and represents an important public health problem. It is estimated that approximately 30% of all the CRC cases correspond to tumors located in the rectum, requiring complex multidisciplinary treatment. In an effort to provide surgeons who treat rectal cancer with the most current information based on the best evidence in the literature, the Brazilian Society of Surgical Oncology (SBCO) has produced the present guidelines for rectal cancer treatment that is focused on the main topics related to daily clinical practice.

OBJECTIVES

The SBCO developed the present guidelines to provide recommendations on the main topics related to the treatment of mid-low rectal cancer based on current scientific evidence.

METHODS

Between May and June 2021, 11 experts in CRC surgery met to develop the guidelines for the treatment of mid-low rectal cancer. A total of 22 relevant topics were disseminated among the participants. The methodological quality of a final list with 221 sources was evaluated, all the evidence was examined and revised, and the treatment guideline was formulated by the 11-expert committee. To reach a final consensus, all the topics were reviewed via a videoconference meeting that was attended by all 11 of the experts.

RESULTS

The prepared guidelines contained 22 topics considered to be highly relevant in the treatment of mid-low rectal cancer, covering subjects related to the tests required for staging, surgical technique-related aspects, recommended measures to reduce surgical complications, neoadjuvant strategies, and nonoperative treatments. In addition, a checklist was proposed to summarize the important information and offer an updated tool to assist surgeons who treat rectal cancer provide the best care to their patients.

CONCLUSION

These guidelines summarize concisely the recommendations based on the most current scientific evidence on the most relevant aspects of the treatment of mid-low rectal cancer and are a practical guide that can help surgeons who treat rectal cancer make the best therapeutic decision.

Organ preservation following short-course radiotherapy for rectal cancer

Background

Non-operative management of rectal cancer is increasingly being used in selected patients. Most reports include patients treated with chemoradiotherapy (CRT) before inclusion into a Watch & Wait (W&W) programme. The aim of this study was to report outcomes from a single-centre W&W programme involving a large cohort of patients.

Methods

Patients treated with chemoradiotherapy (CRT) or short-course radiotherapy (SCRT) with or without chemotherapy, between 2008 and 2020, who showed signs of a clinical complete response (cCR) were reviewed. Patients were assessed using digital rectal examination, flexible endoscopy, carcinoembryonic antigen measurement, MRI, and CT imaging, discussed at the multidisciplinary tumour board meeting, and followed up in a dedicated W&W programme as from 2015. Outcomes including regrowth and 3-year survival (time to regrowth or death) were prospectively evaluated.

Results

Of 142 patients who were assessed, 88 fulfilled the criteria for cCR. Treatment before cCR included CRT, SCRT with chemotherapy, and SCRT alone in 16 (18 per cent), 28 (32 per cent), and 44 (50 per cent) patients, respectively. Patients treated with CRT and SCRT with chemotherapy had more advanced clinical T- and N-stage, compared with patients treated with SCRT alone (clinical T-stage > 2: 81 per cent and 89 per cent versus 47 per cent, respectively; clinical N-stage > 0: 75 per cent and 93 per cent versus 68 per cent, respectively). Overall rate of regrowth was 19 per cent, with 31 per cent, 21 per cent, and 14 per cent following CRT, SCRT with chemotherapy, and SCRT alone, respectively. Uni- and multivariable analyses evaluating the clinical parameters revealed no statistically significant associations with risk of local regrowth. All but one patient with regrowth underwent salvage surgery. The 3-year survival rate (death with regrowth as competing risk) was 93 per cent, with no significant difference between treatment groups.

Conclusion

In this cohort of W&W patients, the vast majority received SCRT with or without chemotherapy and results consistent with previous W&W reports were obtained. No statistically significant differences in terms of regrowth rate were obtained when comparing CRT, SCRT with chemotherapy, and SCRT alone. SCRT can induce sustained cCR and may precede a W&W strategy.

Radiation therapy-associated toxicity: Etiology, management, and prevention

Radiation therapy (RT) is a curative treatment for many malignancies and provides effective palliation in patients with tumor-related symptoms. However, the biophysical effects of RT are not specific to tumor cells and may produce toxicity due to exposure of surrounding organs and tissues. In this article, the authors review the clinical context, pathophysiology, risk factors, presentation, and management of RT side effects in each human organ system. Ionizing radiation works by producing DNA damage leading to tumor death, but effects on normal tissue may result in acute and/or late toxicity. The manifestation of toxicity depends on both cellular characteristics and affected organs' anatomy and physiology. There is usually a direct relationship between the radiation dose and volume to normal tissues and the risk of toxicity, which has led to guidelines and recommended dose limits for most tissues. Side effects are multifactorial, with contributions from baseline patient characteristics and other oncologic treatments. Technological advances in recent decades have decreased RT toxicity by dramatically improving the ability to deliver RT that maximizes tumor dose and minimizes organ dose. Thus the study of RT-associated toxicity is a complex, core component of radiation oncology training that continues to evolve alongside advances in cancer management. Because RT is used in up to one-half of all patients with cancer, an understanding of its acute and late effects in different organ systems is clinically pertinent to both oncologists and nononcologists.

Neoadjuvant Pelvic Radiotherapy in the Management of Rectal Cancer with Synchronous Liver Metastases: Is It Worth It?

BACKGROUND

The use of neoadjuvant pelvic radiotherapy was a major advance in oncologic care for locally advanced rectal cancer in the twentieth century. The extrapolation of the care of locally advanced rectal cancer to the management of rectal cancer with treatable liver metastases is controversial. The aim of this review is to examine the available data on the role of pelvic radiotherapy and chemoradiation in the setting of treatable metastatic liver disease.

METHODS

A systematic search of MEDLINE was performed to report the landmark randomized controlled trials between 1993 and 2021.

RESULTS

Attaining liver clearance and total mesorectal excision with R0 margin remains the mainstay of cure. There is uncertainty regarding the sequencing of treatment. The literature lacks randomized clinical trials comparing the rectal first, liver first, interval strategy, and simultaneous surgical approaches. A multidisciplinary discussion regarding the utility of radiotherapy is emphasized to achieve the goals of treatment. Short-course radiotherapy has proved comparable disease-control outcomes to long-course chemoradiation with a significantly improved cost-performance. The implementation of short-course radiotherapy in the interval strategy and simultaneous surgical approach is promising. Neoadjuvant pelvic radiotherapy can be omitted in patients with metastatic rectal cancer if adequate margin clearance is achievable.

CONCLUSION

The use of radiotherapy in metastatic rectal cancer is popular but is based on limited data. Treatment should be tailored to the local extent of rectal cancer and priority of liver metastasis management. The optimal treatment strategy in patients with rectal cancer and synchronous liver metastatic disease needs to be studied in randomized trials.

Durvalumab (MEDI 4736) in combination with extended neoadjuvant regimens in rectal cancer: a study protocol of a randomised phase II trial (PRIME-RT)

BACKGROUND

Advances in multi-modality treatment of locally advanced rectal cancer (LARC) have resulted in low local recurrence rates, but around 30% of patients will still die from distant metastatic disease. In parallel, there is increasing recognition that with radiotherapy and systemic treatment, some patients achieve a complete response and may avoid surgical resection, including in many cases, the need for a permanent stoma. Extended neoadjuvant regimes have emerged to address these concerns. The inclusion of immunotherapy in the neoadjuvant setting has the potential to further enhance this strategy by priming the local immune microenvironment and engaging the systemic immune response.

METHODS

PRIME-RT is a multi-centre, open label, phase II, randomised trial for patients with newly diagnosed LARC. Eligible patients will be randomised to receive either: short course radiotherapy (25 Gray in 5 fractions over one week) with concomitant durvalumab (1500 mg administered intravenously every 4 weeks), followed by FOLFOX (85 mg/m2 oxaliplatin, 350 mg folinic acid and 400 mg/m2 bolus 5-fluorouracil (5-FU) given on day 1 followed by 2400 mg/m2 5-FU infusion over 46-48 h, all administered intravenously every 2 weeks), and durvalumab, or long course chemoradiotherapy (50 Gray to primary tumour in 25 fractions over 5 weeks with concomitant oral capecitabine 825 mg/m2 twice per day on days of radiotherapy) with durvalumab followed by FOLFOX and durvalumab. The primary endpoint is complete response rate in each arm. Secondary endpoints include treatment compliance, toxicity, safety, overall recurrence, proportion of patients with a permanent stoma, and survival. The study is translationally rich with collection of bio-specimens prior to, during, and following treatment in order to understand the molecular and immunological factors underpinning treatment response. The trial opened and the first patient was recruited in January 2021. The main trial will recruit up to 42 patients with LARC and commence after completion of a safety run-in that will recruit at least six patients with LARC or metastatic disease.

DISCUSSION

PRIME-RT will explore if adding immunotherapy to neoadjuvant radiotherapy and chemotherapy for patients with LARC can prime the tumour microenvironment to improve complete response rates and stoma free survival. Sequential biopsies are a key component within the trial design that will provide new knowledge on how the tumour microenvironment changes at different time-points in response to multi-modality treatment. This expectation is that the trial will provide information to test this treatment within a large phase clinical trial. Trial registration Clinicaltrials.gov NCT04621370 (Registered 9th Nov 2020) EudraCT number 2019-001471-36 (Registered 6th Nov 2020).

Lessons Learned in Managing Patients with Colorectal Cancer During the COVID-19 Pandemic

OPINION STATEMENT

The COVID-19 pandemic forced us to rapidly and dramatically shift our medical priorities and decision making. With little literature or experience to rely on, the initial priority was to minimize patient exposure to the hospital and to others. It remains unclear whether cancer patients are at higher risk of infection or serious complications, or if it is our traditional therapies that place them to be at higher risk. By far, the greatest negative impact was on screening. Routine colonoscopies were considered elective, and as a result, delays in diagnosis will be felt for years to come. The most positive changes were the incorporation of tele-visits, increased use of oral therapies, alterations in treatment schedules of both chemotherapy and radiation, and an increased emphasis on neoadjuvant therapy. These too will be felt for years to come. The colorectal cancer medical community has responded collaboratively and effectively to maintain treatment and to optimize outcomes for our patients during the COVID-19 pandemic.

Neoadjuvant Modified Short-Course Radiotherapy Followed by Delayed Surgery for Locally Advanced Rectal Cancer

Simple Summary

Both short- and long-course neoadjuvant radiotherapy (NA-RT) followed by surgery have been adopted as standard treatments for locally advanced rectal cancer (LARC). We hypothesized that a modified short-course radiotherapy (mSC-RT) using an accelerated hyperfractionated regimen, with a dose of 2.5 Gy twice daily up to a total dose of 25 Gy in 10 fractions, can provide a favorable therapeutic ratio in comparison with the conventional regimens. Ninety-seven consecutive LARC patients undergoing mSC-RT followed by delayed surgery were analyzed in this retrospective study. Additionally, potential prognostic factors for overall survival (OS) were also assessed. The results showed that mSC-RT followed by delayed surgery achieved equivalent anti-tumor efficacy and acute toxicity that were comparable with long- and short-course NA-RT, respectively. A neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 was independently associated with poor OS in LARC patients receiving mSC-RT. Thus, mSC-RT can be a promising alternative to both standard long- and short-course NA-RT regimens.

Abstract

This study aimed to assess the clinical outcomes and predictive factors of neoadjuvant modified short-course radiotherapy (mSC-RT) for locally advanced rectal cancer (LARC). Data from 97 patients undergoing mSC-RT followed by radical surgery for LARC were retrospectively analyzed. A 2.5 Gy dose twice daily up to a total dose of 25 Gy in 10 fractions was administered through mSC-RT, and this was delivered with oral chemotherapy in 95 (97.9%) patients. Radical surgery was performed 6 (range, 3–13) weeks after mSC-RT. The median follow-up among surviving patients was 43 (8–86) months. All patients completed neoadjuvant radiotherapy with no acute toxicity grade ≥ 3. Three- and five-year local control rates were 96.3% and 96.3%, respectively. Three- and five-year overall survival (OS) rates were 92.7% and 79.8%, respectively. Univariate analyses revealed that poor OS was associated with no concurrent administration of capecitabine, C-reactive-protein-to-albumin ratio ≥ 0.053, carcinoembryonic antigen ≥ 3.4 ng/mL, and neutrophil-to-lymphocyte ratio (NLR) ≥ 1.83 (P = 0.045, 0.001, 0.041, and 0.001, respectively). Multivariate analyses indicated that NLR ≥ 1.83 was independently associated with poor OS (p = 0.018). mSC-RT followed by delayed surgery for LARC was deemed feasible and resulted in good clinical outcomes, whereas poor OS was associated with high NLR.

Planning target volume margin assessment for online adaptive MR-guided dose-escalation in rectal cancer on a 1.5 T MR-Linac

PURPOSE

This study assessed the margins needed to cover tumor intrafraction motion during an MR-guided radiotherapy (MRgRT) dose-escalation strategy in intermediate risk rectal cancer.

METHODS

Fifteen patients with rectal cancer were treated with neoadjuvant short-course radiotherapy, 5x5 Gy, according to an online adaptive workflow on a 1.5 T MR-linac. Per patient, 26 3D T2 weighted MRIs were made; one reference scan preceding treatment and five scans per treatment fraction. The primary tumor was delineated on each scan as gross tumor volume (GTV). Target coverage margins were assessed by isotropically expanding the reference GTV until more than 95% of the voxels of the sequential GTVs were covered. A margin with a coverage probability threshold of 90% was defined as adequate. Intra- and interfraction margins to cope with the movement of the GTV in the period between scans were calculated to indicate the target volume margins. Furthermore, the margin needed to cover GTV movement was calculated for different time intervals.

RESULTS

The required margins to cover inter- and intrafraction GTV motion were 17 mm and 6 mm, respectively. Analysis based on time intervals between scans showed smaller margins were needed for adequate GTV coverage as time intervals became shorter, with a 4 mm margin required for a procedure of 15 min or less.

CONCLUSION

The shorter the treatment time, the smaller the margins needed to cover for the GTV movement during an online adaptive MRgRT dose-escalation strategy for intermediate risk rectal cancer. When time intervals between replanning and the end of dose delivery could be reduced to 15 min, a 4 mm margin would allow adequate target coverage.

The Evolving Field of Neoadjuvant Therapy in Locally-advanced Rectal Cancer: Evidence and Prospects

The standard treatment of locally advanced rectal cancer comprises neoadjuvant chemoradiation followed by total mesorectal excision. This strategy provides low local recurrence rate, however distant recurrence is still an issue and may impact on survival rates. Novel approaches in the neoadjuvant setting have been tested to improve early and late outcomes, as well as to reduce treatment-related toxicity and morbidity. In this review, we discuss the current literature of neoadjuvant treatment in locally advanced rectal cancer, including total neoadjuvant methods, protocols for radiation delivery, chemotherapy regimen and efforts to add novel targeted therapies, selective withdrawal of surgery or radiotherapy, and future perspectives. Moreover, we highlight relevant issues that have emerged with these new treatment possibilities.

Comparing neoadjuvant long-course chemoradiotherapy with short-course radiotherapy in rectal cancer

Background

The purpose of this study was to compare short-course radiotherapy (SC) or neoadjuvant long-course chemoradiotherapy (LC) treatment for locally advanced rectal cancer patients.

Methods

Patients with a diagnosis of locally advanced rectal cancer (LARC) who had undergone neoadjuvant radiotherapy before surgery between 2013 and 2018 at the medical center in China were included in this study. All patients’ MRI confirmed T2N+M0 or T3-4N0-3M0 clinical stages. Patients in the SC group received pelvic radiotherapy with a dose of 5 × 5 Gy (with or without chemotherapy at any time), followed by immediate or delayed surgery. Patients in the LC group received a dose of 50–50.4 Gy in 25–28 fractions, concomitantly with FOLFOX or capecitabine-based chemotherapy, followed by surgery 4–6 weeks later. All clinical data were retrospectively collected, and long-term follow-up was completed and recorded at the same time.

Results

A total of 170 were eligible to participate in this study, 32 patients in the SC group, and 138 in the LC group. The median follow-up time of living patients was 39 months. The disease-free survival (DFS) and overall survival (OS) rates in the SC group and LC group at 3 years, were, 84.9% versus 72.4% (P = 0.273) and 96.2% versus 87.2% (P = 0.510), respectively. The complete pathological response (pCR) rates in the SC group and LC group were, 25% versus 18.1% (the difference was not statistically significant, P = 0.375), respectively. However, the SC group had better node(N) downstaging compared to the LC group (P = 0.011).

Conclusions

There were no differences observed in DFS and OS between short-course radiotherapy and long-course chemoradiation, and both can be used as treatment options for patients with locally advanced rectal cancer.

[Neoadjuvant treatment for rectal cancer]

The management of patients with locally advanced rectal cancer has improved significantly in the past few years with preoperative radiotherapy (RT) and total mesorectal excision. The rate of local recurrence is now around 5 % while the risk of metastatic recurrence has not been reduced which is about 30 %. The benefit of adjuvant chemotherapy remains questionable apart from patients with ypN+tumor after preoperative chemoradiotherapy (CRT) for whom FOLFOX is an option. In recent years, several therapeutic trials have evaluated the benefit of extending the time between the end of RT and surgery and/or the benefit of neoadjuvant chemotherapy, administered as induction (before RT) or in consolidation (after RT and before surgery). The first results of two positive phase 3 trials, PRODIGE 23 and RAPIDO, have been reported in 2020. The two regimens evaluated in these trials are markedly different but have shown that neoadjuvant chemotherapy significantly reduces the risk of distant metastasis. Current developments largely related to a de-escalation of therapy: organ conservation according to a "Watch and Wait" strategy or local resection of the scar, administration of neoadjuvant chemotherapy without RT. These therapeutic strategies have not yet been validated but should be in the news tomorrow. The purpose of this review is to present recent data reported in patients with locally advanced rectal cancer.

Prognostic Importance of MRI-Detected Extramural Venous Invasion in Rectal Cancer: A Literature Review and Systematic Meta-Analysis

PURPOSE

Extramural venous invasion (EMVI) is recognized as a poor prognostic factor in rectal cancer. There are well-documented limitations associated with pathology detection of EMVI, including variable reporting and the inability to use it preoperatively to guide neoadjuvant treatment. Magnetic resonance imaging (MRI)-detected EMVI (mrEMVI) has been proposed as an imaging biomarker. This review assesses the prognostic significance of mrEMVI on survival outcomes and whether regression of mrEMVI after neoadjuvant therapy is associated with improvements in survival.

METHODS AND MATERIALS

An electronic search was carried out using MEDLINE and EMBASE databases using the search terms "rectum," "cancer,", "MRI," and "outcomes." A systematic review and meta-analysis were carried out in accordance with Preferred Reporting for Systematic Reviews and Meta-Analyses guidelines using Review Manager software. A qualitative review was performed.

RESULTS

A total of 7399 articles were identified, of which 33 were relevant to the review question. After a qualitative assessment, 20 articles were included in the meta-analysis. Baseline mrEMVI positivity is associated with significantly worsened overall survival (hazard ratio [HR] 1.84; 95% confidence interval [CI], 1.33-2.54; P = .0001) and significantly worsened disease-free survival (HR 2.41; 95% CI, 2.02-2.89; P < .00001). After neoadjuvant treatment, a positive mrEMVI status is associated with a significantly worsened overall and disease-free survival. Only 3 papers specifically looked at mrEMVI regression, but the results show that persistent mrEMVI-positive status after treatment is associated with significantly worsened disease-free survival compared with a change in mrEMVI from positive to negative (HR 1.93; 95% CI, 1.39-2.68; P < .0001). A subgroup analysis of MRI-detected lymph node metastases showed no significant association with survival, with a hazard ratio of 1.33 (95% CI, 0.98-1.80; P = .06).

CONCLUSION

mrEMVI is significantly associated with worsened survival outcomes, both at baseline and after neoadjuvant treatment. Additionally, there is evidence that regression of mrEMVI after neoadjuvant treatment is associated with improved survival compared with mrEMVI persistence. The findings of this review emphasize the need for accurate and consistent reporting of mrEMVI status before and after neoadjuvant treatment and support the inclusion of mrEMVI into staging systems preferentially over lymph node metastases.

Short-course radiotherapy in stage IV rectal cancer with resectable disease

INTRODUCTION

Stage IV rectal cancer with resectable disease presents challenging issues, as the radical treatment of the whole disease is difficult. Surgery and chemotherapy (CT) play an unquestionable role, but the contribution of pelvic radiotherapy (RT) is not very clear.

METHODS

In 2009, we established a prospective treatment protocol that included CT, short-course preoperative radiotherapy (SCRT) with surgery of the primary tumour and all metastatic locations.

RESULTS

Forty patients were included. Eight (20%) patients did not receive CT due to significant comorbidities. Radical surgery treatment was possible in 22 (55%) patients. The mean follow-up was 42.81 months (3.63-105.97). Overall survival at 24 and 36 months was 71.4% and 58.2%, respectively. There was good local control of the disease, as 97.2% of pelvic surgeries were R0 and there were no local recurrences.

CONCLUSION

In stage IV with resectable metastatic disease, the proposed therapeutic regimen seems very appropriate in well selected patients able to tolerate the treatment. We bet on the role of pelvic RT, due to the good local control of the disease in our series.

Initial experience of preoperative short-course radiotherapy followed by oxaliplatin-based consolidation chemotherapy for locally advanced rectal cancer

PURPOSE

We analyzed the safety and feasibility of preoperative short-course radiotherapy (SCRT) followed by consolidation chemotherapy for patients with locally advanced rectal cancer (LARC).

METHODS

From April 2018 to May 2019, 19 patients with LARC were treated with SCRT followed by three cycles of consolidation chemotherapy with leucovorin, fluorouracil, and oxaliplatin (FOLFOX6) before surgery. Adjuvant chemotherapy relied on oxaliplatin. Tumor response, patient compliance, and toxicities were analyzed.

RESULTS

The median age was 60 years (range 44-71), and 16 of the patients were male. The median tumor height was 5 cm (range 0-9) from anal verge. All patients received a total dose of 25 Gy in five fractions. The number of cycles of FOLFOX6 before surgery was three in 17, four in one, five in one. Five patients required dose reductions in consolidation chemotherapy. The median interval between initiation of SCRT and surgery was 10.6 weeks (range 8.6-16.4). A pathologic complete response was seen in two patients (11%). Grade III toxicities to the preoperative treatment were seen in five patients (26%): diarrhea in two, a decreased white blood cell count in one, and anemia in two. Postoperative complications arising within 30 days developed in five patients (26%). During the median follow-up period of 20.4 months, there was no tumor recurrence.

CONCLUSION

Preoperative SCRT followed by oxaliplatin-based consolidation chemotherapy showed acceptable toxicity and feasibility in patients with LARC. Prospective randomized trials are warranted to verify the efficacy and safety of this treatment strategy compared with conventional long-course concurrent chemoradiotherapy.

Efficacy of conversion therapy on initially unresectable locally advanced rectal cancer

Background and purpose: Research on the efficacy of conversion therapy for initially unresectable mid-low rectal cancer (IURC) remained limited. This study aimed to assess the efficacy and safety of the conversion regimen for IURC and analyze the long-term outcomes of these patients.

Methods: We retrospectively analyzed the data of clinically diagnosed IURC patients who received conversion therapy between October 2010 and April 2017. The conversion therapy consisted of long-term radiation, concurrent chemotherapy, delayed surgery and consolidation chemotherapy. The primary end point was the rate of R0 resection, and other short- and long-term outcomes were analyzed.

Results: Sixty-one patients were enrolled in this study. After conversion therapy, 51 (83.6%) patients received R0 resection. The rates of pathologic complete response and downstaging were 16.4% and 62.3%, respectively. The rate of grade 3-4 chemoradiotherapy-related toxicity events was 13.1%. The overall survival at 3 years was 75.4% in all patients, and the disease-free survival at 3 years was 72.5% in patients who received R0 resection.

Conclusion: The conversion regimen showed a high conversion resection rate and good survival outcomes in IURC patients, and might benefit the patients if recommended in clinical practice.

A systematic review and meta-analysis comparing surgical and oncological outcomes of upper rectal, rectosigmoid and sigmoid tumours

AIM

Management paradigms for tumours from the sigmoid colon to the lower rectum vary significantly. The upper rectum (UR) represents the transition point both anatomically and in treatment protocols. Above the UR is clearly defined and managed as colon cancer and below is managed as rectal cancer. This study compares outcomes between sigmoid, rectosigmoid and UR tumours to establish if differences exist in operative and oncological outcomes.

METHODS

Electronic databases were searched for published studies with comparative data on peri-operative and oncological outcome for upper rectal and sigmoid/rectosigmoid (SRS) tumours treated without neoadjuvant radiation. The search adhered to PRISMA guidelines (Preferred Reporting Items in Systematic Reviews and Meta-analyses) guidelines. Data was combined using random-effects models.

RESULTS

Seven comparative series examined outcomes in 4355 patients. There was no difference in ASA grade (OR, 1.28; 95% CI, 0.99-1.67; P = 0.06), T3/T4 tumours (OR, 1.24; 95% CI, 0.95-1.63; P = 0.12), or lymph node positivity (OR, 0.97; 95% CI, 0.70-1.36; P = 0.87). UR cancers had higher rates of operative morbidity (OR, 0.72; 95% CI, 0.55-0.93; P = 0.01) and anastomotic leak (OR, 0.47; 95% CI, 0.31-0.71; P = 0.0004). There was no difference in local recurrence (OR, 0.63; 95% CI, 0.37-1.08; P = 0.10). SRS tumours had lower rates of distant recurrence (OR, 0.83; 95% CI, 0.68-1.0; P = 0.05). Rectosigmoid operative and cancer outcomes were closer to UR than sigmoid.

CONCLUSIONS

Based on existing data, UR and rectosigmoid tumours have higher morbidity, leak rates and distant recurrence than more proximal tumours.

Short-Course Radiotherapy in Locally Advanced Rectal Cancer

To date, we do not know the best therapeutic scheme in locally advanced rectal cancer when patients are older or have comorbidities.

Immunity, immunotherapy, and rectal cancer: A clinical and translational science review

Rectal cancer remains a challenging disease to treat. Therapy for locally advanced rectal cancer (LARC), the most frequent presentation, has evolved to include a multimodal approach of radiation, chemotherapy, and surgery. While this approach improves local disease control, the distant recurrence rate is nearly 30% and treatment-related morbidity is substantial, thus underscoring the need for new therapeutic approaches with better efficacy and lower side effects. Immunotherapy could potentially fill this need, but its promise is not yet realized in rectal cancer. In this translational science review, we address what is known about how cytotoxic therapies shape rectal cancer immunity and potentially prime the tumor microenvironment for response to immune checkpoint inhibitors and other immunotherapies. We also address the role of current immunotherapies in colorectal cancer and highlight where novel immunotherapy approaches are currently being evaluated in LARC. Finally, we address important future directions in LARC immunotherapy including the need to define optimal therapeutic sequencing, predictive biomarkers, strategies to limit treatment-related side effects and the potential of gut microbiome manipulation to improve outcomes. In summary, this review provides a framework to guide future research and inform immunotherapy trial design so as to advance rectal cancer care.

Immune Checkpoint Inhibition as a Strategy in the Neoadjuvant Treatment of Locally Advanced Rectal Cancer

The treatment of locally advanced rectal cancer (LARC) has seen major advances over the past 3 decades, with multimodality treatment now standard of care. Combining surgical resection with radiotherapy and/or chemotherapy can reduce local recurrence from around 20% to approximately 5%. Despite improvements in local control, distant recurrence and subsequent survival rates have not changed. Immune checkpoint inhibitors have improved patient outcomes in several solid tumor types in the neoadjuvant, adjuvant, and advanced disease setting; however, in colorectal cancer, most clinical trials have been performed in the metastatic setting and the benefits confined to microsatellite instability-high tumors. In this article, we review the current preclinical and clinical evidence for using immune checkpoint inhibition in the treatment of LARC and discuss the rationale for specifically exploring the use of this therapy in the neoadjuvant setting. We summarize and discuss relevant clinical trials that are currently in setup and recruiting to test this treatment strategy and reflect on unanswered questions that still need to be addressed within future research efforts.

Long-term Outcomes of Lower Rectal Cancer Patients Treated with Total Mesorectal Excision and Lateral Pelvic Lymph Node Dissection after Preoperative Radiotherapy or Chemoradiotherapy

OBJECTIVES

The standard strategy for advanced rectal cancer (RC) is preoperative short-course radiotherapy (SCRT)/chemoradiotherapy (CRT) plus total mesorectal excision (TME) in Western countries; however, the survival benefit of adding chemotherapy to radiotherapy remains unclear. There is accumulating evidence that either SCRT/CRT or lateral pelvic lymph node dissection (LPND) alone may not be sufficient for local control of advanced RC. We herein retrospectively evaluated the clinical outcomes of patients who were treated by SCRT/CRT+TME+LPND, particularly focusing on the prognostic impact of lateral pelvic lymph node metastasis (LPNM).

METHODS

Patients diagnosed as having clinical Stage II and III lower RC who received SCRT/CRT+TME+LPND between 1999 and 2012 at our hospital were enrolled. Adverse events (AEs), surgery-related complications (SRC), and therapeutic effects were retrospectively analyzed.

RESULTS

Fifty cases (SCRT:25, CRT:25) were analyzed. No significant differences were observed in overall survival (OS), relapse-free survival (RFS), local recurrence (LR), AE, and SRC between the SCRT and CRT groups, although the pathological therapeutic effect was higher in the CRT group. The patients with LPNM showed significantly inferior 5-year OS and 5-year RFS than those without LPNM.

CONCLUSIONS

There were no significant differences in OS, RFS, or LR between SCRT and CRT, although CRT had a significantly greater histological therapeutic effect. The prognosis of the pathological LPNM-positive cases was significantly poorer than that of pathological LPNM-negative cases.

New treatment strategies for non-metastatic rectal cancer

The most widely practiced (standard) treatment of non-metastatic rectal cancer is based on proctectomy with mesorectal excision (partial or total according to the location of the tumor and commonly called TME). Surgery is preceded by CAP50-type chemoradiotherapy (capecitabineand 50 Grays radiation) and performed 6-8 weeks after the end of chemoradiotherapy. The development of new endoscopic, surgical, radiation-based and chemotherapeutic modalities leads surgeons to envisage customized treatment to find the best compromise between functional and oncologic results according to the locoregional extension of the tumor. Superficial lesions are amenable to transanal excision. T2-3 tumors<4cm are amenable to rectal preservation when neoadjuvant treatment obtains a complete response, allowing local excision or close surveillance. Intensification endocavitary radiotherapy and induction and consolidation chemotherapy regimens to avoid recourse to salvage abdomino-perineal resection (APR) are under investigation. For locally advanced rectal cancers (T3-4 and all N+ irrespective of T), the following scenarios can be envisaged: for initially resectable tumors (T3N0, T1-T3N+, circumferential resection margin>2mm), neoadjuvant chemotherapy alone aims to minimize the risk of local recurrence while avoiding the sequelae of radiotherapy. In case of initially non-resectable tumors (T4, circumferential resection margin<1mm), induction chemotherapy before chemoradiotherapy and consolidation chemotherapy after short course radiotherapy provide better results than standard treatment in terms of complete response and recurrence-free survival, and should be routinely proposed in this indication.

Total Neoadjuvant Therapy in Locally Advanced Rectal Cancer: A Systematic Review and Metaanalysis of Oncological and Operative Outcomes

BACKGROUND

Total neoadjuvant therapy in rectal cancer refers to the administration of chemoradiotherapy plus chemotherapy before surgery. Recent studies have shown improved pathological complete response and disease-free survival with this approach. However, survival benefits remain unproven. Our objective is to present a metaanalysis of oncological outcomes of total neoadjuvant therapy in locally advanced rectal cancer.

PATIENTS AND METHODS

A comprehensive search was performed on PubMed, Medline, and Google Scholars. Studies comparing total neoadjuvant therapy with standard neoadjuvant chemoradiotherapy were included. Data extracted from the individual studies were pooled and a metaanalysis performed. The outcomes of interest are the rate of complete pathological response, nodal response, resection margin, anal preservation, anastomotic leak, local recurrence, distant recurrence, disease-free survival, and overall survival.

RESULTS

There were 15 comparative studies with 2437 patients in the neoadjuvant chemoradiotherapy group and 2284 in the total neoadjuvant therapy group. The pooled complete pathological response was 22.3% in the total neoadjuvant therapy group, compared with 14.2% in the standard neoadjuvant chemoradiotherapy group (p < 0.001). Even though there was no difference in local recurrence rate, there was a significantly lower rate of distant recurrence (OR 0.81, p = 0.02), and better 3-year disease-free survival (70.6% vs. 65.3%, respectively, p < 0.001) and overall survival (84.9% vs. 82.3%, respectively, p = 0.006), favoring the total neoadjuvant therapy group. Due to significant heterogeneity in the study protocols, there remains uncertainty on the ideal chemotherapy/radiotherapy sequence.

CONCLUSIONS

This study provides supporting evidence on the favorable immediate and intermediate oncological outcomes with the use of total neoadjuvant therapy for locally advanced rectal cancer.