Long-term outcomes of clinical complete responders after neoadjuvant treatment for rectal cancer in the International Watch & Wait Database (IWWD): an international multicentre registry study

Fractional order calculus model-derived histogram metrics for assessing pathological complete response to neoadjuvant chemotherapy in locally advanced rectal cancer

AIM

This study evaluates the value of diffusion fractional order calculus (FROC) model for the assessment of pathological complete response (pCR) after neoadjuvant chemoradiotherapy (nCRT) for locally advanced rectal cancer (LARC) by using histogram analysis derived from whole-tumor volumes.

MATERIALS AND METHODS

Ninety-eight patients were prospectively included. Every patient received MRI scans before and after nCRT using a 3.0-Tesla MRI machine. Parameters of the FROC model, including the anomalous diffusion coefficient (D), intravoxel diffusion heterogeneity (β), spatial parameter (μ), and the standard apparent diffusion coefficient (ADC), were calculated. Changes in median values (ΔX-median) and ratio (rΔX-median) were calculated. Receiver operating characteristic (ROC) curves were used for evaluating the diagnostic performance.

RESULTS

Pre-treatmentβ-10th percentile values were significantly lower in the pCR group compared to the non-pCR group (p < 0.001). The Δβ-median showed higher diagnostic accuracy (AUC = 0.870) and sensitivity (76.67 %) for predicting tumor response compared to MRI tumor regression grading (mrTRG) scores (AUC = 0.722; sensitivity = 90.0 %).

DISCUSSION

The use of FROC alongside comprehensive tumor histogram analysis was found to be practical and effective in evaluating the tumor response to nCRT in LARC patients.

Radical radiotherapy without surgical tumor resection for rectal cancer

In this editorial, I would like to comment on the article, recently published in the World Journal of Clinical Oncology. The article focuses on non-surgical treatments for locally recurrent rectal cancer, including the watch-and-wait (WW) strategy after total neoadjuvant therapy (TNT) and particle beam therapy. As treatment options for rectal cancer continue to evolve, the high complete response rate achieved with TNT has led to the development of a new non-surgical approach: WW. Chemoradiotherapy followed by consolidation chemotherapy, in particular, has a low rate of tumor growth and is a treatment aimed at achieving a cure without surgery. However, the risk of recurrence within two years is significant, necessitating careful follow-up. Establishing standardized follow-up methods that can be implemented by many physicians is essential. Carbon ion radiotherapy has demonstrated high local control with a low incidence of severe late toxicities, even after previous pelvic radiotherapy. While these new non-surgical curative treatments for rectal cancer require further investigation, future advancements in this field are anticipated.

Visualization analysis of research hotspots and trends in MRI-based artificial intelligence in rectal cancer

Background

Rectal cancer (RC) is one of the most common types of cancer worldwide. With the development of artificial intelligence (AI), the application of AI in preoperative evaluation and follow-up treatment of RC based on magnetic resonance imaging (MRI) has been the focus of research in this field. This review was conducted to develop comprehensive insight into the current research progress, hotspots, and future trends in AI based on MRI in RC, which remains to be studied.

Methods

Literature related to AI based on MRI and RC, as of November 2023, was obtained from the Web of Science Core Collection database. Visualization and bibliometric analyses of publication quantity and content were conducted to explore temporal trends, spatial distribution, collaborative networks, influential articles, keyword co-occurrence, and research directions.

Results

A total of 177 papers (152 original articles and 25 reviews) were identified from 24 countries/regions, 351 institutions, and 81 journals. Since 2019, the number of studies on this topic has rapidly increased. China and the United States have contributed the highest number of publications and institutions, cultivating the most intimate collaborative relationship. The highest number of articles derive from Sun Yat-sen University, while Frontiers in Oncology has published the highest number of relevant articles. Research on MRI-based AI in this field has mainly focused on preoperative diagnosis and prediction of treatment efficacy and prognosis.

Conclusions

This study provides an objective and comprehensive overview of the publications on MRI-based AI in RC and identifies the present research landscape, hotspots, and prospective trends in this field, which can provide valuable guidance for scholars worldwide.

Executive Summary of the American Radium Society on Appropriate Use Criteria for Nonoperative Management of Rectal Adenocarcinoma: Systematic Review and Guidelines

For patients with rectal cancer, the standard approach of chemotherapy, radiation therapy, and surgery (trimodality therapy) is associated with significant long-term toxicity and/or colostomy for most patients. Patient options focused on quality of life (QOL) have dramatically improved, but there remains limited guidance regarding comparative effectiveness. This systematic review and associated guidelines evaluate how various treatment strategies compare to each other in terms of oncologic outcomes and QOL. Cochrane and Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) methodology were used to search for prospective and retrospective trials and meta-analyses of adequate quality within the Ovid Medline database between January 1, 2012, and June 15, 2023. These studies informed the expert panel, which rated the appropriateness of various treatments in 6 clinical scenarios through a well-established consensus methodology (modified Delphi). The search process yielded 197 articles that advised voting. Increasing data have shown that nonoperative management (NOM) and primary surgery result in QOL benefits noted over trimodality therapy without detriment to oncologic outcomes. For patients with rectal cancer for whom total mesorectal excision would result in permanent colostomy or inadequate bowel continence, NOM was strongly recommended as usually appropriate. Restaging with tumor response assessment approximately 8 to 12 weeks after completion of radiation therapy/chemoradiation therapy was deemed a necessary component of NOM. The panel recommended active surveillance in the setting of a near-complete or complete response. In the setting of NOM, 54 to 56 Gy in 27 to 31 fractions concurrent with chemotherapy and followed by consolidation chemotherapy was recommended. The panel strongly recommends primary surgery as usually appropriate for a T3N0 high rectal tumor for which low anterior resection and adequate bowel function is possible, with adjuvant chemotherapy considered if N+. Recent data support NOM and primary surgery as important options that should be offered to eligible patients. Considering the complexity of multidisciplinary management, patients should be discussed in a multidisciplinary setting, and therapy should be tailored to individual patient goals/values.

A phase III randomized trial on the addition of a contact x-ray brachytherapy boost to standard neoadjuvant chemo-radiotherapy for organ preservation in early rectal adenocarcinoma: 5 year results of the OPERA trial

BACKGROUND

The OPERA trial has shown that a contact X Ray Brachytherapy 50kV (CXB) boost with neoadjuvant chemoradiotherapy (NCRT) can increase organ preservation (OP) rate for early rectal adenocarcinoma (ADK) of low-mid rectum. We report the results after 5 years of follow-up.

PATIENTS AND METHODS

OPERA was a multicenter, phase III trial that included operable patients (pts), with cT2-cT3b low-mid rectal ADK, tumors <5 cm, cN0 or cN1 <8 mm. All pts received external beam radiotherapy (EBRT): 45Gy in 25 fractions with concurrent capecitabine. Pts were randomly assigned (1:1) to receive a boost of EBRT in group A (9Gy/5 fractions) or a boost with CXB (90Gy/3 fractions) in group B. The primary end point was OP rate.

RESULTS

Out of 148 patients randomized, 141 were eligible. Between week 14-24, a clinical complete (or near) response was observed in 44 pts in group A (64%) vs 66 in group B (92%); p<0.001. The 3-year OP rate was 59% in group A vs 81% in group B (p=0.003). After update the median follow-up was 61.1 months [56.8-64.5]. The 5-year local regrowth was 39% in group A and 17% in group B (p=0.1). The difference in OP was still highly significant between both groups: A 56% vs B 79% (p=0.004). The difference was more significant if tumors < 3cm, with an OP rate of 93% in group B compared to 54% in group A. Of the 28 local regrowths, 3 occurred after 3 years of follow-up. Rectal bleeding (grade 1-2), which was the most prevalent toxicity during follow-up, disapeared most of the time after three years. Bowel function was not worsened by the CXB boost.

CONCLUSION

The OPERA trial was the first trial to demonstrate that CXB dose escalation was increasing the OP rate with good bowel function at 3 years. At 5 years, these results are sustained, specially in small early-stage tumors. The occurrence of some local regrowth after 3 years necessitates close surveillance of these pts during the 5-year period.

An explainable longitudinal multi-modal fusion model for predicting neoadjuvant therapy response in women with breast cancer

Multi-modal image analysis using deep learning (DL) lays the foundation for neoadjuvant treatment (NAT) response monitoring. However, existing methods prioritize extracting multi-modal features to enhance predictive performance, with limited consideration on real-world clinical applicability, particularly in longitudinal NAT scenarios with multi-modal data. Here, we propose the Multi-modal Response Prediction (MRP) system, designed to mimic real-world physician assessments of NAT responses in breast cancer. To enhance feasibility, MRP integrates cross-modal knowledge mining and temporal information embedding strategy to handle missing modalities and remain less affected by different NAT settings. We validated MRP through multi-center studies and multinational reader studies. MRP exhibited comparable robustness to breast radiologists, outperforming humans in predicting pathological complete response in the Pre-NAT phase (ΔAUROC 14% and 10% on in-house and external datasets, respectively). Furthermore, we assessed MRP's clinical utility impact on treatment decision-making. MRP may have profound implications for enrolment into NAT trials and determining surgery extensiveness.

Dynamics of cell-free tumor DNA correlate with early MRI response during chemoradiotherapy in rectal cancer

BACKGROUND

In locally advanced rectal cancer, the prediction of tumor response during and after neoadjuvant treatment remains challenging. In terms of organ preservation, adaptive radiotherapy, and intensified (total) neoadjuvant therapies, biomarkers are desirable for patient stratification.

METHODS

In 16 patients, weekly blood samples (n = 86) to detect cell-free tumor DNA (ctDNA) during long-course neoadjuvant chemoradiotherapy were analyzed. Data were correlated with initial tumor volumes, MRI response in week 2 and 5 of radiotherapy as well as with pathologic tumor response after resection and outcome parameters.

RESULTS

Most patients showed decreasing ctDNA during the course of radiochemotherapy. However, we found heterogenous dynamics of ctDNA and could identify three groups: (1) decline (2) no clear decline and/or late shedding (3) persistence of ctDNA. In seven patients we could detect significant amounts of ctDNA in week 5 or week 6 of treatment. In our pilot cohort, we did not find significant correlations of ctDNA dynamics with pathologic response or outcome parameters. However, patients with distinct decline of ctDNA had larger tumor volumes prior to treatment, and MRI imaging in week 2 and 5 revealed bigger absolute decrease of tumor volumes. If significant levels of ctDNA were found in week 5 and / or 6, patients showed less absolute tumor volume decrease in week 2 and 5.

CONCLUSIONS

Weekly measurement of ctDNA during radiochemotherapy is feasible and might represent a promising biomarker. Bigger initial primary tumors showed different ctDNA shedding profiles compared with smaller primary tumors and correlations of ctDNA dynamics with early imaging response were found.

Watch and wait in rectal cancer patients with residual mucin on magnetic resonance imaging following neoadjuvant therapy

BACKGROUND

Neoadjuvant therapy leads to a clinical complete response in a considerable proportion of patients with locally advanced rectal cancer, allowing for possible nonoperative management. The presence of mucin on magnetic resonance imaging (MRI) after neoadjuvant therapy leads to uncertainty about residual disease and appropriateness of a watch-and-wait strategy in patients with no evidence of disease on proctoscopy (endoscopic clinical complete response).

METHODS

MRI reports for locally advanced rectal cancer patients seen between July 2016 and January 2020 at Memorial Sloan Kettering Cancer Center were queried for presence of mucin in the tumor bed on MRI following neoadjuvant therapy. Clinicodemographic, pathologic, and outcome data were compiled and analyzed.

RESULTS

Of 71 patients with mucin on posttreatment MRI, 20 had a clinical complete response, and 51 had abnormalities on endoscopy and/or physical exam. One patient with a clinical complete response opted out of watch-and-wait; thus, 19 (27%) patients entered watch-and-wait, and 52 (73%) patients were planned for surgery (non-watch-and-wait). Of the 19 watch-and-wait patients, 15 (79%) have had no local regrowth with median follow-up of 50 months (range = 29-76 months), while 4 (21%) experienced regrowth between 9 and 29 months after neoadjuvant therapy. Of the 52 patients who were planned to have surgery (non-watch-and-wait), 49 underwent resection while 3 developed metastatic disease that precluded curative-intent surgery. Of the 49 patients who underwent surgery, 5 (10%) had a pathologic complete response (including the patient with an endoscopic clinical complete response).

CONCLUSIONS

The presence of mucin after neoadjuvant therapy for locally advanced rectal cancer does not preclude watch-and-wait management in otherwise appropriate candidates who achieve an endoscopic clinical complete response.

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

BACKGROUND

Potential differences in organ preservation between total neoadjuvant therapy (TNT) regimens integrating long-course chemoradiotherapy (LCCRT) and short-course radiotherapy (SCRT) in rectal cancer remain undefined.

PATIENTS AND METHODS

This natural experiment arose from a policy change in response to the COVID-19 pandemic during which our institution switched from uniformly treating patients with LCCRT to mandating that all patients be treated with SCRT. Our study includes 323 locally advanced rectal adenocarcinoma patients treated with LCCRT-based or SCRT-based TNT from January 2018 to January 2021. Patients who achieved clinical complete response were offered organ preservation with watch-and-wait (WW) management. The primary outcome was 2-year organ preservation. Additional outcomes included local regrowth, distant recurrence, disease-free survival (DFS), and overall survival (OS).

RESULTS

Patient and tumor characteristics were similar between LCCRT (n = 247) and SCRT (n = 76) cohorts. Median follow-up was 31 months. Similar clinical complete response rates were observed following LCCRT and SCRT (44.5% versus 43.4%). Two-year organ preservation was 40% [95% confidence interval (CI) 34% to 46%] and 31% (95% CI 22% to 44%) among all patients treated with LCCRT and SCRT, respectively. In patients managed with WW, LCCRT resulted in higher 2-year organ preservation (89% LCCRT, 95% CI 83% to 95% versus 70% SCRT, 95% CI 55% to 90%; P = 0.005) and lower 2-year local regrowth (19% LCCRT, 95% CI 11% to 26% versus 36% SCRT, 95% CI 16% to 52%; P = 0.072) compared with SCRT. The 2-year distant recurrence (10% versus 6%), DFS (90% versus 90%), and OS (99% versus 100%) were similar between WW patients treated with LCCRT and SCRT, respectively.

CONCLUSIONS

While WW eligibility was similar between cohorts, WW patients treated with LCCRT had higher 2-year organ preservation and lower local regrowth than those treated with SCRT, yet similar DFS and OS. These data support induction LCCRT followed by consolidation chemotherapy as the preferred TNT regimen for patients with locally advanced rectal cancer pursuing organ preservation.

The Rise of Patients Declining Rectal Cancer Surgery in the Era of Total Neoadjuvant Therapy

BACKGROUND

The treatment landscape for rectal cancer is rapidly evolving, particularly with the increasing use of neoadjuvant therapies. Still, up to 50% of patients with stage II-III disease require surgical resection post-neoadjuvant therapy to achieve the best oncologic outcomes. Many patients, however, hope to avoid surgery. This study aimed to assess trends and factors associated with declining recommended oncologic resection after systemic therapy nationally and in our institution.

PATIENTS AND METHODS

This is a retrospective analysis using the National Cancer Database from 2009 to 2021 and an institutional cohort at an academic center between 2009 and 2022 including adults with stage I-III rectal adenocarcinoma who underwent neoadjuvant therapy and were suitable for surgery.

RESULTS

Of 96,997 patients nationally, the rate of declining surgery increased from 2.3% in 2009 to 6.3% in 2021, a trend mirrored in our institutional cohort of 365 patients (0% in 2009/2010 to approximately 6-12% in 2021/2022). Locally, patients who declined surgery had higher rates of tobacco use, temporary loss to follow-up during therapy, and a more robust, albeit incomplete, tumor response to neoadjuvant therapy compared with controls who underwent surgery. Despite a stoma being the most cited reason for declining surgery, 30.4% of patients who declined oncologic resection died with a stoma.

CONCLUSIONS

Our findings underscore a notable trend of patients declining oncologic resections following neoadjuvant therapy for rectal cancer. By shedding light on the outcomes of patients who opt against surgery, we address a critical gap in the literature essential for informing patients about potential risks.

Risks of Organ Preservation in Rectal Cancer: Data From Two International Registries on Rectal Cancer

PURPOSE

Organ preservation has become an attractive alternative to surgery (total mesorectal excision [TME]) among patients with rectal cancer after neoadjuvant therapy who achieve a clinical complete response (cCR). Nearly 30% of these patients will develop local regrowth (LR). Although salvage resection is frequently feasible, there may be an increased risk for development of subsequent distant metastases (DM). The aim of this study is to compare the risk of DM between patients with LR after Watch and Wait (WW) and patients with near-complete pathologic response (nPCR) managed by TME at the time of reassessment of response.

METHODS

Data from patients enrolled in the International Watch & Wait Database (IWWD) with cCR managed by WW and subsequent LR were compared with patients managed by TME (with ≤10% cancer cells-nPCR) from the Spanish Rectal Cancer Project (VIKINGO project). The primary end point was DM-free survival at 3 years from decision to WW or TME. The secondary end point was possible risk factors associated with DM.

RESULTS

Five hundred and eight patients with LR were compared with 893 patients with near-complete response after TME. Overall, DM rate was significantly higher among LRs (22.8% v 10.2%; P ≤ .001). Independent risk factors for DM included LR (v TME at reassessment; P = .001), ypT3-4 status (P = .016), and ypN+ status (P = .001) at the time of surgery. 3-year DM-free survival was significantly worse for patients with LR (75% v 87%; P = .001). When stratified for pathologic stage, patients with LR did significantly worse through all stages (P ≤ .009).

CONCLUSION

Patients with LR appear to have a higher risk for subsequent DM development than patients with nPCR managed by TME at restaging irrespective of final pathology. Leaving the primary undetectable tumor in situ until development of LR may result in worse oncologic outcomes.

Predicting pathological complete response following neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer using merged model integrating MRI-based radiomics and deep learning data

BACKGROUND

To construct and compare merged models integrating clinical factors, MRI-based radiomics features and deep learning (DL) models for predicting pathological complete response (pCR) to neoadjuvant chemoradiotherapy (nCRT) in patients with locally advanced rectal cancer (LARC).

METHODS

Totally 197 patients with LARC administered surgical resection after nCRT were assigned to cohort 1 (training and test sets); meanwhile, 52 cases were assigned to cohort 2 as a validation set. Radscore and DL models were established for predicting pCR applying pre- and post-nCRT MRI data, respectively. Different merged models integrating clinical factors, Radscore and DL model were constituted. Their predictive performances were validated and compared by receiver operating characteristic (ROC) and decision curve analyses (DCA).

RESULTS

Merged models were established integrating selected clinical factors, Radscore and DL model for pCR prediction. The areas under the ROC curves (AUCs) of the pre-nCRT merged model were 0.834 (95% CI: 0.737-0.931) and 0.742 (95% CI: 0.650-0.834) in test and validation sets, respectively. The AUCs of the post-nCRT merged model were 0.746 (95% CI: 0.636-0.856) and 0.737 (95% CI: 0.646-0.828) in test and validation sets, respectively. DCA showed that the pretreatment algorithm could yield enhanced clinically benefit than the post-nCRT approach.

CONCLUSIONS

The pre-nCRT merged model including clinical factors, Radscore and DL model constitutes an effective non-invasive tool for pCR prediction in LARC.

Assessing the practice of total neoadjuvant therapy for rectal cancer: an online survey among radiation oncology departments in Germany and German-speaking regions of Austria and Switzerland

Total neoadjuvant therapy (TNT) of rectal cancer improves rates of pathological complete remission and progression-free survival. With improved clinical response rates, interest grew in a non-operative approach/watch and wait (WaW) for this disease. In 2020, the working groups of ACO/AIO/ARO published a consensus statement on the use of TNT, including a non-operative approach. However, the best combination scheme remains unclear. Despite the increasing use of TNT, there is a lack of comprehensive data on its current implementation and practices. To address this knowledge gap, a multicenter survey was conducted to capture the use of TNT protocols in German-speaking radiotherapy departments. At the beginning of 2023, a GDPR-compliant online survey was conducted in Germany, Austria, and German-speaking Switzerland. The questionnaire comprised 43 questions covering various aspects of TNT, including chemotherapy and WaW concepts. Most respondents (98.4%) confirmed awareness of the consensus on TNT for rectal cancer. Institutions treated an average of 30.22 rectal cancer patients annually. Most respondents (76.2%) reported treating over 80% of patients neoadjuvantly. Regarding TNT, 33.3% treated 21-50% with such a protocol. No significant association was found between the institution type and TNT application. In 62/63 cases, tumor board discussion was standard before offering TNT. VMAT was the predominant technique (82.5%). For rectal cancer dosing, the 50/50.4Gy scheme was most common, followed by 45Gy with a boost and the 5 × 5Gy scheme. Dosing schemes for TNT varied slightly, with more participants reporting the use of 5 × 5Gy compared to radiation therapy for rectal cancer in general. CBCT was the primary IGRT method (88.9%). Larger hospitals typically administered chemotherapy themselves, while private practices collaborated with medical oncologists (p < 0.0001). The most common concurrent chemotherapy drugs were 5-fluorouracil/capecitabine (64.4%) and oxaliplatin (37.3%). A WaW strategy was reported to be institutional implemented by 63.8%. The timing of offering WaW was split, with 50% offering it after radiochemotherapy and 47% during the informed consent talk. For planned WaW, 62% prefer normofractionated TNT. TNT appears to be widely implemented in the German-speaking radio-oncological community, regardless of the type of institution. Image-guided therapy, multidisciplinary team decisions, and internal guidelines play an important role. TNT seems to have already altered treatment protocols for rectal cancer toward an organ-preserving approach in selected cases. In these WaW cases, normofractionation appears to be preferred over hypofractionation.

Gut microbiome model predicts response to neoadjuvant immunotherapy plus chemoradiotherapy in rectal cancer

BACKGROUND

Accurate evaluation of the response to preoperative treatment enables the provision of a more appropriate personalized therapeutic schedule for locally advanced rectal cancer (LARC), which remains an enormous challenge, especially neoadjuvant immunotherapy plus chemoradiotherapy (nICRT).

METHODS

This prospective, multicenter cohort study enrolled patients with LARC from 6 centers who received nICRT. The dynamic variation in the gut microbiome during nICRT was evaluated. A species-level gut microbiome prediction (SPEED) model was developed and validated to predict the pathological complete response (pCR) to nICRT.

FINDINGS

A total of 50 patients were enrolled, 75 fecal samples were collected from 33 patients at different time points, and the pCR rate reached 42.4% (14/33). Lactobacillus and Eubacterium were observed to increase after nICRT. Additionally, significant differences in the gut microbiome were observed between responders and non-responders at baseline. Significantly higher abundances of Lachnospiraceae bacterium and Blautia wexlerae were found in responders, while Bacteroides, Prevotella, and Porphyromonas were found in non-responders. The SPEED model showcased a superior predictive performance with areas under the curve of 98.80% (95% confidence interval [CI]: 95.67%-100%) in the training cohort and 77.78% (95% CI: 65.42%-88.29%) in the validation cohort.

CONCLUSIONS

Programmed death 1 (PD-1) blockade plus concurrent long-course CRT showed a favorable pCR rate and is well tolerated in microsatellite-stable (MSS)/mismatch repair-proficient (pMMR) patients with LARC. The SPEED model can be used to predict the pCR to nICRT based on the baseline gut microbiome with high robustness and accuracy, thereby assisting clinical physicians in providing individualized management for patients with LARC.

FUNDING

This research was funded by the China National Natural Science Foundation (82202884).

Quality of life and functional outcome of rectal cancer patients: A prospective cohort study

AIM

In the last decade, the Netherlands has implemented various diagnostic and treatment strategies to enhance rectal cancer outcomes. This study, using data from the Prospective Dutch ColoRectal Cancer (PLCRC) cohort, investigates whether these multidisciplinary advancements have translated into improved health-related quality of life (HRQoL) and functional outcomes for the general Dutch rectal cancer population.

METHODS

Patients with Stage I-III rectal cancer enrolled in the PLCRC cohort were included. HRQoL and functional outcomes were assessed 1 and 2 years after diagnosis using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 (EORTC QLQ-C30), EORTC QLQ Colorectal Cancer 29 and the Low Anterior Resection Syndrome score. HRQoL and functional outcomes were compared based on year of diagnosis (2014-2019).

RESULTS

A total of 1294 patients were included. Two years after diagnosis, patients diagnosed in 2019 (n = 392) had a clinically relevant higher score on physical (8.2, 95% CI 4.1-12.3), role (13.5, 95% CI 7.3-19.7) and social functioning (5.8, 95% CI 0.3-11.2) compared to those diagnosed in 2014 (n = 65). Additionally, patients diagnosed in 2019 experienced less fatigue 2 years after diagnosis compared to those diagnosed in 2014 (-8.6, 95% CI -14.1 to -3.0). The Low Anterior Resection Syndrome score showed no differences.

CONCLUSION

The findings of this study suggest that over the past decade rectal cancer patients in the Netherlands have witnessed improvements in HRQoL across various domains. Most probably, the improvement is due to a combination of implementation of population screening, a more restrictive neoadjuvant radiotherapy policy and advances in minimally invasive surgery and organ preserving treatment options.

Tailoring treatment for locally advanced rectal cancer

The management of locally advanced rectal cancer (LARC) requires personalized treatment to improve outcomes and maintain quality of life. This narrative review examines the recent developments in management, focusing on non-operative management, radiotherapy choices or omission, chemotherapy sequencing, and the role of immunotherapy and brachytherapy boost. Non-operative management can be an option for select patients, and the use of long-course chemoradiation (LCCRT) with consolidation chemotherapy or brachytherapy boost has been shown to enhance rectal preservation rates. For patients requiring surgery, the choice between LCCRT and SCRT depends on the risk of local recurrence and patient preferences. MSI-high LARC patients benefit significantly from single-agent immunotherapy, and early clinical trials show promising results for the application of immunotherapy in MSS tumors. By stratifying patients based on individual and tumor risk factors, clinicians can tailor treatment plans to improve oncologic outcomes and quality of life for patients with LARC.

The impact of short-course total neoadjuvant therapy, long-course chemoradiotherapy, and upfront surgery on the technical difficulty of total mesorectal excision: an observational study with an intraoperative perspective

PURPOSE

Total neoadjuvant therapy (TNT) is becoming the standard of care for locally advanced rectal cancer. However, surgery is deferred for months after completion, which may lead to fibrosis and increased surgical difficulty. The aim of this study was to assess whether TNT (TNT-RAPIDO) is associated with increased difficulty of total mesorectal excision (TME) compared with long-course chemoradiotherapy (LCRT) and upfront surgery.

METHODS

Twelve laparoscopic videos of low anterior resection with TME for rectal cancer were prospectively collected from January 2020 to October 2021, with 4 videos in each arm. Seven colorectal surgeons assessed the videos independently, graded the difficulty of TME using a visual analog scale and attempted to identify which category the videos belonged to.

RESULTS

The median age was 67 years, and 10 patients were male. The median interval to surgery from radiotherapy was 13 weeks in the LCRT group and 24 weeks in the TNT-RAPIDO group. There was no significant difference in the visual analog scale for difficulty in TME between the 3 groups (LCRT, 3.2; TNT-RAPIDO, 4.6; upfront, 4.1; P=0.12). A subgroup analysis showed similar difficulty between groups (LCRT 3.2 vs. TNT-RAPIDO 4.6, P=0.05; TNT-RAPIDO 4.6 vs. upfront 4.1, P=0.54). During video assessments, surgeons correctly identified the prior treatment modality in 42% of the cases. TNT-RAPIDO videos had the highest recognition rate (71%), significantly outperforming both LCRT (29%) and upfront surgery (25%, P=0.01).

CONCLUSION

TNT does not appear to increase the surgical difficulty of TME.

Impact of Sarcopenia on Treatment Outcomes and Toxicity in Locally Advanced Rectal Cancer

Background and Objectives: Sarcopenia, a condition characterized by muscle mass loss, is prevalent in up to 68% of rectal cancer patients and has been described as a negative prognostic factor, impacting overall survival and tumor response. While there are extensive data on rectal cancer globally, only a handful of studies have evaluated the role of sarcopenia in locally advanced rectal cancer (LARC). Our study aimed to investigate the relationship between sarcopenia, overall response rate, and toxicity in patients who underwent total neoadjuvant treatment (TNT) for LARC. Materials and Methods: We performed a retrospective study of patients with rectal cancer treated with TNT and surgery with curative intent between 2021 and 2023 at Prof. Dr. Ion Chiricuta Institute of Oncology, Cluj-Napoca. Sarcopenia was assessed on MRI images by measuring the psoas muscle area (PMA) at the level of the L4 vertebra before and after neoadjuvant therapy. The primary endpoints were the overall complete response rate (oCR) and acute toxicity. Results: This study included 50 patients with LARC. The oCR rate was 18% and was significantly associated with post-treatment sarcopenia (OR 0.08, p = 0.043). Patients who did not achieve a clinical or pathologic complete response had, on average, an 8% muscle loss during neoadjuvant therapy (p = 0.022). Cystitis and thrombocytopenia were significantly associated with post-treatment sarcopenia (p = 0.05 and p = 0.049). Conclusions: Sarcopenia and loss of psoas muscle during neoadjuvant therapy were negatively associated with tumor response in locally advanced rectal cancer. Thrombocytopenia and cystitis are more frequent in sarcopenic than non-sarcopenic patients undergoing neoadjuvant chemoradiation for rectal cancer.

Great Debates: Surgery or Watch and Wait After Total Neoadjuvant Therapy for Rectal Cancer

Locally advanced rectal cancer has traditionally been treated with multimodal therapy including neoadjuvant chemoradiotherapy followed by surgical resection. More recent data suggests that in appropriate patients, total neoadjuvant treatment (TNT) makes it possible to adopt a "watch and wait" approach. Advocates for watch and wait argue that patients with a complete or near-complete clinical response to TNT have comparable overall and disease-free survival to their counterparts who undergo surgical resection, and also have a better quality of life, fewer complications, and potentially avoid a stoma. The dogma of surgery as regional curative intent therapy has been challenged by similar recurrence rates among those treated with total mesorectal excision (TME) and those treated with watch and wait. Furthermore, those who develop local recurrence in the watch and wait groups are equally salvageable, either by surgery, brachytherapy, or chemotherapy. While watch and wait is not appropriate in all patients, this manuscript highlights the benefits and drawbacks of both therapeutic modalities.

Sequence of Contact X-ray Brachytherapy (CXB) and External Beam Radiation (EBRT) in organ-preserving treatment for small rectal cancer

BACKGROUND AND PURPOSE

External Beam Radiotherapy (EBRT) followed by Contact X-ray Brachytherapy (CXB) and vice versa are viable alternatives to surgery for selected rectal cancer patients who have small tumours (≤3 cm). However, the optimal sequence of treatment needs to be established. We compared two approaches using Propensity Score (PS) matching and inverse probability treatment weighting (IPTW) analyses to investigate whether the sequence of treatment affected patient outcomes.

MATERIALS AND METHODS

This retrospective analysis (2008-2019) included patients with rectal adenocarcinoma (cT1-3,N0-1,M0, grade 1-2, size ≤ 3 cm) who received both EBRT and CXB, irrespective of treatment sequence. PS matching and IPTW were conducted to balance covariate standardised mean differences between groups. Oncological outcomes and rate of post-treatment rectal bleeding were assessed.

RESULTS

Following PS matching and IPTW analyses from 251 eligible patients; 103 starting with EBRT (median follow-up: 37 [IQR:18-56] months) and 148 with CXB (median follow-up: 32 [IQR:16-54] months, a significant improvement in 3-year overall survival (77% vs 85%, p = 0.02, [HR:0.58 (95% CI:0.37-0.91)]) and a higher risk of post-treatment rectal bleeding (grade 1 (26%) and grade 2 (6%)) were found in patients who started with CXB (p = 0.08). No significant differences were observed in local regrowth (18% vs 12%, p = 0.47), distant relapse (10% vs 6%, p = 0.53), 3-year organ preservation rates (70% vs 75%, p = 0.20, [HR:0.66 (95% CI: 0.35-1.26)]), or disease-free survival (78% vs 82%, p = 0.17, [HR: 0.47 (95% CI: 0.16-1.38)]) CONCLUSION: In patients with rectal cancer (≤3 cm), commencing with CXB rather than EBRT, was associated with improved overall survival, but had a higher risk of G1/2 rectal bleeding. No statistically significant differences were observed in other oncological outcomes.

Complete Response to Locoregional Therapy Plus Immunotherapy for Hepatocellular Carcinoma

Importance

Previous studies showed that 42% to 50% of patients with locally advanced hepatocellular carcinoma (HCC) achieved complete remission (CR) after combined locoregional therapy (LRT) plus immunotherapy (IO). However, data on predictors of CR and long-term clinical outcomes without surgery and after discontinuation of IO are lacking.

Objective

To assess the long-term clinical outcomes among patients with unresectable HCC who achieved CR after LRT-IO and were placed on a watch-and-wait protocol.

Design, Setting, and Participants

This cohort study included patients with unresectable HCC who achieved CR after LRT-IO in 2 prospective studies between January 2018 and December 2022. The time of data cutoff was June 2023. Radiologic CR was defined per modified Response Evaluation Criteria in Solid Tumors. All patients underwent close surveillance after CR without surgical interventions, and IO was discontinued.

Exposure

All patients had received stereotactic body radiotherapy followed by anti-programmed cell death protein 1 or anti-programmed death ligand 1 therapy. Forty-nine patients had received a dose of transarterial chemoembolization before stereotactic body radiotherapy.

Main Outcomes and Measures

The primary outcome was the 3-year overall survival (OS) rate. Secondary outcomes included the 3-year time-to-progression rate, 3-year local control rate, and relapse pattern. Factors associated with CR were analyzed using multivariate analyses.

Results

A total of 63 patients were enrolled (58 male [92.1%]; median age, 69 years [range, 18-90 years]); 38 patients (60.3%) had macrovascular invasion, and the median tumor diameter was 10 cm (range, 3.8-31.1 cm). The median follow-up time was 34.7 months (95% CI, 6.5-64.6 months). Twenty-nine patients (46.0%) achieved CR. The patients achieving CR had a significantly better 3-year OS rate than patients not achieving CR (75.5% [95% CI, 58.2%-98.3%] vs 28.1% [95% CI, 7.4%-29.4%]; P < .001). Among the 29 patients with CR, the 3-year time-to-progression rate was 58.7% (95% CI, 38.7%-79.1%) and the 3-year local control rate was 90.5% (95% CI, 78.2%-100%). Ten patients (34.5%) developed recurrence; among them, 6 (60.0%) with solitary intrahepatic disease relapse underwent curative surgical treatment. The absence of tumor vascular invasion (odds ratio, 0.30; 95% CI, 0.10-0.89) and the sum of the largest lesion diameters of 8 cm or less (odds ratio, 0.26; 95% CI, 0.07-0.98) were associated with CR.

Conclusions and Relevance

This cohort study of LRT-IO with long-term follow-up data found a durable response in patients with locally advanced unresectable HCC. Long-term survival was attainable in patients with radiologic CR. Further randomized clinical trials are warranted.

ctDNA responds to neoadjuvant treatment in locally advanced rectal cancer

BACKGROUND

Liquid biopsy is a minimally invasive procedure investigating tumor mutations.

METHODS

In our retrospective study, we investigated whether molecular therapy monitoring of patients receiving neoadjuvant radio(chemo)therapy on a daily routine is possible in 17 patients with locally advanced rectal cancer. Six patients received short-course radiotherapy (5 × 5 Gy) with subsequent surgery, six patients were treated according RAPIDO protocol with short-course radiotherapy followed by chemotherapy (FOLFOX4) and subsequent surgery and five patients received conventional neoadjuvant radiochemotherapy with 5-FU followed by surgery. Response was assessed by Dworak. Liquid biopsies were taken before and immediately after neoadjuvant radiotherapy to isolate and ultradeeply sequence cell free DNA with a panel of 127 genes. Somatic mutations were determined bioinformatically by comparison with normal DNA from leukocytes to distinguish them from germline variants or aging mutations.

RESULTS

In 12 patients (71%) at least one somatic mutation was detected. In 8/12 patients a decrease and in 4/12 an increase or mixed response in ctDNA was seen. Statistical correlation between ctDNA analysis and clinical response could not be seen.

CONCLUSION

ctDNA is responding to neoadjuvant therapy and liquid biopsy is easily integrated into a daily routine. As part of translational research this protocol leaves room for further investigations.

Barriers to Offering Organ Preservation for Rectal Cancer in a Predominantly Hispanic Safety Net Hospital

BACKGROUND

Total neoadjuvant therapy (TNT) for locally advanced rectal cancer (LARC) has shown promise in achieving pathologic complete response (pCR) and enabling organ preservation through watch-and-wait (WW) strategies. However, implementation of WW protocols in diverse patient populations and safety-net hospitals faces unique challenges. The objective of this study is to evaluate TNT outcomes and identify barriers to WW implementation in a predominantly Hispanic safety-net hospital in South Texas.

METHODS

A retrospective review was conducted of 40 LARC patients treated with TNT at an academic tertiary referral center in South Texas between 2018 and 2023. Patient demographics, disease characteristics, and pCR rates were analyzed. A survey of multidisciplinary providers assessed perceived institutional and patient-related barriers to WW implementation.

RESULTS

The cohort was 70% Hispanic, with a median age of 54 years. Most patients had advanced disease at diagnosis (57.5% T4, 65% N2). The pCR rate was 18.5% (5/27) among patients undergoing surgery. Re-review of MRIs for pCR patients revealed that 2/5 had minimal residual disease. The provider survey identified MRI quality variability, lack of dedicated treatment coordinators, and concerns about patient compliance and financial barriers as key obstacles to WW implementation.

CONCLUSIONS

Despite advanced disease presentation in a predominantly Hispanic population, TNT achieved pCR rates comparable to international trials. Institutional and patient-level barriers to WW were identified, informing the development of a tailored WW protocol for this unique patient population.

B7H3 Immune Checkpoint Overexpression Is Associated with Decreased Complete Response Rates to Neoadjuvant Therapy in Locally Advanced Rectal Cancer

BACKGROUND AND OBJECTIVES

Rectal cancer accounts for approximately one-third of colorectal cancers, with over 340,000 deaths globally in 2022. Despite advancements in treatment, the five-year overall survival for locally advanced rectal cancer (LARC) remains at 74%, with significant morbidity. B7H3 (CD276), an immune checkpoint protein, plays a role in tumor progression and resistance to therapy, and correlates with poor prognosis in various cancers, including colorectal cancer. This study aims to evaluate the expression of B7H3 in LARC and its impact on overall complete response (oCR) rates to neoadjuvant therapy.

METHODS

A retrospective study was conducted on 60 patients with LARC who received neoadjuvant chemoradiation (nCRT) followed by total mesorectal excision (TME). B7H3 expression was assessed using immunohistochemistry on surgical specimens. Expression levels were categorized as high or low based on a composite score, and their association with oCR rates was analyzed.

RESULTS

High B7H3 expression was observed in 60% of patients, with 73.5% showing expression in more than 50% of tumor cells. Patients who achieved oCR had significantly lower B7H3 expression compared to those with residual disease (p < 0.001). No nuclear expression of B7H3 was detected. No significant correlation was found between B7H3 expression and other clinicopathological variables, except for a higher likelihood of non-restorative surgery in patients with elevated B7H3 levels (p = 0.049). Mucinous adenocarcinoma had high expression of B7H3.

CONCLUSIONS

Elevated B7H3 expression is associated with reduced oCR rates in LARC, highlighting its potential role as a prognostic biomarker. Further studies with larger cohorts are warranted to validate these findings and explore B7H3-targeted therapies as a treatment strategy for LARC.

The Role of Predictive and Prognostic MRI-Based Biomarkers in the Era of Total Neoadjuvant Treatment in Rectal Cancer

The role of magnetic resonance imaging (MRI) in rectal cancer management has significantly increased over the last decade, in line with more personalized treatment approaches. Total neoadjuvant treatment (TNT) plays a pivotal role in the shift from traditional surgical approach to non-surgical approaches such as 'watch-and-wait'. MRI plays a central role in this evolving landscape, providing essential morphological and functional data that support clinical decision-making. Key MRI-based biomarkers, including circumferential resection margin (CRM), extramural venous invasion (EMVI), tumour deposits, diffusion-weighted imaging (DWI), and MRI tumour regression grade (mrTRG), have proven valuable for staging, response assessment, and patient prognosis. Functional imaging techniques, such as dynamic contrast-enhanced MRI (DCE-MRI), alongside emerging biomarkers derived from radiomics and artificial intelligence (AI) have the potential to transform rectal cancer management offering data that enhance T and N staging, histopathological characterization, prediction of treatment response, recurrence detection, and identification of genomic features. This review outlines validated morphological and functional MRI-derived biomarkers with both prognostic and predictive significance, while also exploring the potential of radiomics and artificial intelligence in rectal cancer management. Furthermore, we discuss the role of rectal MRI in the 'watch-and-wait' approach, highlighting important practical aspects in selecting patients for non-surgical management.

Oncological risks associated with the planned watch-and-wait strategy using total neoadjuvant treatment for rectal cancer: A narrative review

Overall survival benefit of total neoadjuvant treatment (TNT) remains unconfirmed. Thus, in our opinion, the main rationale for using TNT is a planned watch-and-wait (w&w) strategy to improve patients' long-term quality of life through organ preservation. The OPRA randomized trial, which examined a planned w&w strategy using TNT, showed a higher organ preservation rate but also a higher regrowth rate compared to studies on the opportunistic w&w strategy. Higher rates of complete clinical response with TNT did not improve disease-free survival compared to historical controls. Therefore, the gain in organ-sparing capability might not be balanced by the increased oncological risk. The ultimate local failure rate in the intention-to-treat analysis of the OPRA trial was 13% for induction chemotherapy and 16% for consolidation chemotherapy, which seems higher than expected compared to 8% in a meta-analysis of w&w studies or 12% after TNT and surgery in the PRODIGE-23 and RAPIDO trials, which enrolled patients with more advanced cancers than the OPRA trial. Other studies also suggest worse local control when surgery is delayed for radio-chemoresistant cancers. Our review questions the safety of the planned w&w strategy using TNT in unselected patients. To reduce the oncological risk while maintaining high organ preservation rates, we suggest that the planned w&w strategy using TNT requires a two-tier patient selection process: before treatment and after tumor response assessment at the midpoint of consolidation chemotherapy. These robust selections should identify patients who are unlikely to achieve organ preservation with TNT and would be better managed by preoperative chemoradiotherapy (without consolidation chemotherapy) and surgery, or by discontinuing consolidation chemotherapy and proceeding directly to surgery.

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)

AIM

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.

METHOD

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.

DISCUSSION

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.

Clinical status and future prospects of neoadjuvant immunotherapy for localized mismatch repair-deficient cancers: a review

Frameshift mutations accumulate in cancers related to mismatch repair deficiency (dMMR), which has the potential to produce various neoantigens, representing a distinct subset of cancers that respond considerably to immunotherapy. In recent years, robust evidence has supported the first-line application of immunotherapy for patients with metastatic dMMR cancers, which provoked extensive investigations of the feasibility and efficacy of immunotherapy in up-front settings, including neoadjuvant therapy. Several completed trials with small sample sizes suggested that neoadjuvant immunotherapy can achieve an impressively high complete response rate, for the first time offering the potential of systemic therapy to cure cancer without the need for surgical resection. However, a difficult dilemma emerges: clinicians are now facing a selection between the standard of care with good evidence for proficient MMR but suboptimal for dMMR cancers and the emerging immunotherapy with promising results but only based on a limited number of patients with shorter duration of follow-up. This review aims to provide a comprehensive summary of the biological rationale and clinical status of neoadjuvant immunotherapy in patients with dMMR cancers. Furthermore, I elaborate on particular issues that must be taken into consideration for further advancement in the field.

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

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

MRI Predicts Residual Disease and Outcomes in Watch-and-Wait Patients with Rectal Cancer

Background MRI plays a crucial role in restaging locally advanced rectal cancer treated with total neoadjuvant therapy (TNT); however, prospective studies have not evaluated its ability to accurately select patients for nonoperative management. Purpose To evaluate the ability of restaging MRI to predict oncologic outcomes and identify imaging features associated with residual disease (RD) after TNT. Materials and Methods This was a secondary analysis of the Organ Preservation in Rectal Adenocarcinoma (OPRA) trial, which randomized participants from April 2014 to March 2020 with stages II or III rectal adenocarcinoma to undergo either induction or consolidation TNT. Participants enrolled in the OPRA trial who underwent restaging MRI were eligible for inclusion in the present study. Radiologists classified participants as having clinical complete response (cCR), near-complete clinical response (nCR), or incomplete clinical response (iCR) based on restaging MRI at a mean of 8 weeks ± 4 (SD) after treatment. Oncologic outcomes according to MRI response category were assessed using Kaplan-Meier curves. Logistic regression analysis was performed to identify imaging characteristics associated with RD. Results A total of 277 participants (median age, 58 years [IQR, 17 years]; 179 male) who were randomized in the OPRA trial had restaging MRI forms completed. The median follow-up duration was 4.1 years. Participants with cCR had higher rates of organ preservation compared with those with nCR (65.3% vs 41.6%, log-rank P < .001). Five-year disease-free survival for participants with cCR, nCR, and iCR was 81.8%, 67.6%, and 49.6%, respectively (log-rank P < .001). The MRI response category also predicted overall survival (log-rank P < .001), distant recurrence-free survival (log-rank P = .005), and local regrowth (log-rank P = .02). Among the 266 participants with at least 2 years of follow-up, 129 (48.5%) had RD. At multivariable analysis, the presence of restricted diffusion (odds ratio, 2.50; 95% CI: 1.22, 5.24) and abnormal nodal morphologic features (odds ratio, 5.04; 95% CI: 1.43, 23.9) remained independently associated with RD. Conclusion The MRI response category was predictive of organ preservation and survival. Restricted diffusion and abnormal nodal morphologic features on restaging MRI scans were associated with increased likelihood of residual tumor. ClinicalTrials.gov identifier: NCT02008656 © RSNA, 2024 Supplemental material is available for this article. See also the editorial by Milot in this issue.

Economic Evaluation of 'Watch and Wait' Following Neoadjuvant Therapy in Locally Advanced Rectal Cancer: A Systematic Review

BACKGROUND

Owing to multimodal treatment and complex surgery, locally advanced rectal cancer (LARC) exerts a large healthcare burden. Watch and wait (W&W) may be cost saving by removing the need for surgery and inpatient care. This systematic review seeks to identify the economic impact of W&W, compared with standard care, in patients achieving a complete clinical response (cCR) following neoadjuvant therapy for LARC.

METHODS

The PubMed, OVID Medline, OVID Embase, and Cochrane CENTRAL databases were systematically searched from inception to 26 April 2024. All economic evaluations (EEs) that compared W&W with standard care were included. Reporting and methodological quality was assessed using the Consolidated Health Economic Evaluation Reporting Standards (CHEERS), BMJ and Philips checklists. Narrative synthesis was performed. Primary and secondary outcomes were (incremental) cost-effectiveness ratios and the net financial cost.

RESULTS

Of 1548 studies identified, 27 were assessed for full-text eligibility and 12 studies from eight countries (2016-2024) were included. Seven cost-effectiveness analyses (complete EEs) and five cost analyses (partial EEs) utilized model-based (n = 7) or trial-based (n = 5) analytics with significant variations in methodological design and reporting quality. W&W showed consistent cost effectiveness (n = 7) and cost saving (n = 12) compared with surgery from third-party payer and patient perspectives. Critical parameters identified by uncertainty analysis were rates of local and distant recurrence in W&W, salvage surgery, perioperative mortality and utilities assigned to W&W and surgery.

CONCLUSION

Despite heterogenous methodological design and reporting quality, W&W is likely to be cost effective and cost saving compared with standard care following cCR in LARC. Clinical Trials Registration PROSPERO CRD42024513874.

Journey through the Decades: The Evolution in Treatment and Shared Decision Making for Locally Advanced Rectal Cancer

The management of locally advanced rectal cancer has undergone significant transformations over the decades and optimal treatment approaches continue to evolve. There have been numerous advances in surgery, chemotherapy, and radiation therapy from the first description of the abdominoperineal resection in 1908, timing of chemotherapy and radiation therapy in the late 20th and early 21st century, and most recently, the introduction of organ preservation or nonoperative management in 2004. Alongside these advancements, the concept of shared decision making in medicine has evolved, prompting a focus on patient-centered care. This evolution in practice has been fueled by a growing recognition of the importance of patient autonomy and the alignment of treatment options with patients' values and preferences. With the growing number of possible treatment options, variability in patient counseling exists, highlighting the need for a standardized approach to shared decision making in locally advanced rectal cancer. This narrative review will describe the evolution of treatment options of locally advanced rectal cancer as well as the concept of shared decision making and decision aids, and will introduce a decision aid for patients with locally advanced rectal cancer who have achieved a complete clinical response and are eligible for watch and wait.

Predictive value of flexible proctosigmoidoscopy and laboratory findings for complete clinical responses after neoadjuvant chemoradiotherapy in patients with locally advanced primary rectal cancer: a retrospective cohort study

PURPOSE

Colorectal cancer is the second leading cause of cancer death worldwide. Standard treatments for locally advanced rectal cancer include neoadjuvant chemoradiotherapy and total mesorectal excision (TME), which are associated with significant morbidity. After neoadjuvant therapy, one-third of patients achieve a pathological complete response (pCR) and are eligible for a watch-and-wait approach without TME. The purpose of this study was to determine the potential predictors of pCR before surgery.

METHODS

The demographic, clinical, and endoscopic data of 119 patients with primary locally advanced rectal cancer without distant metastasis who underwent restaging endoscopy and TME 6-8 weeks after the end of neoadjuvant therapy were collected. The absence of tumor cells in the histological examination of the TME specimen after neoadjuvant therapy was considered pCR. Binary logistic regression and receiver operating characteristic curves were utilized for analysis.

RESULTS

According to the multivariate logistic regression analysis, flattening of marginal tumor swelling (p value < 0.001, odds ratio = 100.605) emerged as an independent predictor of pCR in rectal cancer patients. Additionally, receiver operating characteristic curve analysis revealed that lower preoperative carcinoembryonic antigen and erythrocyte sedimentation rate levels predict pCR, with cutoffs of 2.15 ng/ml and 19.0 mm/h, respectively.

CONCLUSION

Carcinoembryonic antigen and erythrocyte sedimentation rate, along with the presence of flattening of marginal tumor swelling, can predict pCR after neoadjuvant chemoradiotherapy in patients with primary rectal cancer. These factors offer a potential method for selecting candidates for conservative treatment based on endoscopic and laboratory findings.

Predicting the response to neoadjuvant chemoradiation for rectal cancer using nomograms based on MRI tumour regression grade

PURPOSE

This study aimed to develop nomograms that combine clinical factors and MRI tumour regression grade to predict the pathological response of mid-low locally advanced rectal cancer to neoadjuvant chemoradiotherapy.

METHODS

The retrospective study included 204 patients who underwent neoadjuvant chemoradiotherapy and surgery between January 2013 and December 2021. Based on pathological tumour regression grade, patients were categorized into four groups: complete pathological response (pCR, n=45), non-complete pathological response (non-pCR; n=159), good pathological response (pGR, n=119), and non-good pathological response (non-pGR, n=85). The patients were divided into a training set and a validation set in a 7:3 ratio. Based on the results of univariate and multivariate analyses in the training set, two nomograms were respectively constructed to predict complete and good pathological responses. Subsequently, these predictive models underwent validation in the independent validation set. The prognostic performances of the models were evaluated using the area under the curve (AUC).

RESULTS

The nomogram predicting complete pathological response incorporates tumour length, post-treatment mesorectal fascia involvement, white blood cell count, and MRI tumour regression grade. It yielded an AUC of 0.787 in the training set and 0.716 in the validation set, surpassing the performance of the model relying solely on MRI tumour regression grade (AUCs of 0.649 and 0.530, respectively). Similarly, the nomogram predicting good pathological response includes the distance of the tumour's lower border from the anal verge, post-treatment mesorectal fascia involvement, platelet/lymphocyte ratio, and MRI tumour regression grade. It achieved an AUC of 0.754 in the training set and 0.719 in the validation set, outperforming the model using MRI tumour regression grade alone (AUCs of 0.629 and 0.638, respectively).

CONCLUSIONS

Nomograms combining MRI tumour regression grade with clinical factors may be useful for predicting pathological response of mid-low locally advanced rectal cancer to neoadjuvant chemoradiotherapy. The proposed models could be applied in clinical practice after validation in large samples.

Nonoperative management and local excision after neoadjuvant chemoradiation therapy for rectal cancer

Locally advanced extraperitoneal rectal cancer represents a significant clinical challenge, and currently, the standard treatment is based on neoadjuvant chemoradiation therapy (CRT) followed by radical surgical resection with total mesorectal excision (TME). In the last 30 years, its management has undergone significant changes due to the improvement of complementary radio- and chemotherapy treatments, the improvement of minimally invasive surgical approaches and the diffusion of organ-sparing approaches, such as nonoperative management, commonly called "watch and wait" (NOM) and local excision (LE), in highly selected patients who achieve a major or complete response to neoadjuvant CRT. This review aimed to critically examine the efficacy and oncological safety of NOM and LE compared to those of standard TME in rectal cancer patients after neoadjuvant CRT. Both the pros and cons of these approaches were strictly analyzed, providing a comprehensive and critical overview of these novel management strategies for rectal cancer.

Clinical Analysis of the Efficacy and Safety of Different Neoadjuvant Strategies in the Treatment of Locally Advanced Rectal Cancer

OBJECTIVE

In this study, we retrospectively analysed the efficacy and safety of three treatment models, namely, short-course radiotherapy sequential XELOX chemotherapy, neoadjuvant mFOLFOX6 concurrent radiotherapy and long-course concurrent radiotherapy with total mesorectal excision (TME) after treatment of locally advanced rectal cancer with high-risk factors.

METHODS

We collected clinical data on 177 patients with locally advanced rectal cancer (cT3-4 and/or cN+) who were treated at the Department of Abdominal Oncology of the Affiliated Cancer Hospital of Guizhou Medical University from December 2017 to December 2022. All patients were associated with 2-3 risk factors [T4b, N2, Extramural Vascular Invasion (EMVI), Mesorectal Fascia (MRF) positivity], positive lateral lymph nodes. Among them, there were 45 cases in the short course radiotherapy sequential XELOX chemotherapy group (RT + XELOX group); 64 cases in the neoadjuvant mFOLFOX6 concurrent radiotherapy group (mFOLFOX6 + CRT group); and 68 cases in the long course concurrent radiotherapy group (CRT group). The RT + XELOX group and mFOLFOX6 + CRT group completed radiotherapy and 4 cycles of neoadjuvant chemotherapy, respectively, and then rested for 1-2 weeks before TME surgery; the CRT group completed concurrent radiotherapy and then rested for 6-8 weeks before TME surgery.Adjuvant chemotherapy was conducted after surgery in each of the three groups: 2 cycles of adjuvant chemotherapy with XELOX regimen in the RT + XELOX group, 4-6 cycles of adjuvant chemotherapy with mFOLFOX6 in the mFOLFOX6 + CRT group, and 8-12 cycles of adjuvant chemotherapy with mFOLFOX6 in the CRT group.The pathological complete response rate (pCR rate), tumour downstage rate, tumour complete resection rate (R0 resection rate), local recurrence rate, distant metastasis rate, overall survival rate, incidence of adverse reactions, surgical complications and completion rate of perioperative systemic chemotherapy were compared among patients in the three groups of cases after TME.

RESULTS

The pCR rate (21.95% vs 17.24% vs 5.00%, p = 0.034) and and tumour downstage rate (78.05% vs 68.97% vs 53.33%, p = 0.029) were higher in the RT + XELOX group and mFOLFOX6 + CRT group compared to the CRT group. The RT + XELOX group had a lower 3-year distant metastasis rate (14.63% vs 36.67%, p = 0.048) and improved 3-year overall survival (76.57% vs 48.56%, p < 0.001) compared to the CRT group. There was no significant reduction in the 3-year distant metastasis rate in the mFOLFOX6 + CRT group versus the CRT group (27.59% vs 36.67%, p = 0.719), and the 3-year overall survival was similar (51.23% vs 48.56%, p = 0.35). Multi-logistic regression analysis and stratified analysis showed that patients in the RT + XELOX group and mFOLFOX6 + CRT group were more likely to achieve pCR than the CRT group (RT + XELOX group: OR 7.3, 95% CI [2.6-20.8], p < 0.001; mFOLFOX6 + CRT group OR 2.9, 95% CI [1.1-7.9], p = 0.036). The completion rates of perioperative systemic chemotherapy in the RT + XELOX, mFOLFOX6 + CRT, and CRT groups were 82.93% vs. 84.48% vs. 61.67% (χ2=9.95, p = 0.007), respectively. And there were significant differences in grade 3-4 leukopenia and thrombocytopenia (incidence of leukopenia: 15.50% vs. 7.81% vs. 1.47%, p = 0.045; incidence of thrombocytopenia: 13.33% vs 7.81% vs 1.47%, p = 0.027). There was no significant difference in the incidence of intraoperative and postoperative complications among the three groups (p > 0.05).

CONCLUSIONS

RT + XELOX group and mFOLFOX6 + CRT group significantly improved the near-term outcome (e.g., pCR rate) in patients with locally advanced rectal cancer with high-risk factors compared with CRT group. The RT + XELOX group also reduced the 3-year distant metastasis rate, increased the 3-year overall survival rate, and did not increase the incidence of perioperative surgical complications. It provides an effective means for the comprehensive treatment of locally advanced rectal cancer and has important clinical guidance and application value.

Rectal Sparing Approach after preoperative Radio- and/or Chemo-therapy (ReSARCh): a prospective, multicenter, observational study

BACKGROUND

Rectal-sparing approaches for patients with rectal cancer who achieved a complete or major response following neoadjuvant therapy constitute a paradigm of a potential shift in the management of patients with rectal cancer; however, their role remains controversial. The aim of this study was to investigate the feasibility of rectal-sparing approaches to preserve the rectum without impairing the outcomes.

METHODS

This prospective, multicenter, observational study investigated the outcomes of patients with clinical stage II-III mid-low rectal adenocarcinoma treated with any neoadjuvant therapy, and either transanal local excision or watch-and-wait approach, based on tumor response (major or complete) and patient/surgeon choice. The primary endpoint of the study was rectum preservation at a minimum follow-up of 2 years. Secondary endpoints were overall, disease-free, local and distant recurrence-free, and stoma-free survival at 3 years.

RESULTS

Of the 178 patients enrolled in 16 centers, 112 (62.9%) were managed with local excision and 66 (37.1%) with watch-and-wait. At a median (interquartile range) follow-up of 36.1 (30.6-45.6) months, the rectum was preserved in 144 (80.9%) patients. The 3-year rectum-sparing, overall survival, disease-free survival, local recurrence-free survival, and distant recurrence-free survival was 80.6% (95% CI 73.9-85.8), 97.6% (95% CI 93.6-99.1), 90.0% (95% CI 84.3-93.7), 94.7% (95% CI 90.1-97.2), and 94.6% (95% CI 89.9-97.2), respectively. The 3-year stoma-free survival was 95.0% (95% CI 89.5-97.6). The 3-year regrowth-free survival in the watch-and-wait group was 71.8% (95% CI 59.9-81.2).

CONCLUSIONS

In rectal cancer patients with major or complete clinical response after neoadjuvant therapy, the rectum can be preserved in about 80% of cases, without compromising the outcomes.

Tumor Vessel Normalization via PFKFB3 Inhibition Alleviates Hypoxia and Increases Tumor Necrosis in Rectal Cancer upon Radiotherapy

Treatment of patients with locally advanced rectal cancer (RC) is based on neoadjuvant chemoradiotherapy followed by surgery. In order to reduce the development of therapy resistance, it is necessary to further improve previous treatment approaches. Recent in vivo experimental studies suggested that the reduction of tumor hypoxia by tumor vessel normalization (TVN), through the inhibition of the glycolytic activator PFKFB3, could significantly improve tumor response to therapy. We have evaluated in vitro and in vivo the effects of the PFKFB3 inhibitor 2E-3-(3-pyridinyl)-1-(4-pyridinyl)-2-propen-1-one (3PO) on cell survival, clonogenicity, migration, invasion, and metabolism using colorectal cancer cells, patient-derived tumor organoid (PDO), and xenograft (PDX). 3PO treatment of colorectal cancer cells increased radiation-induced cell death and reduced cancer cell invasion. Moreover, gene set enrichment analysis shows that 3PO is able to alter the metabolic status of PDOs toward oxidative phosphorylation. Additionally, in vivo neoadjuvant treatment with 3PO induced TVN, alleviated tumor hypoxia, and increased tumor necrosis. Our results support PFKFB3 inhibition as a possible future neoadjuvant addition for patients with RC.

SIGNIFICANCE

Novel therapies to better treat colorectal cancer are necessary to improve patient outcomes. Therefore, in this study, we evaluated the combination of a metabolic inhibitor (3PO) and standard radiotherapy in different experimental settings. We have observed that the addition of 3PO increased radiation effects, ultimately improving tumor cell response to therapy.

Feasibility of a tailored operative strategy from organ preservation to pelvic exenteration for cT4 rectal cancer depending on neoadjuvant response

PURPOSE

Improvements in neoadjuvant therapy for locally advanced cT4 rectal cancer have led to improved tumour response and thus a variety of suitable management strategies. The aim of this study was to report management and outcomes of patients with cT4 rectal cancer undergoing a spectrum of treatment strategies from organ preservation (OP) to pelvic exenteration (PE).

METHODS

Patients who underwent elective treatment for cT4 rectal cancer between 2016 and 2021 were included. All patients were treated with curative intent. Surgical management was adapted to tumour response. Kaplan-Meier curves were generated to compare 3-year overall survival (3y-OS), local recurrence (3y-LR) and distant metastases (3y-DM) between different strategies.

RESULTS

Among 152 patients included, 13 (8%) underwent OP, 71 (47%) TME and 68 (45%) APR/PE. The median follow-up was 31.3 months. Patients undergoing OP had a lower tumour pretreatment (p < 0.001). Compared to patients with TME, those with APR/PE had a higher rate of ypT4 (p = 0.001) with a lower R0 rate (p = 0.044). The 3y-OS and 3y-DM were 78% and 15.1%, respectively, without significant differences. The 3y-LR was 6.6%, and patients with OP had a significantly worse 3y-local regrowth compared to 3y-LR in patients with TME and APR/PE (30.2% vs. 5.4% vs. 2%, p = 0.008).

CONCLUSION

cT4 tumours may be suitable for the full spectrum of rectal cancer management from organ preservation to pelvic exenteration depending on tumour response to neoadjuvant therapy. However, careful attention is required in OP as local regrowth in up to 30% of cases reinforces the need for sustained active surveillance in Watch&Wait programmes.

Outcomes associated with total neoadjuvant therapy with non-operative intent for rectal adenocarcinoma

Purpose/objectives

To evaluate rates of clinical complete response (cCR), surgery-free survival, permanent ostomy-free survival, and factors associated with these outcomes in patients treated with total neoadjuvant therapy (TNT) with intent for non-operative management of rectal adenocarcinoma.

Methods

A retrospective review was conducted of patients treated with TNT for stage II-IV rectal adenocarcinoma (n=45) at our institution between 2013 - 2022 with curative intent. All patients received radiation with concurrent capecitabine and additional chemotherapy, either prior to or following chemoradiation (CRT), with intent for non-operative management. Response rates were determined based on post-treatment MRI and endoscopy. Kaplan-Meier method was utilized to estimate the 1- and 2-year surgery- and permanent ostomy-free survivals. Cox regression was used to evaluate associations between surgery- and permanent ostomy-free survivals and various factors of interest, including patient and tumor characteristics and clinical response. Chi-squared analysis compared rates of cCR and surgery by sequence of TNT modality and cell count ratios.

Results

Of the 45 patients treated with TNT, most patients had low-lying rectal tumors with a median distance of 4.1 cm from the anal verge (range, 0.0 - 12.0). Overall, 64.4% (n=29) achieved cCR after TNT. 13 patients (28.9%) underwent surgical resection following TNT, 12 of whom had incomplete response and one who elected to undergo surgery after reaching cCR. At median follow up of 32.0 months (range, 7.1 - 86.1), 22.2% (n=10) of patients had a permanent colostomy, with only 2 of these completed for tumor regrowth after cCR. At one and two years, respectively, surgery-free survival was 77.3% and 66.2%, and permanent ostomy-free survival was 90.9% and 78.2%. Rates of cCR were higher in patients who received CRT first compared to those who received chemotherapy first (72.2% vs. 33.3%, p=0.029) and rates of surgery were also lower in patients who received CRT first compared to those who received chemotherapy first (19.4% vs. 66.7%, p=0.005). On Cox regression model, cCR on 6 month post-CRT endoscopy was associated with surgery-free survival (p=0.006) and permanent ostomy-free survival (p=0.033). Clinical response at earlier follow up points did not predict surgery- nor permanent ostomy-free survival.

Conclusion

These results support evidence that TNT may be a non-surgical option for select patients with rectal adenocarcinoma who desire organ preservation. In this investigation at a single institution, the treatment response on 6-month post-CRT endoscopy was the best predictor of surgery- and permanent ostomy-free survival, which are outcomes that are important to patient quality of life. CRT followed by consolidation chemotherapy was associated with higher rates of cCR and lower rates of surgery compared to those treated with induction chemotherapy.

Colorectal cancer

Despite decreased incidence rates in average-age onset patients in high-income economies, colorectal cancer is the third most diagnosed cancer in the world, with increasing rates in emerging economies. Furthermore, early onset colorectal cancer (age ≤50 years) is of increasing concern globally. Over the past decade, research advances have increased biological knowledge, treatment options, and overall survival rates. The increase in life expectancy is attributed to an increase in effective systemic therapy, improved treatment selection, and expanded locoregional surgical options. Ongoing developments are focused on the role of sphincter preservation, precision oncology for molecular alterations, use of circulating tumour DNA, analysis of the gut microbiome, as well as the role of locoregional strategies for colorectal cancer liver metastases. This overview is to provide a general multidisciplinary perspective of clinical advances in colorectal cancer.