Low rectal cancer: impact of radiation and chemotherapy on surgical treatment

Does complete pathological response increase perioperative morbidity risk in rectal cancer?

AIM

The optimal management of patients with clinical complete response after neoadjuvant treatment for rectal cancer is controversial. The aim of this study is to compare the morbidity between patients with locally advanced rectal cancer who have had a pathological complete response (pCR) or not after neoadjuvant chemoradiotherapy (NCRT) and total mesorectal excision (TME). The study hypothesis was that pCR may impact the surgical complication rate.

METHOD

A retrospective cohort study was conducted of a prospectively maintained database in Australia and New Zealand, the Binational Colorectal Cancer Audit, that identified patients with locally advanced rectal cancer (<15 cm from anal verge) from 1 January 2007 to 31 December 2019. Patients were included if they had locally advanced rectal cancer and had undergone NCRT and proceeded to surgical resection.

RESULTS

There were 4584 patients who satisfied the inclusion criteria, 65% being male. The mean age was 63 years and 11% had a pCR (ypT0N0). TME with anastomosis was performed in 67.8% of patients, and the majority of the cohort received long-course radiotherapy (81.7%). Both major and minor complications were higher in the TME without anastomosis group (17.3% vs. 14.7% and 30.6% vs. 20.8%, respectively), and the 30-day mortality was 1.31%. In the TME with anastomosis group, pCR did not contribute to higher rates of surgical complications, but male gender (p < 0.0012), age (p < 0.0001), preoperative N stage (p = 0.0092) and American Society of Anesthesologists (ASA) score ≥3 (p < 0.0002) did. In addition, pCR had no significant effect (p = 0.44) but male gender (p = 0.0047) and interval to surgery (p = 0.015) contributed to higher rates of anastomotic leak. In the TME without anastomosis cohort, the only variable that contributed to higher rates of complications was ASA score ≥3 (p = 0.033).

CONCLUSION

Patients undergoing TME dissection for rectal cancer following NCRT showed no difference in complications whether they had achieved pCR or not.

Outcomes of rectal cancer patients who refuse surgery after incomplete clinical response to neoadjuvant therapy

BACKGROUND AND OBJECTIVES

Total mesorectal excision (TME) remains the standard of care for patients with rectal cancer who have an incomplete response to total neoadjuvant therapy (TNT). A minority of patients will refuse curative intent resection. The aim of this study is to examine the outcomes for these patients.

METHODS

A retrospective cohort study of stage 1-3 rectal adenocarcinoma patients who underwent neoadjuvant chemoradiation therapy or TNT at a single institution. Patients either underwent TME, watch-and-wait protocol, or if they refused TME, were counseled and watched (RCW). Clinical outcomes and resource utilization were examined in each group.

RESULTS

One hundred seventy-one patients (Male 59%) were included with a median surveillance of 43 months. Twenty-nine patients (17%) refused TME and had shortened overall survival (OS). Twelve patients who refused TME converted to a complete clinical response (cCR) on subsequent staging with a prolonged OS. 92% of these patients had a near cCR at initial staging endoscopy. Increased physician visits and testing was utilized in RCW and WW groups.

CONCLUSION

A significant portion of patients convert to cCR and have prolonged OS. Lengthening the time to declare cCR may be considered in select patients, such as those with a near cCR at initial endoscopic staging.

The Predictors of Complete Pathologic Response in Rectal Cancer during the Total Neoadjuvant Therapy Era: A Systematic Review

The modern rectal cancer treatment paradigm offers additional opportunities for organ preservation, most notably via total neoadjuvant therapy (TNT) and consideration for a watch-and-wait (WW) surveillance-only approach. A major barrier to widespread implementation of a WW approach to rectal cancer is the potential discordance between a clinical complete response (cCR) and a pathologic complete response (pCR). In the pre-TNT era, the identification of predictors of pCR after neoadjuvant therapy had been previously studied. However, the last meta-analysis to assess the summative evidence on this important treatment decision point predates the acceptance and dissemination of TNT strategies. The purpose of this systematic review was to assess preoperative predictors of pCR after TNT to guide the ideal selection criteria for WW in the current era. An exhaustive literature review was performed and the electronic databases Embase, Ovid, MEDLINE, PubMed, and Cochrane were comprehensively searched up to 27 June 2023. Search terms and their combinations included "rectal neoplasms", "total neoadjuvant therapy", and "pathologic complete response". Only studies in English were included. Randomized clinical trials or prospective/retrospective cohort studies of patients with clinical stage 2 or 3 rectal adenocarcinoma who underwent at least 8 weeks of neoadjuvant chemotherapy in addition to chemoradiotherapy with pCR as a measured study outcome were included. In this systematic review, nine studies were reviewed for characteristics positively or negatively associated with pCR or tumor response after TNT. The results were qualitatively grouped into four categories: (1) biochemical factors; (2) clinical factors; (3) patient demographics; and (4) treatment sequence for TNT. The heterogeneity of studies precluded meta-analysis. The level of evidence was low to very low. There is minimal data to support any clinicopathologic factors that either have a negative or positive relationship to pCR and tumor response after TNT. Additional data from long-term trials using TNT is critical to better inform those considering WW approaches following a cCR.

Sense and non-sense of imaging in the era of organ preservation for rectal cancer

This review summarizes the current applications and benefits of imaging modalities for organ preservation in the treatment of rectal cancer. The concept of organ preservation in the treatment of rectal cancer has revolutionized the way rectal cancer is managed. Initially, organ preservation was limited to patients with locally advanced rectal cancer who needed neoadjuvant therapy to reduce tumor size before surgery and achieved complete response. However, neoadjuvant therapy is now increasingly utilized for smaller and less aggressive tumors to achieve primary organ preservation. Additionally, more intensive neoadjuvant strategies are employed to improve complete response rates and increase the chances of successful organ preservation. The selection of patients for organ preservation is a critical component of treatment, and imaging techniques such as digital rectal exam, endoscopy, and MRI are commonly used for this purpose. In this review, we provide an overview of what imaging modalities should be chosen and how they can aid in the selection and follow-up of patients undergoing organ-preserving strategies.

"Long-term oncologic outcomes and risk factors for distant recurrence after pathologic complete response following neoadjuvant treatment for locally advanced rectal cancer. A nationwide, multicentre study"

BACKGROUND

Pathologic complete response (pCR) after multimodal treatment for locally advanced rectal cancer (LARC) is used as surrogate marker of success as it is assumed to correlate with improved oncologic outcome. However, long-term oncologic data are scarce.

METHODS

This retrospective, multicentre study updated the oncologic follow-up of prospectively collected data from the Spanish Rectal Cancer Project database. pCR was described as no evidence of tumour cells in the specimen. Endpoints were distant metastases-free survival (DMFS) and overall survival (OS). Multivariate regression analyses were run to identify factors associated with survival.

RESULTS

Overall, 32 different hospitals were involved, providing data on 815 patients with pCR. At a median follow-up of 73.4 (IQR 57.7-99.5) months, distant metastases occurred in 6.4% of patients. Abdominoperineal excision (APE) (HR 2.2, 95%CI 1.2-4.1, p = 0.008) and elevated CEA levels (HR = 1.9, 95% CI 1.0-3.7, p = 0.049) were independent risk factors for distant recurrence. Age (years) (HR 1.1; 95%-CI 1.05-41.09; p < 0.001) and ASA III-IV (HR = 2.0; 95%-CI 1.4-2.9; p < 0.001), were the only factors associated with OS. The estimated 12, 36 and 60-months DMFS rates were 96.9%, 91.3%, and 86.8%. The estimated 12, 36 and 60-months OS rates were 99.1%, 94.9% and 89.3%.

CONCLUSIONS

The incidence of metachronous distant metastases is low after pCR, with high rates of both DMFS and OS. The oncologic prognosis in LARC patients that achieve pCR after neoadjuvant chemo-radiotherapy is excellent in the long term.

Shear wave elastography can stratify rectal cancer response to short-course radiation therapy

Rectal cancer is a deadly disease typically treated using neoadjuvant chemoradiotherapy followed by total mesorectal excision surgery. To reduce the occurrence of mesorectal excision surgery for patients whose tumors regress from the neoadjuvant therapy alone, conventional imaging, such as computed tomography (CT) or magnetic resonance imaging (MRI), is used to assess tumor response to neoadjuvant therapy before surgery. In this work, we hypothesize that shear wave elastography offers valuable insights into tumor response to short-course radiation therapy (SCRT)-information that could help distinguish radiation-responsive from radiation-non-responsive tumors and shed light on changes in the tumor microenvironment that may affect radiation response. To test this hypothesis, we performed elastographic imaging on murine rectal tumors (n = 32) on days 6, 10, 12, 16, 18, 20, 23, and 25 post-tumor cell injection. The study revealed that radiation-responsive and non-radiation-responsive tumors had different mechanical properties. Specifically, radiation-non-responsive tumors showed significantly higher shear wave speed SWS (p < 0.01) than radiation-responsive tumors 11 days after SCRT. Furthermore, there was a significant difference in shear wave attenuation (SWA) (p < 0.01) in radiation-non-responsive tumors 16 days after SCRT compared to SWA measured just one day after SCRT. These results demonstrate the potential of shear wave elastography to provide valuable insights into tumor response to SCRT and aid in exploring the underlying biology that drives tumors' responses to radiation.

The Role of Probe-Based Confocal Laser Endomicroscopy (pCLE) in the Diagnosis of Sustained Clinical Complete Response Under Watch-and-Wait Strategy After Neoadjuvant Chemoradiotherapy for Locally Advanced Rectal Adenocarcinoma: a Score Validation

BACKGROUND

Watch-and-wait strategy has been increasingly accepted for patients with clinical complete response (cCR) after multimodal treatment for locally advanced rectal adenocarcinoma. Close follow-up is essential to the early detection of local regrowth. It was previously demonstrated that probe-based confocal laser endomicroscopy (pCLE) scoring using the combination of epithelial and vascular features might improve the diagnostic accuracy of cCR.

AIM

To validate the pCLE scoring system in the assessment of patients with cCR after neoadjuvant chemoradiotherapy (nCRxt) for advanced rectal adenocarcinoma.

METHODS

Digital rectal examination, pelvic magnetic resonance imaging (MRI), and pCLE were performed in 43 patients with cCR, who presented either a scar (N = 33; 76.7%) or a small ulcer with no signs of tumor, and/or biopsy negative for malignancy (N = 10; 23.3%).

RESULTS

Twenty-five (58.1%) patients were men, and the mean age was 58.4 years. During the follow-up, 12/43 (27.9%) patients presented local regrowth and underwent salvage surgery. There was an association between pCLE diagnostic scoring and final histological report (for patients who underwent surgical resection) or final diagnosis at the latest follow-up (p = 0.0001), while this association was not observed with MRI (p = 0.49). pCLE sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66.7%, 93.5%, 80%, 88.9%, and 86%, respectively. MRI sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 66.7%, 48.4%, 66.7%, 78.9%, and 53.5%, respectively.

CONCLUSIONS

pCLE scoring system based on epithelial and vascular features improved the diagnosis of sustained cCR and might be recommended during follow-up. pCLE might add some valuable contribution for identifying local regrowth. Trial Registration This protocol was registered at the Clinical Trials (ClinicalTrials.gov identifier NCT02284802).

Rectal Cancer Tissue Lipidome Differs According to Response to Neoadjuvant Therapy

Rectal cancer (RC) is a gastrointestinal cancer with a poor prognosis. While some studies have shown metabolic reprogramming to be linked to RC development, it is difficult to define biomolecules, like lipids, that help to understand cancer progression and response to therapy. The present study investigated the relative lipid abundance in tumoral tissue associated with neoadjuvant therapy response using untargeted liquid chromatography-mass spectrometry lipidomics. Locally advanced rectal cancer (LARC) patients (n = 13), clinically staged as T3-4 were biopsied before neoadjuvant chemoradiotherapy (nCRT). Tissue samples collected before nCRT (staging) and afterwards (restaging) were analyzed to discover lipidomic differences in RC cancerous tissue from Responders (n = 7) and Non-responders (n = 6) to nCRT. The limma method was used to test differences between groups and to select relevant feature lipids from tissue samples. Simple glycosphingolipids and differences in some residues of glycerophospholipids were more abundant in the Non-responder group before and after nCRT. Oxidized glycerophospholipids were more abundant in samples of Non-responders, especially those collected after nCRT. This work identified potential lipids in tissue samples that take part in, or may explain, nCRT failure. These results could potentially provide a lipid-based explanation for nCRT response and also help in understanding the molecular basis of RC and nCRT effects on the tissue matrix.

Watch and Wait Approach for Rectal Cancer

The administration of neoadjuvant chemoradiotherapy (nCRT) followed by total mesorrectal excision (TME) and selective use of adjuvant chemotherapy can still be considered the standard of care in locally advanced rectal cancer (LARC). However, avoiding sequelae of TME and entering a narrow follow-up program of watch and wait (W&W), in select cases that achieve a comparable clinical complete response (cCR) to nCRT, is now very attractive to both patients and clinicians. Many advances based on well-designed studies and long-term data coming from big multicenter cohorts have drawn some important conclusions and warnings regarding this strategy. In order to safely implement W&W, it is important consider proper selection of cases, best treatment options, surveillance strategy and the attitudes towards near complete responses or even tumor regrowth. The present review offers a comprehensive overview of W&W strategy from its origins to the most current literature, from a practical point of view focused on daily clinical practice, without losing sight of the most important future prospects in this area.

Rectal Cancer: Clinical and Molecular Predictors of a Complete Response to Total Neoadjuvant Therapy

BACKGROUND

Total neoadjuvant therapy in rectal cancer may increase pathological complete response rates, potentially allowing for a nonoperative approach.

OBJECTIVE

The objective of this study was to identify patient and tumor characteristics that predict a complete response following total neoadjuvant therapy.

DESIGN

This was a retrospective cohort study.

SETTINGS

This study was conducted at a university-based National Cancer Institute-designated Comprehensive Cancer Center.

PATIENTS

The patients include those with stage 2 or 3 rectal adenocarcinoma.

INTERVENTIONS

Interventions included total neoadjuvant therapy, total mesorectal excision, and nonoperative management.

MAIN OUTCOME MEASURES

Complete response was defined as either patients with a clinical complete response undergoing nonoperative management who remained cancer-free or patients undergoing surgery with a pathological complete response.

RESULTS

Among 102 patients, median age was 54 years, 69% were male, median carcinoembryonic antigen level was 3.0 ng/mL, and the median distance of the tumor above the anorectal ring was 3 cm. Thirty-eight (37%) patients had a complete response, including 15 of 18 (83%) nonoperative patients who remained cancer free at a median of 22 months (range, 7-48 months) and 23 of 84 (27%) patients who underwent surgery and had a pathological complete response. The incomplete response group consisted of 61 patients who underwent initial surgery and 3 nonoperative patients with regrowth. There were no differences in gender, T-stage, or tumor location between groups. Younger age (median, 49 vs 55 years), normal carcinoembryonic antigen (71% vs 41%), clinical node-negative (24% vs 9%), smaller tumors (median 3.9 vs 5.4 cm), and wild-type p53 (79% vs 47%) and SMAD4 (100% vs 81%) were more likely to have a complete response (all p < 0.05).

LIMITATIONS

This was a retrospective study with a small sample size.

CONCLUSIONS

In patients with rectal cancer treated with total neoadjuvant therapy, more than one-third will achieve a pathological complete response or sustained clinical complete response with nonoperative management, making oncological resection superfluous in these patients. Smaller, wild-type p53 and SMAD4, and clinically node-negative cancers are predictive features of a complete response. See Video Abstract at http://links.lww.com/DCR/B889 .

CNCER DE RECTO PREDICTORES CLNICOS Y MOLECULARES DE UNA RESPUESTA COMPLETA A LA TERAPIA NEOADYUVANTE TOTAL

ANTECEDENTES:La terapia neoadyuvante total en el cáncer de recto puede aumentar las tasas de respuesta patológica completa y permitir potencialmente un enfoque no quirúrgico.OBJETIVO:El objetivo fue identificar las características tanto del paciente y del tumor que logren predecir una respuesta completa después de la terapia neoadyuvante total.DISEÑO:Este fue un estudio de cohorte retrospectivo.AJUSTES:Este estudio se realizó en un Centro Integral de Cáncer designado por el Instituto Nacional del Cáncer con sede universitaria.PACIENTES:Los pacientes incluyen aquellos con adenocarcinoma de recto en estadio 2 o 3.INTERVENCIONES:Terapia neoadyuvante total, escisión total del mesorrecto, manejo conservador no quirúrgico.PRINCIPALES MEDIDAS DE RESULTADO:La respuesta completa se definió como pacientes con una respuesta clínica completa sometidos a tratamiento no quirúrgico que permanecieron libres de cáncer o pacientes sometidos a cirugía con una respuesta patológica completa.RESULTADOS:Entre 102 pacientes, la mediana de edad fue de 54 años, el 69% fueron hombres, la mediana del nivel de antígeno carcinoembrionario fue de 3.0 ng/ml y la mediana de la distancia del tumor por encima del anillo anorrectal fue de 3 cm. Thirty-eight (37%) pacientes tuvieron una respuesta completa que incluyó a 15 de 18 (83%) pacientes con manejo no operatorio y que permanecieron libres de cáncer en una mediana de 22 meses (rango 7- 48 meses) y 23 de 84 (27%) pacientes que fueron sometidos a cirugía y tuvieron una respuesta patológica completa. El grupo de respuesta incompleta consistió en 61 pacientes que fueron sometidos inicialmente a cirugía y 3 pacientes no quirúrgicos con recrecimiento. No se encontró diferencias de género, estadio T o ubicación del tumor entre los grupos. Edad más joven (mediana 49 frente a 55), antígeno carcinoembrionario normal (71% frente a 41%), ganglios clínicos negativos (24% frente a 9%), tumores más pequeños (mediana de 3,9 frente a 5,4 cm) y p53 de tipo salvaje (79 % vs 47%) y SMAD4 (100% vs 81%) tenían más probabilidades de tener una respuesta completa (todos p < 0,05).LIMITACIONES:Este fue un estudio retrospectivo y con un tamaño de muestra pequeño.CONCLUSIONES:En pacientes con cáncer de recto tratados con terapia neoadyuvante total, más de un tercio logrará una respuesta patológica completa o una respuesta clínica completa sostenida con manejo no operatorio, logrando que la resección oncológica sea superflua en estos pacientes. Los cánceres más pequeños, clínicamente con ganglios negativos, con p53 de tipo salvaje y SMAD4, son características predictoras de una respuesta completa. Consulte Video Resumen en http://links.lww.com/DCR/B889 . (Traducción-Dr. Osvaldo Gauto ).

The Risk of Distant Metastases in Patients With Clinical Complete Response Managed by Watch and Wait After Neoadjuvant Therapy for Rectal Cancer: The Influence of Local Regrowth in the International Watch and Wait Database

BACKGROUND

Nearly 30% of patients with rectal cancer develop local regrowth after initial clinical complete response managed by watch and wait. These patients might be at higher risk for distant metastases.

OBJECTIVE

This study aimed to investigate risk factors for distant metastases using time-dependent analyses.

DESIGN

Data from an international watch and wait database were retrospectively reviewed. Cox regression analysis was used to determine risk factors for worse distant metastases-free survival. Conditional survival modeling was used to investigate the impact of risk factors on the development of distant metastases.

SETTING

Retrospective, multicenter database.

PATIENTS

A total of 793 patients (47 institutions) with rectal cancer and clinical complete response to neoadjuvant treatment from the International Watch & Wait Database were included.

MAIN OUTCOME MEASURES

Distant metastases-free survival.

RESULTS

Of the 793 patients managed with watch and wait (median follow-up 55.2 mo)' 85 patients (10.7%) had distant metastases. Fifty-one of 85 patients (60%) had local regrowth at any time. Local regrowth was an independent factor associated with worse distant metastases-free survival in the multivariable model. Using conditional estimates, patients with local regrowth without distant metastases for 5 years (from decision to watch and wait) remained at higher risk for development of distant metastases for 1 subsequent year compared to patients without local regrowth (5-year conditional distant metastases-free survival 94.9% vs 98.4%).

LIMITATIONS

Lack of information on adjuvant chemotherapy, salvage surgery for local regrowth, and heterogeneity of individual surveillance/follow-up strategies used may have affected results.

CONCLUSIONS

In patients with clinical complete response managed by watch and wait, development of local regrowth at any time is a risk factor for distant metastases. The risk of distant metastases remains higher for 5 years after development of local regrowth. See Video Abstract at http://links.lww.com/DCR/C53.

EL RIESGO DE METSTASIS A DISTANCIA EN PACIENTES CON RESPUESTA CLNICA COMPLETA MANEJADA POR WATCH AND WAIT DESPUS DE LA TERAPIA NEOADYUVANTE PARA EL CNCER DE RECTO LA INFLUENCIA DEL NUEVO CRECIMIENTO LOCAL EN LA BASE DE DATOS INTERNACIONAL WATCH AND WAIT

ANTECEDENTES:Casi el 30 % de los pacientes con cáncer de recto desarrollan un nuevo crecimiento local después de la respuesta clínica completa inicial manejada por watch and wait. Estos pacientes podrían tener un mayor riesgo de metástasis a distancia.OBJETIVO:Investigar los factores de riesgo de metástasis a distancia mediante análisis dependientes del tiempo.DISEÑO:Se revisó retrospectivamente los datos de la base de datos internacional de Watch and Wait. Se utilizó el análisis de regresión de Cox para determinar los factores de riesgo de peor sobrevida libre de metástasis a distancia. Se utilizó un modelo de sobrevida condicional para investigar el impacto de los factores de riesgo en el desarrollo de metástasis a distancia. El tiempo transcurrido hasta el evento se calculó utilizando la fecha de decisión para watch and wait y la fecha del nuevo crecimiento local para el diagnóstico de metástasis a distancia.ESCENARIOBase de datos multicéntrica retrospectiva.PACIENTES:Se incluyeron un total de 793 pacientes (47 instituciones) con cáncer de recto y respuesta clínica completa al tratamiento neoadyuvante de la base de datos internacional de Watch and Wait.PRINCIPALES MEDIDAS DE RESULTADO:Desarrollo de metástasis a distancia.RESULTADOS:De los 793 pacientes tratados con watch and wait (mediana de seguimiento de 55,2 meses), 85 (10,7%) tenían metástasis a distancia. 51 de 85 (60%) tuvieron recrecimiento local en algún momento. El recrecimiento local fue un factor independiente asociado a una peor supervivencia libre de metástasis a distancia en el modelo multivariable. Además, al usar estimaciones condicionales, los pacientes con recrecimiento local sin metástasis a distancia durante 5 años (desde la decisión de watch and wait) permanecieron en mayor riesgo de desarrollar metástasis a distancia durante un año subsiguiente en comparación con los pacientes sin recrecimiento local (sobrevida libre de metástasis a distancia a 5 años: recrecimiento local 94,9% frente a no recrecimiento local 98,4%).LIMITACIONES:La falta de información relacionada con el uso de quimioterapia adyuvante, las características específicas de la cirugía de rescate para el nuevo crecimient o local y la heterogeneidad de las estrategias individuales de vigilancia/seguimiento utilizadas pueden haber afectado los resultados observados.CONCLUSIONES:En pacientes con respuesta clínica completa manejados por Watch and Wait, el desarrollo de recrecimiento local en cualquier momento es un factor de riesgo para metástasis a distancia. El riesgo de metástasis a distancia sigue siendo mayor durante 5 años después del desarrollo de un nuevo crecimiento local. Consulte Video Resumen en http://links.lww.com/DCR/C53. (Traducción-Dr. Felipe Bellolio).

Structured and shared MRI staging lexicon and report of rectal cancer: A consensus proposal by the French Radiology Group (GRERCAR) and Surgical Group (GRECCAR) for rectal cancer

PURPOSE

To develop French guidelines by experts to standardize data acquisition, image interpretation, and reporting in rectal cancer staging with magnetic resonance imaging (MRI).

MATERIALS AND METHODS

Evidence-based data and opinions of experts of GRERCAR (Groupe de REcherche en Radiologie sur le CAncer du Rectum [i.e., Rectal Cancer Imaging Research Group]) and GRECCAR (Groupe de REcherche en Chirurgie sur le CAncer du Rectum [i.e., Rectal Cancer Surgery Research Group]) were combined using the RAND-UCLA Appropriateness Method to attain consensus guidelines. Experts scoring of reporting template and protocol for data acquisition were collected; responses were analyzed and classified as "Recommended" versus "Not recommended" (when ≥ 80% consensus among experts) or uncertain (when < 80% consensus among experts).

RESULTS

Consensus regarding patient preparation, MRI sequences, staging and reporting was attained using the RAND-UCLA Appropriateness Method. A consensus was reached for each reporting template item among the experts. Tailored MRI protocol and standardized report were proposed.

CONCLUSION

These consensus recommendations should be used as a guide for rectal cancer staging with MRI.

Outcomes of Patients With Local Regrowth After Nonoperative Management of Rectal Cancer After Neoadjuvant Chemoradiotherapy

BACKGROUND

Clinical complete responders after chemoradiation for rectal cancer are increasingly being managed by a watch-and-wait strategy. Nonetheless, a significant proportion will experience a local regrowth, and the long-term oncological outcomes of these patients is not totally known.

OBJECTIVE

The purpose of this study was to analyze the outcomes of patients who submitted to a watch-and-wait strategy and developed a local regrowth, and to compare these results with sustained complete clinical responders.

DESIGN

This was a retrospective study.

SETTING

Single institution, tertiary cancer center involved in alternatives to organ preservation.

PATIENTS

Patients with a biopsy-proven rectal adenocarcinoma (stage II/III or low lying cT2N0M0 at risk for an abdominoperineal resection) treated with chemoradiation who were found at restage to have a clinical complete response.

INTERVENTIONS

Rectal cancer patients treated with chemoradiation who underwent a watch-and-wait strategy (without a full thickness local excision) and developed a local regrowth were compared to the remaining patients of the watch-and-wait strategy.

MAIN OUTCOME MEASURES

Overall survival between groups, incidence of regrowth' and results of salvage surgery.

RESULTS

There were 67 patients. Local regrowth occurred in 20 (29.9%) patients treated with a watch-and-wait strategy. Mean follow-up was 62.7 months. Regrowth occurred at mean 14.2 months after chemoradiation, half of them within the first 12 months. Patients presented with comparable initial staging, lateral pelvic lymph-node metastasis, and extramural venous invasion. The regrowth group had a statistically nonsignificant higher incidence of mesorectal fascia involvement (35.0% vs 13.3%, p = 0.089). All regrowths underwent salvage surgery, mostly (75%) a sphincter-sparing procedure. 5-year overall survival was 71.1% in patients with regrowth and 91.1% in patients with a sustained complete clinical response (p = 0.027).

LIMITATIONS

This study was limited by its retrospective evaluation of patient selection for a watch-and-wait strategy and outcomes, as well as its small sample size.

CONCLUSIONS

Local regrowth is a frequent event when following a watch-and-wait policy (29.9%); however, patients could undergo salvage surgical treatment with adequate pelvic control. In this series, overall survival showed a statistically significant difference from patients managed with a watch-and-wait strategy who experienced a local regrowth compared to those who did not. See Video Abstract at http://links.lww.com/DCR/B773.RESULTADOS DE LOS PACIENTES CON REBROTE LOCAL, DESPUÉS DEL MANEJO NO QUIRÚRGICO DEL CÁNCER DE RECTO, DESPUÉS DE LA QUIMIORRADIOTERAPIA NEOADYUVANTEANTECEDENTES:Los respondedores clínicos completos, después de la quimiorradiación para el cáncer de recto, se tratan cada vez más mediante una estrategia de observación y espera. No obstante, una proporción significativa experimentará un rebrote local y los resultados oncológicos a largo plazo de estos pacientes, no se conocen por completo.OBJETIVO:El propósito de este estudio, fue analizar los resultados de los pacientes sometidos a una estrategia de observación y espera, que desarrollaron un rebrote local, y comparar estos resultados con respondedores clínicos completos sostenidos.DISEÑO:Este fue un estudio retrospectivo.ENTORNO CLINICO.Institución única, centro oncológico terciario involucrado en alternativas a la preservación de órganos.PACIENTES:Pacientes con un adenocarcinoma de recto comprobado por biopsia (estadio II / III o posición baja cT2N0M0, en riesgo de resección abdominoperineal), tratados con quimiorradiación, y que durante un reestadiaje, presentaron una respuesta clínica completa.INTERVENCIONES:Los pacientes con cáncer de recto tratados con quimiorradiación, sometidos a una estrategia de observación y espera (sin una escisión local de espesor total) y que desarrollaron un rebrote local, se compararon con los pacientes restantes de la estrategia de observación y espera.PRINCIPALES MEDIDAS DE VALORACION:Supervivencia global entre los grupos, incidencia de rebrote y resultados de la cirugía de rescate.RESULTADOS:Fueron 67 pacientes. El rebrote local ocurrió en 20 (29,9%) pacientes tratados con una estrategia de observación y espera. El seguimiento medio fue de 62,7 meses. El rebrote se produjo a la media de 14,2 meses después de la quimiorradiación, la mitad de ellos dentro de los primeros 12 meses. Los pacientes se presentaron con una estadificación inicial comparable, metástasis en los ganglios linfáticos pélvicos laterales e invasión venosa extramural. El grupo de rebrote tuvo una mayor incidencia estadísticamente no significativa de afectación de la fascia mesorrectal (35,0 vs 13,3%, p = 0,089). Todos los rebrotes se sometieron a cirugía de rescate, en su mayoría (75%) con procedimiento de preservación del esfínter. La supervivencia global a 5 años fue del 71,1% en pacientes con rebrote y del 91,1% en pacientes con una respuesta clínica completa sostenida (p = 0,027).LIMITACIONES:Evaluación retrospectiva de la selección de pacientes para una estrategia y resultados de observar y esperar, tamaño de muestra pequeño.CONCLUSIONES:El rebrote local es un evento frecuente después de la política de observación y espera (29,9%), sin embargo los pacientes podrían someterse a un tratamiento quirúrgico de rescate con un adecuado control pélvico. En esta serie, la supervivencia global mostró una diferencia estadísticamente significativa de los pacientes manejados con una estrategia de observación y espera que experimentaron un rebrote local, en comparación con los que no lo hicieron. Consulte Video Resumen en http://links.lww.com/DCR/B773. (Traducción-Dr. Fidel Ruiz Healy).

Rectal Sparing Approach After Neoadjuvant Therapy in Patients with Rectal Cancer: The Preliminary Results of the ReSARCh Trial

BACKGROUND

Rectum-preservation for locally advanced rectal cancer has been proposed as an alternative to total mesorectal excision (TME) in patients with major (mCR) or complete clinical response (cCR) after neoadjuvant therapy. The purpose of this study was to report on the short-term outcomes of ReSARCh (Rectal Sparing Approach after preoperative Radio- and/or Chemotherapy) trial, which is a prospective, multicenter, observational trial that investigated the role of transanal local excision (LE) and watch-and-wait (WW) as integrated approaches after neoadjuvant therapy for rectal cancer.

METHODS

Patients with mid-low rectal cancer who achieved mCR or cCR after neoadjuvant therapy and were fit for major surgery were enrolled. Clinical response was evaluated at 8 and 12 weeks after completion of chemoradiotherapy. Treatment approach, incidence, and reasons for subsequent TME were recorded.

RESULTS

From 2016 to 2019, 160 patients were enrolled; mCR or cCR at 12 weeks was achieved in 64 and 96 of patients, respectively. Overall, 98 patients were managed with LE and 62 with WW. In the LE group, Clavien-Dindo 3+ complications occurred in three patients. The rate of cCR increased from 8- to 12-week restaging. Thirty-three (94.3%) of 35 patients with cCR had ypT0-1 tumor. At a median 24 months follow-up, a tumor regrowth was found in 15 (24.2%) patients undergoing WW.

CONCLUSIONS

LE for patients achieving cCR or mCR is safe. A 12-week interval from chemoradiotherapy completion to LE is correlated with an increased cCR rate. The risk of ypT > is reduced when LE is performed after cCR.

Biomarkers in Locally Advanced Rectal Cancer: A Review

Locally advanced rectal cancers (LARC) are the subject of a rapidly evolving treatment paradigm. The critical timepoints where management decisions are required during the care of the LARC patient are: prior to the institution of any treatment, post neoadjuvant therapy and post-surgery. This article reviews the clinical, imaging, blood-based, tissue-based, and molecular biomarkers that can assist clinicians at these timepoints in the patient's management, in prognosticating for their LARC patients or in predicting responses to therapy in the multi-modality neoadjuvant treatment era.

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.

Clinical outcome of neoadjuvant chemoradiation in rectal cancer treatment

To determine the clinical and pathological outcome of locally advanced rectal cancer patients treated with neoadjuvant chemoradiation (chemoradiotherapy [CRT]) followed by curative surgery and to identify predictive factors of pathological complete response (pCR).Locally advanced rectal cancer patients undergoing CRT followed by curative surgery from January 2012 to December 2017 were included. Patient's demographic data, pretreatment tumor characteristics, type of CRT regimens, type of surgery, postoperative complications, pathological reports and follow up records were analyzed. Univariate and multivariate analyses were applied to identify predictive factors for pCR. Five-year disease free and overall survival were estimated by Kaplan-Meier method and compared between pCR and non-pCR groups.A total of 85 patients were analyzed. Eighteen patients (21.1%) achieved pCR. The sphincter-saving surgery rate was 57.6%. After univariate analyses, tumor length >4 cm (P = .007) and positive lymph nodes (P = .040) were significantly associated with decreased rate of pCR. Complete clinical response was significantly associated with higher rate of pCR (P = .015). Multivariate analyses demonstrated that tumor length >4 cm (P = .010) was significantly associated with decreased rate of pCR. After a median follow-up of 65 months (IQR 34-79), the calculated 5-year overall survival and disease-free survival rates were 81.4% and 69.7%, respectively. Patients who achieved pCR tend to had longer 5-year disease-free survival (P = .355) and overall survival (P = .361) than those who did not.Tumor length >4 cm was associated with decreased rate of pCR in locally advanced rectal cancer who had CRT followed by surgery. Longer waiting time or more intense adjuvant treatment may be considered to improved pCR and oncological outcomes.

ctDNA on liquid biopsy for predicting response and prognosis in locally advanced rectal cancer: A systematic review

BACKGROUND

The management of locally advanced rectal cancer (LARC) requires a multidisciplinary approach, with an increasing interest for non-operative strategies. Liquid biopsy for obtaining circulating tumor DNA (ctDNA) can provide information on neoadjuvant chemoradiotherapy (nCRT) pathological response and cancer-specific prognosis, and therefore might be a promising guide for these treatments.

METHODS

A systematic review of the studies available in literature has been performed to assess the role of ctDNA as a predictive and prognostic biomarker in LARC patients.

RESULTS

We retrieved 21 publications, of which 17 full-text articles and 4 abstracts. Results have been labelled into two groups: predictive and prognostic. Data about the usefulness of liquid biopsy in this setting is still inconclusive. However, baseline higher levels of longer fragments of cell-free DNA and integrity index, tumor-specific mutations and certain methylated genes could predict non-responders. Also, undetectable baseline ctDNA and decrease of common rectal cancer mutations throughout treatment (dynamic monitoring) were predictive factors of pathological complete response. The continuous detection of ctDNA in different timepoints of treatment (minimal residual disease) was consistently associated with worse prognosis.

CONCLUSIONS

ctDNA is a promising biomarker that could assist predicting treatment response to nCRT and prognosis in patients with LARC. The ideal methods and timings for the liquid biopsy still have to be defined.

Long-term outcomes of transanal endoscopic microsurgery for clinical complete response after neoadjuvant treatment in T2-3 rectal cancer

BACKGROUND

Organ sparing by the transanal endoscopic microsurgery (TEM) procedure is a treatment for patients with locally advanced rectal cancer after chemoradiotherapy (CRT) and complete clinical response (cCR).

AIMS

To assess the surgical and long-term oncological outcomes of TEM for the treatment in T2-3 rectal cancer after CRT and cCR.

METHODS

This study was a retrospective review of a prospective database of patients with rectal cancer who underwent TEM after CRT and cCR from April 2011 to March 2020.

RESULTS

52 patients underwent TEM during a period of 9 years. This group of patients included 27 females and 25 males. The median age was 62 (32-86) years, lesion size was 2.5 (1-4) cm, and lesion distance from the anal verge 7.3 (4-10) cm. Median operative time was 79.5 (25-120) min and hospital stay was 1 day (14 h-4 days). Morbidity rate was 13.5% and reoperation rate due to major complications was 3.8%. Final histological findings confirmed 34 (65.4%) patients with ypT0, 7 (13.5%), 6 (11.5%), and 5 (9.6%) patients with carcinoma ypT1, ypT2, and ypT3, respectively. After a median follow-up period of 86 (5-107) months, 1 (2.4%) patient had local recurrences and 3 (7.3%) distant metastases. The 5-year disease-free survival was 91.7% and 5-year overall survival 89.5%.

CONCLUSION

Our experience has shown significant rates of ypT0 and ypT1 associated with excellent long-term results. Performing TEM to treat T2-3N0 rectal cancer after CRT and cCR appears to be an oncologically safe and effective procedure.

Diagnosis of Clinical Complete Response by Probe-Based Confocal Laser Endomicroscopy (pCLE) After Chemoradiation for Advanced Rectal Cancer

BACKGROUND

Neoadjuvant chemoradiotherapy (nCRxt) followed by radical surgery is the optimal treatment for advanced rectal adenocarcinoma. Patients with clinical complete response (cCR) may be followed closely without immediate surgery. Probe-based confocal laser endomicroscopy (pCLE) is a real-time in vivo method that allows acquisition of optical biopsies with 1000 times magnification, evaluating both epithelial and vascular patterns.

AIM

To evaluate the role of pCLE in the diagnosis of cCR after nCRxt for advanced rectal adenocarcinoma.

METHODS

pCLE was performed in 47 patients with locally advanced rectal adenocarcinoma (T3/T4, or N+) who underwent nCRxt (5-fluorouracil, 5040 cGy).

RESULTS

Twenty-seven (57.5%) patients were men, and the mean age was 62.8 years. Thirty-seven had partial response confirmed by pCLE. Ten (21.3%) patients had good endoscopic response and presented small ulcer (n = 5) or residual scar (n = 5). After nCRxt, the essential features to differentiate malignancy from post-radiation alterations at pCLE were the presence of irregular crypts, budding, back-to-back glands, cribriform pattern, increased vessel/crypt ratio, and fluorescein leakage. A scoring system was created considering these epithelial and vascular features, with high accuracy for differentiating patients with complete response from those with residual neoplasia (p < 0.00001). pCLE sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were 100%, 71.4%, 95.2%, 100%, and 95.7%, respectively.

CONCLUSIONS

(1) pCLE evaluation of epithelial and vascular features may improve the diagnosis of cCR and may alter patient management; (2) pCLE might be valuable for identifying patients with advanced rectal cancer who will benefit from watch and wait strategy, avoiding immediate surgical treatment.

Patient-derived organoids as individual patient models for chemoradiation response prediction in gastrointestinal malignancies

Chemoradiotherapy (CRT) is an important treatment modality for specific gastrointestinal (GI) cancers, as it has been shown to improve clinical outcomes. Recent developments in the neoadjuvant setting such as wait-and-see strategies for rectal as well as for esophageal cancers have even proven that CRT might be an effective organ-sparing treatment. However, due to molecular heterogeneity, only a subset of patients will show a complete response to CRT, which addresses the need for an individualized treatment approach. In recent years, the demand for more physiologically relevant predictive in vitro models has fostered the development of patient-derived tumor organoids. In this review, we describe the current treatment options for patients with GI cancers who are treated with (neo)adjuvant CRT. Furthermore, we provide an in-depth discussion of the organoid technology in the context of predicting CRT response for GI cancers as well as possible challenges for clinical implementation.

MRI Assessment of Complete Response to Preoperative Chemoradiation Therapy for Rectal Cancer: 2020 Guide for Practice from the Korean Society of Abdominal Radiology

Objective

To provide an evidence-based guide for the MRI interpretation of complete tumor response after neoadjuvant chemoradiation therapy (CRT) for rectal cancer using visual assessment on T2-weighted imaging (T2) and diffusion-weighted imaging (DWI).

Materials and Methods

PubMed MEDLINE, EMBASE, and Cochrane Library were searched on November 28, 2019 to identify articles on the following issues: 1) sensitivity and specificity of T2 or DWI for diagnosing pathologic complete response (pCR) and the criteria for MRI diagnosis; 2) MRI alone vs. MRI combined with other test(s) in sensitivity and specificity for pCR; and 3) tests to select patients for the watch-and-wait management. Eligible articles were selected according to meticulous criteria and were synthesized.

Results

Of 1615 article candidates, 55 eligible articles (for all three issues combined) were identified. Combined T2 and DWI performed better than T2 alone, with a meta-analytic summary sensitivity of 0.62 (95% confidence interval [CI], 0.43–0.77; I² = 80.60) and summary specificity of 0.89 (95% CI, 0.80–0.94; I² = 92.61) for diagnosing pCR. The criteria for the complete response on T2 in most studies had the commonality of remarkable tumor decrease to the absence of mass-like or nodular intermediate signal, although somewhat varied, as follows: (near) normalization of the wall; regular, thin, hypointense scar in the luminal side with (near) normal-appearance or homogeneous intermediate signal in the underlying wall; and hypointense thickening of the wall. The criteria on DWI were the absence of a hyperintense signal at high b-value (≥ 800 sec/mm²) in most studies. The specific algorithm to combine T2 and DWI was obscure in half of the studies. MRI combined with endoscopy was the most utilized means to select patients for the watch-and-wait management despite a lack of strong evidence to guide and support a multi-test approach.

Conclusion

This systematic review and meta-analysis provide an evidence-based practical guide for MRI assessment of complete tumor response after CRT for rectal cancer.

Ten-year survival after pathologic complete response in rectal adenocarcinoma

BACKGROUND

Multimodal treatment is the standard of care for rectal adenocarcinoma, with a subset of patients achieving a pathologic complete response (pCR). While pCR is associated with improved overall survival (OS), long-term data on patients with pCR is limited.

METHODS

This is a single institution retrospective cohort study of all patients with clinical stages II/III rectal adenocarcinoma who underwent neoadjuvant chemoradiation therapy and operative resection (January 1, 2004-December 31, 2017). PCR was defined as no tumor identified in the rectum or associated lymph nodes by final pathology.

RESULTS

Of 370 patients in this cohort, 50 had a pCR (13.5%). For pCR patients, 5-year disease-free survival (DFS) was 92%, 5-year OS was 95%. Twenty-six patients had surgery > 10 years before the study end date, of which 20 had an OS > 10 years (77%) with median OS 12.1 years and 95% alive to date (19/20). Of the 50 pCR patients, there was a single recurrence in the lung at 44.3 months after proctectomy which was surgically resected.

CONCLUSION

For patients with rectal adenocarcinoma that undergo neoadjuvant chemoradiation and surgical resection, pCR is associated with excellent long-term DFS and OS. Many patients live greater than 10 years with no evidence of disease recurrence.

Watch and wait approach in rectal cancer: Current controversies and future directions

According to the main international clinical guidelines, the recommended treatment for locally-advanced rectal cancer is neoadjuvant chemoradiotherapy followed by surgery. However, doubts have been raised about the appropriate definition of clinical complete response (cCR) after neoadjuvant therapy and the role of surgery in patients who achieve a cCR. Surgical resection is associated with significant morbidity and decreased quality of life (QoL), which is especially relevant given the favourable prognosis in this patient subset. Accordingly, there has been a growing interest in alternative approaches with less morbidity, including the organ-preserving watch and wait strategy, in which surgery is omitted in patients who have achieved a cCR. These patients are managed with a specific follow-up protocol to ensure adequate cancer control, including the early identification of recurrent disease. However, there are several open questions about this strategy, including patient selection, the clinical and radiological criteria to accurately determine cCR, the duration of neoadjuvant treatment, the role of dose intensification (chemotherapy and/or radiotherapy), optimal follow-up protocols, and the future perspectives of this approach. In the present review, we summarize the available evidence on the watch and wait strategy in this clinical scenario, including ongoing clinical trials, QoL in these patients, and the controversies surrounding this treatment approach.

Unintended consequences of treating early rectal cancers for complete clinical response with chemoradiotherapy

The aim was to examine the current trend in rectal cancer, which is to extend ’watch-and-wait’ to earlier-stage tumors, not normally treated with chemoradiotherapy, to define the up-side and down-side regarding quality of life (QOL) and anorectal/sexual/urinary function from this approach. We reviewed the literature regarding a ‘watch-and-wait’ strategy after neoadjuvant chemoradiotherapy. The primary outcome measure was complete clinical response. Secondary measures included colostomy rate, functional outcomes and QOL. There is a trend to use chemoradiotherapy in earlier tumors using dose-escalation of radiation and/or additional chemotherapy, resulting in high rates of complete clinical response, which may impact adversely on QOL if radical surgery is subsequently required. Focusing on organ-preservation as the primary goal of treatment rather than overall functional outcomes and QOL for the whole population, may not provide patients with sufficient information for optimal decision-making.

A Case with Rectal Cancer Relapses After Clinical Complete Remission Following Neoadjuvant Chemoradiotherapy

Despite advancements in diagnosis and therapy, relapse of rectal cancer after clinical complete remission (cCR) remains a frequent event. The key factors influencing the treatment strategy for the management of patients achieving cCR following neoadjuvant chemoradiotherapy (Neo-CRT) remain to be identified. We present the case of a 64-year-old man with rectal cancer. The patient was initially admitted to the hospital in September 2011 with a 3-month history of change in his stools. Following his re-hospitalization in November 2011, a biopsy specimen of the neoplasm suggested the presence of rectal adenocarcinoma; laboratory investigations also revealed elevated levels of carcinoembryonic antigens (CEA; carbohydrate antigen 199) in the serum. Subsequently, the patient received Neo-CRT, as well as symptomatic and supportive treatment. The level of serum CEA returned to normal, without signs of swollen lymph nodes in the pelvic cavity. The patient was diagnosed with rectal cancer based on the elevated level of serum CEA, colonoscopy, and contrast-enhanced magnetic resonance imaging. He relapsed 4 months after cCR following Neo-CRT and underwent laparoscopic Miles’ surgery in April 2013. The relapse may have been mainly attributed to residual tumor cells. This case report and literature review may contribute to the clinical recognition of treatment for patients with rectal cancer achieving cCR following Neo-CRT.

Rectal cancer MR staging: pearls and pitfalls at baseline examination

In recent years, rectal MRI has become a central diagnostic tool in rectal cancer staging. Indeed, rectal MR has the ability to accurately evaluate a number of important findings that may impact patient management, including distance of the tumor to the mesorectal fascia, presence of extramural vascular invasion (EMVI), presence of lymph nodes, and involvement of the peritoneum/anterior peritoneal reflection. Many of these findings are difficult to assess in nonexpert hands. In this review, we present a practical approach for radiologists to provide high-quality interpretations at initial baseline exams, based on recent guidelines from the Society of Abdominal Radiology, Rectal and Anal Cancer Disease Focused Panel. Practical pearls and pitfalls are discussed, focusing on optimization of technique including, patient preparation and protocol recommendations, interpretation, and essentials of reporting.

Diagnostic performance of magnetic resonance to assess treatment response after neoadjuvant therapy in patients with locally advanced rectal cancer

PURPOSE

Our study aimed to evaluate the diagnostic performance of rectal magnetic resonance imaging (MRI) for local restaging in patients with non-metastatic locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (CRT) using surgical histopathology of total mesorectal excision as the reference standard.

METHODS

Ninety-five patients with LARC who underwent rectal MRI after CRT between January 2014 and December 2016 were included. Accuracy, sensitivity, specificity, positive, and negative predictive value for local staging regarding T-stage, N-stage, circumferential resection margin, and MRI tumor regression grade (ymriTRG) were calculated, and inter-test agreements were assessed.

RESULTS

22/95 (23.2%) patients had radiological complete response (rCR), whereas 20/95 (21.1%) had pathological complete response (pCR). Among the patients with pCR, 11/20 (55%) had rCR. Fair agreement was demonstrated between ymriTRG and pathological TRG (ypTRG) (κ = 0.255). The sensitivity and specificity for detection of pCR were 61.1% (95% CI 35.7-82.7) and 89.6% (95% CI 80.6-95.4). For the detection of ypTRG grades 1 and 2, the corresponding values were 67.2% (95% CI 54.3-78.4) and 51.6 (95% CI 33.1-69.8). The accuracy of ymriTRG was 24.2% (95% CI 15.6-32.8). Inter-test agreement in TRG between MRI and pathology was overall fair (κ = 0.255) and slight (κ = 0.179), if TRG 1 + 2.

CONCLUSION

Qualitative assessment on MRI for diagnosing pCR showed moderate sensitivity and high specificity, whereas the diagnosis of TRG had moderate sensitivity and low specificity with slight to fair inter-test agreement when compared with pathological specimens.

Rectal cancer sub-clones respond differentially to neoadjuvant therapy

Treatment of locally advanced rectal cancer includes chemotherapy, radiation, and surgery but patient responses to neoadjuvant treatment are variable. We have shown that rectal tumors are comprised of multiple genetically distinct sub-clones. Unique sub-clones within tumors may harbor mutations which contribute to inter-patient variation in response to neoadjuvant chemoradiotherapy (nCRT). Analysis of the influence of nCRT on the extent and nature of intra-tumoral genetic heterogeneity in rectal cancer may provide insights into mechanisms of resistance.

Locally advanced rectal cancer patients underwent pre-treatment biopsies. At the time of surgery, tissue from the treated tumor was obtained and analyzed. Pre- and post-treatment specimens were subjected to whole exome and confirmatory deep sequencing for somatic mutations. Copy number variation was assessed using OncoScan SNP arrays. Genomic data were analyzed using PyClone to identify sub-clonal tumor population following nCRT. Alterations that persisted or were enriched in the post-treatment tumor specimen following nCRT were defined for each patient.

Thirty-two samples were obtained from ten patients. PyClone identified 2 to 10 genetic sub-clones per tumor. Substantial changes in the proportions of individual sub-clones in pre- versus post-treatment tumor material were found in all patients. Resistant sub-clones recurrently contained mutations in TP53, APC, ABCA13, MUC16, and THSD4. Recurrent copy number variation was observed across multiple chromosome regions after nCRT. Pathway analysis including variant alleles and copy number changes associated with resistant sub-clones revealed significantly altered pathways, especially those linked to the APC and TP53 genes, which were the two most frequently mutated genes.

Intra-tumoral heterogeneity is evident in pre-treatment rectal cancer. Following treatment, sub-clonal populations are selectively modified and enrichment of a subset of pre-treatment sub-clones is seen. Further studies are needed to define recurrent alterations at diagnosis that may contribute to resistance to nCRT.

Neoadjuvant radiotherapy for rectal cancer management

Thirty per cent of all colorectal tumours develop in the rectum. The location of the rectum within the bony pelvis and its proximity to vital structures presents significant therapeutic challenges when considering neoadjuvant options and surgical interventions. Most patients with early rectal cancer can be adequately managed by surgery alone. However, a significant proportion of patients with rectal cancer present with locally advanced disease and will potentially benefit from down staging prior to surgery. Neoadjuvant therapy involves a variety of options including radiotherapy, chemotherapy used alone or in combination. Neoadjuvant radiotherapy in rectal cancer has been shown to be effective in reducing tumour burden in advance of curative surgery. The gold standard surgical rectal cancer management aims to achieve surgical removal of the tumour and all draining lymph nodes, within an intact mesorectal package, in order to minimise local recurrence. It is critically important that all rectal cancer cases are discussed at a multidisciplinary meeting represented by all relevant specialties. Pre-operative staging including CT thorax, abdomen, pelvis to assess for distal disease and magnetic resonance imaging to assess local involvement is essential. Staging radiology and MDT discussion are integral in identifying patients who require neoadjuvant radiotherapy. While Neoadjuvant radiotherapy is potentially beneficial it may also result in morbidity and thus should be reserved for those patients who are at a high risk of local failure, which includes patients with nodal involvement, extramural venous invasion and threatened circumferential margin. The aim of this review is to discuss the role of neoadjuvant radiotherapy in the management of rectal cancer.

Liquid biopsy for rectal cancer: A systematic review

BACKGROUND

The management of locally advanced rectal cancer (RC) is an evolving clinical field where the multidisciplinary approach can reach its best, and liquid biopsy for obtaining tumor-derived component such as circulating tumor DNA (ctDNA) might provide complementary informations.

METHODS

A systematic review of studies available in literature of liquid biopsy in non-metastatic RC has been performed according to PRISMA criteria to assess the role of ctDNA as a diagnostic, predictive and prognostic biomarker in this setting.

RESULTS

Twenty-five publications have been retrieved, of which 8 full-text articles, 7 abstracts and 10 clinical trials. Results have been categorized into three groups: diagnostic, predictive and prognostic. Few but promising data are available about the use of liquid biopsy for early diagnosis of RC, with the main limitation of sensitivity due to low concentrations of ctDNA in this setting. In terms of prediction of response to chemoradiation, still inconclusive data are available about the utility of a pre-treatment liquid biopsy, whereas some studies report a positive correlation with a dynamic (pre/post-treatment) monitoring. The presence of minimal residual disease by ctDNA was consistently associated with worse prognosis across studies.

CONCLUSIONS

The use of liquid biopsy for monitoring response to chemoradiation and assess the risk of disease recurrence are the most advanced potential applications for liquid biopsy in RC, with implications also in the context of non-operative management strategies.

The impact of total neo-adjuvant treatment on nonoperative management in patients with locally advanced rectal cancer: The evaluation of 66 cases

BACKGROUND

The study aimed to assess if adherence to a total-neoadjuvant-treatment (TNT) protocol followed by observation(watch-and-wait) led to the successful nonoperative-management of low-rectal-cancer.

METHODS

In this study, patients with primary, resectable-T3-T4, N0-N1 distal-rectal-adenocarcinoma underwent-chemoradiotherapy + consolidation-chemotherapy (TNT). During the-TNT-period, endoscopy, MRI, and FDG-PET/CT were performed. We allocated patients with complete-clinical-tumor-regression, who underwent endoscopy every two months, MRI every-four-months, and PET/CT every-six-months-after-treatment, to the observation-group(OG). All other patients were referred for surgery. The OG was followed-up. The primary endpoint was local tumor-ecurrence after allocation to the OG.

RESULTS

Between 2015 and 2018, we enrolled 66-patients. Of 60-patients who were eligible to participate, 39 had complete-clinical-response(cCR) and were allocated to the OG, six underwent local-excision (LE), and 15 underwent total-mesorectal-excision (TME). The median follow-up duration was 22 (9-42) months. The local-recurrence-rate in the OG was 15.3%, and the LE and TME rates were 16.6% and 0%, respectively. All recurrence cases were salvaged through either LE or TME. The-distant-metastasis rate was 5.1%, 16.6%, and 12.5% in the OG, LE, and TME groups, respectively. The endoscopic negative-predictive-value(NPV) was 50%, and the positive-predictive-value(PPV) was 76.9% in the surgery group (LE + TME). MRI; NPV-50%, PPV-76.9%. PET/CT; NPV-100%, PPV-93.3%. Six patients(28.57%) from surgery group achieved complete pathological response (cPR).

CONCLUSION

Our results indicated a high proportion of selected-rectal-cancers with-cCR after neo-adjuvant-therapy could potentially be managed non-operatively, and major surgery may be avoided.

Gold nanoparticles modified hollow carbon system for dual-responsive release and chemo-photothermal synergistic therapy of tumor

Thermochemotherapy has shown a synergistic anti-cancer efficiency and can enhance the therapeutic effect of simple chemotherapy. The photothermal conversion characteristics of carriers are vital in thermo-chemotherapy. Therefore, hollow mesoporous carbon (HMC) with excellent heating efficiency and a large specific surface area was used to ensure the high loading capacity. Next, approximately 4 nm spherical gold nanoparticles (NPs) were employed as gatekeepers of the tunnels of HMC by Au-S bonds, which have the same size as HMC mesopores. Additionally, the gold NPs could avoid the premature release of the drug and enhance the photothermal properties of the delivery system. The surface of the carriers was modified with polyethylene glycol (PEG) to increase the biocompatibility and dispersity of doxorubicin (DOX) loaded DOX/HMC-Au@PEG. DOX release was markedly accelerated in the presence of glutathione (GSH) and near-infrared (NIR), indicating that the system had redox and NIR dual-triggered drug release characteristics. Cytotoxicity experiments proved that combined therapy induced the highest cell killing level. Additionally, the combination index (CI) of DOX/HMC-Au@PEG was 0.452, indicating the synergistic effect of chemotherapy and photo-thermal therapy (PTT). In vivo antitumor experiments were also carried out and showed the same trend. In general, the results of this study indicated that DOX/HMC-Au@PEG has great potential in dual-triggered drug delivery and thermochemotherapy.

The effect of time interval from chemoradiation to surgery on postoperative complications in patients with rectal cancer

BACKGROUND

A prolonged time interval between chemoradiation and total mesorectal excision (TME) may render more rectal cancer patients eligible for organ-sparing approaches but may also cause more pelvic fibrosis and surgical morbidity. We estimated the effect of time interval on postoperative complications and other surgical outcomes in rectal cancer patients.

METHODS

This is a population-based cohort study using data of the Dutch Colorectal Audit. Rectal cancer patients treated with chemoradiation followed by TME after an interval of 3-20 weeks were selected (n = 6,268). Time interval from completion of chemoradiation to TME was categorized into 3-6, 7-8, 9-10, 11-12 and 13-20 weeks. Outcomes included postoperative complication (any, and stratified by medical and surgical complications), reintervention, intraoperative complication, incomplete resection, positive circumferential margin (CRM) and pathological complete response (pCR). The interval of 7-8 weeks was the reference group.

RESULTS

Prolonged time intervals were not associated with a higher risk of a postoperative complication (any, surgical or medical), reintervention, and incomplete resection. Intraoperative complications were however more common after 11-12 weeks than after 7-8 weeks (odds ratio (OR) = 1.79, 95% confidence interval (CI) = 1.20-2.69). The interval of 9-10 weeks was associated with less CRM positive resections, and 9-10 and 13-20 weeks with more pCR (relative to 7-8 weeks, OR = 0.74, 95%CI = 0.56-0.98; OR = 1.28, 95%CI = 1.04-1.58; and OR = 1.33, 95%CI = 1.04-1.71, respectively).

CONCLUSIONS

Compared with 7-8 weeks, longer time intervals up to 13-20 weeks between chemoradiation and TME are not associated with more postoperative complications or more positive resection margins. Accordingly, prolonging the interval aiming for organ-sparing treatment is safe.

Robotic Transanal Minimally Invasive Surgery for the Excision of Rectal Neoplasia: Clinical Experience With 58 Consecutive Patients

BACKGROUND

Given the significant perioperative risks and costs of total mesorectal excision, minimally invasive transanal surgical approaches have grown in popularity for early rectal cancer and rectal polyps. This article discusses a transanal robotic surgery technique to perform full-thickness resections of benign and malignant rectal neoplasms.

OBJECTIVE

The purpose of this study was to describe an initial experience with robotic transanal minimally invasive surgery.

DESIGN

This was a retrospective cohort study of consecutive patients who underwent robotic transanal minimally invasive surgery.

SETTINGS

The study was conducted at a high-volume colorectal surgery practice with a large health maintenance organization.

PATIENTS

Patients at Southern California Kaiser Permanente with early rectal cancer and rectal polyps amenable to transanal excision were included.

INTERVENTIONS

Transanal resection of rectal tumors were removed using robotic transanal minimally invasive surgery.

MAIN OUTCOME MEASURES

Local recurrence of rectal pathology was measured.

RESULTS

A total of 58 patients underwent robotic transanal minimally invasive surgery with full-thickness rectal resection by 4 surgeons for the following indications: rectal cancer (n = 28), rectal polyp (n = 18), rectal carcinoid (n = 11), and rectal GI stromal tumor (n = 1). Mean operative time was 66.2 minutes (range, 17-180 min). The mean tumor height from the anal verge was 8.8 cm (range, 4-14 cm), and the mean specimen size was 3.3 cm (range, 1.3-8.2 cm). A total of 57 (98.3%) of 58 specimens were intact, and 55 (94.8%) of 58 specimens had negative surgical margins. At a mean follow-up of 11.5 months (range, 0.3-33.3 mo), 3 patients (5.5%) developed local recurrences, and all underwent successful salvage surgery.

LIMITATIONS

The study was limited by being a retrospective, nonrandomized trial with short follow-up.

CONCLUSIONS

Robotic transanal minimally invasive surgery is a safe, oncologically effective surgical approach for rectal polyps and early rectal cancers. It offers the oncologic benefits and perioperative complication profile of other transanal minimally invasive surgical approaches but also enhances surgeon ergonomics and provides an efficient transanal rectal platform. See Video Abstract at http://links.lww.com/DCR/A759.

Non-operative management of rectal cancer: understanding tumor biology

The management of locally-advanced rectal cancer involves a combination of chemotherapy, chemoradiation, and surgical resection to provide excellent local tumor control and overall survival. However, aspects of this multimodality approach are associated with significant morbidity and long-term sequelae. In addition, there is growing evidence that patients with a clinical complete response to chemotherapy and chemoradiation treatments may be safely offered initial non-operative management in a rigorous surveillance program. Weighed against the morbidity and significant sequelae of rectal resection, recognizing how to best optimize non-operative strategies without compromising oncologic outcomes is critical to our understanding and treatment of this disease.

Treatment and survival of rectal cancer patients over the age of 80 years: a EURECCA international comparison

Background

The optimal treatment strategy for older rectal cancer patients remains unclear. The current study aimed to compare treatment and survival of rectal cancer patients aged 80+.

Methods

Patients of ≥80 years diagnosed with rectal cancer between 2001 and 2010 were included. Population-based cohorts from Belgium (BE), Denmark (DK), the Netherlands (NL), Norway (NO) and Sweden (SE) were compared side by side for neighbouring countries on treatment strategy and 5-year relative survival (RS), adjusted for sex and age. Analyses were performed separately for stage I–III patients and stage IV patients.

Results

Overall, 19 634 rectal cancer patients were included. For stage I–III patients, 5-year RS varied from 61.7% in BE to 72.3% in SE. Proportion of preoperative radiotherapy ranged between 7.9% in NO and 28.9% in SE. For stage IV patients, 5-year RS differed from 2.8% in NL to 5.6% in BE. Rate of patients undergoing surgery varied from 22.2% in DK to 40.8% in NO.

Conclusions

Substantial variation was observed in the 5-year relative survival between European countries for rectal cancer patients aged 80+, next to a wide variation in treatment, especially in the use of preoperative radiotherapy in stage I–III patients and in the rate of patients undergoing surgery in stage IV patients.

'Watch and wait' after chemoradiotherapy for rectal cancer

Surgery remains the cornerstone of rectal cancer treatment. However, there is significant morbidity and mortality associated with pelvic surgery, and the past decade has illustrated that a cohort of rectal cancer patients sustain a remission of local disease with chemoradiation alone. Thus, questions remain regarding the optimal management for rectal cancer; namely, accurately identifying patients who have a complete pathologic response and determining the oncologic safety of the observational approach for this patient group. This review aims to summarize the current evidence to provide an overview to the 'watch and wait' approach in rectal cancer patients with a complete response to neoadjuvant chemoradiation therapy.

MicroRNA molecular profiling identifies potential signaling pathways conferring resistance to chemoradiation in locally-advanced rectal adenocarcinoma

Purpose

There has been growing interest in using chemoradiation (CRT) for non-operative management of rectal cancer, and identifying patients who might benefit most from this approach is crucial. This study identified miRNAs (miRs) associated with clinical outcomes and treatment resistance by evaluating both pre- and post-CRT expression profiles.

Methods

Forty patients, 9 with pathologic complete response (pCR) and 31 with pathologic incomplete response (pIR) were included. MicroRNA was extracted from 40 pre-therapy tumor samples and 31 post-chemoradiation surgical samples with pathologic incomplete response (pIR). A generalized linear model was used to identify miRs associated with pCR. A linear mixed effects model was used to identify miRs differentially expressed before and after treatment. miR expression was dichotomized at the mean and clinical outcomes were evaluated using Cox proportional hazard modeling.

Results

Nine miRs were associated with pCR (p<0.05), but none were significant after false discovery rate correction. Among patients with pIR, 68 miRs were differentially expressed between the pre and post-CRT groups (FDR p<0.05). Ingenuity pathway analysis (IPA) demonstrated multiple signaling networks associated with pIR, including p38MAPK, TP53, AKT, IL-6, and RAS. Increased let-7b was correlated with increased distant metastasis (DM), worse relapse-free survival (RFS), and worse overall survival (OS) (p<0.05).

Conclusions

No miRs were significantly correlated with pCR. We identified miRs that were differentially expressed between pre- and post-CRT tumor samples, and these miRs implicated multiple signaling pathways that may confer resistance to CRT. In addition, we identified an association between increased let-7b and worse clinical outcomes (DM, DFS, OS).