Assessing Endoscopic Response in Locally Advanced Rectal Cancer Treated with Total Neoadjuvant Therapy: Development and Validation of a Highly Accurate Convolutional Neural Network.

BACKGROUND: Rectal tumors display varying degrees of response to total neoadjuvant therapy (TNT). We evaluated the performance of a convolutional neural network (CNN) in interpreting endoscopic images of either a non-complete response to TNT or local regrowth during watch-and-wait surveillance. METHODS: Endoscopic images from stage II/III rectal cancers treated with TNT from 2012 to 2020 at a single institution were retrospectively reviewed. Images were labelled as Tumor or No Tumor based on endoscopy timing (before, during, or after treatment) and the tumor's endoluminal response. A CNN was trained using ResNet-50 architecture. The area under the curve (AUC) was analyzed during training and for two test sets. The main test set included images of tumors treated with TNT. The other contained images of local regrowth. The model's performance was compared to sixteen surgeons and surgical trainees who evaluated 119 images for evidence of tumor. Fleiss' kappa was calculated by respondent experience level. RESULTS: A total of 2717 images from 288 patients were included; 1407 (51.8%) contained tumor. The AUC was 0.99, 0.98, and 0.92 for training, main test, and local regrowth test sets. The model performed on par with surgeons of all experience levels for the main test set. Interobserver agreement was good ( k = 0.71-0.81). All groups outperformed the model in identifying tumor from images of local regrowth. Interobserver agreement was fair to moderate ( k = 0.24-0.52). CONCLUSIONS: A highly accurate CNN matched the performance of colorectal surgeons in identifying a noncomplete response to TNT. However, the model demonstrated suboptimal accuracy when analyzing images of local regrowth.

Association of Lateral Pelvic Lymph Nodes with Disease Recurrence and Organ Preservation in Patients with Distal Rectal Adenocarcinoma Treated with Total Neoadjuvant Therapy.

OBJECTIVE: Assess the significance of enlarged lateral lymph nodes (LLN) for disease recurrence, metastasis, and organ preservation in patients with rectal cancer. BACKGROUND: Optimal treatment of rectal adenocarcinoma involving LLN is subject to debate. METHODS: A post hoc analysis of the OPRA trial, a multicenter study of patients with rectal cancer treated with total neoadjuvant therapy (TNT) followed by total mesorectal excision or watch-and-wait management. We analyzed the association of visible LLN (LLN+), LLN≥7 mm (short axis) on baseline MRI, and LLN≥4 mm on restaging MRI with recurrence, metastasis, and rectum preservation. RESULTS: At baseline, 57 out of 324 (18%) patients had LLN+. In 30 (53%) of 57 patients with LLN+ on baseline MRI, the LLN disappeared after TNT. Disease recurrence in LLN was rare (3.5% of patients with LLN+ and 0.4% of patients with LLN-). All patients with recurrence in LLN also had distant metastasis. The rate of organ preservation was significantly lower in patients with LLN≥4 mm on restaging MRI (P=0.013). We found no significant differences in rates of local recurrence or metastasis between patients with LLN+ vs. LLN- and in patients with LLN≥7 vs.<7 mm on baseline MRI. LLN dissection was performed in 3 patients; 2 of them died of distant metastasis. CONCLUSIONS: LLN involvement is not associated with disease recurrence or metastasis, but persistence of LLN≥4 mm after TNT is negatively associated with rectum preservation in patients with locally advanced rectal cancer treated with TNT. Dissection of lateral nodes likely benefits few patients.

Tumour deposits are independently associated with recurrence in colon cancer.

AIM: Tumour deposits are focal aggregates of cancer cells in pericolic fat and mesentery, distinct from vessels, nerves and lymphatics. Their presence upstages lymph node negative patients but is ignored in lymph node positive patients. We investigated the clinicopathological factors associated with tumour deposits and their impact on recurrence in lymph node positive and negative patients. METHOD: Clinicopathological variables were collected from the medical records of patients with Stage I-III colon cancer who underwent resection in 2017-2019. Pathology was reviewed by a gastrointestinal pathologist. Patients with rectal cancer, metastasis, and concurrent malignancy were excluded. RESULTS: Tumour deposits were noted in 69 (9%) of 770 patients. They were associated with the presence of lymph node metastasis, advanced T category, poorly differentiated tumours, microsatellite stable subtype and lymphovascular and perineural invasion (p < 0.05). The presence of tumour deposits (hazard ratio 2.48, 95% CI 1.49-4.10) and of lymph node metastasis (hazard ratio 3.04, 95% CI 1.72-5.37) were independently associated with decreased time to recurrence. There was a weak correlation (0.27) between the number of tumour deposits and the number of positive lymph nodes. CONCLUSION: Tumour deposits are associated with more advanced disease and high-risk pathological features. The presence of tumour deposits and lymph node metastasis were found to be independent risk factors for decreased time to recurrence. A patient with both lymph node metastasis and tumour deposits is more than twice as likely to have recurrence compared with a patient with only lymph node metastasis. Tumour deposits independently predict recurrence and should not be ignored in lymph node positive patients.

Long-Term Results of Organ Preservation in Patients With Rectal Adenocarcinoma Treated With Total Neoadjuvant Therapy: The Randomized Phase II OPRA Trial.

Clinical trials frequently include multiple end points that mature at different times. The initial report, typically based on the primary end point, may be published when key planned co-primary or secondary analyses are not yet available. Clinical Trial Updates provide an opportunity to disseminate additional results from studies, published in JCO or elsewhere, for which the primary end point has already been reported.To assess long-term risk of local tumor regrowth, we report updated organ preservation rate and oncologic outcomes of the OPRA trial (ClinicalTrials.gov identifier: NCT02008656). Patients with stage II/III rectal cancer were randomly assigned to receive induction chemotherapy followed by chemoradiation (INCT-CRT) or chemoradiation followed by consolidation chemotherapy (CRT-CNCT). Patients who achieved a complete or near-complete response after finishing treatment were offered watch-and-wait (WW). Total mesorectal excision (TME) was recommended for those who achieved an incomplete response. The primary end point was disease-free survival (DFS). The secondary end point was TME-free survival. In total, 324 patients were randomly assigned (INCT-CRT, n = 158; CRT-CNCT, n = 166). Median follow-up was 5.1 years. The 5-year DFS rates were 71% (95% CI, 64 to 79) and 69% (95% CI, 62 to 77) for INCT-CRT and CRT-CNCT, respectively (P = .68). TME-free survival was 39% (95% CI, 32 to 48) in the INCT-CRT group and 54% (95% CI, 46 to 62) in the CRT-CNCT group (P = .012). Of 81 patients with regrowth, 94% occurred within 2 years and 99% occurred within 3 years. DFS was similar for patients who underwent TME after restaging (64% [95% CI, 53 to 78]) and patients in WW who underwent TME after regrowth (64% [95% CI, 53 to 78]; P = .94). Updated analysis continues to show long-term organ preservation in half of the patients with rectal cancer treated with total neoadjuvant therapy. In patients who enter WW, most cases of tumor regrowth occur in the first 2 years.

Nonoperative management of the primary tumor in patients with unresectable stage IV colon cancer treated with systemic chemotherapy: Higher complication rates for left-sided colon tumors.

INTRODUCTION: Treatment of the primary tumor in asymptomatic patients with unresectable colorectal metastases remains controversial. METHODS: Data from patients with synchronous stage IV colon cancer and an untreated primary tumor who started treatment aimed at metastatic disease at a specialized cancer center between 2014 and 2018 were analyzed retrospectively. Main outcome was primary tumor-related complications comparing left-sided and right-sided colon cancer. A competing-risk regression model was used to identify predictors of complications. RESULTS: Of 523 patients with metastatic colon cancer at presentation, 221 started treatment aimed at metastatic disease; these patients constituted the study cohort. The primary tumor was left-sided in 109 patients (49%) and right-sided in 112 patients (51%). In total, 46 patients (21%) developed a complication that required invasive intervention. Complications occurred more frequently in patients with left-sided tumors than in patients with right-sided tumors (29% vs 13%, P = 0.003). Eighteen patients (8%) underwent non-surgical intervention. Six patients (33%) failed non-surgical management and underwent surgery. Of 34 patients (15%) who underwent surgical intervention, 20 underwent an emergency colectomy and 14 underwent diversion with a permanent stoma. Overall, 10% of patients ended up with a permanent stoma. In competing-risk analysis, only left-sided primary tumor (hazard ratio 2.62; 95% CI 1.40-4.89; P = 0.003) was significantly associated with primary tumor-related complications requiring invasive intervention. CONCLUSIONS: Patients with asymptomatic metastatic left-sided tumors have a higher risk for primary tumor-related complications than patients with right-sided tumors. Close monitoring and early surgical rescue should be considered for patients with left-sided colon cancer who are managed nonoperatively.

Anal Adenocarcinoma Treated in the Era of Total Neoadjuvant Therapy and Nonoperative Management.

BACKGROUND: Anal adenocarcinoma bears a treatment strategy unique to other anal cancers. OBJECTIVE: This study aimed to describe oncologic outcomes of total neoadjuvant therapy followed by watch-and-wait approach for anal adenocarcinoma. DESIGN: Retrospective analysis. SETTINGS: This study was conducted at a comprehensive cancer center. PATIENTS: Patients with anal adenocarcinoma treated between 2004 and 2019 were selected. INTERVENTIONS: Fifty-four patients received neoadjuvant therapy and were divided into 2 groups according to their treatment strategy: total neoadjuvant therapy versus single neoadjuvant modality therapy. MAIN OUTCOME MEASURES: Organ preservation, tumor regrowth, local failure, distant metastasis rates, recurrence-free survival, and overall survival. RESULTS: This study included 70 patients with anal adenocarcinoma. Fifty-four patients (77%) received neoadjuvant therapy, of whom 30 (42%) received total neoadjuvant therapy and 24 (34%) received single neoadjuvant modality. Twenty-three (33%) patients achieved complete clinical response and were managed by watch-and-wait approach. The proportion of patients able to continue to watch-and-wait approach was higher after receiving total neoadjuvant therapy (60%) compared with single neoadjuvant modality therapy (20%; p = 0.004). A tumor regrowth rate of 22% was observed in the total neoadjuvant therapy group. The 5-year overall survival rate was 70% (95% CI, 59%-83%), including 61% (95% CI, 42%-88%) for the total neoadjuvant therapy and 65% (95% CI, 48%-88%) for the single neoadjuvant modality groups. Colostomy was avoided in 50% of patients who received total neoadjuvant therapy and 83% of watch-and-wait patients. Five-year recurrence-free survival rates of 55% (95% CI, 39%-79%) and 30% (95% CI, 15%-58%) were observed in the total neoadjuvant therapy and single neoadjuvant modality groups. LIMITATIONS: Retrospective nature. CONCLUSIONS: This is the first report in the literature describing the safety and feasibility of nonoperative management for anal adenocarcinoma. Anal adenocarcinoma treated with total neoadjuvant therapy and nonoperative management achieve regrowth rates comparable to those observed in rectal cancer, with oncologic outcomes similar to those of traditional treatment strategies. See Video Abstract . ADENOCARCINOMA ANAL TRATADO EN LA ERA DE LA TERAPIA NEOADYUVANTE TOTAL Y EL TRATAMIENTO NO QUIRRGICO: ANTECEDENTES:El adenocarcinoma anal conlleva una estrategia de tratamiento único para otros cánceres anales.OBJETIVO:Describir los resultados oncológicos de la terapia neoadyuvante total seguida de observar y esperar en adenocarcinoma anal.DISEÑO:Análisis retrospectivo.AJUSTE:Este estudio se llevó a cabo en un centro oncológico integral.PACIENTES:Se seleccionaron pacientes con adenocarcinoma anal tratados entre 2004-2019.INTERVENCIONES:Cincuenta y cuatro pacientes recibieron terapia neoadyuvante y se dividieron en dos grupos según su estrategia de tratamiento: terapia neoadyuvante total versus terapia de modalidad neoadyuvante única.PRINCIPALES MEDIDAS DE RESULTADO:Preservación de órganos, recurrencia tumoral, falla local, tasas de metástasis a distancia, libre de recurrencia y supervivencia general.RESULTADOS:El estudio incluyó a 70 pacientes con adenocarcinoma anal. Cincuenta y cuatro pacientes (77%) recibieron terapia neoadyuvante, de los cuales 30 (42%) recibieron terapia neoadyuvante total y 24 (34%) recibieron modalidad neoadyuvante única. Veintitrés (33%) pacientes presentaron una respuesta clínica completa y fueron tratados con vigilancia y espera. La proporción de pacientes capaces de continuar en observar y esperar fue mayor después de recibir terapia neoadyuvante total (60%) en comparación con la terapia de modalidad neoadyuvante única (20%) ( p = 0,004). Se observó una tasa de recurrencia tumoral del 22% en el grupo de terapia neoadyuvante total. La tasa de supervivencia general a 5 años fue del 70% (IC95% 59%-83 %), incluido el 61% (IC95% 42%-88%) para la terapia neoadyuvante total y el 65% (IC95% 48%-88%) para grupos de modalidad neoadyuvante única. Se evitó la colostomía en el 50% de los pacientes que recibieron terapia neoadyuvante total y el 83% de los pacientes en observar y esperar. Se observaron tasas de supervivencia libre de recurrencia a cinco años del 55% (IC95% 39%-79%) y del 30% (IC95% 15%-58%) en los grupos de terapia neoadyuvante total y modalidad neoadyuvante única, respectivamente.LIMITACIONES:Diseño retrospectivo.CONCLUSIONES:Este es el primer informe en la literatura que describe la seguridad y viabilidad del tratamiento no quirúrgico del adenocarcinoma anal. El adenocarcinoma anal tratado con terapia neoadyuvante total y manejo no quirúrgico logra tasas de recurrencia comparables a las observadas en el cáncer de recto, con resultados oncológicos similares a las estrategias de tratamientos tradicionales. (Traducción-Dr. Fidel Ruiz Healy ).

Lymph Node Metastases and Associated Recurrence-Free Survival in Microsatellite Stable and Unstable Colon Cancer.

BACKGROUND: In contrast to microsatellite stable (MSS) colon cancer, predictors of lymph node metastases and their association with recurrence are not well-defined in microsatellite instability (MSI) colon cancer. METHODS: A cohort of nonmetastatic colon cancer patients undergoing surgery between 2015 and 2021 were evaluated for predictors of lymph node metastases (LNMs) and their association with recurrence-free survival (RFS). RESULTS: Of 1466 patients included in the analyses, 361 (25 %) had MSI. Compared with MSS, MSI was associated with earlier stage, fewer LNMs in the patients with N1 or N2 disease, and fewer high-risk features. Compared with the T3-T4 MSS patients, the odds ratios for LNM were 0.52 (95% confidence interval [CI], 0.38-0.71) for the T3-T4 MSI patients, 0.27 (95% CI, 0.38-0.71) for the T1-T2 MSS patients, and 0.15 (95 % CI, 0.08-0.26) for the T1-T2 MSI patients. In both groups, LNMs were associated with T category, patient age, and venous, lymphatic, or perineural invasion. In the MSS patients, LNMs were additionally associated with patient sex and histologic grade. Compared with the MSS patients, the MSI patients with N0 and N1 disease had a better 3-year RFS. However, the MSI patients with N2 disease had a lower rate of 3-year RFS than the MSS patients (hazard ratio, 19.75 vs 4.49). CONCLUSIONS: In MSI colon cancer, LNMs are 50 % less prevalent, but the factors associated with LNM are like those in MSS colon cancer. The improved prognosis traditionally associated with early-stage MSI colon cancers dissipates with four or more LNMs. These findings should be taken into consideration by clinicians selecting the most appropriate course of treatment for MSI colon cancer.

Comparison of short-term outcomes and survival between minimally invasive colectomy and open colectomy in patients 80 years of age and older.

We investigated the short- and long-term outcomes of patients 80 years of age and older with colon cancer who underwent robotic colectomy versus laparoscopic colectomy. Data for patients treated at a comprehensive cancer center between January 2006 and November 2018 were collected retrospectively. Outcomes from minimally invasive laparoscopic or robotic colectomy were compared. Survival was analyzed by the Kaplan-Meier method with significance evaluated by the log-rank test. The laparoscopic (n = 104) and the robotic (n = 75) colectomy groups did not differ across baseline characteristics. Patients who underwent a robotic colectomy had a shorter median length of hospital stay (5 versus 6 days; p < 0.001) and underwent fewer conversions to open surgery (3% versus 17%; p = 0.002) compared to the laparoscopic cohort. The groups did not differ in postoperative complication rates, overall survival or disease-free survival. Elderly patients undergoing robotic colectomy for colon cancer have a shorter hospital stay and lower rates of conversion without compromise to oncologic outcomes.

MRI Assessment of Extramural Venous Invasion Before and After Total Neoadjuvant Therapy for Locally Advanced Rectal Cancer and Its Association with Disease-Free and Overall Survival.

BACKGROUND: Extramural venous invasion (EMVI) on baseline MRI is associated with poor prognosis in patients with locally advanced rectal cancer. This study investigated the association of persistent EMVI after total neoadjuvant therapy (TNT) (chemoradiotherapy and systemic chemotherapy) with survival. METHODS: Baseline MRI, post-TNT MRI, and surgical pathology data from 175 patients with locally advanced rectal cancer who underwent TNT and total mesorectal excision between 2010 and 2017 were retrospectively analyzed for evidence of EMVI. Two radiologists assessed EMVI status with disagreement adjudicated by a third. Pathologic EMVI status was assessed per departmental standards. Cox regression models evaluated the associations between EMVI and disease-free and overall survival. RESULTS: EMVI regression on both post-TNT MRI and surgical pathology was associated with disease-free survival (hazard ratio, 0.17; 95% confidence interval (CI), 0.04-0.64) and overall survival (hazard ratio, 0.11; 95% CI, 0.02-0.68). In an exploratory analysis of 35 patients with EMVI on baseline MRI, only six had EMVI on pathology compared with 18 on post-TNT MRI; these findings were not associated (p = 0.2). Longer disease-free survival was seen with regression on both modalities compared with remaining positive. Regression on pathology alone, independent of MRI EMVI status, was associated with similar improvements in survival. CONCLUSIONS: Baseline EMVI is associated with poor prognosis even after TNT. EMVI regression on surgical pathology is common even with persistent EMVI on post-TNT MRI. EMVI regression on surgical pathology is associated with improved DFS, while the utility of post-TNT MRI EMVI persistence for decision-making and prognosis remains unclear.

Comparison of Robotic, Laparoscopic, and Open Resections of Nonmetastatic Colon Cancer.

BACKGROUND: Laparoscopic resection for colon cancer has not been associated with improvements in oncological outcomes in comparison to open resection. Robotic resections are associated with increased lymph node yield and radicality of mesenteric resection in patients with right-sided tumors. It is unclear whether lymph node yield is higher in robotic resections in other parts of the colon and whether higher lymph node yield is associated with improved survival. OBJECTIVE: To compare survival rates between robotic, laparoscopic, and open resections in a large cohort of patients with nonmetastatic colon cancer. DESIGN: This is a retrospective observational study. SETTING: A single comprehensive cancer center. PATIENTS: Patients who underwent resection of nonmetastatic primary colon cancer between January 2006 and December 2018. MAIN OUTCOME MEASURES: Univariable and multivariable models were used to identify predictors of disease-free and overall survival. Lymph node yield and perioperative outcomes were compared between operative approaches. RESULTS: There were 2398 patients who met the inclusion criteria: 699 (29%) underwent open, 824 (34%) underwent laparoscopic, and 875 (36%) underwent robotic resection. The median follow-up was 3.8 years (45.4 months). Robotic surgery was associated with higher lymph node yield and radicality of mesenteric resection. On multivariable analysis, the surgical approach was not associated with a difference in disease-free or overall survival. Minimally invasive colectomy was associated with fewer complications and shorter length of stay in comparison to open surgery. In a direct comparison between the 2 minimally invasive approaches, robotic colectomy was associated with fewer complications, shorter length of stay, and lower conversion rate than laparoscopy. LIMITATIONS: This was a single-center retrospective study. CONCLUSIONS: Our data indicate that the 3 surgical approaches are similarly effective in treating primary resectable colon cancer and that differences in outcomes are observed primarily in the early postoperative period. See Video Abstract at http://links.lww.com/DCR/C115 . COMPARACIN DE RESECCIONES ROBTICAS, LAPAROSCPICAS Y ABIERTAS DE CNCER DE COLON NO METASTSICO: ANTECEDENTES:La resección laparoscópica para el cáncer de colon no se ha asociado con mejoras en los resultados oncológicos en comparación con la resección abierta. Las resecciones robóticas se asocian con un mayor rendimiento de los ganglios linfáticos y la radicalidad de la resección mesentérica en pacientes con tumores del lado derecho. No está claro si la cosecha ganglionar es mayor en las resecciones robóticas en otras partes del colon y si un mayor rendimiento de los ganglios linfáticos se asocia con una mejor supervivencia.OBJETIVO:Comparar las tasas de supervivencia entre resecciones robóticas, laparoscópicas y abiertas en una gran cohorte de pacientes con cáncer de colon no metastásico.DISEÑO:Este es un estudio observacional retrospectivo.ESCENARIO:Este estudio se realizó en un único centro oncológico integral.PACIENTES:Pacientes que se sometieron a resección de cáncer de colon primario no metastásico entre enero de 2006 y diciembre de 2018.PRINCIPALES MEDIDAS DE RESULTADO:Se utilizaron modelos univariables y multivariables para identificar predictores de supervivencia libre de enfermedad y global. La cosecha ganglionar y los resultados perioperatorios se compararon entre los abordajes quirúrgicos.RESULTADOS:Hubo 2398 pacientes que cumplieron con los criterios de inclusión: 699 (29%) se sometieron a cirugía abierta, 824 (34%) se sometieron a resección laparoscópica y 875 (36%) se sometieron a resección robótica. La mediana de seguimiento fue de 3,8 años (45,4 meses). La cirugía robótica se asoció con una mayor cosecha ganglionar y la radicalidad de la resección mesentérica. En el análisis multivariable, el abordaje quirúrgico no se asoció con una diferencia en la supervivencia general o libre de enfermedad. La colectomía mínimamente invasiva se asoció con menos complicaciones y una estancia más corta en comparación con la cirugía abierta. En una comparación directa entre los dos enfoques mínimamente invasivos, la colectomía robótica se asoció con menos complicaciones, una estancia más corta y una tasa de conversión más baja que la laparoscopia.LIMITACIONES:Este fue un estudio retrospectivo de un solo centro.CONCLUSIONES:Nuestros datos indican que los tres enfoques quirúrgicos son igualmente efectivos en el tratamiento del cáncer de colon resecable primario y que las diferencias en los resultados se observan principalmente en el período posoperatorio temprano. Consulte Video Resumen en http://links.lww.com/DCR/C115 . (Traducción-Dr. Felipe Bellolio ).

The RECOURSE Study: Long-term Oncologic Outcomes Associated With Robotically Assisted Minimally Invasive Procedures for Endometrial, Cervical, Colorectal, Lung, or Prostate Cancer: A Systematic Review and Meta-analysis.

OBJECTIVE: To assess long-term outcomes with robotic versus laparoscopic/thoracoscopic and open surgery for colorectal, urologic, endometrial, cervical, and thoracic cancers. BACKGROUND: Minimally invasive surgery provides perioperative benefits and similar oncological outcomes compared with open surgery. Recent robotic surgery data have questioned long-term benefits. METHODS: A systematic review and meta-analysis of cancer outcomes based on surgical approach was conducted based on Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines using Pubmed, Scopus, and Embase. Hazard ratios for recurrence, disease-free survival (DFS), and overall survival (OS) were extracted/estimated using a hierarchical decision tree and pooled in RevMan 5.4 using inverse-variance fixed-effect (heterogeneity nonsignificant) or random effect models. RESULTS: Of 31,204 references, 199 were included (7 randomized, 23 database, 15 prospective, 154 retrospective studies)-157,876 robotic, 68,007 laparoscopic/thoracoscopic, and 234,649 open cases. Cervical cancer: OS and DFS were similar between robotic and laparoscopic [1.01 (0.56, 1.80), P =0.98] or open [1.18 (0.99, 1.41), P =0.06] surgery; 2 papers reported less recurrence with open surgery [2.30 (1.32, 4.01), P =0.003]. Endometrial cancer: the only significant result favored robotic over open surgery [OS; 0.77 (0.71, 0.83), P <0.001]. Lobectomy: DFS favored robotic over thoracoscopic surgery [0.74 (0.59, 0.93), P =0.009]; OS favored robotic over open surgery [0.93 (0.87, 1.00), P =0.04]. Prostatectomy: recurrence was less with robotic versus laparoscopic surgery [0.77 (0.68, 0.87), P <0.0001]; OS favored robotic over open surgery [0.78 (0.72, 0.85), P <0.0001]. Low-anterior resection: OS significantly favored robotic over laparoscopic [0.76 (0.63, 0.91), P =0.004] and open surgery [0.83 (0.74, 0.93), P =0.001]. CONCLUSIONS: Long-term outcomes were similar for robotic versus laparoscopic/thoracoscopic and open surgery, with no safety signal or indication requiring further research (PROSPERO Reg#CRD42021240519).

Quality of life and function after rectal cancer surgery with and without sphincter preservation.

Despite improvements in surgical techniques, functional outcomes and quality of life after therapy for rectal cancer remain suboptimal. We sought to prospectively evaluate the effect of bowel, bladder, and sexual functional outcomes on health-related quality of life (QOL) in patients with restorative versus non-restorative resections after rectal cancer surgery. A cohort of 211 patients with clinical stage I-III rectal cancer who underwent open surgery between 2006 and 2009 at Memorial Sloan Kettering were included. Subjects were asked to complete surveys preoperatively and at 6, 12, and 24 months after surgery. Validated instruments were used to measure QOL, bowel, bladder, and sexual function. Univariable and multivariable regression analyses evaluated predictors of 24- month QOL. In addition, longitudinal trends over the study period were evaluated using repeated measures models. In total, 180 patients (85%) completed at least 1 survey, and response rates at each time point were high (>70%). QOL was most impaired at 6 and 12 months and returned to baseline levels at 24 months. Among patients who underwent sphincter-preserving surgery (SPS; n=153 [85%]), overall bowel function at 24 months was significantly impaired and never returned to baseline. There were no differences in QOL at 24 months between patients who underwent SPS and those who did not (p=.29). Bowel function was correlated with QOL at 24 months (Pearson correlation,.41; p<.001). QOL among patients who have undergone SPS for rectal cancer is good despite poor function. Patients with ostomies are able to adjust to the functional changes and, overall, have good global QOL. Patients with low anastomoses had lower global QOL at 24 months than patients with permanent stomas. Our findings can help patients set expectations about function and quality of life after surgery for rectal cancer with and without a permanent stoma.

A Dynamic Clinical Calculator for Estimating Conditional Recurrence-Free Survival After Total Neoadjuvant Therapy for Rectal Cancer and Either Surgery or Watch-and-Wait Management.

Importance: The risk of recurrence in patients with locally advanced rectal cancer has historically been determined after surgery, relying on pathologic variables. A growing number of patients are being treated without surgery, and their risk of recurrence needs to be calculated differently. Objective: To develop a dynamic calculator for estimating the probability of recurrence-free survival (RFS) in patients with rectal cancer who undergo total neoadjuvant therapy (TNT) (induction systemic chemotherapy and chemoradiotherapy) and either surgery or watch-and-wait management. Design, Setting, and Participants: This cohort study included patients who presented with stage II or III rectal cancer between June 1, 2009, and March 1, 2015, at a comprehensive cancer center. Conditional modeling was incorporated into a previously validated clinical calculator to allow the probability of RFS to be updated based on whether the patient remained in watch-and-wait management or underwent delayed surgery. Data were analyzed from November 2021 to March 2022. Exposure: TNT followed by immediate surgery or watch-and-wait management with the possibility of delayed surgery. Main Outcomes and Measures: RFS, concordance index, calibration curves. Results: Of the 302 patients in the cohort, 204 (68%) underwent surgery within 3 months from TNT completion (median [range] age, 51 [22-82] years; 78 [38%] women), 54 (18%) underwent surgery more than 3 months from TNT completion (ie, delayed surgery; median [range] age, 62 [31-87] years; 30 [56%] female), and 44 (14%) remained in watch-and-wait management as of April 21, 2021 (median [range] age, 58 [32-89] years; 16 [36%] women). Among patients who initially opted for watch-and-wait management, migration to surgery due to regrowth or patient choice occurred mostly within the first year following completion of TNT, and RFS did not differ significantly whether surgery was performed 3.0 to 5.9 months (73%; 95% CI, 52%-92%) vs 6.0 to 11.9 months (71%; 95% CI, 51%-99%) vs more than 12.0 months (70%; 95% CI, 49%-100%) from TNT completion (P = .70). RFS for patients in the watch-and-wait cohort at 12 months from completion of TNT more closely resembled patients who had undergone surgery and had a pathologic complete response than the watch-and-wait cohort at 3 months from completion of TNT. Accordingly, model performance improved over time, and the concordance index increased from 0.62 (95% CI, 0.53-0.71) at 3 months after TNT to 0.66 (95% CI, 0-0.75) at 12 months. Conclusions and Relevance: In this cohort study of patients with rectal cancer, the clinical calculator reliably estimated the likelihood of RFS for patients who underwent surgery immediately after TNT, patients who underwent delayed surgery after entering watch-and-wait management, and patients who remained in watch-and-wait management. Delayed surgery following attempted watch-and-wait did not appear to compromise oncologic outcomes. The risk calculator provided conditional survival estimates at any time during surveillance and could help physicians counsel patients with rectal cancer about the consequences of alternative treatment pathways and thereby support informed decisions that incorporate patients' preferences.

Genomic and transcriptomic determinants of response to neoadjuvant therapy in rectal cancer.

The incidence of rectal cancer is increasing in patients younger than 50 years. Locally advanced rectal cancer is still treated with neoadjuvant radiation, chemotherapy and surgery, but recent evidence suggests that patients with a complete response can avoid surgery permanently. To define correlates of response to neoadjuvant therapy, we analyzed genomic and transcriptomic profiles of 738 untreated rectal cancers. APC mutations were less frequent in the lower than in the middle and upper rectum, which could explain the more aggressive behavior of distal tumors. No somatic alterations had significant associations with response to neoadjuvant therapy in a treatment-agnostic manner, but KRAS mutations were associated with faster relapse in patients treated with neoadjuvant chemoradiation followed by consolidative chemotherapy. Overexpression of IGF2 and L1CAM was associated with decreased response to neoadjuvant therapy. RNA-sequencing estimates of immune infiltration identified a subset of microsatellite-stable immune hot tumors with increased response and prolonged disease-free survival.

Predictors of operative difficulty in robotic low anterior resection for rectal cancer.

AIM: This study evaluates the relationship of tumour and anatomical features with operative difficulty in robotic low anterior resection performed by four experienced surgeons in a high-volume colorectal cancer practice. METHODS: Data from 382 patients who underwent robotic low anterior resection by four expert surgeons between January 2016 and June 2019 were included in the analysis. Operating time was used as a measure of operative difficulty. Univariate and multivariate mixed models were used to identify associations between baseline characteristics and operating time, with surgeon as a random effect, thereby controlling for variability in surgeon speed and proficiency. In an exploratory analysis, operative difficulty was defined as conversion to laparotomy, a positive margin or an incomplete mesorectum. RESULTS: Median operating time was 4.28 h (range 1.95-11.33 h) but varied by surgeon from 3.45 h (1.95-6.10 h) to 5.93 h (3.33-11.33 h) (P < 0.001). Predictors of longer operating time in multivariate analysis were male sex, higher body mass index, neoadjuvant radiotherapy, low tumour height, greater sacral height and larger mesorectal area at the S5 vertebral level. Conversion occurred in two cases (0.5%), and incomplete mesorectum and positive margins were found in nine (2.4%) and 19 (5.0%) patients, respectively. Neoadjuvant radiotherapy and larger pelvic outlet were the only characteristics associated with the exploratory measure of difficulty. CONCLUSION: Predicting operative difficulty based on easy to identify, preoperative radiological and clinical variables is feasible in robotic anterior resection.

PD-1 Blockade in Mismatch Repair-Deficient, Locally Advanced Rectal Cancer.

BACKGROUND: Neoadjuvant chemotherapy and radiation followed by surgical resection of the rectum is a standard treatment for locally advanced rectal cancer. A subset of rectal cancer is caused by a deficiency in mismatch repair. Because mismatch repair-deficient colorectal cancer is responsive to programmed death 1 (PD-1) blockade in the context of metastatic disease, it was hypothesized that checkpoint blockade could be effective in patients with mismatch repair-deficient, locally advanced rectal cancer. METHODS: We initiated a prospective phase 2 study in which single-agent dostarlimab, an anti-PD-1 monoclonal antibody, was administered every 3 weeks for 6 months in patients with mismatch repair-deficient stage II or III rectal adenocarcinoma. This treatment was to be followed by standard chemoradiotherapy and surgery. Patients who had a clinical complete response after completion of dostarlimab therapy would proceed without chemoradiotherapy and surgery. The primary end points are sustained clinical complete response 12 months after completion of dostarlimab therapy or pathological complete response after completion of dostarlimab therapy with or without chemoradiotherapy and overall response to neoadjuvant dostarlimab therapy with or without chemoradiotherapy. RESULTS: A total of 12 patients have completed treatment with dostarlimab and have undergone at least 6 months of follow-up. All 12 patients (100%; 95% confidence interval, 74 to 100) had a clinical complete response, with no evidence of tumor on magnetic resonance imaging, 18F-fluorodeoxyglucose-positron-emission tomography, endoscopic evaluation, digital rectal examination, or biopsy. At the time of this report, no patients had received chemoradiotherapy or undergone surgery, and no cases of progression or recurrence had been reported during follow-up (range, 6 to 25 months). No adverse events of grade 3 or higher have been reported. CONCLUSIONS: Mismatch repair-deficient, locally advanced rectal cancer was highly sensitive to single-agent PD-1 blockade. Longer follow-up is needed to assess the duration of response. (Funded by the Simon and Eve Colin Foundation and others; ClinicalTrials.gov number, NCT04165772.).

Programme of self-reactive innate-like T cell-mediated cancer immunity.

Cellular transformation induces phenotypically diverse populations of tumour-infiltrating T cells1-5, and immune checkpoint blockade therapies preferentially target T cells that recognize cancer cell neoantigens6,7. Yet, how other classes of tumour-infiltrating T cells contribute to cancer immunosurveillance remains elusive. Here, in a survey of T cells in mouse and human malignancies, we identified a population of αß T cell receptor (TCR)-positive FCER1G-expressing innate-like T cells with high cytotoxic potential8 (ILTCKs). These cells were broadly reactive to unmutated self-antigens, arose from distinct thymic progenitors following early encounter with cognate antigens, and were continuously replenished by thymic progenitors during tumour progression. Notably, expansion and effector differentiation of intratumoural ILTCKs depended on interleukin-15 (IL-15) expression in cancer cells, and inducible activation of IL-15 signalling in adoptively transferred ILTCK progenitors suppressed tumour growth. Thus, the antigen receptor self-reactivity, unique ontogeny, and distinct cancer cell-sensing mechanism distinguish ILTCKs from conventional cytotoxic T cells, and define a new class of tumour-elicited immune response.

Technical feasibility of salvage endoscopic submucosal dissection after chemoradiation for locally advanced rectal adenocarcinoma.

BACKGROUND AND AIMS: The standard treatment of locally advanced rectal cancer is chemoradiation (CRT) followed by proctectomy and adjuvant chemotherapy. However, there is an emerging role for nonsurgical management after CRT or total neoadjuvant therapy (TNT) consisting of CRT and neoadjuvant chemotherapy. Endoscopic submucosal dissection (ESD) after CRT or TNT for rectal cancer, termed "salvage ESD," may be a viable nonsurgical option for carefully selected patients. We aimed to evaluate the feasibility and safety of salvage ESD. METHODS: A retrospective chart review of cases of salvage ESD for locally advanced rectal cancer and standard ESD for rectal tumors without prior CRT from July 2018 to August 2020 at our institution was performed. Clinical factors and imaging, procedural, and pathology results were collected and compared. RESULTS: Twelve salvage ESD cases were compared with 27 standard ESD cases. Before CRT, 83.3% of lesions in the salvage ESD group were initially clinically staged as T3. The en-bloc resection rates were 92.7% and 91.7% (P = 1.00) and R0 resection rates 66.7% and 75.0% (P = .55) for the standard and salvage groups, respectively. In the salvage ESD group, no adverse events were observed, and 75.0% of the adenocarcinomas in the salvage ESD group had morphologically changed to hyperplasia or adenoma after CRT, with no identifiable lesions greater than T1 tumor depth. CONCLUSIONS: Salvage ESD for locally advanced rectal cancer is technically feasible with low adverse event rates. There may be a diagnostic role in salvage ESD in assessing pathologic response to CRT and a possible therapeutic role in resection of residual lesions with the potential to avoid surgery.