Neoadjuvant chemoradiation and local excision for T2-3 rectal cancer

The application of the golden-angle radial sparse parallel technique in T restaging of locally advanced rectal cancer after neoadjuvant chemoradiotherapy

PURPOSE

To evaluate the diagnostic performance of Golden-Angle Radial Sparse Parallel (GRASP) MRI in identifying pathological stage T0-1 (ypT0-1) after neoadjuvant chemoradiotherapy (nCRT) in patients with rectal cancer, compared to T2-weighted imaging (T2WI) combined with Diffusion Weighted Imaging (DWI).

METHODS

In this retrospective study, 168 patients were carefully selected based on inclusion criteria that targeted individuals with biopsy-confirmed primary rectal adenocarcinoma, identified via MRI as having locally advanced disease (≥ T3 and/or positive lymph node results) prior to nCRT. Post-nCRT, all MRI images obtained after nCRT were assessed by two observers independently. The area under the receiver operating characteristic curve (AUC), sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and accuracy for identifying ypT0-1 based on GRASP and T2 + DWI were calculated. Multivariable regression analysis was used to explore the factors independently associated with ypT0-1 tumor.

RESULTS

45 patients out of these cases were ypT0-1, and the accuracy, sensitivity, specificity, PPV, and NPV of GRASP were higher than the T2 + DWI (88% vs 74%, 93% vs 71%, 86% vs 75%, 71% vs 52% and 97% vs 88%), the AUC in identifying ypT0-1 tumor based on GRASP was 0.90 (95% CI:0.84, 0.94), which was better than the T2 + DWI (0.73; 95% CI: 0.66, 0.80). Multivariable logistic regression analysis showed that the yT stage on GRASP scans was the only factor independently associated with ypT0-1 tumor (P < 0.001).

CONCLUSION

The GRASP helped distinguish ypT0-1 tumor after nCRT and can select patients who may be suitable for local excision.

The Outcome of Local Excision of Rectal Adenomas with High-Grade Dysplasia by Transanal Endoscopic Microsurgery: A Single-Center Experience

Background: Local excision by transanal endoscopic microsurgery (TEM) is considered an acceptable treatment for rectal adenomas with high-grade dysplasia (HGD). This study aims to assess the likelihood of harboring an invasive carcinoma in preoperatively diagnosed HGD polyps and evaluate the risk factors for tumor recurrence in patients with final HGD pathology. Methods: Data from patients who underwent TEM procedures for adenomatous lesions with HGD from 2005 to 2018 at the Rabin Medical Center, Hasharon Hospital, were analyzed. Collected data included patient demographics, preoperative workup, tumor characteristics and postoperative results. Follow-up data including recurrence assessment and further treatments were reviewed. The analysis included two subsets: preoperative pathology of HGD (sub-group 1) and postoperative final pathology of HGD (sub-group 2) patients. Results: Forty-five patients were included in the study. Thirty-six patients had a preoperative diagnosis of HGD, with thirteen (36%) showing postoperative invasive carcinoma. Thirty-two patients had a final pathology of HGD, and three (9.4%) experienced tumor recurrence. Large tumor size (>5 cm) was significantly associated with recurrence (p = 0.03). Conclusions: HGD rectal polyps are associated with a significant risk of invasive cancer. Tumor size was a significant factor in predicting tumor recurrence in patients with postoperative HGD pathology. The TEM procedure is an effective first-line treatment for such lesions.

A study on the radiomic correlation between CBCT and pCT scans based on modified 3D-RUnet image segmentation

Purpose

The present study is based on evidence indicating a potential correlation between cone-beam CT (CBCT) measurements of tumor size, shape, and the stage of locally advanced rectal cancer. To further investigate this relationship, the study quantitatively assesses the correlation between positioning CT (pCT) and CBCT in the radiomics features of these cancers, and examines their potential for substitution.

Methods

In this study, 103 patients diagnosed with locally advanced rectal cancer and undergoing neoadjuvant chemoradiotherapy were selected as participants. Their CBCT and pCT images were used to divide the participants into two groups: a training set and a validation set, with a 7:3 ratio. An improved conventional 3D-RUNet (CLA-UNet) deep learning model was trained on the training set data and then applied to the validation set. The DSC, HD95 and ASSD were calculated for quantitative evaluation purposes. Then, radiomics features were extracted from 30 patients of the test set.

Results

The experiments demonstrate that, the modified model achieves an average DSC score 0.792 for pCT and 0.672 for CBCT scans. 1037 features were extracted from each patient's CBCT and pCT images, 73 image features were found to have R values greater than 0.9, including three features related to the staging and prognosis of rectal cancer.

Conclusion

In this study, we proposed an automatic, fast, and consistent method for rectal cancer GTV segmentation for pCT and CBCT scans. The findings of radiomic results indicate that CBCT images have significant research value in the field of radiomics.

Short-course radiotherapy combined with chemotherapy and PD-1 inhibitor in low-lying early rectal cancer: study protocol for a single-arm, multicentre, prospective, phase II trial (TORCH-E)

INTRODUCTION

Current standard treatment for patients with early rectal cancer is radical surgical resection. Although radical surgery provides effective local tumour control, it also increases the mortality risk and considerable adverse effects, including bowel, bladder, sexual dysfunction and loss of anal function, especially in patients with low-lying rectal cancer. Recent studies have shown promising synergistic effects of the combination of programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) inhibitors and radiotherapy in improving tumour regression. For patients who reach a clinical complete response (cCR) after neoadjuvant therapy, a 'Watch & Wait' (W&W) approach can be adopted to preserve anorectal function and improve quality of life. Thus, this study aims to explore the efficacy and safety of radiotherapy combined with chemotherapy and PD-1 antibody in patients with low early rectal cancer.

METHODS AND ANALYSIS

TORCH-E study is designed as a multicentre, prospective, phase II trial of short-course radiotherapy (SCRT) combined with chemotherapy and PD-1 inhibitor in patients with cT1-3bN0M0 low rectal cancer. The trial was initiated in December 2022 and is currently recruiting patients, with an anticipated completion of participant enrolment by June of the following year. The enrolled 34 patients will receive SCRT (25 Gy/5 Fx), followed by four cycles of capecitabine plus oxaliplatin chemotherapy and PD-1 antibody (toripalimab) and finally receive surgery or the W&W strategy. The primary endpoint is the complete response (CR) rate, that is, the rate of pathological complete response (pCR) plus cCR. The secondary endpoints include organ preservation rate, 3-year local recurrence-free survival rate, 3-year disease-free survival rate, 3-year overall survival rate, grade 3-4 adverse effects rate and patients' quality of life.

ETHICS AND DISSEMINATION

This trial has been approved by the Ethics Committee of Fudan University Shanghai Cancer Center. Trial results will be disseminated via peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

NCT05555888 (ClinicalTrials.gov).

Limits of Clinical Restaging in Detecting Responders After Neoadjuvant Therapies for Rectal Cancer

BACKGROUND

Accurate clinical restaging is required to select patients who respond to neoadjuvant chemoradiotherapy for locally advanced rectal cancer and who may benefit from an organ preservation strategy.

OBJECTIVE

The purpose of this study was to review our experience with the clinical restaging of rectal cancer after neoadjuvant therapy to assess its accuracy in detecting major and pathological complete response to treatment.

DESIGN

This was a retrospective cohort study.

SETTING

This study was conducted at 2 high-volume Italian centers for Colorectal Surgery.

PATIENTS

Data were included from all consecutive patients who underwent neoadjuvant therapy and surgery for locally advanced rectal cancer from January 2012 to July 2020. Criteria to define clinical response were no palpable mass, a superficial ulcer <2 cm (major response), or no mucosal abnormality (complete response) at endoscopy and no metastatic nodes at MRI.

MAIN OUTCOME MEASURES

The main outcome measures were sensitivity, specificity, positive predictive values, and negative predictive values of clinical restaging in detecting pathological complete response (ypT0) or major pathological response (ypT0-1) after neoadjuvant therapy.

RESULTS

A total of 333 patients were included; 81 (24.3%) had a complete response whereas 115 (34.5%) had a pathological major response. Accuracy for clinical complete response was 80.8% and for major clinical response was 72.9%. Sensitivity was low for both clinical complete response (37.5%) in detecting ypT0 and clinical major response (59.3%) in detecting ypT0-1. Positive predictive value was 68.2% for ypT0 and 60.4% for ypT0-1.

LIMITATIONS

The main limitation of the study its retrospective nature.

CONCLUSION

Accuracy of actual clinical criteria to define pathological complete response or pathological major response is poor. Failure to achieve good sensitivity and precision is a major limiting factor in the clinical setting. Current clinical assessments need to be revised to account for indications for rectal preservation after neoadjuvant chemoradiotherapy. See Video Abstract at http://links.lww.com/DCR/C63 .

LMITES DE LA REESTADIFICACIN CLNICA EN LA DETECCIN DE RESPONDEDORES DESPUS DE TERAPIAS NEOADYUVANTES PARA EL CNCER DE RECTO

ANTECEDENTES:Se requiere una nueva reestadificación clínica precisa para seleccionar pacientes que respondan a la quimiorradioterapia neoadyuvante para el cáncer de recto localmente avanzado y que puedan beneficiarse de una estrategia de preservación de órganos.OBJETIVO:El propósito de este estudio fue revisar nuestra experiencia con la reestadificación clínica del cáncer de recto después de la terapia neoadyuvante para evaluar su precisión en la detección de una respuesta patológica importante y completa al tratamiento.DISEÑO:Estudio de cohorte retrospectivo.AJUSTE:Este estudio se realizó en dos centros italianos de alto volumen para cirugía colorrectal.PACIENTES:Incluimos datos de todos los pacientes consecutivos que se sometieron a terapia neoadyuvante y cirugía por cáncer de recto localmente avanzado desde enero de 2012 hasta julio de 2020. Los criterios para definir la respuesta clínica fueron ausencia de masa palpable, úlcera superficial <2 cm (respuesta mayor) o ausencia de anomalías en la mucosa. (respuesta completa) en la endoscopia, y sin ganglios metastásicos en la resonancia magnética.PRINCIPALES MEDIDAS DE RESULTADO:Exploramos la sensibilidad, la especificidad, los valores predictivos positivos y negativos de la reestadificación clínica para detectar una respuesta patológica completa (ypT0) o mayor (ypT0-1) después de la terapia neoadyuvante.RESULTADOS:Se incluyeron 333 pacientes; 81 (24,3%) tuvieron una respuesta completa mientras que 115 (34,5%) tuvieron una respuesta patológica mayor. La precisión de la respuesta clínica completa y la respuesta clínica importante fue del 80,8 % y el 72,9 %, respectivamente. La sensibilidad fue baja tanto para la respuesta clínica completa (37,5 %) en la detección de ypT0 como para la respuesta clínica mayor (59,3 %) en la detección de ypT0-1. El valor predictivo positivo fue del 68,2 % para ypT0 y del 60,4 % para ypT0-1.LIMITACIONES:Nuestro estudio tiene como principal limitación su carácter retrospectivo.CONCLUSIÓNES:La precisión de los criterios clínicos reales para definir una respuesta patológica completa o mayor es pobre. El hecho de no lograr una buena sensibilidad y precisión es un factor limitante importante en el entorno clínico. La indicación para la preservación rectal después de la quimiorradioterapia neoadyuvante necesita una mejora de la evaluación clínica actual. Consulte Video Resumen en http://links.lww.com/DCR/C63 . (Traducción-Dr. Mauricio Santamaria ).

[Transanal Tumor Resection: Indication, Surgical Technique and Management of Complications]

Transanal resection procedures are special operations for the minimally invasive treatment of rectal tumours. Apart from benign tumours, this procedure is suitable for the excision of low-risk T1 rectal carcinomas, if these can be completely removed (R0 resection). With stringent patient selection, very good oncological results are achieved. Various international trials are currently evaluating whether local resection procedures are oncologically sufficient if there is a complete or near complete response after neoadjuvant radio-/chemotherapy. Numerous studies have shown that the functional results and the postoperative quality of life after local resection are excellent, especially considering the well-known functional deficits of alternative operations, such as low anterior or abdominoperineal resection.Severe complications are very rare. Most complications, such as urinary retention or subfebrile temperatures, are minor in nature. Suture line dehiscences are usually clinically unremarkable. Major complications comprise significant haemorrhage and the opening of the peritoneal cavity. The latter must be recognized intraoperatively and can usually be managed by primary suture. Infection, abscess formation, rectovaginal fistula, injury of the prostate or even urethra are extremely rare complications.

Contemporary, national patterns of surgery after preoperative therapy for stage II/III rectal adenocarcinoma

BACKGROUND

Contemporary treatment of stage II/III rectal cancer combines chemotherapy, chemoradiation, and surgery, though the sequence of surgery with neoadjuvant treatments and benefits of minimally-invasive surgery (MIS) is debated.

AIM

To describe patterns of surgical approach for stage II/III rectal cancer in relation to neoadjuvant therapies.

METHODS

A retrospective cohort was created using the National Cancer Database. Primary outcome was rate of sphincter-sparing surgery after neoadjuvant therapy. Secondary outcomes were surgical approach (open, laparoscopic, or robotic), surgical quality (R0 resection and 12+ lymph nodes), and overall survival.

RESULTS

A total of 38927 patients with clinical stage II or III rectal adenocarcinoma underwent surgical resection from 2010-2016. Clinical stage II patients had neoadjuvant chemoradiation less frequently compared to stage III (75.8% vs 84.7%, P < 0.001), but had similar rates of total neoadjuvant therapy (TNT) (27.0% vs 27.2%, P = 0.697). Overall rates of total mesorectal excision without sphincter preservation were similar between clinical stage II and III (30.0% vs 30.3%) and similar if preoperative treatment was chemoradiation (31.3%) or TNT (30.2%). Over the study period, proportion of cases approached laparoscopically increased from 24.9% to 32.5% and robotically 5.6% to 30.7% (P < 0.001). This cohort showed improved survival for MIS approaches compared to open surgery (laparoscopy HR 0.85, 95%CI 0.78-0.93, and robotic HR 0.82, 95%CI 0.73-0.92).

CONCLUSION

Sphincter preservation rates are similar across stage II and III rectal cancer, regardless of delivery of preoperative chemotherapy, chemoradiation, or both. At a national level, there is a shift to predominantly MIS approaches for rectal cancer, regardless of whether sphincter sparing procedure is performed.

A Multidisciplinary Approach for the Personalised Non-Operative Management of Elderly and Frail Rectal Cancer Patients Unable to Undergo TME Surgery

Despite it being the optimal curative approach, elderly and frail rectal cancer patients may not be able to undergo a total mesorectal excision. Frequently, no treatment is offered at all and the natural course of the disease is allowed to unfold. These patients are at risk for developing debilitating symptoms that impair quality of life and require palliative treatment. Recent advancements in non-operative treatment modalities have enhanced the toolbox of alternative treatment strategies in patients unable to undergo surgery. Therefore, a proposed strategy is to aim for the maximal non-operative treatment, in an effort to avoid the onset of debilitating symptoms, improve quality of life, and prolong survival. The complexity of treating elderly and frail patients requires a patient-centred approach to personalise treatment. The main challenge is to optimise the balance between local control of disease, patient preferences, and the burden of treatment. A comprehensive geriatric assessment is a crucial element within the multidisciplinary dialogue. Since limited knowledge is available on the optimal non-operative treatment strategy, these patients should be treated by dedicated multidisciplinary rectal cancer experts with special interest in the elderly and frail. The aim of this narrative review was to discuss a multidisciplinary patient-centred treatment approach and provide a practical suggestion of a successfully implemented clinical care pathway.

Pretreatment Apparent Diffusion Coefficient Cannot Predict Histopathological Features and Response to Neoadjuvant Radiochemotherapy in Rectal Cancer: A Meta-Analysis

AIM

Our purpose was to perform a systemic literature review and meta-analysis regarding use of apparent diffusion coefficient (ADC) for prediction of histopathological features in rectal cancer (RC) and to prove if ADC can predict treatment response to neoadjuvant radiochemotherapy (NARC) in RC.

METHODS

MEDLINE library, EMBASE, Cochrane, and SCOPUS database were screened for associations between ADC and histopathology and/or treatment response in RC up to June 2020. Authors, year of publication, study design, number of patients, mean value, and standard deviation of ADC were acquired. The methodological quality of the collected studies was checked according to the Quality Assessment of Diagnostic Studies instrument. The meta-analysis was undertaken by using the RevMan 5.3 software. DerSimonian and Laird random-effects models with inverse-variance weights were used to account the heterogeneity between the studies. Mean ADC values including 95% confidence intervals were calculated.

RESULTS

Overall, 37 items (2,015 patients) were included. ADC values of tumors with different T and N stages and grades overlapped strongly. ADC cannot distinguish RC with a high- and low-carcinoembryonic antigen level. Regarding KRAS status, ADC cannot discriminate mutated and wild-type RC. ADC did not correlate significantly with expression of vascular endothelial growth factor and hypoxia-inducible factor 1a. ADC correlates with Ki 67, with the calculated correlation coefficient: -0.52. The ADC values in responders and nonresponders overlapped significantly.

CONCLUSION

ADC correlates moderately with expression of Ki 67 in RC. ADC cannot discriminate tumor stages, grades, and KRAS status in RC. ADC cannot predict therapy response to NARC in RC.

Prognostic Factors and Treatment of Recurrence after Local Excision of Rectal Cancer

PURPOSE

Indications for local excision in patients with rectal cancer remain controversial. We reviewed factors affecting survival rate and treatment effectiveness in cancer recurrence after local excision among patients with rectal cancer.

MATERIALS AND METHODS

A total of 831 patients was enrolled. Of these, 391 patients were diagnosed with primary rectal cancer and underwent local excision. A retrospective observational study was performed on patients who underwent full-thickness local excision for rectal cancer.

RESULTS

The median duration of follow-up was 61 months. The overall recurrence rate was 11.5%. The rate of local recurrence was 5.1%. Five-year overall survival rate among recurrent patients was 66.8%; the rate among patients who underwent salvage operation due to recurrence was 84.7%, compared with 44.2% among patients treated with non-operative management (p<0.001). Multivariate analysis of disease-free survival identified distance from the anal verge (p=0.038) and histologic grade (p=0.047) as factors predicting poor prognosis. Multivariate analysis of overall survival showed that age (p<0.001), serum carcinoembryonic antigen (CEA) levels (p=0.001), and histologic grade (p=0.013) also affected poor prognosis. In subgroup analysis of patients with recurrence, 25 patients underwent reoperation, while 20 patients did not. For 5-year overall survival rate, there was a significant difference between 84.7% of the reoperation group and 44.2% of the non-operation group (p<0.001).

CONCLUSION

The risk factors affecting overall survival rate after local excision were age 65 years or older, preoperative CEA level 5 or higher, and high histologic grade. In cases of recurrence after local excision of rectal cancer, salvage operation might improve overall survival.

Prevalence of nodal involvement in rectal cancer after chemoradiotherapy

BACKGROUND

The purpose of this study was to investigate the prevalence of ypN+ status according to ypT category in patients with locally advanced rectal cancer treated with chemoradiotherapy and total mesorectal excision, and to assess the impact of ypN+ on disease recurrence and survival by pooled analysis of individual-patient data.

METHODS

Individual-patient data from 10 studies of chemoradiotherapy for rectal cancer were included. Pooled rates of ypN+ disease were calculated with 95 per cent confidence interval for each ypT category. Kaplan-Meier and Cox regression analyses were undertaken to assess influence of ypN status on 5-year disease-free survival (DFS) and overall survival (OS).

RESULTS

Data on 1898 patients were included in the study. Median follow-up was 50 (range 0-219) months. The pooled rate of ypN+ disease was 7 per cent for ypT0, 12 per cent for ypT1, 17 per cent for ypT2, 40 per cent for ypT3, and 46 per cent for ypT4 tumours. Patients with ypN+ disease had lower 5-year DFS and OS (46.2 and 63.4 per cent respectively) than patients with ypN0 tumours (74.5 and 83.2 per cent) (P < 0.001). Cox regression analyses showed ypN+ status to be an independent predictor of recurrence and death.

CONCLUSION

Risk of nodal metastases (ypN+) after chemoradiotherapy increases with advancing ypT category and needs to be considered if an organ-preserving strategy is contemplated.

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.

Artificial intelligence in rectal cancer

Accurate and rapid diagnosis is essential for correct treatment in rectal cancer. Determining the optimal treatment plan for a patient with rectal cancer is a complex process, and the oncological results and toxicity are not the same in every patient with the same treatment at the same stage. In recent years, the increasing interest in artificial intelligence in all fields of science has also led to the development of innovative tools in oncology. Artificial intelligence studies have increased in many steps from diagnosis to follow-up in rectal cancer. It is thought that artificial intelligence will provide convenience in many ways from personalized treatment to reducing the workload of the physician. Prediction algorithms can be standardized by sharing data between centers, diversifying data, and creating big data.

Could the conservative approach be considered safe in the treatment of locally advanced rectal cancer in case of a clinical near-complete or complete response? A retrospective analysis

Background

Conservative approach has emerged as an option for the management of rectal cancer (RC) patients with a near or complete clinical response after neoadjuvant chemoradiotherapy (nCRT). The aim of this study is to assess the impact of the conservative approach by comparing patients’ survival outcomes and quality of life with those who had surgical resection.

Methods

A single-institution and retrospective study including RC patients who reached a near complete or complete clinical response after nCRT from January 2010 to September 2019. Conservative approaches included local excision or watch and wait strategy; surgery approaches included anterior resection or abdominal-perineal resection.

Local regrowth (LR), overall survival, disease free survival, metastasis free survival and colostomy free survival were evaluated through Kaplan-Meier curves and compared trough log-rank tests. Quality of life was measured by the following validated questionnaires: EORTC QLC30, EORTC QLQ – CR29 and Fecal Incontinence Quality of Life scale.

Results

Overall 157 patients were analyzed: 105 (66,9%) underwent radical surgery and 52 (33,1%) had a conservative approach. With a median follow-up of 51 months, 2 patients in the surgical group had a local recurrence and 8 in the conservative group had a LR, respectively. Distance metastasis occurred in 7 and 1 patients of surgical and conservative group, respectively. No differences were detected in terms of survival outcomes except for colostomy free survival (p: 0,01). The conservative group showed better intestinal (p < 0.01) and sexual (p: 0,04) function and emotional status (p: 0,02).

Conclusions

Conservative approach seems to be safe in terms of survival outcomes with a significant advantage on quality of life in RC patients who achieved clinical complete response after nCRT.

Pathologic-Based Nomograms for Predicting Overall Survival and Disease-Free Survival Among Patients with Locally Advanced Rectal Cancer

Purpose

Preoperative neoadjuvant therapy is standard before surgery for locally advanced rectal cancer in current clinical treatment. However, patients with the same clinical TNM stage before treatment vary in clinical outcomes. More and more studies noted that pathological findings after preoperative neoadjuvant therapy are better prognostic factors to determine prognosis than clinical TNM stage in patients with locally advanced rectal cancer. The purpose of this study is to develop and validate models based on pathological findings to predict overall survival (OS) and disease-free survival (DFS).

Patients and Methods

A total of 3026 patients from two hospitals were included. The endpoint was OS and DFS. Significant predictors of OS on multivariate analysis were used to establish the nomogram.

Results

The Harrell’s C index for OS prediction was 0.72 (95% confidence interval [CI], 0.68 to 0.77) in the training cohort, 0.66 (95% CI, 0.60 to 0.72) and 0.68 (95% CI, 0.64 to 0.73) in the internal and external validation cohorts. Using this nomogram, high- and low-risk groups for OS were defined in the training cohort. The 3-year OS was 78.1% (95% CI: 72.4–84.2%) for the high-risk group and 95% (95% CI: 93.6–96.5%) in the low-risk group (HR: 4.42, 95% CI: 3.22–6.05; P<0.001). This finding was also applied in the two external cohorts. Similarly, a nomogram that contained the same indices was developed and validated to predict for DFS.

Conclusion

Nomograms based on pathological findings are a reliable tool to predict 3-year OS and DFS rate in patients with locally advanced rectal cancer.

Clinical predictors of pathological good response in locally advanced rectal cancer

Purpose

The aim of this study was to identify the clinical predictors of pathological good response (PGR) after neoadjuvant chemoradiotherapy (nCRT) in locally advanced rectal cancer (LARC) to clarify the indications for local excision.

Methods and materials

A total of 173 patients with LARC (cT3–4/N +) who were treated with nCRT followed by surgery were enrolled in our retrospective study. Patients were categorized into two groups according to the different tumor responses of surgical pathology. Stage ypT0–1N0 was defined as the group with PGR, and stage ypT2–4N0/ypTanyN + was the defined as the pathological poor response (PPR) group, and the potential predictors were compared.

Results

Of 173 patients, PGR was achieved in 57 patients (32.95%). The distance from the inferior margin of the tumor to the anal verge, cT classification, pretreatment carcinoembryonic antigen (CEA) and the interval from the end of radiation to surgery were correlated with pathological response. In the multivariate analysis, the distance from anal verge < 5 cm (OR = 0.443, p = 0.019), pretreatment CEA < 5 ng/mL (OR = 0.412, p = 0.015) and the interval from the end of radiation to surgery ≥ 84 days (OR = 2.652, p = 0.005) were independent predictors of PGR.

Conclusions

The distance from the inferior margin of the tumor to the anal verge, pretreatment CEA and the interval from the end of radiation to surgery were significant predictors of PGR in LARC. A prospective study is needed to further validate these results in the future.

Diffusion-weighted MR volume and apparent diffusion coefficient for discriminating lymph node metastases and good response after chemoradiation therapy in locally advanced rectal cancer

OBJECTIVE

To determine diagnostic performance of diffusion-weighted (DW) magnetic resonance (MR) volume and apparent diffusion coefficient values (ADCs) for assessing lymph node metastases (LNM) and good response after chemoradiation therapy (CRT) in patients with locally advanced rectal cancer (LARC).

MATERIALS AND METHODS

This retrospective study consisted of 61 patients with LARC who underwent pre- and post-CRT DW images. Two radiologists independently placed free-hand regions of interest in each tumor-containing section on DW images to calculate pre- and post-CRT tumor volume and tumor volume reduction rates (Δvolume). Regions of interest were drawn to include tumor on maximum cross-sectional slice to obtain ADCs. Areas under the receiver operating characteristic curves (AUCs) were calculated to evaluate diagnostic performance in identifying LNM and good response after CRT using these parameters.

RESULTS

Inter-observer agreement and intra-observer agreement were excellent for pre- and post-CRT DW MR volume (intraclass correlation coefficient [ICC], 0.889-0.948) and moderate for pre- and post-CRT ADCs (ICC, 0.535-0.811). AUCs for identifying LNM were 0.508 for pre-CRT DW MR volume versus 0.705 for pre-CRT ADC, 0.855 for post-CRT DW MR volume versus 0.679 for post-CRT ADC, and 0.887 for Δvolume versus 0.533 for ΔADC. AUCs for identifying good response were 0.518 for pre-CRT volume versus 0.506 for pre-CRT ADC, 0.975 for post-CRT volume versus 0.723 for post-CRT ADC, and 0.987 for Δvolume versus 0.655 for ΔADC.

CONCLUSION

DW MR Δvolume provided high diagnostic performance in discriminating LNM after CRT. DW MR Δvolume was equally as accurate as post-CRT DW MR volume for evaluating good response.

KEY POINTS

• Inter-observer agreement and intra-observer agreement were excellent for pre- and post-CRT DW MR volume (intraclass correlation coefficient [ICC], 0.889-0.948) and moderate for pre- and post-CRT ADCs (ICC, 0.535-0.811). • DW MR Δvolume provided high diagnostic performance in identifying LNM after CRT (AUC, 0.887) and good response (AUC, 0.987) and was significantly more accurate than pre-CRT DW MR volume (AUC, 0.508 and 0.518, respectively) and ADCs (AUC, 0.705 and 0.506, respectively). • DW MR Δvolume (AUC, 0.987) was equally as accurate as post-CRT DW MR volume (AUC, 0.975) for evaluating good response, while pre-CRT DW MR volume and ADCs were not reliable for evaluating LNM and good response after CRT (AUC, 0.506-0.723).

Response Assessment with MRI after Chemoradiotherapy in Rectal Cancer: Current Evidences

Baseline magnetic resonance imaging (MRI) has become the primary staging modality for surgical plans and stratification of patient populations for more efficient neoadjuvant treatment. Patients who exhibit a complete response to chemoradiotherapy (CRT) may achieve excellent local tumor control and better quality of life with organ-preserving treatments such as local excision or even watch-and-wait management. Therefore, the evaluation of tumor response is a key factor for determining the appropriate treatment following CRT. Although post-CRT MRI is generally accepted as the first-choice method for evaluating treatment response after CRT, its application in the clinical decision process is not fully validated. In this review, we will discuss various oncologic treatment options from radical surgical technique to organ-preservation strategies for achieving better cancer control and improved quality of life following CRT. In addition, the current status of post-CRT MRI in restaging rectal cancer as well as the main imaging features that should be evaluated for treatment planning will also be described for the tailored treatment.

Genomic variation as a marker of response to neoadjuvant therapy in locally advanced rectal cancer

There is variation in the responsiveness of locally advanced rectal cancer to neoadjuvant chemoradiation, from complete response to total resistance. This study compared genetic variation in rectal cancer patients who had a complete response to chemoradiation versus poor response, using tumor tissue samples sequenced with genomics analysis software. Rectal cancer patients treated with chemoradiation and proctectomy June 2006-March 2017 were grouped based on response to chemoradiation: those with no residual tumor after surgery (CR, complete responders, AJCC-CPR tumor grade 0, n = 8), and those with poor response (PR, AJCC-CPR tumor grade two or three on surgical resection, n = 8). We identified 195 variants in 83 genes in tissue specimens implicated in colorectal cancer biopathways. PR patients showed mutations in four genes not mutated in complete responders: KDM6A, ABL1, DAXX-ZBTB22, and KRAS. Ten genes were mutated only in the CR group, including ARID1A, PMS2, JAK1, CREBBP, MTOR, RB1, PRKAR1A, FBXW7, ATM C11orf65, and KMT2D, with specific discriminating variants noted in DMNT3A, KDM6A, MTOR, APC, and TP53. Although conclusions may be limited by small sample size in this pilot study, we identified multiple genetic variations in tumor DNA from rectal cancer patients who are poor responders to neoadjuvant chemoradiation, compared to complete responders.

18F-FDG PET/MRI for Rectal Cancer TNM Restaging After Preoperative Chemoradiotherapy: Initial Experience

OBJECTIVE

F-FDG-PET/MRI is a novel hybrid techinque that has been recently introduced in oncological imaging, showing promising results. The aim of this study is to assess the value of whole-body F-FDG-PET/MRI for predicting the pathological stage of locally advanced rectal cancer after preoperative chemoradiotherapy.

DESIGN

This was a prospective observational study.

SETTINGS

The study was conducted at a tertiary care hospital.

PATIENTS

Thirty-six patients with locally advanced rectal cancer (25 male, median age 68.5 years) were prospectively assessed with PET/MRI and thoracoabdominal CT before and after preoperative chemoradiotherapy. Twenty-seven patients underwent low anterior or abdominoperineal resection. Nine patients with a complete clinical response underwent organ-preserving treatment (8 local excision and 1 watch-and-wait approach) with >1-year follow-up.

MAIN OUTCOME MEASURES

One radiologist evaluated pelvic MRI and CT. A second radiologist and a nuclear medicine physician jointly assessed PET/MRI. The imaging was compared with histology or follow-up (ypT0 vs T ≥1 and ypN0 vs ypN+ categories). Metastases were confirmed with biopsy or a follow-up CT scan at least at 1 year after preoperative chemoradiotherapy. The sensitivity, specificity, and accuracy values of the imaging techniques were calculated using standard formulas.

RESULTS

The accuracy for ypT staging was 89% and 92%, and the accuracy for ypN was 86% and 92% for MRI and PET/MRI. Compared with CT, PET/MRI correctly diagnosed 4 of 5 metastases, but it did not detect a lung metastatic nodule. In 11% of the patients, the PET/MRI changed the treatment strategy.

LIMITATIONS

This study is limited by its small sample size.

CONCLUSIONS

Although the whole-body PET/MRI was more accurate than the pelvic MRI alone for the prediction of tumor and node response to preoperative chemoradiotherapy, the technique performed worse than CT in detecting small lung metastasis. See Video Abstract at http://links.lww.com/DCR/B108. TOMOGRAFÍA POR EMISIÓN DE POSITRONES DE 18F- FLUORODEOXIGLUCOSA (FDG) / RESONANCIA MAGNÉTICA (TEP/RM) PARA ESTADIFICACIÓN TUMORAL TNM DE CÁNCER DEL RECTO DESPUÉS DE LA QUIMIORRADIOTERAPIA PREOPERATORIA - EXPERIENCIA INICIAL: Evaluar el valor de la tomografía por emisión de positrones de 18F-fluorodeoxiglucosa / resonancia magnética (TEP/RM) para predecir el estadio patológico del cáncer de recto localmente avanzado después de la quimiorradioterapia preoperatoria.Este fue un estudio prospectivo observacional.El estudio se realizó en un hospital de atención terciaria.Treinta y seis pacientes con cáncer rectal localmente avanzado (25 hombres, edad media de 68.5 años) fueron evaluados prospectivamente con TEP/RM y tomografía computarizada (TC) toraco-abdominal antes y después de la quimiorradioterapia preoperatoria. Veintisiete pacientes se sometieron a resección anterior baja o abdominoperineal. Nueve pacientes con una respuesta clínica completa se sometieron a un tratamiento de preservación de órganos (8 escisión local y 1 un enfoque de observar y esperar) con un seguimiento de> 1 año.Un radiólogo evaluó la RM pélvica y la TC. Un segundo radiólogo y un médico de medicina nuclear evaluaron conjuntamente TEP / RM. La imagen se comparó con la histología o el seguimiento (ypT0 vs T ≥1 y ypN0 vs ypN + categorías). Las metástasis se confirmaron con biopsia o una TC de seguimiento al menos 1 año después de la quimiorradioterapia preoperatoria. Los valores de sensibilidad, especificidad y precisión de las técnicas de imagen se calcularon utilizando fórmulas estándar.La precisión para la estadificación ypT fue del 89% y 92%, y la precisión para ypN fue del 86% y 92% para RM y TEP/RM respectivamente. En comparación con la TC, la TEP / RM diagnosticó correctamente 4 de 5 metástasis, pero no detectó un nódulo metastásico pulmonar. En el 11% de los pacientes, la TEP / RM cambió la estrategia de tratamiento.Este estudio está limitado por su pequeño tamaño de muestra.Si bien la TEP / RM de todo el cuerpo fue más precisa que la RM pélvica sola para la predicción de la respuesta tumoral y ganglionar a la quimiorradioterapia preoperatoria, la técnica funcionó peor que la TC para detectar metástasis pulmonares pequeños. Consulte Video Resumen en http://links.lww.com/DCR/B108.

Organ-saving surgery for rectal cancer after neoadjuvant chemoradiation: Analysis of failures and long-term results

BACKGROUND

To analyze long-term results and risk of relapse in the clinical TNM stages II and III, mid-low rectal cancer patients (RC pts), treated with transanal local excision (LE) after major response to neoadjuvant chemoradiation (n-CRT).

METHODS

Thirty-two out of 345 extraperitoneal cT3-4 or N+ RC pts (9.3%) underwent LE.

INCLUSION CRITERIA

extraperitoneal RC, adenocarcinoma, ECOG Performance Status ≤2. Pts with distant metastases were excluded.

RESULTS

All pts showed histologically clear margins of resection and 81.2% were restaged ypT0/mic/1. Nine out of 32 (28.1%) pts relapsed: 7 (21.8%) showed a local recurrence, of which 5 (15.6%) at the endorectal suture, 1 (3.1%) pelvic and 1 (3.1%) mesorectal. Two pts (6.2%) relapsed distantly. Among the pT0/1, 11.5% relapsed vs 100% of the pT2 and pT4 ones. The six pts relapsing locally or in the mesorectal fat underwent a salvage total mesorectal excision surgery. The old patient with pelvic recurrence relapsed after 108 months and underwent a re-irradiation; the two pts with distant metastases were treated with chemotherapy followed by radical surgery.

CONCLUSIONS

Presently combined approach seems a valid option in major responders, confirming its potential curative impact in the ypT0/mic/1 pts. A strict selection of pts is basic to obtain favourable results.

Laparoscopic Ultra Low Anterior Resection: Single Center, 6-Year Study

Background: This study represents a prospective analysis of a series of laparoscopic ultra low anterior resection (ULAR) done at a laparoscopic surgical center to assess the surgical outcome, oncological efficacy, and quality of life after surgery. Methods: Over a period of 6 years (2013-2018), 43 patients aged between 40 and 68 years, with very low rectal cancers (3-6 cm from the anal verge), within T3N1M0 stage, assessed by positron emission tomography-computed tomography and pelvic magnetic resonance imaging, underwent neoadjuvant chemoradiotherapy (nCRT) followed by laparoscopic ULAR and simultaneous diversion ileostomy. Results: The overall complication rate was low and there was an overall leak rate of 9.3% with a radiological leak (Grade A) in 3 of the 43 patients (7%), but only 1 (2.3%) patient required a local lavage and a resuturing for secondary hemorrhage. Recurrence was seen in 2/43 (4.7%), one of whom had a conversion to abdominoperineal resection. The other had distant metastasis and refused further treatment. The functional outcome is assessed in 41 (95.3%) patients by low anterior resection syndrome (LARS) score and a reasonable quality of life with major LARS was seen in only 7.3% of the patients at a follow-up ranging from 1 to 6 years. Conclusion: The nCRT followed by laparoscopic ULAR is a feasible option for operable very low rectal cancers and is associated with minimal postoperative events, a low local recurrence and less incidence of LARS.

Endoscopy and magnetic resonance imaging-based prediction of ypT stage in patients with rectal cancer who received chemoradiotherapy: Results from a prospective study of 110 patients

Accurate tumor response determination remains inconclusive after preoperative chemoradiation therapy (CRT) for rectal cancer. This study aimed to investigate whether clinical assessment, such as endoscopy and magnetic resonance imaging (MRI), can accurately predict ypT stage and select candidates for pelvic organ-preserving surgery in rectal cancer after preoperative CRT. A total of 110 patients who underwent preoperative CRT followed by curative resection for rectal cancer were prospectively enrolled. Magnetic resonance tumor regression grade (mrTRG) using T2-MRI, endoscopic evaluation, and combination modality (combination of endoscopy and mrTRG) were used to analyze tumor response after preoperative CRT. Endoscopic findings were categorized as 3 grades and the mrTRG was assessed into 5 grades. Twenty-nine patients (26.4%) had achieved pathologic complete response. When predicting ypT0, endoscopy showed significantly higher area under the curve (AUC 0.818) than did mrTRG (AUC 0.568) and combination modality (AUC 0.768) in differentiating good response from poor response (P < .001). Both endoscopy and combination modality showed significantly higher diagnostic performance in sensitivity (79.31%), positive predictive value (PPV 67.65%), negative predictive value (NPV 92.11%), and accuracy (84.55%) than those of MR tumor response (sensitivity 37.93%, PPV 36.67%, NPV 77.50%, and accuracy 66.36%) for the prediction of ypT0 (P < .001). Combination modality showed significantly higher diagnostic performance in sensitivity (56.92%), NPV (56.92%), and accuracy (67.27%) compared with those of mrTRG. Neither endoscopy, nor mrTRG, nor the combination modality had adequate diagnostic performances to be clinically acceptable in selecting candidates for nonoperative treatment strategies. However, endoscopy may be incorporated in clinical restaging strategy in planning the extent of surgical resection in patients with rectal cancer.

Is It Possible a Conservative Approach After Radiochemotherapy in Locally Advanced Rectal Cancer (LARC)? A Systematic Review of the Literature and Meta-analysis

BACKGROUND

Locally advanced rectal cancer is usually treated with a preoperative approach with radiochemotherapy followed by surgery. Patients obtaining a pathologic complete response have a very favorable long-term prognosis. This study was intended to assess whether major surgery can reduce tumor recurrences and prolong survival of patients with a complete response after radiochemotherapy.

METHODS

Computerized literature search was performed to identify relevant articles. Comparative studies reporting the outcomes of non-operative and operative management in patients after neoadjuvant treatment were reviewed. Data synthesis was performed using Review Manager 5.0 software.

RESULTS

Twelve non-randomized comparative studies with a total of 1812 patients were suitable for analysis. There was no significant difference in overall survival at 3 and 5 years (odds ratio [OR] 1.31; 95% CI 0.64-2.69; p = 0.46 and 1.48; 95% CI 1.00-2.20; p = 0.50) and in disease-free survival at 3 and 5 years (odds ratio [OR] 1.20; 95% CI 0.68-2.14; p = 0.53 and 1.22; 95% CI 0.86-1.74; p = 0.26, respectively) between locally advanced rectal cancer patients treated with and without operative approach.

CONCLUSIONS

Major surgery does not seem to improve prognosis in patients obtaining a complete response after radiochemotherapy. Clinical trials, using clear criteria to identify complete response patients, are needed to recommend non-operative approach.

Machine learning for prediction of chemoradiation therapy response in rectal cancer using pre-treatment and mid-radiation multi-parametric MRI

PURPOSE

To predict the neoadjuvant chemoradiation therapy (CRT) response in patients with locally advanced rectal cancer (LARC) using radiomics and deep learning based on pre-treatment MRI and a mid-radiation follow-up MRI taken 3-4 weeks after the start of CRT.

METHODS

A total of 51 patients were included, 45 with pre-treatment, 41 with mid-radiation therapy (RT), and 35 with both MRI sets. The multi-parametric MRI protocol included T2, diffusion weighted imaging (DWI) with b-values of 0 and 800 s/mm², and dynamic-contrast-enhanced (DCE) MRI. After completing CRT and surgery, the specimen was examined to determine the pathological response based on the tumor regression grade. The tumor ROI was manually drawn on the post-contrast image and mapped to other sequences. The total tumor volume and mean apparent diffusion coefficient (ADC) were measured. Radiomics using GLCM texture and histogram parameters, and deep learning using a convolutional neural network (CNN), were performed to differentiate pathologic complete response (pCR) vs. non-pCR, and good response (GR) vs. non-GR.

RESULTS

Tumor volume decreased and ADC increased significantly in the mid-RT MRI compared to the pre-treatment MRI. For predicting pCR vs. non-pCR, combining ROI and radiomics features achieved an AUC of 0.80 for pre-treatment, 0.82 for mid-RT, and 0.86 for both MRI together. For predicting GR vs. non-GR, the AUC was 0.91 for pre-treatment, 0.92 for mid-RT, and 0.93 for both MRI together. In deep learning using CNN, combining pre-treatment and mid-RT MRI achieved a higher accuracy compared to using either dataset alone, with AUC of 0.83 for predicting pCR vs. non-pCR.

CONCLUSION

Radiomics based on pre-treatment and early follow-up multi-parametric MRI in LARC patients receiving CRT could extract comprehensive quantitative information to predict final pathologic response.

Non-operative treatment outcome for rectal cancer patient with clinical complete response after neoadjuvant chemoradiotherapy

BACKGROUND

Among rectal cancer patients, some of good responders after neoadjuvant chemoradiotherapy (nCRT) are considered for non-operative treatments to avoid postoperative morbidities and permanent stoma. However, oncologic feasibility of non-operative treatment has not been fully understood.

METHODS

From 2008 to 2017, we retrospectively reviewed patient's records who had lower or mid rectal cancer and diagnosed to clinical complete response by magnetic resonance imaging after nCRT. Clinical differences and oncologic outcomes were compared among Radical surgery (RS), Local excision (LE) and Wait-and-see (WS) group.

RESULTS

Number of 129, 25, 15 patients included to RS, LE, WS groups. Local recurrence was frequent type of recurrence in both of LE and WS group (RS; 31.3%, LE; 80%, WS; 66.7%), and many patients in WS group omitted salvage treatment (RS; 75%, LE; 100%, WS; 33.3%). 5-years local-recurrence/disease-free survival rate (LRFS, DFS) between RS and LE were similar between each group, but WS showed significantly inferior outcomes than that of RS (LRFS; p = 0.001, DFS; p = 0.001). In multivariate analysis, WS protocol (OR; 7.163, 95% CI; 1.995-25.715) and cT4 stage (OR; 8.206, 95% CI; 1.596-42.198) were independent factors for LRFS.

CONCLUSIONS

Wait-and-see group showed high rate of rejection of salvage treatments for recurrence, and poor oncologic outcomes. However, recent low-level evidences reported favorable outcome of WS protocol when salvage treatment was followed after recurrence. It seems that the application of WS protocol should be postponed until the results of randomized-controlled trials are available. Local excision seems to be good alternative option to radical surgery when salvage treatment is followed.

Current Imaging Modalities Understage One-Third of Patients with Stage I Rectal Cancer: Implications for Treatment Selection

Accurate preoperative clinical staging is essential to optimize the treatment of rectal cancer. Primary surgical resection is typically indicated for stage I disease, whereas neoadjuvant therapy is recommended for stages II and III. The objective of this study is to examine the accuracy of clinical staging using current imaging modalities in predicting pathologic stage and, thus, selecting appropriate treatment. Adult patients with nonmetastatic rectal cancer who underwent primary surgical resection were identified from the National Cancer Database between 2006 and 2014. Data on clinical and pathologic staging was obtained. Kappa index was used to determine the correlation between clinical and pathologic staging. A total of 13,175 patients were identified. The correlation between clinical and pathologic staging was 69 per cent for stage I (31% upstaged) (Kappa 0.54, P < 0.001). One-third of patients who were clinically staged as stage I, and were therefore treated with primary surgical resection, had pathologic stage II or III disease. Based on their clinical staging, those patients did not receive the neoadjuvant therapy recommended by present guidelines. Where accurate clinical staging is in doubt, oncologists should carefully examine the quality of staging modality and perhaps consider multimodal imaging using both endorectal ultrasound and MRI.

Transanal Endoscopic Microsurgery with or without Completion Total Mesorectal Excision for T2 and T3 Rectal Carcinoma

AIM

Transanal endoscopic microsurgery (TEM) is used for the resection of large rectal adenomas and well or moderately differentiated T1 carcinomas. Due to difficulty in preoperative staging, final pathology may reveal a carcinoma not suitable for TEM. Although completion total mesorectal excision is considered standard of care in T2 or more invasive carcinomas, this completion surgery is not always performed. The purpose of this article is to evaluate the outcome of patients after TEM-only, when completion surgery would be indicated.

METHODS

In this retrospective multicenter, observational cohort study, outcome after TEM-only (n = 41) and completion surgery (n = 40) following TEM for a pT2-3 rectal adenocarcinoma was compared.

RESULTS

Median follow-up was 29 months for the TEM-only group and 31 months for the completion surgery group. Local recurrence rate was 35 and 11% for the TEM-only and completion surgery groups respectively. Distant metastasis occurred in 16% of the patients in both groups. The 3-year overall survival was 63% in the TEM-only group and 91% in the completion surgery group respectively. Three-year disease-specific survival was 91 versus 93% respectively.

CONCLUSIONS

Although local recurrence after TEM-only for pT2-3 rectal cancer is worse compared to the recurrence that occurs after completion surgery, disease-specific survival is comparable between both groups. The lower unadjusted overall survival in the TEM-only group indicates that TEM-only may be a valid alternative in older and frail patients, especially when high morbidity of completion surgery is taken into consideration. Nevertheless, completion surgery should always be advised when curation is intended.

Local excision for ypT2 rectal cancer following preoperative chemoradiation therapy: it should not be justified

PURPOSE

Among individuals who respond well to preoperative chemoradiation therapy (CRT) for ypT0-1, local excision (LE) could provide acceptable oncological outcomes. However, in ypT2 cases, the oncological safety of LE has not been determined. This study aimed to compare oncological outcomes between LE and total mesorectal excision of ypT2-stage rectal cancer after chemoradiation therapy and investigate the oncological safety of LE in these patients.

METHODS

We included 351 patients who exhibited ypT2-stage rectal cancer after CRT followed by LE (n = 16 [5%]) or total mesorectal excision (TME) (n = 335 [95%]) after preoperative CRT between January 2007 and December 2013. After propensity matching, oncological outcomes between LE group and TME group were compared.

RESULTS

The median follow-up period was 57 months (range, 12-113 months). In the LE group, local recurrence occurred more frequently (18 vs. 4%; p = 0.034) but not distant metastases (12 vs. 11%; p = 0.690). The 5-year local recurrence-free (76 vs. 96%; p = 0.006), disease-free (64 vs. 84%; p = 0.075), and overall survival (79 vs. 93%; p = 0.045) rates of the LE group were significantly lower than those of the TME group. After propensity matching, 5-year local recurrence-free survival of the LE group was significantly lower than that of the TME group (76 vs. 97%, p = 0.029).

CONCLUSION

The high local failure rate and poor oncological outcomes for ypT2-stage rectal cancer patients who undergo CRT followed by LE cannot be justified as an indication for LE. Salvage surgery should be recommended in these patients.

Decision-Making Strategy for Rectal Cancer Management Using Radiation Therapy for Elderly or Comorbid Patients

Rectal cancer predominantly affects patients older than 70 years, with peak incidence at age 80 to 85 years. However, the standard treatment paradigm for rectal cancer oftentimes cannot be feasibly applied to these patients owing to frailty or comorbid conditions. There are currently little information and no treatment guidelines to help direct therapy for patients who are elderly and/or have significant comorbidities, because most are not included or specifically studied in clinical trials. More recently various alternative treatment options have been brought to light that may potentially be utilized in this group of patients. This critical review examines the available literature on alternative therapies for rectal cancer and proposes a treatment algorithm to help guide clinicians in treatment decision making for elderly and comorbid patients.

Total Mesorectal Excision Versus Local Excision After Preoperative Chemoradiotherapy in Rectal Cancer With Lymph Node Metastasis: A Propensity Score-Matched Analysis

PURPOSE

To determine whether local excision (LE) outcomes were comparable to total mesorectal excision (TME) outcomes in node-positive (cN+) rectal cancer patients who were good responders.

METHODS AND MATERIALS

This retrospective study included clinical T2-3 and cN+ low rectal cancer patient who received preoperative chemoradiotherapy (PCRT) followed by TME or LE. Clinical stage T1 or T4 tumors, upper-to-middle rectal tumors (>7 cm from anal verge), and synchronous distant metastases were excluded. Lymph nodes ≥5 mm in size were defined as tumor-positive, and patients with metastatic lymph nodes >20 mm in size were excluded. Preoperative chemoradiotherapy comprised radiation (50-50.4 Gy/25-28 fractions over 5 weeks) with 2 cycles of 5-fluorouracil or oral capecitabine. Propensity scores were computed from tumor and patient variables and used for 1-to-1 matched analysis. Local recurrence-free survival, disease-free survival, and overall survival were compared between the 2 matched groups.

RESULTS

Between January 2007 and December 2013, 563 and 55 patients underwent TME and LE, respectively. The median follow-up period was 54 months. In propensity score-matched analysis, 48 patients were included in each group. No statistical differences were observed in 3-year local recurrence-free survival (97.9% vs 97.9%, P = .994), 3-year disease-free survival (91.5% vs 91.4%, P = .968), or 3-year OS (93.7% vs 97.9%, P = .809) between the TME and LE groups.

CONCLUSIONS

In clinical N+ rectal cancer patients, oncologic outcomes of PCRT followed by LE were comparable to those of TME; this finding might be applicable only to those patients with good response in the primary tumor and small lymph node metastases.

Standardized Index of Shape (DCE-MRI) and Standardized Uptake Value (PET/CT): Two quantitative approaches to discriminate chemo-radiotherapy locally advanced rectal cancer responders under a functional profile

Purpose

To investigate dynamic contrast enhanced-MRI (DCE-MRI) in the preoperative chemo-radiotherapy (CRT) assessment for locally advanced rectal cancer (LARC) compared to¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT).

Methods

75 consecutive patients with LARC were enrolled in a prospective study. DCE-MRI analysis was performed measuring SIS: linear combination of percentage change (Δ) of maximum signal difference (MSD) and wash-out slope (WOS). ¹⁸F-FDG PET/CT analysis was performed using SUV maximum (SUV_max). Tumor regression grade (TRG) were estimated after surgery. Non-parametric tests, receiver operating characteristic were evaluated.

Results

55 patients (TRG1-2) were classified as responders while 20 subjects as non responders. ΔSIS reached sensitivity of 93%, specificity of 80% and accuracy of 89% (cut-off 6%) to differentiate responders by non responders, sensitivity of 93%, specificity of 69% and accuracy of 79% (cut-off 30%) to identify pathological complete response (pCR). Therapy assessment via ΔSUV_max reached sensitivity of 67%, specificity of 75% and accuracy of 70% (cut-off 60%) to differentiate responders by non responders and sensitivity of 80%, specificity of 31% and accuracy of 51% (cut-off 44%) to identify pCR.

Conclusions

CRT response assessment by DCE-MRI analysis shows a higher predictive ability than ¹⁸F-FDG PET/CT in LARC patients allowing to better discriminate significant and pCR.

Pretreatment identification of patients likely to have pathologic complete response after neoadjuvant chemoradiotherapy for rectal cancer

PURPOSE

In selected patients, a wait-and-see strategy after chemoradiotherapy for rectal cancer might be feasible provided that the probability of pathologic complete response (pCR) is high. This study aimed to identify clinical parameters associated with pCR. Furthermore, we attempted to identify subgroups with increased probability of pCR that might aid in clinical decision making.

METHODS

A total of 6444 patients that underwent surgical resection of a single primary carcinoma of the rectum after neoadjuvant chemoradiotherapy (nCRT) between January 2009 and December 2016 in the Netherlands were included in the study. Data on the outcome variable, pCR, and potential covariates were retrieved from a nationwide database. The variables included in the analysis were selected based on previous studies and were analyzed using univariate and multivariate logistic regression analyses.

RESULTS

pCR was observed in 1010 patients (15.7%). Pretreatment clinical tumor stage and signs of obstruction were independently associated with pCR. Nodal stage and presence of metastatic disease decreased chances of pCR significantly. The best response rate was observed in patients diagnosed with a non-obstructive, well-/moderately differentiated adenocarcinoma of the lower rectum with no clinical apparent nodal or distant metastatic disease (pCR ratio 18.8%). The percentage of patients demonstrating pCR decreased in case of symptoms of pretreatment obstruction or poorly differentiated tumors (pCR ratio of 11.8 and 6.7%, respectively).

CONCLUSION

This nationwide study confirms several of the previously reported clinical predictors of pCR.

Controversial issues in radiotherapy for rectal cancer: a systematic review

The role of radiotherapy (RT) as an adjuvant to surgical options in the treatment of locally advanced rectal cancer has been established as it reduces local recurrence when combined with surgical resection and enhances survival when used in multidisciplinary treatment. However, many issues need to be addressed; some of these can render RT unnecessary, whereas others can reveal a new role of RT in rectal cancer. This review will discuss not only the basic role of RT but also the associated but controversial issues in detail in an attempt to find answers and determine future directions for the next decade.

Complete response after chemoradiotherapy for rectal cancer: what is the reasonable approach?

With the increasing use of preoperative treatment rather than upfront surgery, it has become evident that the response of rectal carcinoma to standard chemoradiotherapy (CRT) shows a great variety that includes histopathologiocally confirmed complete tumor regression in 10–30% of cases. Adaptive strategies to avoid radical surgery, either by local excision or non-operative management, have been proposed in these highly responsive tumors. A growing number of prospective clinical trials and experiences from large databases, such as the European Registration of Cancer Care (EURECCA) watch-and-wait database, or the recent Oncological Outcome after Clinical Complete Response in Patients with Rectal Cancer (OnCoRe) project, will provide more information on its safety and efficacy, and help to select appropriate patients. Future studies will have to establish appropriate inclusion criteria and optimize CRT regimens in order to maximize the number of patients achieving complete response. Standardized re-staging procedures have to be investigated to improve the prediction of a sustained complete response, and long-term close follow-up with thorough documentation of failure patterns and salvage therapies will have to prove the oncological safety of this approach.

Radiomics Analysis for Evaluation of Pathological Complete Response to Neoadjuvant Chemoradiotherapy in Locally Advanced Rectal Cancer

Purpose: To develop and validate a radiomics model for evaluating pathologic complete response (pCR) to neoadjuvant chemoradiotherapy in patients with locally advanced rectal cancer (LARC).Experimental Design: We enrolled 222 patients (152 in the primary cohort and 70 in the validation cohort) with clinicopathologically confirmed LARC who received chemoradiotherapy before surgery. All patients underwent T2-weighted and diffusion-weighted imaging before and after chemoradiotherapy; 2,252 radiomic features were extracted from each patient before and after treatment imaging. The two-sample t test and the least absolute shrinkage and selection operator regression were used for feature selection, whereupon a radiomics signature was built with support vector machines. Multivariable logistic regression analysis was then used to develop a radiomics model incorporating the radiomics signature and independent clinicopathologic risk factors. The performance of the radiomics model was assessed by its calibration, discrimination, and clinical usefulness with independent validation.Results: The radiomics signature comprised 30 selected features and showed good discrimination performance in both the primary and validation cohorts. The individualized radiomics model, which incorporated the radiomics signature and tumor length, also showed good discrimination, with an area under the receiver operating characteristic curve of 0.9756 (95% confidence interval, 0.9185-0.9711) in the validation cohort, and good calibration. Decision curve analysis confirmed the clinical utility of the radiomics model.Conclusions: Using pre- and posttreatment MRI data, we developed a radiomics model with excellent performance for individualized, noninvasive prediction of pCR. This model may be used to identify LARC patients who can omit surgery after chemoradiotherapy. Clin Cancer Res; 23(23); 7253-62. ©2017 AACR.

Understanding and Resetting Radiation Sensitivity in Rectal Cancer

OBJECTIVE

The aim of the study was to explore specific microRNAs (miRs) in rectal cancer that would predict response to radiation and identify target pathways that may be exploited for neoadjuvant therapies.

SUMMARY BACKGROUND DATA

Chemoradiotherapy (CRT) response is a predictor of survival in rectal cancer. Studies have demonstrated changes in RNA expression correlate with chemoradiation sensitivity across cancers.

METHODS

Forty-five rectal cancer patients, partial responders (PR = 18), nonresponders (NR = 13), and complete responders (CR = 14) to CRT, as defined by a tumor regression score, were examined. miRs differentially expressed, using NanoString microArray profiling, were validated with qPCR. We quantified 1 miR and its downstream targets in patient samples. Chemosensitivity was measured in HCT-116, a human colorectal carcinoma cell line, using inhibitors of SHP2 and RAF.

RESULTS

miR-451a, 502-5p, 223-3p, and 1246 were the most upregulated miRs (>1.5-fold change) in a NanoString profiling miR panel. qPCR revealed a decrease in expression of miR-451a in NRs. EMSY and CAB39, both downstream targets of miR-451a and involved in carcinogenesis (shown in TCGA) were increased in NRs (qPCR). Both targets are associated with worse survival in colorectal cancer. Inhibition of miR-451a in HCT-116 cells significantly decreased cell proliferation with treatment of SHP2 and RAF inhibitors.

CONCLUSIONS

An integrated analysis of rectal cancer miRs may yield biomarkers of radioresistance and offer treatment targets for resensitization.

Local Excision of Rectal Cancer

Local excision (LE) of early-stage rectal cancer avoids the morbidity associated with radical surgery but has historically been associated with inferior oncologic outcomes. Newer techniques, including transanal endoscopic microsurgery (TEM) and transanal minimally invasive surgery (TAMIS), have been developed to improve the quality of LE and extend the benefits of LE to tumors in the more proximal rectum. This article provides an overview of conventional LE, TEM, and TAMIS techniques, including indications for their use and pertinent literature on their associated outcomes for rectal cancer.

A nomogram predicting pathological complete response to neoadjuvant chemoradiotherapy for locally advanced rectal cancer: implications for organ preservation strategies

PURPOSE

To determine predictors of pathological complete response (pCR) in locally advanced rectal cancer patients treated with neoadjuvant chemoradiotherapy (nCRT), and develop a predictive nomogram.

METHODS

A total of 522 locally advanced rectal cancer patients undergoing nCRT and curative resection between 2008 and 2014 were included. Uni- and multivariate analysis was performed to identify predictors of pCR. A nomogram was developed and validated by internal (n=425) and external validation (n=97).

RESULTS

With a median follow-up of 55 months, pCR was associated with better 5-year overall and disease-free survival, distant control, but similar local control. Logistic regression showed that post-CRT distance from the anal verge (OR =0.840, P = 0.022), post-CRT tumor size (OR = 0.565, P = 0.003), post-CRT circumferential extent of tumor (OR = 0.021, P < 0.001), pre-CRT CEA level (OR = 2.004, P = 0.033), and post-CRT CEA level (OR = 3.767, P = 0.038) were independently associated with pCR. A nomogram was developed with a C-index of 0.81 and 0.75 on internal and external validation, respectively.

CONCLUSION

pCR was associated with better long-term outcome. A nomogram was successfully developed to predict pCR. It could support decision-making in organ preservation strategies.

Transanal Endoscopic Microsurgery for Early Rectal Cancer: A Single-Center Experience

BACKGROUND

There is debate regarding the appropriate use of transanal endoscopic microsurgery for rectal cancer.

OBJECTIVE

This study analyzed our single-center experience with transanal endoscopic microsurgery for early rectal cancer.

DESIGN

Medical charts of patients who underwent transanal endoscopic microsurgery were reviewed to determine lesion characteristics, as well as operative and treatment characteristics. Complications and recurrences were recorded.

SETTINGS

The study was conducted at a single academic medical center.

PATIENTS

Patients with early stage cancer (T1 or T2, N0, and M0) of the rectum were included.

MAIN OUTCOME MEASURES

Local and overall recurrence and disease-specific survival were measured.

RESULTS

A total of 92 patients were analyzed. Median follow-up was 4.6 years. Negative margins were obtained in 98.9%. Length of stay was 1 day for 95.4% of patients. The complication rate was 10.9% (n = 10), including urinary retention at 4.3% (n = 4) and postoperative bleeding at 4.3% (n = 4). Preoperative staging included 54 at T1 (58.7%) and 38 at T2 (41.3%). Adjuvant therapy was recommended for all of the T2 and select T1 lesions with adverse features on histology. The final pathologic stages of tumors were ypT0 at 8.7% (n = 8), pT1 at 58.7% (n = 54), pT2 at 23.9% (n = 22), and ypT2 at 8.7% (n = 8). The 3-year local recurrence risk was 2.4% (SE = 1.7), and overall recurrence was 6.7% (SE = 2.9). There were no recurrences among patients with complete pathologic response to neoadjuvant therapy. Mean time to recurrence was 2.5 years (SD = 1.43). A total of 89.2% of patients with very low tumors underwent curative resection without a permanent stoma (33/37). The 3-year disease-specific survival rate was 98.6% (95% CI, 90.4%-99.8%), and overall survival rate was 89.4% (95% CI, 79.9%-94.6%).

LIMITATIONS

The study was limited by its single-center retrospective experience.

CONCLUSIONS

Transanal endoscopic microsurgery provides comparable oncologic outcomes to radical resection in properly selected patients with early rectal cancer. Sphincter preservation rates approach 90% even in patients with very distal rectal cancer.

Management of Rectal Polyps

Colorectal cancer is one of the most common causes of cancer and cancer morbidity in the United States. In comparison to colon polyps, rectal polyps pose a unique challenge. Advances in endoscopic techniques have allowed for more thorough rectal adenoma detection and removal; however, there remains a concern over piecemeal resection and negative resection margins. Advances in transanal excision techniques, such as transanal endoscopic microsurgery, have been proposed for the removal of benign polyps as well as some early stage rectal cancers, with emphasis on proper patient selection. This review will discuss the current endoscopic and surgical considerations of both benign and malignant rectal polyps.

Rectal Cancer: Assessment of Neoadjuvant Chemoradiation Outcome based on Radiomics of Multiparametric MRI

PURPOSE

To evaluate multiparametric MRI features in predicting pathologic response after preoperative chemoradiation therapy (CRT) for locally advanced rectal cancer (LARC).

EXPERIMENTAL DESIGN

Forty-eight consecutive patients (January 2012-November 2014) receiving neoadjuvant CRT were enrolled. All underwent anatomical T1/T2, diffusion-weighted MRI (DWI) and dynamic contrast-enhanced (DCE) MRI before CRT. A total of 103 imaging features, analyzed using both volume-averaged and voxelized methods, were extracted for each patient. Univariate analyses were performed to evaluate the capability of each individual parameter in predicting pathologic complete response (pCR) or good response (GR) evaluated based on tumor regression grade. Artificial neural network with 4-fold validation technique was further utilized to select the best predictor sets to classify different response groups and the predictive performance was calculated using receiver operating characteristic (ROC) curves.

RESULTS

The conventional volume-averaged analysis could provide an area under ROC curve (AUC) ranging from 0.54 to 0.73 in predicting pCR. While if the models were replaced by voxelized heterogeneity analysis, the prediction accuracy measured by AUC could be improved to 0.71-0.79. Similar results were found for GR prediction. In addition, each subcategory images could generate moderate power in predicting the response, which if combining all information together, the AUC could be further improved to 0.84 for pCR and 0.89 for GR prediction, respectively.

CONCLUSIONS

Through a systematic analysis of multiparametric MR imaging features, we are able to build models with improved predictive value over conventional imaging metrics. The results are encouraging, suggesting the wealth of imaging radiomics should be further explored to help tailoring the treatment into the era of personalized medicine. Clin Cancer Res; 22(21); 5256-64. ©2016 AACR.

High nodal positivity rates even in good clinical responders after chemoradiation of rectal cancer: is organ preservation feasible?

AIM

Local excision (LE) is emerging as a treatment option for rectal cancer responding well to chemoradiation. However, it does not address the mesorectal nodal burden. We aimed to identify the factors influencing nodal positivity and subsequently defined a low-risk group by including only patients at low risk.

METHOD

A single-centre, retrospective database analysis was carried out of patients with radically resected rectal cancer after neoadjuvant chemoradiation.

RESULTS

This study included 524 patients with predominantly low rectal tumours. Nodal positivity among ypT0, T1 and T2 groups was 14.7%, 28% and 30%, respectively. Multivariate analysis with stepwise logistic regression identified the following low-risk features: age ≥ 40 years, nonsignet ring cell carcinoma (SRCC) histology and pathological complete response (pCR). Sixty-nine patients fulfilling all three criteria were analysed and the nodal positivity was found to be 10.1%, which implies that, if these patients had been selected for LE, one in 10 would have had positive mesorectal nodes.

CONCLUSION

Even in patients with low-risk criteria (pCR, non-SRCC histology and age ≥ 40 years), the residual positive nodal disease burden is 10%. Whether this high incidence of residual nodal disease translates into a similar risk of locoregional recurrence if an organ-preservation strategy is adopted is unclear.

Long-Term Outcome of Rectal Cancer With Clinically (EUS/MRI) Metastatic Mesorectal Lymph Nodes Treated by Neoadjuvant Chemoradiation: Role of Organ Preservation Strategies in Relation to Pathologic Response

BACKGROUND

Organ preservation strategies are under investigation for patients with locally advanced rectal cancer (LARC) who achieve a complete pathologic response in the primary tumor (ypT0) after neoadjuvant chemoradiation therapy (CRT). This study explored the value of this approach for cN+ patients.

METHODS

Data were retrieved from our institutional prospective rectal cancer database. Tumors with mesorectal lymph nodes larger than 5 mm shown on endorectal ultrasonography, pelvic magnetic resonance imaging, or both were staged as cN+.

RESULTS

The study population comprised 226 patients (142 men and 84 women; median age, 64 years) with LARC who underwent CRT followed by surgery including total mesorectal excision (TME) (n = 179) and full-thickness local excision (LE) (n = 47) between 1996 and 2013. At staging, 123 patients (54.4 %) were cN+. In 65 cases (28.7 %), ypCR was observed. Metastatic mesorectal lymph nodes (ypN+) were detected in 41.6 % of the cN+ patients and in 2.8 % of the cN0 patients (P < 0.01). Among the cN+ patients, 16 % of the ypT0 cases were ypN+ compared with 51.8 % of the no-ypT0 cases (P < 0.01). Among the cN+ patients who underwent TME, the 5-year disease-specific survival (DSS) and disease-free survival (DFS) rates were respectively 100 and 91.6 % for the ypT0 patients compared with 71.2 and 58.0 % for the no-ypT0 patients (P = 0.01). Among the ypN+ patients, the 5-year DSS and DFS rates were both 100 % for the ypT0 cases compared with 59.1 and 43.3 % for the no-ypT0 patients. Among the cN+ and ypT0 patients, the 5-year DSS and DFS were respectively 100 and 85.7 % for the TME patients compared with 100 and 91.6 % for the LE patients. In the multivariate analysis, ypT0 was the only independent prognostic factor.

CONCLUSIONS

Protocols aimed at organ preservation in LARC that achieve ypT0 after CRT can be offered also to cN+ patients.

A Nomogram to Predict Lymph Node Positivity Following Neoadjuvant Chemoradiation in Locally Advanced Rectal Cancer

BACKGROUND

Patients with locally advanced rectal cancer typically receive neoadjuvant chemoradiation followed by total mesorectal excision. Other treatment approaches, including transanal techniques and close surveillance, are becoming increasingly common following positive responses to chemoradiation. Lack of pathologic lymph node staging is one major disadvantage of these novel strategies.

OBJECTIVE

The purposes of this study were to determine clinicopathologic factors associated with positive lymph nodes following neoadjuvant chemoradiation for rectal cancer and to create a nomogram using these factors to predict rates of lymph node positivity.

DESIGN

This is a retrospective cohort analysis.

SETTINGS

This study used the National Cancer Database.

PATIENTS

Patients aged 18 to 90 with clinical stage T3/T4, N0, M0 or Tany, N1-2, M0 adenocarcinoma of the rectum who underwent neoadjuvant chemoradiation before total mesorectal excision from 2010 to 2012 were identified.

MAIN OUTCOME MEASURES

The primary outcome measure was lymph node positivity after neoadjuvant chemoradiation for locally advanced rectal cancer. Bivariate and multivariate analyses were used to determine the associations of clinicopathologic variables with lymph node positivity.

RESULTS

Eight thousand nine hundred eighty-four patients were included. Young age, lower Charlson score, mucinous histology, poorly differentiated and undifferentiated tumors, the presence of lymphovascular invasion, elevated CEA level, and clinical lymph node positivity were significantly predictive of pathologic lymph node positivity following neoadjuvant chemoradiation. The predictive accuracy of the nomogram is 70.9%, with a c index of 0.71. There was minimal deviation between the predicted and observed outcomes.

LIMITATIONS

This study is retrospective, and it cannot be determined when in the course of treatment the data were collected.

CONCLUSIONS

We created a nomogram to predict lymph node positivity following neoadjuvant chemoradiation for locally advanced rectal cancer that can serve as a valuable complement to imaging to aid clinicians and patients in determining the best treatment strategy.