Local Recurrence of Rectal Cancer After Total Mesorectal Excision Without Preoperative Radiotherapy

Does Completeness of the Mesorectal Excision Still Correlate With Local Recurrence?

BACKGROUND

Total mesorectal excision is the standard surgical procedure for rectal cancer treatment. Several studies have shown a close correlation between the prognosis of patients with rectal cancer and the completeness of the mesorectal specimen.

OBJECTIVE

To assess the correlation between macroscopic assessment of mesorectal excision and long-term oncological outcomes.

DESIGN

Retrospective analysis of an Institutional Review Board-approved database.

SETTINGS

Tertiary referral center.

PATIENTS

Patients with rectal cancer who were operated on between March 2016 and October 2019 were classified into 3 groups based on the mesorectal specimen quality: complete, near complete, and incomplete. Only patients with a follow-up of ≥2 years and without signs of preoperative distant disease were included.

MAIN OUTCOME MEASURES

Relationship between total mesorectal excision and local and distant recurrence rates in patients with rectal cancer.

RESULTS

A total of 124 patients (35.5% females) were included in the analysis, with a mean age of 58.1 (SD 12) years and a mean BMI of 26.4 (SD 4.59) kg/m². Neoadjuvant chemoradiation was administered to 71% of patients, whereas 13.7% received total neoadjuvant therapy. Restorative procedures were performed in 107 patients (86.3%), whereas 17 patients (13.7%) underwent abdominoperineal resection. The majority of mesorectal excision specimens (87.09%) were complete or near complete. Local recurrence rates were 6.3% (1/16) in the incomplete and 7.4% (8/108) in the complete/near complete group ( p = 0.86). Metachronous distant metastases occurred in 6 patients (37.5%) in the incomplete group and in 24 patients (22.2%) in the complete/near complete group (p = 0.18). Thus, specimen quality did not appear to impact disease-free survival.

LIMITATIONS

Retrospective, single-center study with relatively short follow-up.

CONCLUSIONS

In the era of a multidisciplinary approach and extensive use of neoadjuvant therapy, macroscopic completeness of total mesorectal excision may not be as valuable a prognosticator as in the past. Larger studies with longer follow-ups are needed to clarify these preliminary findings. See Video Abstract at http://links.lww.com/DCR/C129.

LA INTEGRIDAD DE LA ESCISIN MESORRECTAL TODAVA SE CORRELACIONA CON LA RECURRENCIA LOCAL

ANTECEDENTES:La escisión total desl mesorrecto es el estándar de oro para el tratamiento del cáncer de recto. Varios estudios han demostrado una estrecha correlación entre el pronóstico de los pacientes con cáncer de recto y la integridad espécimen mesorrectal.OBJETIVO:Evaluar la correlación entre la evaluación macroscópica de la escisión mesorrectal y los resultados oncológicos a largo plazo en pacientes con cáncer de recto.DISEÑO:Análisis retrospectivo de una base de datos aprobada por el IRB.ENTORNO CLINICO:El estudio se realizó en un centro de referencia terciario de una sola institución.PACIENTES:Todos los pacientes con cáncer de recto operados entre 3/2016-10/2019. Los pacientes se clasificaron en 3 grupos, según la calidad del espécimen mesorrectal: completo, casi completo e incompleto. Solo se incluyeron pacientes con seguimiento >2 años y sin signos de enfermedad a distancia preoperatoria.PRINCIPALES MEDIDAS DE RESULTADO:Identificar la relación entre la escisión mesorrectal total y las tasas de recurrencia local y a distancia en pacientes con cáncer de recto.RESULTADOS:Se incluyeron 124 pacientes (35,5% mujeres) con una edad media de 58,1 años (DE 12) y un índice de masa corporal medio de 26,4 (DE 4,59). Se administró quimiorradiación neoadyuvante al 71% de los pacientes, mientras que el 13,7% recibió terapia neoadyuvante total. Se realizaron procedimientos de restauración en 107 pacientes (86,3%), mientras que 17 pacientes (13,7%) se sometieron a resección abdominoperineal. La mayoría (87,09%) de los especímenes de escisión mesorrectal fueron completas o casi completas. Las tasas de recurrencia local fueron 1/16 (6,3%) en el grupo incompleto y 8/108 (7,4%) en el grupo completo/casi completo ( p = 0,86). Se produjeron metástasis a distancia metacrónicas en 6 pacientes (37,5%) en el grupo incompleto y 24 (22,2%) en el grupo completo/casi completo ( p = 0,18). Por lo tanto, la calidad del espécimen no pareció afectar la supervivencia libre de enfermedad.LIMITACIONES:Estudio retrospectivo de un solo centro con pequeño número de casos y seguimiento relativamente corto.CONCLUSIÓN:En la era de un enfoque multidisciplinario y el uso extensivo de la terapia neoadyuvante, la integridad macroscópica de la escisión total del mesorrecto, puede no ser un pronóstico tan valioso como en el pasado. Se necesitan estudios más amplios con períodos de seguimiento más prolongados para aclarar estos hallazgos preliminares. Consulte Video Resumen en http://links.lww.com/DCR/C129 . (Traducción-Dr. Fidel Ruiz Healy ).

Artificial Intelligence-Based Total Mesorectal Excision Plane Navigation in Laparoscopic Colorectal Surgery

BACKGROUND

Total mesorectal excision is the standard surgical procedure for rectal cancer because it is associated with low local recurrence rates. To the best of our knowledge, this is the first study to use an image-guided navigation system with total mesorectal excision.

IMPACT OF INNOVATION

The impact of innovation is the development of a deep learning-based image-guided navigation system for areolar tissue in the total mesorectal excision plane. Such a system might be helpful to surgeons because areolar tissue can be used as a landmark for the appropriate dissection plane.

TECHNOLOGY, MATERIALS, AND METHODS

This was a single-center experimental feasibility study involving 32 randomly selected patients who had undergone laparoscopic left-sided colorectal resection between 2015 and 2019. Deep learning-based semantic segmentation of areolar tissue in the total mesorectal excision plane was performed. Intraoperative images capturing the total mesorectal excision scene extracted from left colorectal laparoscopic resection videos were used as training data for the deep learning model. Six hundred annotation images were created from 32 videos, with 528 images in the training and 72 images in the test data sets. The experimental feasibility study was conducted at the Department of Colorectal Surgery, National Cancer Center Hospital East, Chiba, Japan. Dice coefficient was used to evaluate semantic segmentation accuracy for areolar tissue.

PRELIMINARY RESULTS

The developed semantic segmentation model helped locate and highlight the areolar tissue area in the total mesorectal excision plane. The accuracy and generalization performance of deep learning models depend mainly on the quantity and quality of the training data. This study had only 600 images; thus, more images for training are necessary to improve the recognition accuracy.

CONCLUSION AND FUTURE DIRECTIONS

We successfully developed a total mesorectal excision plane image-guided navigation system based on an areolar tissue segmentation approach with high accuracy. This may aid surgeons in recognizing the total mesorectal excision plane for dissection.

[Preoperative imaging for colorectal cancer: surgeons' perspective]

Preoperative radiological diagnostics in patients with colorectal cancer has several objectives. The diagnostic localization of the colonic tumor is essential for planning the resection. The radiologically suspected infiltration of neighboring structures may lead to the decision for neoadjuvant treatment. In patients with rectal carcinomas, the T and N stages, the distance to the circumference resection margin (CRM), and the penetration of the tumor into the mesentery must be determined. This crucial to determine whether the patient should undergo neoadjuvant treatment. Prior to the planned relocation of an upstream stoma, radiological diagnostics may be added to clinical and endoscopic assessment but should not be routinely used.

Can CRM Status on MRI Predict Survival in Rectal Cancers: Experience from the Indian Subcontinent

To determine the role of MRI as a predictor of circumferential resection margin (CRM) involvement. To study the impact of CRM status on MRI on recurrence and survival, in correlation with pathology. Analysis of a prospective database was performed over a period of 1 year. All patients with adenocarcinoma of rectum were included in the study. The MRI at presentation for all patients irrespective of stage (MRIT), pre-NACTRT MRI (MRI₁) for patients with locally advanced tumours, and post-NACTRT MRI (MRI₂) of these patients were analysed separately. The status of CRM on MRI was compared to that on histopathology and as a predictor of recurrence and survival. Two hundred twenty-one patients were included with a median follow-up 30 months. Sensitivity, specificity, positive predictive value, negative predictive value (NPV) and accuracy were 50%, 65.46%, 5.63%, 96.95% and 64.85% for MRIT; 50%, 55.32%, 5.97%, 95.12% and 55.03% for MRI1; and 77.78%, 63.29%, 10.77%, 98.04% and 64.07% for MRI2, respectively. On multivariate analysis, pathological positive margin alone predicted a poor overall survival (OS) whereas involved CRM on pathology and MRIT predicted poorer disease-free survival (DFS) and local recurrence. Pre-treatment and post-treatment MRI scans have a moderate sensitivity, specificity and accuracy and a high negative predictive value to predict CRM status on pathology. Pathological CRM status is the only factor to impact OS, DFS and LR on multivariate analysis. CRM status on MRI at presentation (MRI_T) does impact DFS and local recurrence but not OS.

The quality of total mesorectal excision specimen: A review of its macroscopic assessment and prognostic significance

As a surgical procedure which could significantly lower the recurrence rate of cancers, total mesorectal excision (TME) has been the gold standard for middle and lower rectal cancer treatment. However, previous studies have shown that the procedure did not achieve the ideal theoretical local recurrence rates of rectal cancers. Some researchers pointed out it was very likely that not all so-called TME treatments completely removed the mesorectum, implying that some of these TME surgical treatments failed to meet oncological quality standards. Therefore, a suitable assessment tool for the surgical quality of TME is necessary. The notion of “macroscopic assessment of mesorectal excision (MAME)” was put forward by some researchers as a better assessment tool for the surgical quality of TME and has been confirmed by a series of studies. Besides providing rapid and accurate surgical quality feedbacks for surgeons, MAME also effectively assesses the prognosis of patients with rectal cancer. However, as a new assessment tool used for TME surgical quality, MAME has an only limited influence on the current guidelines and is yet to be widely applied in most countries. The aims of this review are to provide a detailed introduction to MAME for clinical practice and to summarize the current prognostic significance of MAME.

A study on the usefulness of methylcellulose in rectal CT based on the analysis of the differences in absorption of radiation-permeable and radiation-impermeable materials

PURPOSE

The purpose of this study was to use various radiation-permeable and radiation-impermeable materials, used to facilitate the observation of a lesion during a rectal computed tomography (CT) scan, in order to determine the best material to use.

MATERIALS AND METHODS

In regard to the study method, the radiation-permeable and radiation-impermeable materials of physiological saline, methylcellulose, contrast medium, ultrasound gel, and air were used to perform scanning with scan parameters that were used in general abdominal scanning. The GSI mode was used for material analysis.

RESULTS

According to the results of the phantom study, the average CT value was 25.5 ± 5.9 HU for physiological saline, 77.6 ± 7.3 HU for methylcellulose, 3,070 ± 0.1 HU for contrast medium, 74.1 ± 11.9 HU for ultrasound gel, and -954.1 ± 10.3 HU for air. According to the analysis of materials by energy, contrast medium and physiological saline showed a dramatic decrease in the CT value as energy increased. Methylcellulose showed a gradual decrease in CT value, whereas air showed a small change in CT value according to the graph.

CONCLUSIONS

Out of these materials, methylcellulose had the advantage of reducing discomfort in patients, and was more convenient for examiners before and after the rectal CT scan.

Restaging of locally advanced rectal cancer with magnetic resonance imaging and endoluminal ultrasound after preoperative chemoradiotherapy: a systemic review and meta-analysis

BACKGROUND

Magnetic resonance imaging and endoluminal ultrasound play an important role in the restaging of locally advanced rectal cancer after preoperative chemoradiotherapy, yet their diagnostic accuracy is still controversial.

OBJECTIVE

Meta-analysis was performed to estimate the diagnostic performance of MRI and endoluminal ultrasound.

DATA SOURCES

Electronic databases from 1996 to March 2012 were searched.

STUDY SELECTION AND INTERVENTIONS

Either MRI or endoluminal ultrasound was used to restage rectal cancer after chemoradiotherapy or radiation.

MAIN OUTCOME MEASURES

T category, lymph node, and circumferential resection involvement were measured.

RESULTS

The sensitivity estimate for rectal cancer diagnosis (T0) by endoluminal ultrasound (37.0%; 95% CI, 24.0%-52.1%) was higher (p = 0.04) than the sensitivity estimate for MRI (15.3%; 95% CI, 6.5%-32.0%). For T3-4 category, sensitivity estimates of MRI and endoluminal ultrasound were comparable, 82.1% and 87.6%, whereas specificity estimates were poor (53.5% and 66.4%). For lymph node involvement, there was no significant difference between the sensitivity estimates for MRI (61.8%) and endoluminal ultrasound (49.8%). Specificity estimates for MRI and endoluminal ultrasound were 72.0% and 78.7%. For circumferential resection margin involvement, MRI sensitivity and specificity were 85.4% and 80.0%.

LIMITATIONS

To identify the heterogeneity, metaregression was performed on covariates. However, few of the covariates were identified to be statistically significant because of the lack of adequate original data.

CONCLUSION

Accurate restaging of locally advanced rectal cancer by MRI and endoluminal ultrasound is still a challenge. Identifying T0 rectal cancer by imaging is not reliable. Before performing surgery, restaging is important, but some of the T0-2 patients are likely overestimated as T3-4. Both modalities for lymph node involvement are not very good. Magnetic resonance imaging may be a good method to reassess circumferential resection margin.

The therapeutic and adverse effects of modified radiation fields for patients with rectal cancer

PURPOSE

To compare the therapeutic effect and complications of modified radiation fields (MRFs) with those of conventional pelvic radiation fields (CPRFs) for rectal cancer.

METHODS AND MATERIALS

From December 1996 to October 2009, a total of 160 patients with rectal carcinoma who received total mesorectal excision and postoperative radiotherapy were examined. Ninety-four patients were in the CPRFs group, and 66 were in the MRFs group. The dose was 50 Gy per 25 fractions in the initial plan.

RESULTS

The treatment volume and the volume of small bowel that received more than 15 Gy of the MRFs was smaller than that of the CPRFs (P < .001). The rates of local recurrence, overall survival, and disease-free survival were not statistically significant between the MRFs and CPRFs groups (P > .05). There was a statistical difference (P < .05) in the incidence of acute toxicity, which included serious complications in the lower digestive tract (grade ≥3). The completion rate for the initial radiotherapy plan was higher in the MRFs group than in the CPRFs group (P = .027).

CONCLUSIONS

Compared with CPRFs, MRFs manifested a lower incidence of complications and the same therapeutic effects. This finding will facilitate the clinical application of MRFs for patients with rectal cancer.

Sonography transmission gel as endorectal contrast agent for tumor visualization in rectal cancer

OBJECTIVE

The purpose of our study is to show the usefulness and safety of sonography transmission gel as an endorectal contrast agent in preoperative rectal MRI for tumor visualization in rectal cancer.

CONCLUSION

Sonography transmission gel is an effective and safe endorectal contrast agent for rectal MRI.

Factors that influence the adequacy of total mesorectal excision for rectal cancer

OBJECTIVE

In 1997 with the start of CRO7 trial it was agreed that adequacy of surgical resection of rectal cancer would be determined by a pathologically determined grading of the mesorectum the so called total mesorectal excision score (TME score). Scores ranged from 1-3 with 3 being a perfect specimen. The aim of this study was to investigate factors which may influence TME scores and establish if local recurrence is related to them.

METHOD

Data on all patients undergoing resectional surgery for rectal cancer in our unit are entered prospectively onto a database. Pathology reports of those patients who underwent total mesorectal excision were examined and the TME scores added to the database. Categorical variables were analysed using the chi2 test, continuous variables using ANOVA. Statistical significance was taken as P < 0.05.

RESULTS

Between January 2000 and June 2005, 518 patients underwent surgery for adenocarcinoma of the rectum, of these, 287 patients had a total mesorectal excision for mid or lower third tumours under the care of seven colorectal surgeons. All resected specimens were scored by a Consultant GI pathologist. Two hundred and fourteen patients underwent anterior resection and 73 underwent abdomino-perineal resection. The median age of the patients was 73 years (range 38-95 years). One hundred and ninety-four patients were male. Seventy-eight patients were treated with preoperative radiotherapy, 59 short course and 19 long course. TME scores were TME1 n = 30, TME2 n = 99, TME3 n = 158. Fifteen patients developed local pelvic recurrence at 2 years. Total mesorectal excision scores were not statistically influenced by Dukes' stage, width of tumour, preoperative radiotherapy or grade of surgeon. Male patients were statistically more likely to have a TME score of 2 or 3 compared with female P = 0.04. Patients undergoing an anterior resection were statistically more likely to have a TME score of 2 or 3 compared with abdomino-perineal resection P = 0.0001. Tumours with a circumferential resection margin (CRM) of more than 1 mm were more likely to have a TME score of 2 or 3 score (P = 0.0001). There was no relationship between TME and local recurrence (P = 0.966).

CONCLUSION

There is no relationship between the TME score in patients undergoing resectional surgery for adenocarcinoma of the rectum and the development of local recurrence at 2 years. Other factors such as CRM involvement are more likely to have an impact on local recurrence. The factors that influence the quality of TME are the operative procedure of anterior resection, male gender and CRM positivity. There appear to be no deleterious effects on the TME score by Specialist Registrars performing the operation under Consultant supervision. While TME scores may be an index of a technical performance, they appear to have little role in predicting future outcomes.

[Surgical treatment of recurrent locoregional rectal cancer]

Local recurrence (LR) after curative surgery for rectal cancer occurs in 4 to 33% of cases especially if surgery is sub-optimal (without total excision of the mesorectum). In many cases, diagnosis of LR is made at a late stage because of the high rate of asymptomatic patients, 56% in the experience of the Mayo Clinic. MRI and PETscan are most effective for assessing local and general extension, with a high diagnostic accuracy. Surgical treatment alone or with radiation (preoperative and/or intraoperative) is the only curative treatment of LR with R0 resectability rates of 30% to 45%. Morbidity and mortality rates are high, especially for total exenteration and abdomino-sacral resection. After curative surgery, 5-year global survival is between 30% and 40%. Palliative resection of macroscopic residues is not recommended. Careful patient selection for curative surgery is the best way to optimize treatment in these cases.

Diagnostic accuracy of preoperative magnetic resonance imaging in predicting curative resection of rectal cancer: prospective observational study

OBJECTIVE

To assess the accuracy of preoperative staging of rectal cancer with magnetic resonance imaging to predict surgical circumferential resection margins.

DESIGN

Prospective observational study of rectal cancers treated by colorectal multidisciplinary teams between January 2002 and October 2003.

SETTING

11 colorectal units in four European countries.

PARTICIPANTS

408 consecutive patients presenting with all stages of rectal cancer and undergoing magnetic resonance imaging before total mesorectal excision surgery and histopathological assessment of the surgical specimen.

MAIN OUTCOME MEASURES

Accuracy of magnetic resonance imaging in predicting a curative resection based on the histological yardstick of presence or absence of tumour at the margins of the specimen.

RESULTS

354 of the 408 patients had a clear circumferential resection margin (87%, 95% confidence interval 83% to 90%). Specificity for prediction of a clear margin by magnetic resonance imaging was 92% (327/354, 90% to 95%). High resolution scans were technically satisfactory in 93% (379/408). Surgical specimens were histopathologically graded as complete or moderate in 80% (328/408), and the median lymph node harvest was 12 (range 0-49). Magnetic resonance imaging predicted clear margins in 349 patients. At surgery 327 had clear margins (94%, 91% to 96%).

CONCLUSION

High resolution magnetic resonance imaging accurately predicts whether the surgical resection margins will be clear or affected by tumour. This technique can be reproduced accurately in multiple centres to predict curative resection and warns the multidisciplinary team of potential failure of surgery, thus enabling selection of patients for preoperative treatment.

Diagnostic accuracy of preoperative magnetic resonance imaging in predicting curative resection of rectal cancer: prospective observational study

OBJECTIVE

To assess the accuracy of preoperative staging of rectal cancer with magnetic resonance imaging to predict surgical circumferential resection margins.

DESIGN

Prospective observational study of rectal cancers treated by colorectal multidisciplinary teams between January 2002 and October 2003.

SETTING

11 colorectal units in four European countries.

PARTICIPANTS

408 consecutive patients presenting with all stages of rectal cancer and undergoing magnetic resonance imaging before total mesorectal excision surgery and histopathological assessment of the surgical specimen.

MAIN OUTCOME MEASURES

Accuracy of magnetic resonance imaging in predicting a curative resection based on the histological yardstick of presence or absence of tumour at the margins of the specimen.

RESULTS

354 of the 408 patients had a clear circumferential resection margin (87%, 95% confidence interval 83% to 90%). Specificity for prediction of a clear margin by magnetic resonance imaging was 92% (327/354, 90% to 95%). High resolution scans were technically satisfactory in 93% (379/408). Surgical specimens were histopathologically graded as complete or moderate in 80% (328/408), and the median lymph node harvest was 12 (range 0-49). Magnetic resonance imaging predicted clear margins in 349 patients. At surgery 327 had clear margins (94%, 91% to 96%).

CONCLUSION

High resolution magnetic resonance imaging accurately predicts whether the surgical resection margins will be clear or affected by tumour. This technique can be reproduced accurately in multiple centres to predict curative resection and warns the multidisciplinary team of potential failure of surgery, thus enabling selection of patients for preoperative treatment.