Magnetic resonance imaging (MRI)-based indication for neoadjuvant treatment of rectal carcinoma and the surrogate endpoint CRM status

Tumour-specific mesorectal excision for rectal cancer: Systematic review and meta-analysis of oncological and functional outcomes

BACKGROUND

Tumour-specific mesorectal excision (TSME) practice for rectal cancer only relies on small retrospective studies. This study aimed to perform a systematic review and meta-analysis to assess the oncological and functional outcomes of TSME practice.

METHODS

A systematic review protocol was drawn to include all the studies that compared partial versus total mesorectal excision (PME vs TME) practised for rectal adenocarcinoma up to 16 cm from the anal verge. A systematic literature search was conducted on EMBASE-Medline, Pubmed and Cochrane Library. Reports were screened for the study's outcomes: oncological radicality, postoperative anastomotic leak risk and functional outcomes. Included studies were appraised for risk-of-bias and meta-analysed. Evidence was rated with the GRADE approach.

RESULTS

Twenty-seven studies were included, consisting of 12325 patients (PME n = 4460, 36.2%; TME n = 7865, 63.8%). PME was performed for tumours higher than 10 cm from the anal verge in 54.5% of patients. There was no difference between PME and TME in circumferential resection margin positivity (OR 1.31, 95%CI 0.43-3.95, p = 0.64; I2 = 38%), and local recurrence risk (HR 1.05, 95%CI 0.52-2.10, p = 0.90; I2 = 40%). The postoperative leak risk (OR 0.42, 95%CI 0.27-0.67, p < 0.001; I2 = 60%) and the major low anterior resection syndrome risk (OR 0.34, 95%CI 0.28-0.40, p < 0.001; I2 = 0%) were lower after PME surgery. No difference was found in urinary incontinence (OR 0.68, 95%CI 0.13-3.67, p = 0.66) and urinary retention after early catheter removal (OR 2.00, 95%CI 0.24-16.51, p = 0.52).

CONCLUSIONS

Evidence from this meta-analysis shows that TSME for rectal cancer has good oncological results and leads to the best-fitted functional results possible for the patient's condition.

The Circumferential Resection Margin Is a Prognostic Predictor in Colon Cancer

Objective: This study aimed to investigate the potential value of circumferential resection margin (CRM) in colon cancer prognostics.

Summary Background Data: CRM has been extensively studied as an important prognostic factor in rectal and esophageal cancer, but not in colon cancer.

Methods: Data from 6,681 CRM-positive patients and 25,908 CRM-negative patients diagnosed with colon cancer in 2010–2015 were obtained from the Surveillance, Epidemiology, and End Results database. Statistical analysis methods utilized included the chi-square test, Kaplan-Meier estimates, Cox proportional, and X-tile software analyses.

Results: After propensity score matching, CRM positivity was found to be negatively related with survival (P < 0.001). X-tile software identified 0 and 30 mm as optimal cutoff values (P < 0.001) for prognosis, which was applicable only in stage II–IV patients. A 20 and 33% risk decrease were observed in patients with CRM between 0 and 30 mm [95% confidence interval (CI) = 0.76–0.84], and larger than 30 mm (95% CI = 0.62–0.71), respectively. Chemotherapy strongly benefited prognosis with a hazard ratio of 0.36 (95% CI = 0.34–0.38) for overall survival (OS). Patients with a CRM value of 0–30 mm seemed to benefit most from chemotherapy compared with other groups. CRM and number of regional lymph nodes are independent risk factors, and the latter is a good substitute for CRM in AJCC stage I patients.

Conclusion: CRM positivity is a strong unfavorable survival indicator for colon cancer patients. A better outcome is expected with CRM values larger than 30 mm. This cutoff value only applied to stage II–IV patients. For stage I patients, number of regional lymph nodes is a good substitute to predict survival. Chemotherapy was another favorable prognostic factor, especially for patients with a CRM value between 0 and 30 mm.

Role of the status of the mesorectal fascia in the selection of patients with rectal cancer for preoperative radiation therapy: a retrospective cohort study

Background

Patients with rectal cancer in whom the mesorectal fascia is threatened by tumour are more likely than all patients with stage II/III disease to benefit from preoperative radiotherapy (RT). The objective of this study was to assess whether the status of the mesorectal fascia versus a stage II/III designation can best inform the use of preoperative RT in patients undergoing major rectal cancer resection.

Methods

We reviewed the charts of consecutive patients with primary rectal cancer treated by a single surgeon at McMaster University, Hamilton, Ontario, between March 2006 and December 2012. The status of the mesorectal fascia was assessed by digital rectal examination, pelvic computed tomography and, when needed, pelvic magnetic resonance imaging (MRI). Patients whose mesorectal fascia was threatened or involved by tumour received preoperative RT. The study outcomes were rates of positive circumferential radial margin (CRM) and local tumour recurrence.

Results

A total of 153 patients were included, of whom 76 (49.7%) received preoperative RT because of concerns of a compromised mesorectal fascia. The median length of follow-up was 4.5 years. The number of CRM-positive cases in the RT and no-RT groups was 16 (22%) and 1 (1%), respectively (p < 0.01), and the number of cases of local tumour recurrence was 5 (7%) and 2 (3%), respectively (p = 0.2). Rates were similar when only patients with stage II/III tumours were included. Overall, 26 patients (17.0%) received MRI.

Conclusion

The status of the mesorectal fascia, not tumour stage, may best identify patients for preoperative RT.

Use of Preoperative Magnetic Resonance Imaging to Select Patients with Rectal Cancer for Neoadjuvant Chemoradiation--Interim Analysis of the German OCUM Trial (NCT01325649)

INTRODUCTION

Introduction of total mesorectal excision (TME) surgery for rectal cancer decreased local recurrence dramatically. Additional neoadjuvant chemoradiation (nCR) is frequently given in UICC II and III tumors based on TNM staging which is of limited accuracy. We aimed to evaluate determination of circumferential margin by magnetic resonance imaging (mrCRM) as an alternative criterium for nCR.

METHODS

Multicenter prospective cohort study which enrolled 642 patients in 13 centers with non-metastasized rectal adenocarcinoma. Patients with T4 tumors or patients with a mrCRM of 1 mm or less were treated by neoadjuvant chemoradiation. All others proceeded directly to surgery when inclusion criteria and no exclusion criteria were met. Quality of TME and accuracy of mrCRM determination were assessed during pathology workup.

RESULTS

TME was complete in 381 of 389 patients after surgery without nCR (97.9%) and in 245 of 253 patients (96.8%) after nCR. Negative pathology circumferential margins (pCRM) were seen in 97.4% without nCR and in 89% of patients after nCR. Negative pCRM was predicted by negative mrCRM in 98.3% of rectal cancers. NCR was given to 253 of 642 patients (39.5%). Lymph node count was 23 (range 7-79; median/range) for surgery without nCR and 19 (range 2-56) for surgery after nCR.

CONCLUSIONS

Surgical quality determined by pathology workup of specimen was very good in this study. Magnetic resonance imaging guided indication for nCR allows to achieve superb results concerning surrogate parameters for good oncological outcome. Thus, use of neoadjuvant chemoradiation with its potential detrimental side effects may be substantially reduced in selected patients.

Multidisciplinary treatment of rectal cancer in 2014: Where are we going?

In the present review we discuss the recent developments and future directions in the multimodal treatment of locally advanced rectal cancer, with respect to staging and re-staging modalities, to the current role of neoadjuvant chemo-radiation and to the conservative and more limited surgical approaches based on tumour response after neoadjuvant combined therapy. When initial tumor staging is considered a high accuracy has been reported for T pre-treatment staging, while preoperative lymph node mapping is still suboptimal. With respect to tumour re-staging, all the current available modalities still present a limited accuracy, in particular in defining a complete response. The role of short vs long-course radiotherapy regimens as well as the optimal time of surgery are still unclear and under investigation by means of ongoing randomized trials. Observational management or local excision following tumour complete response are promising alternatives to total mesorectal excision, but need further evaluation, and their use outside of a clinical trial is not recommended. The preoperative selection of patients who will benefit from neoadjuvant radiotherapy or not, as well as the proper identification of a clinical complete tumour response after combined treatment modalities,will influence the future directions in the treatment of locally advanced rectal cancer.

Patterns of use and outcomes for radiation therapy in the Quality Initiative in Rectal Cancer (QIRC) trial

BACKGROUND

The Quality Initiative in Rectal Cancer (QIRC) trial targeted surgeon intraoperative technique and not radiation therapy (RT) use. We performed a post hoc analysis of RT use among patients in the QIRC trial, not by arm of trial but rather for the entire group. We wished to identify associations between local recurrence risk and use of preoperative, postoperative or no RT.

METHODS

We compared demographic, tumour and process of care measures among patients receiving preoperative, postoperative or no RT. A multivariable Cox regression model assessed local recurrence risk.

RESULTS

The QIRC trial enrolled 1015 patients at 16 hospitals between 2002 and 2004. Radiation therapy use did not differ between trial arms, and median follow-up was 3.6 years. For the preoperative, postoperative and no RT groups, respectively, the percentage of patients was 12.8%, 19.3% and 67.9%; the percentage of stage II/III tumours was 57.0%, 88.7% and 48.1%; and the local recurrence rate was 5.3%, 10.2% and 5.5% (p = 0.05). After controlling for patient and tumour characteristics, including tumour stage, the hazard ratio (HR) for local recurrence was increased in the postoperative RT versus the no RT group (HR 1.64, 95% confidence interval 1.04-2.58, p = 0.027).

CONCLUSION

Use of preoperative RT was low; most patients with stage II/III disease did not receive RT and, as expected, the postoperative RT group had the highest risk of local recurrence. Our results suggest opportunities to improve rectal cancer RT use in Ontario.

Increased use of multidisciplinary treatment modalities adds little to the outcome of rectal cancer treated by optimal total mesorectal excision

PURPOSE

Total mesorectal excision (TME) is the standard surgical treatment for rectal cancer. The roles of chemotherapy and radiotherapy have become more defined, accompanied by improvements in preoperative staging and histopathological assessment. We analyse our ongoing results in the light of changing patterns of treatment over consecutive time periods.

METHODS

In total, 151 consecutive patients underwent potentially curative rectal excision for cancer in a single institution. Management and outcomes were compared between 1993-1999 and 2000-2007 which corresponded with the restructuring of the regional oncological services.

RESULTS

We found an increase in patients treated with neoadjuvant chemoradiotherapy after 1999 (20/89 vs 1/62, p < 0.001). There was an increase in the mean number of lymph nodes examined (11.9 vs 9.4, p = 0.037). The locoregional recurrence rate was 5.3%. The rates were not significantly different between the two study periods [4/89 (4.5%) 1999-2007 vs 4/62 (6.5%) 1993-1999, p = 0.597]. There was no statistical difference in overall or disease-free survival in the time periods examined.

CONCLUSIONS

Increasing use of neoadjuvant therapy and concomitant improvement in lymph node assessment did not translate into a concurrent reduction in the local recurrence, disease-free and overall survival rates. Our results demonstrate the enduring benefit of specialist training in TME in the outcome of rectal cancer surgery. This observational study suggests that low local recurrence rates are surrogate markers for improved overall and disease-free survival. Multidisciplinary team practice should be examined and made cost effective according to the individual unit's local recurrence rate in the light of this and other reports.

Rectal Cancer: MR imaging of the mesorectal fascia and effect of chemoradiation on assessment of tumor involvement

PURPOSE

To evaluate the impact of chemoradiation on the reliability of MRI in assessing tumor involvement of the mesorectal fascia in patients with rectal cancer.

MATERIALS AND METHODS

Presurgical MRI was performed in 150 patients; among them 85 had received neoadjuvant long-course chemoradiation. A standardized imaging protocol (1.5 Tesla [T] system, image voxel size 0.6 × 0.4 × 3 mm(3) ), standardized surgery, and histopathological examination were applied for the entire patient population. Images were analyzed to identify potential tumor involvement of the mesorectal fascia (minimum tumor distance to fascia ≤1 mm) and compared with histopathology as the reference standard. Results of nonirradiated and irradiated patients were compared to define the impact of chemoradiation on imaging reliability.

RESULTS

In nonirradiated patients, MRI was reliable in predicting or excluding tumor involvement of the mesorectal fascia, positive predictive value 80%, negative predictive value 89%. The frequency of overestimating tumor involvement was significantly higher in irradiated patients (P = 0.005, positive predictive value 42%).

CONCLUSION

Discussions about MRI assessment of tumor involvement of the mesorectal fascia as a basis for recommending neoadjuvant chemoradiation should focus on investigations that excluded irradiated patients, because MRI is less reliable after chemoradiation and tends to overestimate mesorectal tumor involvement.

Extended abdominoperineal excision vs. standard abdominoperineal excision in rectal cancer--a systematic overview

BACKGROUND

After introduction of total mesorectal excision (TME) as the gold standard for rectal cancer surgery, oncologic results appeared to be inferior for abdominoperineal excision (APE) as compared to anterior resection. This has been attributed to the technique of standard APE creating a waist at the level of the tumor-bearing segment. This systematic review investigates outcome of both standard and extended techniques of APE regarding inadvertent bowel perforation, circumferential margin (CRM) involvement, and local recurrence.

METHODS

A literature search was performed to identify all articles reporting on APE after the introduction of TME using Medline, Ovid, and Embase. Extended APE was defined as operations that resected the levator ani muscle close to its origin. All other techniques were taken to be standard. Studies so identified were evaluated using a validated instrument for assessing nonrandomized studies. Rates for perforation, CRM involvement, and local recurrence were compared using chi-square statistics.

RESULTS

In the extended group, 1,097 patients, and in the standard group, 4,147 patients could be pooled for statistical analysis. The rate of inadvertent bowel perforation and the rate of CRM involvement for extended vs. standard APE was 4.1% vs. 10.4% (relative risk reduction 60.6%, p = 0.004) and 9.6% vs. 15.4% (relative risk reduction 37.7%, p = 0.022), respectively. The local recurrence rate was 6.6% vs. 11.9% (relative risk reduction 44.5%, p < 0.001) for the two groups.

CONCLUSION

This systematic review suggests that extended techniques of APE result in superior oncologic outcome as compared to standard techniques.

Anterior-entry abdominoperineal resection: a variation in the method of perineal dissection

BACKGROUND

For patients with rectal cancer, there is a greater risk of a positive radial margin or local tumor recurrence when an abdominoperineal versus low anterior resection is performed, or when tumors are in an anterior versus nonanterior location. In response, clinical leaders have encouraged perineal dissection in the prone position or in concert with a coccygectomy. We describe anterior-entry abdominoperineal resection, which may minimize the need for such maneuvers and negative patient outcomes.

METHODS

Anterior-entry abdominoperineal resection was provided by one surgeon to 10 patients over an 18-month period. Pelvic dissection used total mesorectal excision techniques. Anteriorly, in men, the perineal dissection occurred between the external anal sphincter and the bulbospongiosus and transversus perinei superficialis muscles. Initial entry into the pelvis occurred anteriorly under direct vision. Rectal specimen quality was graded out of 5 using Quirke methods.

RESULTS

There were 8 male and 2 female subjects with a median age of 65 years. Eight of 10 tumors had some component of an anterior location. Seven patients received preoperative radiation. The radial margin was positive in 1 case. Median Quirke score for quality of the surgical specimen was 5 of 5.

CONCLUSIONS

Anterior-entry abdominoperineal resection follows anatomic planes in the perineum and demands initial entry into the pelvis anteriorly and under direct vision. It may minimize rates of positive radial margins, may be especially suited for tumors with a locally advanced anterior component, and in many patients may avoid the need for perineal dissection in the jackknife position.

Outcomes following a limited approach to radiotherapy in rectal cancer

BACKGROUND

Variation in the use of neoadjuvant and adjuvant radiotherapy for rectal cancer suggests an opportunity to avoid it in all but patients at highest risk of local recurrence.

METHODS

Between 1 July 1999 and 1 February 2006, patients with primary rectal cancer were treated by a single surgeon operating at McMaster University, Hamilton, Ontario, Canada. Digital rectal examination and pelvic computed tomography were used to determine whether the mesorectal margin was threatened by tumour and thus whether preoperative radiotherapy would be needed. The study outcome was local tumour recurrence.

RESULTS

Forty-six (48 per cent) of 96 patients received preoperative radiation therapy. The median follow-up was 4·2 years. Tumours were fixed or tethered in 31 (67 per cent) of the 46 irradiated patients. In contrast, no tumour was fixed in unirradiated patients and only ten (20 per cent) of the 50 tumours were tethered. The proportion of patients with stage I or II tumours based on final pathology was similar: 61 per cent (28 of 46) and 56 per cent (28 of 50) in irradiated and unirradiated groups respectively (P = 0·287). There were four (9 per cent) and two (4 per cent) local recurrences among irradiated and unirradiated patients respectively (P = 0·422).

CONCLUSION

Limiting preoperative radiotherapy in rectal cancer to patients with a threatened circumferential margin does not compromise patient outcome.

Clinical significance of magnetic resonance imaging findings in rectal cancer

Staging of rectal cancer is essential to help guide clinicians to decide upon the correct type of surgery and determine whether or not neoadjuvant therapy is indicated. Magnetic resonance imaging (MRI) is currently one of the most accurate modalities on which to base treatment decisions for patients with rectal cancer. MRI can accurately detect the mesorectal fascia, assess the invasion of the mesorectum or surrounding organs and predict the circumferential resection margin. Although nodal disease remains a difficult radiological diagnosis, new lymphographic agents and diffusion weighted imaging may allow identification of metastatic nodes by criteria other then size. In light of this, we have reviewed the literature on the accuracy of specific MRI findings for staging the local extent of primary rectal cancer. The aim of this review is to establish a correlation between MRI findings, prognosis, and available treatment options.

MRI-based indications for neoadjuvant radiochemotherapy in rectal carcinoma: interim results of a prospective multicenter observational study

BACKGROUND

This study evaluated use of circumferential resection margin status in preoperative MRI (mrCRM) as an indication for neoadjuvant radiochemotherapy (nRCT) in rectal carcinoma patients.

MATERIALS AND METHODS

In a multicenter prospective study, nRCT was given to patients with carcinoma of the middle rectum with positive mrCRM (≤1 mm), with cT3 low rectal carcinoma, and all patients with cT4 tumors. The short-term endpoints were pathologic pCRM (≤1 mm) as a strong predictor of local recurrence rate and the quality of total mesorectal excision according to the plane of surgery. These endpoints were compared in patients with and without nRCT.

RESULTS

Of 230 patients that met the inclusion criteria, 96 (41.7%) received a long course of nRCT and 134 (58.3%) were primarily operated on. The pCRM was positive in 13 of 230 (5.7%) (primarily operated on, 2 of 134 [1.5%]; after nRCT, 11 of 96 [11%]). In 1 of 134 (0.7%) case, the mrCRM was falsely negative. Patients at participating centers varied in terms of preoperative stage but not in pCRM positivity (0%-13%, P = .340). The plane of surgery was mesorectal (good) in 209 of 230 (90.9%), intramesorectal (moderate) in 16 of 230 (7%), and the muscularis propria plane (poor) in 2.2% (5 of 230).

CONCLUSIONS

Low pCRM positivity and the high quality of mesorectal excision support use of MRI-based nRCT in rectal carcinoma. nRCT was avoidable in 45% of patients with stage II and III disease without significant risk of undertreatment. Preoperative MRI thus allows identification of patients with high risk of local recurrence and use of selective nRCT.

Individualized magnetic resonance imaging-based neoadjuvant chemoradiation for middle and lower rectal carcinoma

AIM

In most institutions neoadjuvant chemoradiation for middle and lower rectal carcinoma is currently given to patients with tumours of clinical stages II or III (cT3,4 and/or N1,2). The possibility of a reduction in the use of neoadjuvant chemoradiation by an individualized magnetic resonance imaging (MRI)-based indication for neoadjuvant chemoradiation was analysed.

METHOD

Assessment of the pathological and oncological principles indicating for neoadjuvant treatment was used to determine the prognostic importance of the distance between the tumour and the circumferential resection margin and pretherapeutic assessment using modern MRI.

RESULTS

Based on the results of pretreatment MRI scanning, a proposal is presented for the treatment of middle and lower rectal carcinoma with neoadjuvant chemoradiation. Adopting this proposal, the frequency of neoadjuvant chemoradiation decreased from 70% to 35% and the early and late adverse effects of this therapy were reduced. In contrast, the expected locoregional recurrence rate increased from 6% to 11% if all quality criteria were met and to 18% if not.

CONCLUSION

An MRI-based indication for neoadjuvant chemoradiation is justified only for centres with regular quality assurance of MRI, surgery, radiotherapy and pathology. The proposal needs confirmation by long-term follow up and by prospective studies with larger numbers of patients.

Magnetic resonance imaging (MRI) in rectal cancer: a comprehensive review

Magnetic resonance imaging (MRI) has established itself as the primary method for local staging in patients with rectal cancer. This is due to several factors, most importantly because of the ability to assess the status of circumferential resection margin. There are several newer developments being introduced continuously, such as diffusion-weighted imaging and imaging with 3 T. Assessment of loco-regional lymph nodes has also been investigated extensively using different approaches, but more work needs to be done. Finally, evaluation of tumours during or after preoperative treatment is becoming an everyday reality. All these new aspects prompt a review of the most recent advances and opinions. In this review, a comprehensive overview of the current status of MRI in the loco-regional assessment and management of rectal cancer is presented. The findings on MRI and their accuracy are reviewed based on the most up-to-date evidence. Optimisation of MRI acquisition and relevant regional anatomy are also presented, based on published literature and our own experience.

Regional lymph node metastasis and locoregional recurrence of rectal carcinoma in the era of TME [corrected] surgery. Implications for treatment decisions

BACKGROUND AND AIMS

For rectal carcinoma treated according to the concept of total mesorectal excision (TME surgery), the independent influence of regional lymph node metastasis on the locoregional recurrence risk is still in discussion. A reliable assessment of this risk is important for an individualised selective indication for neoadjuvant radio-/radiochemotherapy.

METHODS

Analysis of literature, especially of the last 20 years, and consideration of pathological and oncological basic research. Multivariate analysis of data of the Erlangen Registry of Colorectal Carcinoma.

RESULTS

The clinical assessment of the pretherapeutic regional lymph node status by the present available imaging methods is still unreliable. The analysis of the association between pretherapeutic regional lymph node status and locoregional recurrence risk has to be based on follow-up data of patients treated by primary surgery and has to be distinguished between patients treated by conventional and optimised quality-assured TME surgery, respectively. Data from Erlangen show an increase of the local recurrence risk for patients with at least four involved regional lymph nodes.

CONCLUSIONS

For patients with at least four involved regional lymph nodes, a neoadjuvant radiochemotherapy may be indicated. However, today, the pretherapeutic diagnosis is uncertain and results in overtherapy in 40%. Thus, in case of positive lymph node findings by imaging methods, the benefits and risk of neoadjuvant therapy in such situations should always be discussed with the patient in the sense of informed consent and shared decision.

[Neoadjuvant radiochemotherapy for rectal cancer]

Neoadjuvant radiochemotherapy has become established treatment for rectal cancer. It is indicated when primary R0 resection is not an option, in cases of higher risk of locoregional relapse following surgical treatment alone, and when initially impossible conservation of the anal sphincter becomes possible in conjunction with neoadjuvant radiochemotherapy. The indication for radiochemotherapy in the upper third of the rectum is still controversial. Reevaluation of the tumor situation following neoadjuvant treatment is necessary before decisions on operative strategy. Modern imaging techniques are limited in this respect, as they hardly allow differentiation between living tumor tissue and lesions. In case of doubt clarity is possible only through surgical exploration, taking R1 resection into account. Overall the recognition of lymph node metastasis is not a sufficient indicator of local relapse. The frequency of postoperative complications following neoadjuvant radiochemotherapy is independent of the operative method. The effect of neoadjuvant radiochemotherapy on long-term survival and formation of distant metastases is still not clarified. Current studies seek clarification through the use of new chemotherapies and modified treatment regimes. Further, the correct time interval between the end of neoadjuvant radiochemotherapy and the following surgical therapy has yet to be determined. This applies also to the management of patients following complete remission.

Quality management in rectal carcinoma: what is feasible?

PURPOSE

A cohort study was carried out to analyse quality indicators in the diagnosis and treatment of rectal carcinoma.

METHODS

A total of 2,470 patients with rectal carcinoma treated between 1985 and 2007 at the Department of Surgery, University of Erlangen, were analysed and compared within four time intervals.

RESULTS

Most of the indicators analysed from 2004 to 2007 fulfilled the defined target values. The indicators for process quality of surgical treatment and the surrogate indicators of outcome quality in surgery showed excellent results. Comparing this to previous data, it displays the new developments such as introduction of multimodal treatment for high-risk patients. While the rate of locoregional recurrences decreased, no significant improvement in survival was found.

CONCLUSIONS

Careful analysis of quality indicators is important for both quality management and comparison of treatment results. The progress in diagnosis and treatment requires a continuous update of definitions and target values.

Rectal cancer surgery and regional lymph nodes

In patients with rectal cancer, the status of regional or mesorectal lymph nodes is central to both tumor staging and predicting local and distant recurrence. The importance of mesorectal lymph nodes in rectal cancer should inform treatment decisions around pre-operative diagnostic imaging, surgical techniques, pathologic assessment, and the use of radiation therapy.