Diagnostic accuracy of MRI for assessment of T category, lymph node metastases, and circumferential resection margin involvement in patients with rectal cancer: a systematic review and meta-analysis

A scoring system to predict inferior mesenteric artery lymph node metastasis and prognostic value of its involvement in rectal cancer

PURPOSE

The aim of this study is to establish a prediction scoring system for inferior mesenteric artery (IMA) lymph node metastasis and to assess the prognostic impact of dissection of positive IMA node on patients with stage III rectal cancer.

METHODS

A retrospective study was performed in 264 patients with stage III rectal cancer undergoing curative surgery. Clinicopathological, survival, and recurrence data were compared between 29 patients with positive IMA nodes and 235 patients with negative IMA nodes. Clinicopathological data which were found to be significantly associated with IMA nodal status were incorporated into a scoring system.

RESULTS

In the training samples, tumor differentiation and preoperative serum CEA were significant predictors of IMA node metastasis in multivariate analysis, which were incorporated into a scoring system. Using receiver operating characteristic curve analysis, we determined a cutoff value of 46.5 for scores, at which the system's sensitivity was 86 % and specificity 61 %. When applied to testing sample, the sensitivity was 80 % and specificity 60 %. Survival analysis showed that 5-year disease-free survival rate (5-DFS) and 5-year overall survival (5-OS) in the positive IMA node group (24.4 and 27.6 %, respectively) were significantly lower than in the negative IMA node group (61.8 and 71.3 %, respectively) (P < 0.001). Furthermore, multivariate analysis indicated that IMA lymph node metastasis was an unfavorable independent prognostic factor for 5-DFS and 5-OS.

CONCLUSIONS

IMA lymph node metastasis is an independent poor prognostic factor for stage III rectal cancer. The prediction scoring system for IMA node metastasis would be beneficial in determining the appropriate level of IMA ligation.

Magnetic resonance imaging in rectal cancer: A surgeon’s perspective

Magnetic resonance imaging (MRI) in rectal cancer was first investigated in 1999 and has become almost mandatory in planning rectal cancer treatment. MRI has a high accuracy in predicting circumferential resection margin involvement and is used to plan neoadjuvant therapy. The accuracy of MRI in assessing mesorectal lymph nodes remains moderate, as there are no reliable criteria to assess nodal involvement. MRI seems to be good in assessing peritoneal involvement in upper rectal cancer; this however has been assessed in only a few studies and needs further research. For low rectal cancers, mesorectum is thin at the level of levator ani especially in relation to prostate; so predicting circumferential resection margin involvement is not easy. However high spatial resolution coronal imaging shows levator muscles, sphincter complex and intersphincteric plane accurately. This is used to stage low rectal tumors and plan plane of surgery (standard surgery, intersphincteric resection, Extralevator abdominoperineal resection). While most centres perform MRI post chemoradiotherapy, its role in accurate staging post neoadjuvant therapy remains debatable. THe role of Diffusion weighted MRI post neoadjuvant therapy is being evaluated in research settings.

Accuracy of high-resolution MRI with lumen distention in rectal cancer staging and circumferential margin involvement prediction

Objective

To evaluate the accuracy of magnetic resonance imaging (MRI) with lumen distention for rectal cancer staging and circumferential resection margin (CRM) involvement prediction.

Materials and Methods

Seventy-three patients with primary rectal cancer underwent high-resolution MRI with a phased-array coil performed using 60-80 mL room air rectal distention, 1-3 weeks before surgery. MRI results were compared to postoperative histopathological findings. The overall MRI T staging accuracy was calculated. CRM involvement prediction and the N staging, the accuracy, sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) were assessed for each T stage. The agreement between MRI and histological results was assessed using weighted-kappa statistics.

Results

The overall MRI accuracy for T staging was 93.6% (k = 0.85). The accuracy, sensitivity, specificity, PPV and NPV for each T stage were as follows: 91.8%, 86.2%, 95.5%, 92.6% and 91.3% for the group ≤ T2; 90.4%, 94.6%, 86.1%, 87.5% and 94% for T3; 98,6%, 85.7%, 100%, 100% and 98.5% for T4, respectively. The predictive CRM accuracy was 94.5% (k = 0.86); the sensitivity, specificity, PPV and NPV were 89.5%, 96.3%, 89.5%, and 96.3% respectively. The N staging accuracy was 68.49% (k = 0.4).

Conclusion

MRI performed with rectal lumen distention has proved to be an effective technique both for rectal cancer staging and involved CRM predicting.

Sphincter-sparing surgery in patients with low-lying rectal cancer: techniques, oncologic outcomes, and functional results

BACKGROUND

Rectal cancer management has evolved into a complex multimodality approach with survival, local recurrence, and quality of life parameters being the relevant endpoints. Surgical treatment for low rectal cancer has changed dramatically over the past 100 years.

DISCUSSION

Abdominoperineal resection, once the standard of care for all rectal cancers, has become much less frequently utilized as surgeons devise and test new techniques for preserving the sphincters, maintaining continuity, and performing oncologically sound ultra-low anterior or local resections. Progress in rectal cancer surgery has been driven by improved understanding of the anatomy and pathophysiology of the disease, innovative surgical technique, improved technology, multimodality approaches, and increased appreciation of the patient's quality of life. The patient with a low rectal cancer, once almost universally destined for impotence and a colostomy, now has the real potential for improved survival, avoidance of a permanent stoma, and preservation of the normal route of defecation.

Accuracy of preoperative MRI in predicting pathology stage in rectal cancers: node-for-node matched histopathology validation of MRI features

BACKGROUND

Few studies that meticulously match individual lymph nodes seen on MRI with their precise histologic counterparts after total mesorectal excision have been reported.

OBJECTIVE

The objective of this study was to determine whether preoperative MRI could detect lymph node metastases accurately in the node-by-node analysis.

DESIGN

This was a prospective, observational cohort study.

SETTINGS

The study was conducted at a tertiary-care hospital.

PATIENTS

Forty patients with rectal cancer were enrolled.

MAIN OUTCOME MEASURES

Specimens were assessed using MRI for clinical staging. After surgical resection of the tumor, the specimens were again imaged with ex vivo ultrasound scan to localize the perirectal node. The locations of each lymph node were precisely matched with its corresponding magnetic resonance image to enable a node-for-node comparison of magnetic resonance images and histologic findings.

RESULTS

Agreement between MRI and histologic assessment of T stage was 82.5%. Of the 341 nodes harvested, 120 were too small (<3 mm) to be depicted on magnetic resonance images, and 18 of these contained metastasis (15%). A correlation between the results of MRI and histopathology was feasible for 205 lymph nodes, and the overall success rate of matching between the 2 techniques was 91.1% (205 of 221). Preoperative MRI revealed a node-by-node sensitivity and positive predictive value of 58.0%, and 61.7%. There was no difference in the diagnostic accuracy between the primary surgery subgroup and preoperative radiation subgroups.

LIMITATIONS

The study is limited by its heterogeneity of cohorts including the subgroup with preoperative chemoradiation and the lack of preoperative ultrasound assessment.

CONCLUSIONS

Preoperative MRI was moderately accurate for the prediction of mesorectal lymph node metastasis. Moreover, preoperative MRI was insufficient for detecting small lymph nodes (<3 mm) with metastasis.

Is adjuvant radiotherapy warranted in resected pT1-2 node-positive rectal cancer?

Background

Stage T1-2 rectal cancers are unlikely to have lymph node metastases and neoadjuvant therapy is not routinely administered. Postoperative management is controversial if lymph node metastases are detected in the resected specimen. We studied the outcomes of patients with pT1-2 node-positive rectal cancer in order to determine whether adjuvant radiotherapy was beneficial.

Methods

We conducted a retrospective analysis of 284 patients with pathological T1-2 node-positive rectal cancer from a single institution. Outcomes, including local recurrence (LR), distant metastasis (DM), disease free survival (DFS) and overall survival (OS), were studied in patients with detailed TN staging and different adjuvant treatment modalities.

Results

The overall 5-year LR, DM, DFS and OS rates for all patients were 12.5%, 32.9%, 36.4% and 76.8%, respectively. Local control was inferior among patients who received no adjuvant therapy. Patients could be divided into three risk subsets: Low-risk, T1N1; Intermediate-risk, T2N1 and T1N2; and High-risk, T2N2. The 5-year LR rates were 5.3%, 9.8% and 26.4%, respectively (p = 0.005). In High-risk patients, addition of radiotherapy achieved a 5-year LR rate of 9.1%, compared 34.8% without radiotherapy.

Conclusions

In our study, we provide the detailed outcomes and preliminary survival analysis in a relatively infrequent subset of rectal cancer. Three risk subsets could be identified based on local control for pT1-2 node positive rectal cancer. Postoperative treatment needs to be individualized for patients with pT1-2 node-positive rectal cancer.

Preoperative magnetic resonance imaging assessment of circumferential resection margin predicts disease-free survival and local recurrence: 5-year follow-up results of the MERCURY study

PURPOSE

The prognostic relevance of preoperative high-resolution magnetic resonance imaging (MRI) assessment of circumferential resection margin (CRM) involvement is unknown. This follow-up study of 374 patients with rectal cancer reports the relationship between preoperative MRI assessment of CRM staging, American Joint Committee on Cancer (AJCC) TNM stage, and clinical variables with overall survival (OS), disease-free survival (DFS), and time to local recurrence (LR).

PATIENTS AND METHODS

Patients underwent protocol high-resolution pelvic MRI. Tumor distance to the mesorectal fascia of ≤ 1 mm was recorded as an MRI-involved CRM. A Cox proportional hazards model was used in multivariate analysis to determine the relationship of MRI assessment of CRM to survivorship after adjusting for preoperative covariates.

RESULTS

Surviving patients were followed for a median of 62 months. The 5-year OS was 62.2% in patients with MRI-clear CRM compared with 42.2% in patients with MRI-involved CRM with a hazard ratio (HR) of 1.97 (95% CI, 1.27 to 3.04; P < .01). The 5-year DFS was 67.2% (95% CI, 61.4% to 73%) for MRI-clear CRM compared with 47.3% (95% CI, 33.7% to 60.9%) for MRI-involved CRM with an HR of 1.65 (95% CI, 1.01 to 2.69; P < .05). Local recurrence HR for MRI-involved CRM was 3.50 (95% CI, 1.53 to 8.00; P < .05). MRI-involved CRM was the only preoperative staging parameter that remained significant for OS, DFS, and LR on multivariate analysis.

CONCLUSION

High-resolution MRI preoperative assessment of CRM status is superior to AJCC TNM-based criteria for assessing risk of LR, DFS, and OS. Furthermore, MRI CRM involvement is significantly associated with distant metastatic disease; therefore, colorectal cancer teams could intensify treatment and follow-up accordingly to improve survival outcomes.

Local resection for small rectal cancer

Rectal resection with total mesorectal excision is the standard treatment for rectal cancers. Local excision represents an alternative with less post-operative mortality and morbidity and preservation of intestinal and bladder function. However, local excision cannot provide adequate nodal staging. Presently, endorectal ultrasound and magnetic resonance imaging are used to select the appropriate patients for local excision, those with limited T1 rectal tumors. There is general agreement that the ideal tumors for local excision are less or equal to 3 cm in diameter, superficial (usTis and/or usT1N0), infra-peritoneal, located below the middle rectal valve, and involving no more than 40% of the rectal circumference. Transanal tumor excision is suitable for distal tumors and transanal endoscopic microsurgery for mid and upper lesions. The principles of adequate resection margin, non-fragmentation, and full-thickness excision are similar to those for any cancer resection. Unfavorable pathologic criteria, as assessed on the fixed rectal specimen, include depth of tumor invasion (submucosal [T1sm3] or muscular [T2]), positive resection margins, vascular and/or lymphatic invasion, and poor differentiation. Further radical surgery is required in case of unfavorable criteria. Simple surveillance may be advised for superficial tumors (T1sm1) without any unfavorable criteria. Management of T1sm2 tumors without any unfavorable criteria should be discussed on a case-by-case basis.

MRI-based treatment of rectal cancer: is prognostication of the recurrence risk solid enough to render radiation redundant?

BACKGROUND

Most current guidelines recommend neoadjuvant short course radiotherapy (sRT) or radio-chemotherapy (nRCT) for rectal cancer stage II and III. After the introduction of total mesorectal excision (TME) and magnetic resonance imaging (MRI), this proceeding has been questioned and omission of neoadjuvant treatment according to preoperative MRI-criteria has been propagated. Aim of the present paper is to review the state of evidence regarding MRI-based treatment decision depending on the predicted width of the circumferential resection margin (CRM).

METHODS

A comprehensive survey of the literature was performed using the search terms "rectal cancer", "radiotherapy", "radio-chemotherapy", "MRI-based therapy", "circumferential resection margin". Data from lately published observational studies were compared to results from randomized trials and outcome analyses of the Norwegian national cancer registry.

RESULTS

Only one observational study using MRI-based treatment according to the anticipated CRM provided 5 year local recurrence data, however only for 65 patients. The second study did not yet evaluate recurrence rates. Two randomized trials comparing sRT to primary TME showed significantly worse outcome for non-irradiated patients. Data from the Norwegian rectal cancer registry demonstrate that TME alone is associated with higher LRR than achievable with preoperative RT.

CONCLUSIONS

Current evidence does not support the omission of neoadjuvant treatment for stage II-III rectal cancer on the basis of an MRI-predicted negative CRM. Randomized studies are warranted to clarify whether and for which subgroups TME alone is safe in terms of local recurrences.

Factors associated with lymph node metastasis in radically resected rectal carcinoids: a systematic review and meta-analysis

BACKGROUND

Although various guidelines regarding neuroendocrine tumors were released, treatment for rectal neuroendocrine tumors with size between 1 and 2 cm has not been explicitly elucidated. The determinant factor of the choice between endoscopic resection and radical surgery is whether lymph node involvement exists.

AIM

This study aims to explore factors associated with lymph node involvement in rectal neuroendocrine tumors by conducting a meta-analysis.

METHODS

A broad literature research of Pubmed, Embase&Medline, and The Cochrane Library was performed, and systematic review and meta-analysis about factors associated with lymph node involvement were conducted.

RESULTS

Seven studies were included in this meta-analysis. Tumor size > 1 cm (odds ratio (OR) 6.72, 95% confidence interval (CI) [3.23, 14.02]), depth of invasion (OR 5.06, 95% CI [2.30, 11.10]), venous invasion (OR 5.92, 95% CI [2.21, 15.87]), and central depression (OR 3.00, 95% CI [1.07, 8.43]) were significantly associated with lymph node involvement.

CONCLUSION

The available clinical evidence suggests that tumor size > 1 cm, invasion of muscularis properia, venous invasion, and central depression could be risk factors of lymph node involvement, while other factors reported by few studies need further research.

Efficacy of high resolution magnetic resonance imaging in preoperative local staging of rectal cancer

OBJECTIVE

To assess the efficacy of high-resolution magnetic resonance imaging (HRMRI) for preoperative local staging in patients with rectal cancer who did not receive preoperative radiochemotherapy.

METHODS

In this retrospective study, 30 patients with biopsy proved primary rectal cancer were evaluated by HRMRI. Two observers independently scored the tumour and lymph node stages, and circumferential resection margin (CRM) involvement. The sensitivity, specificity, the negative predictive value and the positive predictive value of HRMRI findings were calculated within the 95% confidence interval. The area under the curve was measured for each result. Agreement between two observers was assessed by means of the Kappa test.

RESULTS

In T staging the accuracy rate of HRMRI was 47-67%, overstaging was 10-21%, and understaging was 13-43%. In the prediction of extramural invasion with HRMRI, the sensitivity was 79-89%, the specificity was 72-100%, the PPV was 85-100%, the NPV was 73-86%, and the area under the curve was 0.81-0.89. In the prediction of lymph node metastasis, the sensitivity was 58-58%, the specificity was 50-55%, the PPV was 43-46%, and the NPV was 64-66%. The area under the curve was 0.54-0.57. When the cut off value was selected as 1 mm, the sensitivity of HRMRI was 38-42%, the specificity was 73-82%, the PPV was 33-42%, and NPV was 79-81% in the prediction of the CRM involvement. The correlation between the two observers was moderate for tumour staging, substantial for lymph node staging and predicting of CRM involvement.

CONCLUSION

Preoperative HRMRI provides good predictive data for extramural invasion but poor prediction of lymph node status and CRM involvement.

CONFLICT OF INTEREST

None declared.

Rectal cancer staging: focus on the prognostic significance of the findings described by high-resolution magnetic resonance imaging

High-resolution (HR) magnetic resonance imaging (MRI) has become an indispensable tool for multidisciplinary teams (MDTs) addressing rectal cancer. It provides anatomic information for surgical planning and allows patients to be stratified into different groups according to the risk of local and distant recurrence. One of the objectives of the MDT is the preoperative identification of high-risk patients who will benefit from neoadjuvant treatment. For this reason, the correct evaluation of the circumferential resection margin (CRM), the depth of tumor spread beyond the muscularis propria, extramural vascular invasion and nodal status is of the utmost importance. Low rectal tumors represent a special challenge for the MDT, because decisions seek a balance between oncologic safety, in the pursuit of free resection margins, and the patient's quality of life, in order to preserve sphincter function. At present, the exchange of information between the different specialties involved in dealing with patients with rectal cancer can rank the contribution of colleagues, auditing their work and incorporating knowledge that will lead to a better understanding of the pathology. Thus, beyond the anatomic description of the images, the radiologist's role in the MDT makes it necessary to know the prognostic value of the findings that we describe, in terms of recurrence and survival, because these findings affect decision making and, therefore, the patients' life. In this review, the usefulness of HR MRI in the initial staging of rectal cancer and in the evaluation of neoadjuvant treatment, with a focus on the prognostic value of the findings, is described as well as the contribution of HR MRI in assessing patients with suspected or confirmed recurrence of rectal cancer.

[Individualization of guidelines. Approach for rectal cancer in UICC stages II and III]

BACKGROUND

The German guidelines for the therapy of rectal carcinoma in Union Internationale Contre le Cancer (UICC) stages II and III raise questions of overtherapy. This is why we have individualized the therapy in suitable isolated cases (localization in the upper third of the rectum and wider safety margins in cases of small T3).

MATERIAL AND METHODS

All 131 patients with rectal cancer stages II and III, who were operated on within a time period of 4 years were retrospectively included in the study. In 30 favorable cases no radiotherapy was given and in 15 of these no chemotherapy. After an average of 57 months follow-up the course of the disease could be clarified in 95 % of the patients.

RESULTS

The 5-year survival rate in the whole group was 81.5 % with a local recurrence rate of 8 %. Of the patients with no additional therapy (or only adjuvant chemotherapy), 30 had a 5-year survival rate of 100 % (86.7 %) and a local recurrence rate of 6.7 % (6.7 %).

CONCLUSIONS

In this study it could be shown that an individualization of guidelines in special cases does not lead to a higher mortality rate or to a higher rate of local recurrence. The study highlights that chemotherapy and radiotherapy with all the negative consequences could be avoided for several patients.

Selecting patients with locally advanced rectal cancer for neoadjuvant treatment strategies

Rectal cancer remains a significant problem worldwide. Outcomes vary significantly according to the stage of disease and prognostic factors, including the distance of the tumor from the circumferential resection margin. Accurate staging, including high-resolution magnetic resonance imaging, allows stratification of patients into low-, moderate-, and high-risk disease; this information can be used to inform multidisciplinary team decisions regarding the role of neoadjuvant therapy. Both neoadjuvant short-course radiotherapy and long-course chemoradiation reduce the risk of local recurrence compared with surgery alone, but they have little impact on survival. Although there remains a need to reduce overtreatment of those patients at moderate risk, evaluation of intensified regimens for those with high-risk disease is still required to reduce distant failure rates and improve survival in these patients with an otherwise poor prognosis.

Stage and size using magnetic resonance imaging and endosonography in neoadjuvantly-treated rectal cancer

AIM: To assess the stage and size of rectal tumours using 1.5 Tesla (1.5T) magnetic resonance imaging (MRI) and three-dimensional (3D) endosonography (ERUS).

METHODS: In this study, patients were recruited in a phase I/II trial of neoadjuvant chemotherapy for biopsy-proven rectal cancer planned for surgical resection with or without preoperative radiotherapy. The feasibility and accuracy of 1.5T MRI and 3D ERUS were compared with the histopathology of the fixed surgical specimen (pathology) to determine the stage and size of the rectal cancer before and after neoadjuvant chemotherapy. A Philips Intera 1.5T with a cardiac 5-channel synergy surface coil was used for the MRI, and a B-K Medical Falcon 2101 EXL 3D-Probe was used at 13 MHz for the ERUS. Our hypothesis was that the staging accuracy would be the same when using MRI, ERUS and a combination of MRI and ERUS. For the combination, MRI was chosen for the assessment of the lymph nodes, and ERUS was chosen for the assessment of perirectal tissue penetration. The stage was dichotomised into stage I and stage II or greater. The size was measured as the supero-inferior length and the maximal transaxial area of the tumour.

RESULTS: The staging feasibility was 37 of 37 for the MRI and 29 of 36 for the ERUS, with stenosis as a limiting factor. Complete sets of investigations were available in 18 patients for size and 23 patients for stage. The stage accuracy by MRI, ERUS and the combination of MRI and ERUS was 0.65, 0.70 and 0.74, respectively, before chemotherapy and 0.65, 0.78 and 0.83, respectively, after chemotherapy. The improvement of the post-chemotherapy staging using the combination of MRI and ERUS compared with the staging using MRI alone was significant (P = 0.046). The post-chemotherapy understaging frequency by MRI, ERUS and the combination of MRI and ERUS was 0.18, 0.14 and 0.045, respectively, and these differences were non-significant. The measurements of the supero-inferior length by ERUS compared with MRI were within 1.96 standard deviations of the difference between the methods (18 mm) for tumours smaller than 50 mm. The agreement with pathology was within 1.96 standard deviations of the difference between imaging and pathology for all tumours with MRI (15 mm) and for tumours that did not exceed 50 mm with ERUS (22 mm). Tumours exceeding 50 mm in length could not be reliably measured by ERUS due to the limit in the length of each recording.

CONCLUSION: MRI is preferable to use when assessing the size of large or stenotic rectal tumours. However, staging accuracy is improved by combining MRI with ERUS.

Prediction of tumor stage and lymph node involvement with dynamic contrast-enhanced MRI after chemoradiotherapy for locally advanced rectal cancer

PURPOSE

The usefulness of restaging by magnetic resonance imaging (MRI) after chemoradiotherapy (CTx/RTx) in patients with locally advanced rectal cancer has not yet been established, mostly due to the difficult differentiation between viable tumor and fibrosis. MRI with dynamic contrast-enhanced (DCE) sequences may be of additional value in distinguishing malignant from nonmalignant tissue. The aim of this study was to assess the accuracy of tumor, nodal staging, and circumferential resection margin (CRM) involvement by MRI with DCE sequences after CTx/RTx.

METHODS

The accuracies were assessed by MRI on T2-weighted magnetic resonance (MR) images with DCE sequences in patients with locally advanced rectal cancer after a long course of CTx/RTx. MR images were assessed by two independent radiologists.

RESULTS

For tumor staging and CRM involvement, MRI with DCE sequences had an accuracy of 45 and 60 %, respectively. The accuracy for nodal staging was 93 %. On MRI, malignant lymph nodes had a median diameter of 8 mm (range, 4-18) and benign lymph nodes a median diameter of 4 mm (range, 3-11). A significant indicator for benign nodes was hypointensity on T2-weighted images (p < 0.001) and early complete arterial phase enhancement on DCE-weighted images (p < 0.001). A significant indicator for malignant nodes was heterogeneity on T2-weighted images (χ (2), p < 0.000) and early incomplete arterial phase enhancement on DCE (p < 0.001).

CONCLUSIONS

MRI with DCE is a useful tool for nodal staging after CTx/RTx. The addition of DCE sequences did not improve the accuracy of determining the tumor stage, CRM involvement, and in detecting complete response.

Rectal cancer : when is the local recurrence risk low enough to refrain from the aim to prevent it?

Recently, preliminary results of the OCUM study (optimized surgery and MRI-based multimodal therapy of rectal cancer) were published and raised concern in the scientific community. In this observational study, the circumferential resection margin status assessed in preoperative MRI (mrCRM) was used to decide for either total mesorectal excision (TME) alone or neoadjuvant radiochemotherapy (nRCT). In contrast to current guidelines, neither T3 stage (with negative CRM) nor clinically positive lymph nodes were an indication for nRCT. Pathologically node-positive patients received chemotherapy (ChT). Overall, 230 patients were included, of whom 96 CRM-positive patients received nRCT. The CRM was accurately predicted in MRI, the rate of mesorectal plane resection was high. Recurrence rates have not yet been reported, but an impressive rate of down-staging for both T and N stage after nRCT was observed, while acute side effects were minimal. Nonetheless, the authors conclude that a substantial number of patients could be "spared severe radiation toxicity" and propagate their concept for prospectively replacing current guidelines. This is based on the hypothesis that CRM is a valid surrogate parameter for the risk of local recurrence and in case of a negative CRM, nRCT becomes dispensable. Moreover, it is assumed that lymph node status is no more relevant. Both assumptions are a contradiction to recent data from randomized studies as specified below. As 5-year locoregional recurrence rate (LRR) of only of 5-8% and < 5% in low risk rectal cancer can be achieved by the addition of RT, the noninferiority of surgery alone can not be presumed unless the expected 5-year LRR is ≤ 5-8%, whereas any excess of this range renders the study design inacceptable. Unless a publication explicitly specifies 5-year LRR, results are not exploitable for clinical decisions.

Mortality risk after preoperative versus postoperative chemotherapy and radiotherapy in lymph node-positive rectal cancer

INTRODUCTION

Persistent lymph node-positive disease after preoperative radiotherapy for rectal cancer is associated with adverse outcomes. We quantified mortality risks of persistent pathologic lymph nodes in lymph node-positive rectal cancer patients treated with preoperative versus postoperative chemoradiation.

METHODS

This was a retrospective population-based analysis of 2,038 patients with stage III rectal cancer diagnosed 1994-2005 with follow-up through 2007 using data from the California Cancer Registry. Survival estimates were generated using the Kaplan-Meier method. Multivariate cancer-specific and overall mortality analyses were performed using Cox proportional hazard ratios with adjustment for age, gender, race/ethnicity, tumor grade, T stage, N stage, socioeconomic status, and time period (1994-1997, 1998-2001, and 2002-2005).

RESULTS

Overall survival was higher among lymph node-positive patients receiving postoperative chemoradiation compared to lymph node-positive patients receiving preoperative chemoradiation (median overall survival = 87 versus 62 months, P = 0.0002). In adjusted analyses, patients with persistent lymph node-positive disease after preoperative chemoradiation treatment had increased overall (HR = 1.69; 95 % CI, 1.42-2.01) and CRC-specific (HR = 1.78; 95 % CI, 1.44-2.19) mortality risk compared to lymph node-positive disease after postoperative chemoradiation treatment.

CONCLUSIONS

Stage III rectal cancer patients with persistent pathologic lymph nodes after preoperative chemoradiation represent a high-risk group, with higher mortality than those treated with postoperative chemoradiation.

Do MRI reports contain adequate preoperative staging information for end users to make appropriate treatment decisions for rectal cancer?

PURPOSE

This study was designed to elicit end-user opinions regarding the importance and diagnostic accuracy of MRI for T-category, threatened or involved circumferential margin (CRMi), and lymph node involvement (LNi) for preoperative staging of rectal cancer and to determine completeness of MRI reports for these elements on a population based level.

METHODS

The first part of this study was a mailed survey of surgeons, radiation oncologists, and medical oncologists to elicit their opinions regarding the importance and diagnostic accuracy of T-category, CRMi, and LNi on MRI. The second part of the study was an audit of MRI reports issued for pre-operative staging of rectal cancer to assess the completeness of these reports for T-category, CRMi, and LNi.

RESULTS

Although T-category, CRMi, and LNi were considered essential by 97, 94, and 77 % of respondents, respectively, the MRI report audit showed that only 40 % of MRI reports captured all of these elements. The majority of end users reported moderate diagnostic accuracy on MRI for T-category and CRMi and low diagnostic accuracy for LNi (52.3, 43, and 48.5 % respectively). Multivariate analysis showed that specialty was the only independent predictor of correct reporting of the diagnostic accuracy for each of the MRI elements.

CONCLUSIONS

While end users consider T-category, CRMi and LNi essential for preoperative staging of rectal cancer, less than 40 % of MRI reports captured all of these elements. Therefore, strategies to improve communication between radiologists and end users are critical to improve the overall quality of care for rectal cancer patients.

[Local diagnostics for rectal cancer. What is realistic?]

Accurate pretherapeutic staging of rectal cancer is crucial for further therapeutic management and important for prognosis. The most accurate diagnostic tools in the assessment of T and N categories of rectal cancer are endorectal ultrasound (EUS) and magnetic resonance imaging (MRI). Furthermore, MRI can accurately predict the distance of the tumor to the colorectal membrane (CRM) and computed tomography (CT) is more suitable for detecting distant metastases. In the routine care of rectal cancer EUS is the most frequently used diagnostic tool for local staging. The achieved accuracy for determining T category by EUS in routine clinical staging is lower than results reported in the literature. Furthermore, the accuracy of EUS depends on the experience of the examiner. Currently the frequency of using MRI for routine clinical staging of rectal cancer is low and in one out of five cases the local staging of rectal cancer is exclusively carried out by CT.