Lymph node micrometastasis in stage II distal rectal cancer following neoadjuvant chemoradiation therapy

Prognostic Value of the Distribution of Lymph Node Metastasis in Locally Advanced Rectal Cancer After Neoadjuvant Chemoradiotherapy

Background: The objective of this study is to assess the prognostic value of lymph node metastasis distribution (LND) in locally advanced rectal cancer (LARC) after neoadjuvant chemoradiotherapy (nCRT). Methods: This study included 179 patients with pathological stage III LARC who underwent nCRT followed by radical surgery. LND was classified into three groups: LND1, lymph node metastasis at the mesorectum (140/179, 78.2%); LND2, lymph node metastasis along the inferior mesenteric artery trunk nodes (26/179, 14.5%); LND3, lymph node metastasis at the origin of the IMA (13/179, 7.3%). Clinicopathologic characteristics were analyzed to identify independent prognostic factors. Result: LND showed better stratification for 3-year DFS (LND1 66.8, LND2 50, and LND3 15.4%, P < 0.01) compared to the ypN (3-year DFS: N1 59.9 and N2 60.3%, P = 0.34) and ypTNM (3-year DFS: IIIA 68.6%, IIIB 57.5%, and IIIC 53.5, P = 0.19) staging systems. Similar results were found for 3-year LRFS and DMFS. According to multivariate survival analysis, LND was shown to be an independent prognostic factor for DFS, LRFS, and DMFS in patients with positive lymph nodes (P < 0.01, in all cases). Conclusion: LND is an independent prognostic factor in stage III rectal cancer after nCRT. LND can be used as a supplementary indicator for the ypTNM staging system in patients with LARC after nCRT.

MRI for Restaging Locally Advanced Rectal Cancer: Detailed Analysis of Discrepancies With the Pathologic Reference Standard

OBJECTIVE. The purpose of this study was to analyze causes of discrepancies between restaging MRI and pathologic findings in the assessment of morphologic indicators of tumor response in patients with rectal cancer who have undergone neoadjuvant treatment. MATERIALS AND METHODS. MRI and pathologic data from 57 consecutively registered patients who underwent neoadjuvant treatment and total mesorectal excision between August 2015 and July 2018 were retrospectively analyzed. The sensitivity and specificity of restaging MRI in determining tumor regression grade, T category, N category, circumferential resection margin, and extramural vascular invasion were calculated with pathologic results as the reference standard. One-by-one comparisons between MRI and pathologic findings were conducted to identify causes of discrepancies. RESULTS. The sensitivity of MRI in determining tumor regression grades 3-5 was 77.1%; T3 and T4 category, 100.0%; node-positive disease, 75.0%; circumferential resection margin, 87.5%; and extramural vascular invasion, 91.7%. The specificity values were 72.7%, 62.5%, 70.7%, 85.7%, and 64.4%. Overstaging was mainly caused by misinterpretation of fibrotic areas as residual tumor. Inflammatory cell infiltration could appear as high signal intensity in fibrotic areas on DW images, an appearance similar to that of residual tumor. Edematous mucosa and submucosa adjacent to the tumor and muscularis propria could also be mistaken for residual tumor because of their intermediate signal intensity on T2-weighted MR images. CONCLUSION. MRI was prone to overstaging of disease. Discrepancies between MRI and pathologic findings were mainly caused by misinterpretation of fibrosis. Inflammatory cell infiltration, pure mucin, edematous mucosa and submucosa adjacent to the tumor, and muscularis propria could also be misinterpreted as residual tumor.

Unnecessity of lymph node regression evaluation for predicting gastric adenocarcinoma outcome after neoadjuvant chemotherapy

BACKGROUND

Neoadjuvant chemotherapy has been applied worldwide to improve the survival of patients with gastric adenocarcinoma (GAC). The evaluation of histological regression in primary tumors is valuable for predicting prognosis. However, the prognostic effect of regression change in lymph nodes (LNs) remains unclear.

AIM

To confirm whether the evaluation of regression change in LNs could predict the prognosis of GAC patients who received neoadjuvant chemotherapy followed by surgery.

METHODS

In this study, we evaluated the histological regression of resected LNs from 192 GAC patients (including those with esophagogastric junction adenocarcinoma) treated with neoadjuvant chemotherapy. We classified regression change and residual tumor in LNs into four groups: (A) true negative LNs with no evidence of a preoperative therapy effect, (B) no residual metastasis but the presence of regression change in LNs, (C) residual metastasis with regression change in LNs, and (D) metastasis with minimal or no regression change in LNs. Correlations between regression change and residual tumor groups in LNs and regression change in the primary tumor, as well as correlations between regression change in LNs and clinicopathological characteristics, were analyzed. The prognostic effect of regression change and residual tumor groups in LNs was also analyzed.

RESULTS

We found that regression change and residual tumor groups in LNs were significantly correlated with regression change in the primary tumor, tumor differentiation, ypT stage, ypN stage, ypTNM stage, lymph-vascular invasion, perineural invasion and R0 resection status. Regression change and residual tumor groups in LNs were statistically significant using univariate Cox proportional hazards analysis, but were not independent predictors. For patients who had no residual tumor in LNs, the 5-year overall survival (OS) rates were 67.5% in Group A and 67.4% in Group B. For the patients who had residual tumors in LNs, the 5-year OS rates were 28.2% in Group C and 39.5% in Group D. The patients in Groups A+B had a significantly better outcome than the patients in Groups C+D (P < 0.01). No significant differences in survival were found between Groups A and B, or between Groups C and D.

CONCLUSION

The existence of residual tumor in LNs, rather than regression change in LNs, is useful for predicting the prognosis after neoadjuvant chemotherapy in GAC patients. In practice, it may not be necessary to report regression change in LNs.

Wait-and-see treatment strategies for rectal cancer patients with clinical complete response after neoadjuvant chemoradiotherapy: a systematic review and meta-analysis

Wait-and-see treatment strategies may benefit rectal cancer patients who achieve a clinical complete response (cCR) after neoadjuvant chemoradiotherapy (NCRT). In this study, we analyzed data from 9 eligible trials to compare the oncologic outcomes of 251 rectal cancer patients achieving a cCR through nonsurgical management approaches with the outcomes of 344 patients achieving a pathologic complete response (pCR) through radical surgery. The two patient groups did not differ in distant metastasis rates or disease-free and overall survival, but the nonsurgical group had a higher risk of 1, 2, 3, and 5-year local recurrence. Hence, we concluded that for rectal cancer patients achieving a cCR after NCRT, a wait-and-see strategy with strict selection criteria, an appropriate follow-up schedule, and salvage treatments achieved outcomes at least as good as radical surgery. Long-term randomized and controlled trials with more uniform inclusion criteria and standardized follow-up schedules will help clarify the risks and benefits of wait-and-see treatment strategies for these patients.

Lymph nodes regression grade is a predictive marker for rectal cancer after neoadjuvant therapy and radical surgery

Neoadjuvant therapy (NT) for rectal cancer (RC) reduces primary tumors and involved lymph nodes. While a prognostic value of tumor regression grade (TRG) has been identified, involved lymph node regression grade (LRG) has not been systematically evaluated. Here, we evaluated the association of LRG with oncologic outcomes of RC patients after NT followed by radical surgery. 347 patients with locally advanced RC who received NT and then underwent radical surgery were retrospectively recruited between 2004 and 2011. Response to NT was evaluated by a 3-tier LRG and TRG based on the ratio of residual tumor to fibrosis. LRG was assessed in all patients (LRG 0, 170 patients [49.0%]; LRG 1, 100 patients [28.8%]; and LRG 2, 77 patients [22.2%]). LRG correlated with 5-year distant metastasis and 5-year disease free survival (p=0.029 and 0.023, respectively). LRG also correlated with TRG (p=0.017). We conclude that the LRG system may be an independent predictive factor of long-term oncologic outcomes of rectal cancer patients after NT and radical surgery.

Good and complete responding locally advanced rectal tumors after chemoradiotherapy: where are the residual positive nodes located on restaging MRI?

PURPOSE

Aim of this study was to evaluate the distribution of persistent mesorectal lymph node metastases on restaging MRI in patients with a good or complete response of their primary tumor (ypT0-2) after CRT for locally advanced rectal cancer.

METHODS

Two hundred and twenty eight locally advanced rectal cancer patients underwent CRT, which resulted in a good response (downstaging to yT0-2) in 144 patients. Forty-nine patients were excluded (no surgery/insufficient follow-up or lacking lesion-by-lesion histology results). This resulted in a final study group of 95 yT0-2 patients. For the patients with a yN(+)-status, a detailed lesion-by-lesion comparison between restaging MRI and histology was performed to evaluate the characteristics and distribution of the individual N(+)-nodes.

RESULTS

7/95 patients (7%) had a yT0-2N(+) status (11/880 (1%) N(+) nodes): no N(+) were found below the tumor level, 55% of the N(+) nodes were located at the level of the tumor, and 45% proximal to the tumor (at a median distance of 1.4 cm above the tumor level). In axial plane, 82% of the nodes were located at the ipsilateral circumference of the tumor, at a median distance of 0.9 cm from the tumor/rectal wall.

CONCLUSIONS

The incidence of persistent metastatic mesorectal nodes after CRT in patients with a good tumor response after CRT is very low. No N(+) nodes are found below the tumor level. All N(+) nodes are located at the level of or proximal to the primary tumor, of which the majority very close to the tumor/lumen.

Apparent diffusion coefficient for lymph node characterization after chemoradiation therapy for locally advanced rectal cancer

BACKGROUND

Because further treatment plans depends on lymph node (LN) status after neoadjuvant chemoradiation therapy (CRT), the accurate characterization of LN is important.

PURPOSE

To evaluate the diagnostic performance of apparent diffusion coefficient (ADC) for LN characterization after CRT and to compare the performance with that of LN size.

MATERIAL AND METHODS

Fifty-three patients (36 men, 17 women; mean age, 58 years; age range, 34-79 years) who underwent CRT and subsequent surgery were included. All patients underwent 1.5-T magnetic resonance imaging (MRI). Each regional LN on post-CRT MRI was identified in consensus by two radiologists after reviewing the pre-CRT MRI. The ADC value and size in each LN was measured. To compare the mean ADC values and sizes of the metastatic and non-metastatic LNs after CRT, the t-test was used. To calculate the performance, a ROC curve analysis was performed. The histopathological examinations served as the reference standard.

RESULTS

A total of 115 LNs (29 metastatic and 86 non-metastatic) were matched and analyzed. The mean ADC of the metastatic LNs was significantly higher than that of the non-metastatic LNs (1.36 ± 0.27 × 10(-3)mm(2)/s; 1.13 ± 0.23 × 10(-3)mm(2)/s, P < 0.0001). The mean size of the metastatic LNs was also significantly larger than that of the non-metastatic LNs (5.6 ± 3.1; 3.9 ± 1.2, P = 0.0078). There was no significant difference between the areas under the curve of the ADC and size (0.742 [95% CI, 0.652-0.819]; 0.680 [0.586-0.764], respectively, P = 0.4090).

CONCLUSION

The performance of ADC for LN characterization after CRT was comparable to that of LN size.

The impact of lymph node size to predict nodal metastasis in patients with rectal cancer after preoperative chemoradiotherapy

PURPOSE

During restaging after preoperative chemoradiotherapy (CRT), the assessment of lymph node (LN) metastasis is vital for selecting further treatment strategies. This study aimed to evaluate the impact of LN size to predict LN metastasis in rectal cancer patients after preoperative CRT.

METHODS

A total of 30 consecutive patients who underwent preoperative CRT followed by curative resection of primary rectal cancer were selected as a study group (CRT group). As a control group (non-CRT group), 30 patients who underwent primary tumor resection were selected using a 1:1 case-match design. Matching criteria were gender, age, and clinical T stage. The size of each LN was measured from the surgical specimen. To clarify optimal cutoff values for node size according to the risk of detecting metastasis, receiving-operator characteristic (ROC) curves were generated.

RESULTS

In the non-CRT group, 39/474 LNs were confirmed to have metastasis. In the CRT group, 29/422 LNs showed metastasis. The median size of metastatic LNs was 6.0 mm in CRT group, which was significantly larger than 4.0 mm in the non-CRT group (p = 0.006). The optimal cutoff value for determining metastasis in the CRT group was 4.5 mm, compared to 3.5 mm in the non-CRT group. The accuracy of the cutoff value was much higher in the CRT group (CRT vs. non-CRT, 77.9 vs. 59.9%).

CONCLUSIONS

LN size is a strong indicator for prediction of regional LN metastasis in rectal cancer patients after preoperative CRT, compared to those without CRT.

Immediate surgery or clinical follow-up after a complete clinical response?

Neoadjuvant chemoradiation (CRT) is considered as one of the preferred treatment strategies for patients with locally advanced rectal cancer. This treatment strategy may lead to significant tumor regression, ultimately leading to complete pathological response in up to 42% of patients. Assessment of tumor response following CRT and before radical surgery may identify patients with complete clinical response that could be managed non operatively with strict follow-up (Watch & Wait Strategy).

Pathological prognostic factors in locally advanced rectal carcinoma after neoadjuvant radiochemotherapy: analysis of 113 cases

AIMS

Neoadjuvant radiochemotherapy (RCT) followed by surgical resection is the treatment for locally advanced mid-rectal or low rectal cancer. The aim of this study was to evaluate postoperative histological prognostic factors in a series of surgical specimens after neoadjuvant RCT.

METHODS AND RESULTS

One hundred and thirteen patients were included. Macroscopic and microscopic examinations were performed according to CAP recommendations, with additional criteria such as tumour budding, the presence of calcifications, and response to neoadjuvant therapy assessed according to Modified Rectal Cancer Regression Grade (m-RCRG). The 3-year disease-free survival (DFS) was 67.6%. In univariate analysis, ypTN stage, tumour budding, circumferential margin, invaded margin and vascular and perineural invasion were prognostic factors. In multivariate analysis, the presence of calcifications (P = 0.04) and an involved circumferential margin (P = 0.03) were the only independent factors for worse DFS. mRCRG was not correlated with DFS. Among the 50 m-RCRG1 tumours, DFS was better in ypT0 patients than in other ypT stages (P = 0.003).

CONCLUSIONS

The presence of calcifications in the tumour bed is described for the first time as a prognostic factor in rectal cancer. The prognostic value of budding was demonstrated in this study after neoadjuvant RCT. ypT stage appears to be a more reliable predictor of oncological outcome than histological tumour regression grade, which needs to be standardized for better reproducibility.

ypN0 nodal status after neoadjuvant chemoradiotherapy for rectal carcinoma is not associated with adverse prognosis as compared with pN0 after primary surgery

BACKGROUND AND AIMS

Neoadjuvant chemoradiotherapy (nCRT) has been established as standard treatment for locally advanced rectal cancer (cT3/4 or cN+ cM0, distance from circumferential resection margin ≤1 mm) to enhance local disease control and minimize the rate of locoregional recurrence. As a consequence of downstaging, a significant proportion of patients show non-viable tumor deposits within regional lymph nodes that qualify as ypN0 according to the current TNM classification irrespective of the actual pre-treatment status. Accordingly, the prognostic relevance of ypN0 status as compared with true pN0 without preceding nCRT is not known.

PATIENTS AND METHODS

We retrospectively analyzed 132 patients who underwent standard total mesorectal excision (TME) surgery after nCRT for rectal carcinoma and were classified as ypN0, and compared their prognoses with those of 341 patients with pN0 without nCRT.

RESULTS

Re-evaluation of regional lymph nodes after nCRT showed no evidence of previous metastasis in 91 cases (ypN0(-)), sure but non-viable metastasis in 14 patients (ypN0(+)), and unsure status in 27 patients (ypN0(X)). The local recurrence rate, distant metastases, and disease-free, observed, and cancer-related survival were similar in all subgroups (p = 0.447, 0.695, 0.759, 0.655, and 0.354, respectively).

CONCLUSION

Our results showed a similar outcome in patients with ypN0 and in the control group with pN0 regarding local recurrence rate, distant metastases, and disease-free, observed, and cancer-related survival. Validation of these results is necessary to clarify the questions regarding postoperative adjuvant chemotherapy for patients with ypN0(+).

Performance of gadofosveset-enhanced MRI for staging rectal cancer nodes: can the initial promising results be reproduced?

OBJECTIVES

A previous study showed promising results for gadofosveset-trisodium as a lymph node magnetic resonance imaging (MRI) contrast agent in rectal cancer. The aim of this study was to prospectively confirm the diagnostic performance of gadofosveset MRI for nodal (re)staging in rectal cancer in a second patient cohort.

METHODS

Seventy-one rectal cancer patients were prospectively included, of whom 13 (group I) underwent a primary staging gadofosveset MRI (1.5-T) followed by surgery (± preoperative 5 × 5 Gy) and 58 (group II) underwent both primary staging and restaging gadofosveset MRI after a long course of chemoradiotherapy followed by surgery. Nodal status was scored as (y)cN0 or (y)cN+ by two independent readers (R1, R2) with different experience levels. Results were correlated with histology on a node-by-node basis.

RESULTS

Sensitivity, specificity and area under the receiver operating characteristics curve (AUC) were 94%, 79% and 0.89 for the more experienced R1 and 50%, 83% and 0.74 for the non-experienced R2. R2's performance improved considerably after a learning curve, to an AUC of 0.83. Misinterpretations mainly occurred in nodes located in the superior mesorectum, nodes located in between vessels and nodes containing micrometastases.

CONCLUSIONS

This prospective study confirms the good diagnostic performance of gadofosveset MRI for nodal (re)staging in rectal cancer.

KEY POINTS

• Gadofosveset-enhanced MRI shows high performance for nodal (re)staging in rectal cancer. • Gadofosveset MRI may facilitate better selection of patients for personalised treatment. • Results can be reproduced by non-expert readers. • Experience of 50-60 cases is required to achieve required expertise level. • Main pitfalls are nodes located between vessels and nodes containing micrometastases.

Risk factors for local recurrence following neoadjuvant chemoradiotherapy for rectal cancers

Local recurrence (LR) has an adverse impact on rectal cancer treatment. Neoadjuvant chemoradiotherapy (nCRT) is increasingly administered to patients with progressive cancers to improve the prognosis. However, LR still remains a problem and its pattern can alter. Correspondingly, new risk factors have emerged in the context of nCRT in addition to the traditional risk factors in patients receiving non-neoadjuvant therapies. These risk factors are decisive when reviewing treatment options. This review aims to elucidate the distinctive risk factors related to LR of rectal cancers in patients receiving nCRT and to clarify their clinical significance. A search was conducted on PubMed to identify original studies investigating patients with rectal cancer receiving nCRT. Outcomes of interest, especially potential risk factors for LR in patients with nCRT, were then analyzed. The clinical importance of these risk factors is discussed. Remnant cancer cells, lymph-nodes and tumor response were found to be major risk factors. Remnant cancer cells decide the status of resection margins. Local excision following nCRT is promising in ypT0-1N0M0 cases. Dissection of lateral lymph nodes should be considered in advanced low-lying cancers. Although better tumor response resulted in a relatively lower recurrence rate, the evidence available is insufficient to justify a non-operative approach in clinical complete responders to nCRT. LR cannot be totally avoided by current multidisciplinary approaches. The related risk factors resulting from nCRT should be considered when making decisions regarding treatment selection.

What does absence of lymph node in resected specimen mean after neoadjuvant chemoradiation for rectal cancer

Background

The effect of insufficient node sampling in patients with rectal cancer managed by neoadjuvant chemoradiation followed by surgery has not been clearly determined. We evalulated the impact of insufficient sampling or even abscence of lymph nodes in the specimen on survival in patients at high-risk (T3, T4 or node positive) for rectal cancer.

Methods

We conducted a single institution, retrospective analysis of all patients who underwent surgical rectal resection following neoadjuvant chemoradiation for treatment of mid to lower rectal cancer between 1997 and 2009. ypNX was defined as the absence of lymph nodes retrieved in the resected specimen.

Results

A total of 132 patients underwent resection for treatment of rectal cancer following neoadjuvant chemoradiation. Ninety four patients (71.2%) were considered as having node-negative disease, including ypNx and ypN0. In 38 patients (28.8%), the primary tumor was associated with regional lymph node metastases (ypNpos). The mean number of retrieved nodes per specimen was 14.2, respectively. The five-year overall survival from initial operation for the ypNx group was 100%, respectively. The estimated five-year overall survival for ypN0 and ypNpos was 84.0% and 60.3%, respectively (P =0.001). No significant differences in overall survival were observed between the ypNx and ypN0 group (P =0.302).

Conclusion

Absence of recovered LN in resected specimens after neoadjuvant chemoradiation was observed in 7.6% of specimens. Absence of LN should not be regarded as a risk factor for poor survival or as a sign of less radical surgery.

Lymph node micrometastasis in gastrointestinal tract cancer--a clinical aspect

Lymph node micrometastasis (LNM) can now be detected thanks to the development of various biological methods such as immunohistochemistry (IHC) and reverse transcription-polymerase chain reaction (RT-PCR). Although several reports have examined LNM in various carcinomas, including gastrointestinal (GI) cancer, the clinical significance of LNM remains controversial. Clinically, the presence of LNM is particularly important in patients without nodal metastasis on routine histological examination (pN0), because patients with pN0 but with LNM already in fact have metastatic potential. However, at present, several technical obstacles are impeding the detection of LNM using methods such as IHC or RT-PCR. Accurate evaluation should be carried out using the same antibody or primer and the same technique in a large number of patients. The clinical importance of the difference between LNM and isolated tumor cells (≤0.2 mm in diameter) will also be gradually clarified. It is important that the results of basic studies on LNM are prospectively introduced into the clinical field. Rapid diagnosis of LNM using IHC and RT-PCR during surgery would be clinically useful. Currently, minimally invasive treatments such as endoscopic submucosal dissection and laparoscopic surgery with individualized lymphadenectomy are increasingly being performed. Accurate diagnosis of LNM would clarify issues of curability and safety when performing such treatments. In the near future, individualized lymphadenectomy will develop based on the establishment of rapid, accurate diagnosis of LNM.

The role of hilar lymphadenectomy in patients subjected to hepatectomy due to colorectal metastasis

CONTEXT

Hepatectomy is the treatment of choice for colorectal liver metastases, and several studies have shown good results, with 5-year survival rates ranging from 40% to 57%. Several clinical and pathological predictive factors for survival after liver resection have been studied. Involvement of the hepatic hilum lymph nodes, the incidence of which varies from 2% to 10%, indicates a poor long-term prognosis.

RESULTS

Despite variable results, some authors have reported a not-insignificant improvement in survival rate in liver-metastasis patients with hilar lymph node involvement who undergo combined liver resection and lymphadenectomy. Due to the low rates of morbidity and mortality for liver-resection surgery, several specialized centers perform liver resections combined with lymphadenectomies in selected cases. It should be noted that the therapeutic value of systemic lymphadenectomy is not yet entirely understood, and only controlled studies comparing groups with and without lymphadenectomy can fully resolve the issue.

CONCLUSION

In any case, hilar lymph node dissection has been shown to be a useful tool for improving the accuracy of extra hepatic disease staging, regardless of its impact on survival.

Number of lymph nodes after neoadjuvant therapy for rectal cancer: How many are needed?

Dear readers,

In the February 2012 issue of the World J Gastrointest Surg (4(2):32-35) Scabini and Ferrando published an editorial entitled “Number of lymph nodes after neoadjuvant therapy for rectal cancer: how many are needed?”.It has been brought to our attention that segments of the editorial are identical or closely resemble the essential parts of the discussion of the original article “Preoperative chemoradiotherapy does not necessarily reduce lymph node retrieval in rectal cancer specimens ¨C Results from a prospective evaluation with extensive pathological work-up” that was published in the Journal of Gastrointestinal Surgery in 2009. Given the striking similarities of the two works, the World J Gastrointest Surg has decided to retract the editorial by Scabini and Ferrando.

Timothy M. Pawlik, MD, MPH, PhD

Editor-in-Chief, World Journal of Gastrointestinal Surgery

Lymphangiogenesis in regional lymph nodes is an independent prognostic marker in rectal cancer patients after neoadjuvant treatment

One of the major prognostic factors in rectal cancer is lymph node metastasis. The formation of lymph node metastases is dependent on the existence of a premetastatic niche. An important factor preceding metastasis are lymph vessels which are located in the lymph node. Accordingly, the occurrence of intranodal lymphangiogenesis is thought to indicate distant metastasis and worse prognosis. To evaluate the significance of lymph node lymphangiogenesis, we studied formalin fixed, paraffin embedded adenocarcinomas and regional lymph nodes of 203 rectal cancer patients who were treated with neoadjuvant radiochemotherapy and consecutive curative surgery with cancer free surgical margins (R0). Regional lymph node lymph vessels were detected by immunohistochemistry for podoplanin (D2-40). Our results show that the presence of lymphatic vessels in regional lymph nodes significantly affects the disease-free survival in univariate and multivariate analyses. In contrast, there was no correlation between peritumoral or intratumoral lymph vessel density and prognosis. Indeed, our study demonstrates the importance of lymphangiogenesis in regional lymph nodes after neoadjuvant radiochemotherapy and consecutive surgery as an independent prognostic marker. Staining for intranodal lymphangiogenesis and methods of intravital imaging of lymphangiogenesis and lymphatic flow may be a useful strategy to predict long-term outcome in rectal cancer patients. Furthermore, addition of VEGF-blocking agents to standardized neoadjuvant treatment schemes might be indicated in advanced rectal cancer.

Complete clinical response after neoadjuvant chemoradiation for distal rectal cancer

Multimodality treatment of rectal cancer, with the combination of radiation therapy, chemotherapy, and surgery has become the preferred approach to locally advanced rectal cancer. The use of neoadjuvant chemoradiation therapy (CRT) has resulted in reduced toxicity rates, significant tumor downsizing and downstaging, better chance of sphincter preservation, and improved functional results. A proportion of patients treated with neoadjuvant CRT may ultimately develop complete clinical response. Management of these patients with complete clinical response remains controversial and approaches including radical resection, transanal local excision, and observation alone without immediate surgery have been proposed. The use of strict selection criteria of patients after neoadjuvant CRT has resulted in excellent long-term results with no oncological compromise after observation alone in patients with complete clinical response. Recurrences are detectable by clinical assessment and frequently amenable to salvage procedures.

Neoadjuvant chemo-radiotherapy and rectal cancer: can the UK watch and wait with Brazil?

OBJECTIVE

It has recently been reported that up to one-third of patients with nonmetastatic distal rectal cancer managed with neoadjuvant chemoradiation therapy (CRT) had a complete clinical response (cCR) to treatment. In the selected cases, this has been used as the sole treatment. The aim of this study was to determine the frequency of complete pathological response for patients receiving CRT in one centre in the UK.

METHOD

Patients receiving 6 weeks of neoadjuvant CRT were identified using the two cancer audit databases in two different tertiary hospitals from January 2002 to November 2007. Pathology was reviewed and the histopathological response of the resected specimen to CRT was evaluated using the Mandard classification (1 = complete response, 5 = no response)

RESULTS

One hundred and thirty-two consecutive patients [median age 61 (range 44-86) years, 90 men] with nonmetastatic locally advanced rectal cancer received neoadjuvant chemo radiotherapy between 2002 and 2007 followed by resection of the tumour. Data were available from 129 patients.

CONCLUSION

Only 13 out of 132 (10%) of patients had a complete pathological response. This is one-third of the cCR previously reported. Nonsurgical therapy for rectal cancer using the Habr-Gama treatment algorithm may only be effective in a very small proportion of patients with rectal cancer in the UK and nonoperative treatment would not be recommended.

Preoperative chemoradiotherapy does not necessarily reduce lymph node retrieval in rectal cancer specimens--results from a prospective evaluation with extensive pathological work-up

PURPOSE

Preoperative chemoradiotherapy (CRT) is supposed not only to reduce lymph node metastases but also lymph node recovery in rectal cancer specimens. The objective of this prospective study was to determine the effects of chemoradiation on mesorectal lymph node retrieval under terms of a meticulous histopathological evaluation.

METHODS

Specimens from 64 consecutive patients with stage II/III rectal cancer receiving preoperative 5-FU-based CRT were investigated. All patients were treated within the German Rectal Cancer Trial CAO/ARO/AIO-04. After surgery (including quality assessed total mesorectal excision), extensive pathological diagnostics was performed with embedding and microscopic evaluation of the whole mesorectal soft tissue compartment.

RESULTS

A total number of 2,021 lymph nodes were recovered (31.6 per specimen) within pathological work-up. There was no significant correlation between the number of retrieved nodes and patient- as well as tumor-dependent parameters. Lymph node size constantly amounted for less than 0.5 cm. Twenty patients (31.3%) had persistent nodal metastases. A considerable incidence of residual micrometastatic involvement in lymph nodes <0.3 cm (in 9.4% of all patients) was detected by extensive pathologic work-up.

CONCLUSION

Reliable nodal staging with high numbers of detected nodes was feasible after neoadjuvant CRT. Micrometastases frequently occur in small lymph nodes detected by microscopic evaluation.

Lymphadenectomy in colorectal cancer liver metastases resection: incidence of hilar lymph nodes micrometastasis

BACKGROUND

Liver resection is considered the best treatment for metastatic colorectal cancer. Several prognostic factors have been investigated, and many studies have shown that hepatic hilum lymph nodes involvement has a negative impact on prognosis. The present study evaluated the frequency of microscopic involvement of hilar lymph nodes, through systematic lymphadenectomy and analysis of micrometastases in patients undergoing hepatectomy due to colorectal metastasis.

METHODS

A total of 28 patients underwent hepatic resection with hilar lymphadenectomy. Lymph nodes considered negative by conventional hematoxylin and eosin (H&E) staining were analyzed by serial sectioning with 100-microm intervals and immunohistochemistry (IHC) with anti-human pancytokeratin antibody AE1/AE3.

RESULTS

In average, 6.18 lymph nodes were dissected per patient. No morbidity or mortality was associated to lymphadenectomy. In two patients, conventional H&E analysis showed presence of microscopic lymph node metastasis. IHC analysis allowed the identification of three other patients with lymph node micrometastases. The overall frequency of microscopic metastases, including micrometastasis, was 18%.

CONCLUSIONS

Systematic lymphadenectomy allowed the detection of microscopic lymph node metastases, resulting in more accurate staging of extrahepatic disease. The inclusion of IHC increased the detection of lymph node micrometastasis.

Lymph node size in rectal cancer following neoadjuvant chemoradiation--can we rely on radiologic nodal staging after chemoradiation?

OBJECTIVES

Local excision is currently being considered as an alternative strategy for ypT0-2 rectal cancer. However, patient selection is crucial to rule out nodal disease and is performed by radiologic studies that consider size as a surrogate marker for positive nodes. The purpose of this study was to determine the difference in size between metastatic and nonmetastatic nodes and the critical lymph node size after neoadjuvant chemoradiation therapy.

METHODS

The 201 lymph nodes available from 31 patients with ypT0-2 rectal cancer were reviewed and measured. Lymph nodes were compared according to the presence of metastases and size.

RESULTS

There was a mean of 6.5 lymph nodes per patient and 12 positive nodes of the 201 recovered (6%). Ninety-five percent of all lymph nodes were <5 mm, whereas 50% of positive lymph nodes were <3 mm. Metastatic lymph nodes were significantly greater in size (5.0 vs. 2.5mm; P = 0.02). Lymph nodes >4.5 mm had a greater risk of harboring metastases (P = 0.009).

CONCLUSIONS

Patients with ypT0-2 rectal cancer following neoadjuvant chemoradiation have very small perirectal nodes. Individual metastatic lymph nodes are significantly larger. However, a significant number of lymph nodes after neoadjuvant chemoradiation (negative and positive) are <3 mm. Individual lymph node size is not a good predictor of nodal metastases and may lead to inaccurate radiologic staging.

The role of carcinoembriogenic antigen in predicting response and survival to neoadjuvant chemoradiotherapy for distal rectal cancer

PURPOSE

Carcinoembriogenic antigen (CEA) is the most frequently used tumor marker in rectal cancer. A decrease in carcinoembriogenic antigen after radical surgery is associated with survival in these patients. Neoadjuvant chemoradiotherapy may lead to significant primary tumor downstaging, including complete tumor regression in selected patients. Therefore, we hypothesized that a decrease in CEA after neoadjuvant chemoradiotherapy could reflect tumor response to chemoradiotherapy, affecting final disease stage and ultimately survival.

METHODS

Patients with distal rectal cancer managed by neoadjuvant chemoradiotherapy and available pretreatment and postchemoradiotherapy levels of CEA were eligible for the study. Outcomes studied included final disease stage, relapse, and survival, and these were compared according to initial CEA level, post-chemoradiotherapy CEA level, and the reduction in CEA.

RESULTS

Overall 170 patients were included. Post-chemoradiotherapy CEA levels <5 ng/ml were associated with increased rates of complete clinical response and pathologic response. Additionally, postchemoradiotherapy CEA levels <5 ng/ml were associated with increased overall and disease-free survival (P = 0.01 and P = 0.03). There was no correlation between initial CEA level or reduction in CEA and complete response or survival.

CONCLUSION

A postchemoradiotherapy CEA level <5 ng/ml is a favorable prognostic factor for rectal cancer and is associated with increased rates of earlier disease staging and complete tumor regression. Postchemoradiotherapy CEA levels may be useful in decision making for patients who may be candidates for alterative treatment strategies.

Absence of lymph nodes in the resected specimen after radical surgery for distal rectal cancer and neoadjuvant chemoradiation therapy: what does it mean?

PURPOSE

The number of retrieved lymph nodes during radical surgery has been considered of great importance to ensure adequate staging and radical resection. However, this finding may not be applicable after neoadjuvant therapy in which, not only is there a decrease in lymph nodes recovered, but also a subgroup of patients with absence of lymph nodes in the resected specimen.

METHODS

Patients with absence of lymph nodes were compared with patients with ypN0 disease and patients with ypN+ disease.

RESULTS

Thirty-two patients (11 percent) had absence of lymph nodes, 171 patients (61 percent) had ypN0 disease, and 78 patients (28 percent) had ypN+ disease. Patients with absence of lymph nodes had significantly lower ypT status (ypT0-1, 40 vs. 13 percent; P<0.001) and decreased risk of perineural invasion (6 vs. 21 percent; P=0.04) compared with ypN0 patients. Five-year disease-free survival (74 percent) was similar to patients with ypN0 (59 percent; P=0.2), and both were significantly better than patients with ypN+ disease (30 percent; P<0.001).

CONCLUSIONS

Absence of lymph nodes retrieved from the resected specimen is associated with favorable pathologic features (ypT and perineural invasion status) and good disease-free survival rates. In this setting, absence of retrieved lymph nodes may reflect improved response to neoadjuvant chemoradiation therapy rather than inappropriate or suboptimal oncologic radicality.

Interval between surgery and neoadjuvant chemoradiation therapy for distal rectal cancer: does delayed surgery have an impact on outcome?

BACKGROUND

The optimal interval between neoadjuvant chemoradiation therapy (CRT) and surgery in the treatment of patients with distal rectal cancer is controversial. The purpose of this study is to evaluate whether this interval has an impact on survival.

METHODS AND MATERIALS

Patients who underwent surgery after CRT were retrospectively reviewed. Patients with a sustained complete clinical response (cCR) 1 year after CRT were excluded from this study. Clinical and pathologic characteristics and overall and disease-free survival were compared between patients undergoing surgery 12 weeks or less from CRT and patients undergoing surgery longer than 12 weeks from CRT completion and between patients with a surgery delay caused by a suspected cCR and those with a delay for other reasons.

RESULTS

Two hundred fifty patients underwent surgery, and 48.4% had CRT-to-surgery intervals of 12 weeks or less. There were no statistical differences in overall survival (86% vs. 81.6%) or disease-free survival rates (56.5% and 58.9%) between patients according to interval (< or =12 vs. >12 weeks). Patients with intervals of 12 weeks or less had significantly higher rates of Stage III disease (34% vs. 20%; p = 0.009). The delay in surgery was caused by a suspected cCR in 23 patients (interval, 48 +/- 10.3 weeks). Five-year overall and disease-free survival rates for this subset were 84.9% and 51.6%, not significantly different compared with the remaining group (84%; p = 0.96 and 57.8%; p = 0.76, respectively).

CONCLUSIONS

Delay in surgery for the evaluation of tumor response after neoadjuvant CRT is safe and does not negatively affect survival. These results support the hypothesis that shorter intervals may interrupt ongoing tumor necrosis.

Evaluating mesorectal lymph nodes in rectal cancer before and after neoadjuvant chemoradiation using thin-section T2-weighted magnetic resonance imaging

PURPOSE

To apply thin-section T2-weighted magnetic resoance imaging (MRI) to evaluate the number, size, distribution, and morphology of benign and malignant mesorectal lymph nodes before and after chemoradiation treatment compared with histopathologic findings.

METHODS AND MATERIALS

Twenty-five patients with poor-risk adenocarcinoma of the rectum treated with neoadjuvant chemoradiation were evaluated prospectively. Thin-section T2-weighted MR images obtained before and after chemoradiation treatment were independently reviewed in consensus by 2 expert radiologists to determine the tumor stage, nodal size, nodal distribution, and nodal stage. Total mesorectal excision surgery after chemoradiation allowed MR nodal stage to be compared with histopathology using kappa statistics. Nodal downstaging was compared using the Chi-square test.

RESULTS

Before chemoradiation, 152 mesorectal nodes were visible (mean, 6.2 mm; 100 benign, 52 malignant) and 4 of 52 malignant nodes were in contact with the mesorectal fascia. The nodal staging was 7/25 N0, 10/25 N1, and 7/25 N2. After chemoradiation, only 29 nodes (mean, 4.1 mm; 24 benign, 5 malignant) were visible, and none were in contact with the mesorectal fascia. Nodal downstaging was observed: 20/25 N0 and 5/25 N1 (p < 0.01, Chi-square test). There was good agreement between MRI and pathologic T-staging (kappa = 0.64) and N-staging (kappa = 0.65) after chemoradiation.

CONCLUSIONS

Neoadjuvant chemoradiation treatment resulted in a decrease in size and number of malignant- and benign-appearing mesorectal nodes on MRI. Nodal downstaging and nodal regression from the mesorectal fascia were observed after treatment. MRI is a useful tool for assessing nodal response to neoadjuvant treatment.

Local excision for ypT2 rectal cancer--much ado about something

BACKGROUND

The role of local excision for pT2 distal rectal cancer has been challenged because of the observation of high rates of lymph node metastases and local failure. However, neoadjuvant chemoradiation therapy (CRT) has led to increased local disease control and significant tumor downstaging, possibly decreasing rates of lymph node metastases. In this setting, a possible role for local excision of ypT2 has been suggested.

METHODS

A total of 401 patients with distal rectal cancer underwent neoadjuvant CRT. Tumor response assessment was performed after at least 8 weeks from CRT completion. One hundred and twelve patients with complete clinical response were not immediately operated on and were excluded from the study, and 289 patients with incomplete clinical response were managed by radical surgery. Patients with final pathological stage ypT2 were analyzed to determine the risk of unfavorable pathological features that could represent unacceptable risk for local failure after local excision.

RESULTS

Eighty-eight (30%) patients had ypT2 rectal cancer. Final ypT status was not associated with pretreatment radiological staging (p = 0.62). ypT status was significantly associated with the risk of lymph node metastases, risk of perineural and vascular invasion, and recurrence (p = 0.001). Lymph node metastases were present in 19% of patients with ypT2 rectal cancer. The risk of lymph node metastases in ypT2 was associated with the presence of perineural invasion (47% vs 4%; p = <0.001), vascular invasion (59% vs 6%; p < 0.001), and decreased mean interval CRT surgery (12 vs 18 weeks; p < 0.001), but not with mean tumor size (3.2 vs 3.1 cm; p = 0.8). Disease-free and overall survival rates were significantly better for patients with ypT2N0 (p = 0.02 and 0.006, respectively). Fifty-five (63%) patients with ypT2 had at least one unfavorable pathological feature for local excision (lymph node metastases, vascular or perineural invasion, mucinous type or tumor size >3 cm).

CONCLUSION

Lymph node metastases were present in 19% of patients with ypT2 and were significantly associated with poor overall and disease-free survival rates. The risk of lymph node metastases could not be predicted by radiological staging or tumor size. Radical surgery should be considered the standard treatment option for ypT2 rectal cancer after CRT.

Tumor regression in mesorectal lymphnodes after neoadjuvant chemoradiation for rectal cancer

AIMS

The histological modification produced by neoadjuvant chemoradiation on primary rectal cancer has been investigated by many authors, and a prognostic value of tumor regression grade (TRG) has been identified. Tumor regression grade on metastatic mesorectal lymphnodes has been never evaluated. The purpose of this study is to analyse the TRG on mesorectal lymphnodes (lymphnode regression grade, LRG) after preoperative chemoradiation in rectal cancer patients and to determine the correlation with TRG of primary tumor.

METHODS

Surgical specimens from 35 patients who underwent chemoradiation were included. LRG on mesorectal lymphnodes was assessed by immunohistochemistry. Response to treatment was evaluated by a 5-point LRG based on the ratio of residual tumor to fibrosis.

RESULTS

Complete pathologic response (LRG 1) was observed in 18 patients (51%). In 4 patients (11%) no regression was observed (LRG 5). In 4 cases only reactive lymphnodes were found. LRG on lymphnodes significantly correlated with TRG on primary tumor (p<0.05).

CONCLUSIONS

Neoadjuvant chemoradiation determines a tumor regression on mesorectal lymphnodes as on primary tumor; further studies are needed to evaluate the prognostic value of LRG.

Patterns of failure and survival for nonoperative treatment of stage c0 distal rectal cancer following neoadjuvant chemoradiation therapy

Neoadjuvant chemoradiation therapy (CRT) is the preferred treatment option for distal rectal cancer. Complete pathological response after CRT has led to the proposal of nonoperative approach as an alternative treatment for highly selected patients with complete clinical response. However, patterns of failure following this strategy remains undetermined. Three hundred sixty-one patients with distal rectal cancer were managed by neoadjuvant CRT including 5-FU, leucovorin, and 5040 cGy. Tumor response assessment was performed at 8 weeks following CRT. Patients with complete clinical response were not immediately operated on and were closely followed. One hundred twenty-two patients were considered to have complete clinical response after the first tumor response assessment. Of these, only 99 patients sustained complete clinical response for at least 12 months and were considered stage c0 (27.4%) and managed nonoperatively. Mean follow-up was 59.9 months. There were 13 (13.1%) recurrences: 5 (5%) endorectal, 7 (7.1%) systemic, and 1 (1%) combined recurrence. All 5 isolated endorectal recurrences were salvaged. Mean recurrence interval was 52 months for local failure and 29.5 months for systemic failure. There were five cancer-related deaths after systemic recurrences. Overall and disease-free 5-year survivals were 93% and 85%. Even though surgery remains the standard treatment for rectal cancer, nonoperative treatment after complete clinical response following neoadjuvant CRT may be safe and associated with good survival rates in a highly selected group of patients. Survival in these patients is significantly affected by systemic failure. Exclusive local failure occurs late after CRT completion and is frequently amenable to salvage therapy.

Patterns of failure and survival for nonoperative treatment of stage c0 distal rectal cancer following neoadjuvant chemoradiation therapy

Neoadjuvant chemoradiation therapy (CRT) is the preferred treatment option for distal rectal cancer. Complete pathological response after CRT has led to the proposal of nonoperative approach as an alternative treatment for highly selected patients with complete clinical response. However, patterns of failure following this strategy remains undetermined. Three hundred sixty-one patients with distal rectal cancer were managed by neoadjuvant CRT including 5-FU, leucovorin, and 5040 cGy. Tumor response assessment was performed at 8 weeks following CRT. Patients with complete clinical response were not immediately operated on and were closely followed. One hundred twenty-two patients were considered to have complete clinical response after the first tumor response assessment. Of these, only 99 patients sustained complete clinical response for at least 12 months and were considered stage c0 (27.4%) and managed nonoperatively. Mean follow-up was 59.9 months. There were 13 (13.1%) recurrences: 5 (5%) endorectal, 7 (7.1%) systemic, and 1 (1%) combined recurrence. All 5 isolated endorectal recurrences were salvaged. Mean recurrence interval was 52 months for local failure and 29.5 months for systemic failure. There were five cancer-related deaths after systemic recurrences. Overall and disease-free 5-year survivals were 93% and 85%. Even though surgery remains the standard treatment for rectal cancer, nonoperative treatment after complete clinical response following neoadjuvant CRT may be safe and associated with good survival rates in a highly selected group of patients. Survival in these patients is significantly affected by systemic failure. Exclusive local failure occurs late after CRT completion and is frequently amenable to salvage therapy.

[Lymph node evaluation in colorectal cancer]

BACKGROUND

In Brazil, colorectal carcinoma is the third cause of death by malignant tumors among women, and the fifth among men. Lymph node involvement is one of the most relevant prognostic maker in these tumors.

AIM

To study lymph node involvement in colorectal carcinoma in relationship to biological behavior and tumor location.

PATIENTS AND METHODS

One hundred and eight five colorectal carcinoma cases were studied. Lymph node involvement was analyzed according to tumor location, diameter, vessel invasion, and TNM staging.

RESULTS

Three thousand nine hundred and six lymph nodes were harvested in 185 patients (21.1 lymph nodes/patient). Metastasis were detected in 399/2,573 peritumoral lymph nodes (15.5%) and in 72/1,333 non-peritumoral lymph nodes (5.4%). Eighty-six patients presented metastasis; in these patients 471/1942 lymph nodes were compromised. In 26 patients peritumoral and non-peritumoral lymph nodes were involved; in 57 cases metastasis were detected only in peritumoral lymph nodes and in 3, only non-peritumoral lymph nodes were involved. The number of lymph node was higher among cecal tumors and smaller in the rectum and sigmoid. There was a positive correlation between the number of metastatic lymph node and pT, tumor diameter and lymphatic and venous invasion; there was a negative correlation between lymph node involvement and lymphocytic response; pN was significantly associated with pT.

CONCLUSIONS

Colorectal carcinoma involves preferentially peritumoral lymph node, but in 29 patients (15,7%) non-peritumoral lymph nodes were affected, which is important for tumor staging and prognosis. pN and the number of metastatic lymph nodes were associated with other behaviour markers.

Assessment and management of the complete clinical response of rectal cancer to chemoradiotherapy

Preoperative chemoradiotherapy is considered by many as the preferred treatment strategy for distal rectal cancer. The observation of complete tumour regression has led to the proposition of nonoperative management of selected patients with complete clinical response (cCR) following treatment. We present results for the treatment of distal rectal cancer during 1991-2005. We have outlined the issues concerning adequate tumour assessment, the definition of complete response, and the advantages and disadvantages of conservative or surgical resection in patients with clinical and radiological evidence of cCR.