Predicting the node-negative mesorectum after preoperative chemoradiation for locally advanced rectal carcinoma

Relevance of shrinkage versus fragmented response patterns in rectal cancer

AIMS

Partial response to neoadjuvant chemoradiotherapy (CRT) presents with one of two main response patterns: shrinkage or fragmentation. This study investigated the relevance of these response patterns in rectal cancer, correlation with other response indicators, and outcome.

METHODS AND RESULTS

The study included a test (n = 197) and a validation cohort (n = 218) of post-CRT patients with rectal adenocarcinoma not otherwise specified and a partial response. Response patterns were scored by two independent observers using a previously developed three-step flowchart. Tumour regression grading (TRG) was established according to both the College of American Pathologists (CAP) and Dworak classifications. In both cohorts, the predominant response pattern was fragmentation (70% and 74%), and the scoring interobserver agreement was excellent (k = 0.85). Patients with a fragmented pattern presented with significantly higher pathological stage (ypTNM II-IV, 78% versus 35%; P < 0.001), less tumour regression with Dworak (P = 0.004), and CAP TRG (P = 0.005) compared to patients with a shrinkage pattern. As a predictor of prognosis, the shrinkage pattern outperformed the TRG classification and stratified patients better in overall (fragmented pattern, hazard ratio [HR] 2.04, 95% confidence interval [CI] 1.19-3.50, P = 0.008) and disease-free survival (DFS; fragmented pattern, HR 2.50, 95% CI 1.23-5.10, P = 0.011) in the combined cohorts. The multivariable regression analyses revealed pathological stage as the only independent predictor of DFS.

CONCLUSIONS

The heterogeneous nature of tumour response following CRT is reflected in fragmentation and shrinkage. In rectal cancer there is a predominance of the fragmented pattern, which is associated with advanced stage and less tumour regression. While not independently associated with survival, these reproducible patterns give insights into the biology of tumour response.

MRI radiomics signature to predict lymph node metastasis after neoadjuvant chemoradiation therapy in locally advanced rectal cancer

PURPOSE

To investigative the performance of MRI-radiomics analysis derived from T2WI and apparent diffusion coefficients (ADC) images before and after neoadjuvant chemoradiation therapy (nCRT) separately or simultaneously for predicting post-nCRT lymph node status in patients with locally advanced rectal cancer (LARC). MATERIALS AND METHODS: Eighty-three patients (training cohort, n = 57; validation cohort, n = 26) with LARC between June 2017 and December 2022 were retrospectively enrolled. All the radiomics features were extracted from volume of interest on T2WI and ADC images from baseline and post-nCRT MRI. Delta-radiomics features were defined as the difference between radiomics features before and after nCRT. Seven clinical-radiomics models were constructed by combining the most predictive radiomics signatures and clinical parameters selected from support vector machine. Receiver operating characteristic curve (ROC) was used to evaluate the performance of models. The optimum model-based LNM was applied to assess 5-years disease-free survival (DFS) using Kaplan-Meier analysis. The end point was clinical or radiological locoregional recurrence or distant metastasis during postoperative follow-up.

RESULTS

Clinical-deltaADC radiomics combined model presented good performance for predicting post-CRT LNM in the training (AUC = 0.895,95%CI:0.838-0.953) and validation cohort (AUC = 0.900,95%CI:0.771-1.000). Clinical-deltaADC radiomics-postT2WI radiomics combined model also showed good performances (AUC = 0.913,95%CI:0.838-0.953) in the training and (AUC = 0.912,95%CI:0.771-1.000) validation cohort. As for subgroup analysis, clinical-deltaADC radiomics combined model showed good performance predicting LNM in ypT0-T2 (AUC = 0.827;95%CI:0.649-1.000) and ypT3-T4 stage (AUC = 0.934;95%CI:0.864-1.000). In ypT0-T2 stage, clinical-deltaADC radiomics combined model-based LNM could assess 5-years DFS (P = 0.030).

CONCLUSION

Clinical-deltaADC radiomics combined model could predict post-nCRT LNM, and this combined model-based LNM was associated with 5-years DFS in ypT0-T2 stage.

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

PURPOSE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

Transanal minimally invasive surgery using laparoscopic instruments of the rectum: A review

Transanal minimally invasive surgery (TAMIS) was first described in 2010 as an alternative to transanal endoscopic microsurgery (TEM). The TAMIS technique can be access to the proximal and mid-rectum for resection of benign and early-stage malignant rectal lesions and also used for noncurative intent surgery of more advanced lesions in patients who are not candidates for radical surgery. TAMIS has a shorter learning curve, reduced device setup time, flexibility in instrument use, and versatility in application than TEM. Also, TAMIS shows similar results in a view of the operation time, conversion rate, reoperation rate, and complication to TEM. For these reasons, TAMIS is an easily accessible, technically feasible, and cost-effective alternative to TEM. Overall, TAMIS has enabled the performance of high-quality local excision of rectal lesions by many colorectal surgeons. As TAMIS becomes more broadly utilized such as pelvic abscess drainage, rectal stenosis, and treatment of anastomotic dehiscence, the acquisition of appropriate training must be ensured, and the continued assessment and assurance of outcome must be maintained.

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

OBJECTIVE

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

MATERIALS AND METHODS

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

RESULTS

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

CONCLUSION

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

KEY POINTS

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

Clinicopathologic determinants of pathologic treatment response in neoadjuvant treated rectal adenocarcinoma

Neoadjuvant treatment (NAT) followed by total mesorectal excision is currently considered the standard of treatment for rectal adenocarcinoma. The degree of pathologic treatment response (pTR) correlates significantly with the recurrence free survival and overall survival (OS). However, it remains unclear which clinical and pathologic factors are associated with a more robust response to NAT, including showing pathologic complete response (pCR). Chemokine receptor 4 (CXCR4) overexpression has been associated with unfavorable OS in some studies. In this study, we sought to evaluate the clinicopathologic determinants of pTR in neoadjuvant treated rectal adenocarcinoma (NAT-RA). We retrospectively identified 91 patients who underwent pre-treatment diagnostic biopsy, NAT, and surgical resection at our institution. The archival slides were reviewed for pathologic features in the pre-treatment biopsies and for assessment of pTR in the resection specimens according to the current College of American Pathologist (CAP)'s guidelines. pCR was obtained in 16.5% of the cases, whereas 20.9% had near pCR, 30.8% had partial response, and 31.9% had a poor/no response. CXCR4 immunohistochemical analysis was also performed on the pre-treatment biopsies. Lower pre-treatment cT-stage (p = 0.019) and pre-treatment AJCC cTNM stage groups (p = 0.004), longer time interval between completion of NAT and resection (p = 0.022), and presence of tumor-infiltrating lymphocytes in the pre-treatment biopsies (p = 0.019) were significantly associated with a better pTR. CXCR4 nuclear expression was associated with a lower percentage of residual tumor (p = 0.036). Pre-treatment CEA levels, tumor differentiation, CAP treatment response groups and lower percentage of residual tumor were associated with a better OS.

Type of preoperative therapy and stage-specific survival after surgery for rectal cancer: a nationwide population-based cohort study

Preoperative chemoradiation therapy (CRT) may induce downstaging in rectal cancer (RC). Short-course radiation therapy (SC-RT) with immediate surgery does not cause substantial downstaging. However, the TNM classification adds the “y” prefix in both groups to indicate possible treatment effects. We aim to compare stage-specific survival in these patients. RC patients treated with surgery only, preoperative SC-RT followed by surgery within 10 days, or preoperative CRT, and diagnosed between 2008 and 2014 were included in this population-based study. Clinicopathological and outcome characteristics were analyzed. The study included 11,925 patients. Large discrepancies existed between clinical and pathological stages after surgery only. Surgery-only patients were older with more comorbidities compared with SC-RT and CRT and had worse 5-year survival (64%, 76%, and 74%, respectively; p < 0.001). Five-year survival for stage I was similar after CRT and SC-RT (85% vs. 85%; p = 0.167) and comparable between CRT-treated patients with stage I and those reaching a pathological complete response (pCR; 85% vs. 89%; p = 0.113). CRT was independently associated with worse overall survival compared with SC-RT for stage II (HR 1.57 [95%CI 1.27–1.95]; p < 0.001) and stage III (HR 1.43 [95%CI 1.23–1.70]; p < 0.001). Stage I disease after CRT has an excellent prognosis, comparable with pCR and with same-stage SC-RT-treated patients without regression. Stage II or III after CRT has worse prognosis than after SC-RT with immediate surgery. TNM should take the impact of preoperative therapy type on stage-specific survival into account. In addition, clinical stage was a poor predictor of pathological stage.

The risk of nodal disease in patients with pathological complete responses after neoadjuvant chemoradiation for rectal cancer: a systematic review, meta-analysis, and meta-regression

BACKGROUND

This systematic review and meta-analysis seek to evaluate the prevalence of nodal disease in rectal cancer patients with pathological complete responses (pCR) after neoadjuvant chemoradiotherapy (ypT0N+).

METHODS

This study conformed to the PRISMA guidelines. A search was performed on major databases to identify relevant articles. Meta-analyses of pooled proportions were performed on rectal cancer with pCR and ypT0N+. Meta-regression was undertaken to identify sources of heterogeneity, and the Newcastle-Ottawa Scale (NOS) was employed to assess the risk of bias.

RESULTS

A total of 18 studies were included, totaling 7568 patients. The overall risk of bias was low, since all studies scored 6 and above out of 9 on the NOS. Preoperatively, the pooled proportions of patients with T3/T4 tumors and clinically positive nodal disease were 84.08% (95% CI 74.19 to 91.99%) and 52.14% (95% CI 35.02 to 69.00%) respectively. The prevalence of pCR in the whole pool was 18.52% (95% CI 13.31 to 24.35%; I² = 93.85%; P = 0.00), and meta-regression showed a significantly negative relationship with patient age (β = - 0.03, 95% CI - 0.03 to - 0.02; P = 0.00). The pooled prevalence of ypT0N+ was 4.61% (95% CI 2.41 to 7.28%; I² = 52.27%; P = 0.01), and meta-regression demonstrated a significantly positive relationship with male gender (β = 1.06, 95% CI 1.00 to 1.12; P = 0.04).

CONCLUSION

There is a small risk of ypN+ in patients with pCR after neoadjuvant CRT and surgery for rectal cancer. However, further research is warranted to establish these findings and to identify predictive factors for this specific group of patients.

Assessment of remaining tumour involved lymph nodes with MRI in patients with complete luminal response after neoadjuvant treatment of rectal cancer

OBJECTIVE

To assess the accuracy of MRI to predict remaining lymph node metastases in patients with complete pathological luminal response (ypT0) after neoadjuvant therapy.

METHODS

Data from a national registry were used. 19 patients with histopathologically remaining lymph node metastases (ypT0N+) were identified. Another 19 patients without lymph node metastases (ypT0N0) were used as matched controls. Two radiologists blinded to all patient information evaluated staging and restaging MRI that was compared to histopathological findings of the resected specimen.

RESULTS

The average size of the largest lymph node on restaging MRI was significantly larger (4.5 mm) in the ypT0N+ group than in the ypT0N0 group (2.6 mm) (p = 0.04). Presence of ypN+ was correctly predicted by MRI in 7 of 19 patients. In patients without lymph node metastases (ypT0N0), these were correctly classified by MRI in 16 of 19 patients. All patients who had MR-identified lymph nodes larger than 8 mm at restaging were ypTN+. The sensitivity, specificity, positive predictive value and negative for prediction of remaining lymph node metastasis with MRI were 37, 84, 70 and 57%.

CONCLUSION

In patients with ypT0 in rectal cancer after neoadjuvant treatment, remaining regional lymph node metastases cannot safely be predicted by restaging MRI alone using presently known criteria. Presence of a lymph node over 8 mm on restaging MRI strongly indicates yPN+. Advances in knowledge: This is one of the first studies on MRI lymph node assessment after chemo-radiotherapy (CRT) in luminal complete response.

Laparoscopic Total Mesorectal Excision Following Transanal Endoscopic Microsurgery for Rectal Cancer

BACKGROUND

Patients' selection for transanal endoscopic microsurgery (TEM) depends on diagnostic modalities; however, there are still some limitations in the preoperative diagnosis of rectal lesions, and in some reports, up to third of the adenomas resected by TEM were found to be adenocarcinoma; therefore, salvage radical resection (RR) remains necessary for achieving oncological resection. Salvage RR may encounter some technical problems as the violation of the mesorectum and the scar formation. In this study, we aimed to report the outcome in patients undergoing salvage RR in terms of morbidity and oncological results.

MATERIALS AND METHODS

Demographic and clinical data pertaining to patients undergoing RR following TEM between 2004 and 2014 were retrospectively collected.

RESULTS

One hundred forty one TEM were performed in the study period, 53 (38%) for malignant rectal lesions. Indication for TEM: 15 (28%) benign adenoma, 25 (47%) early rectal cancer, and 13 (25%) had clinical complete response after neoadjuvant radiochemotherapy. Ten (19%) patients had no residual tumor in TEM specimen, 15 (28%) had T1, and 2 of them underwent salvage low anterior resection (LAR). Ten (19%) had T2, 4 had LAR, and 1 had abdominoperineal resection (APR). Five (9%) had a T3, 3 underwent LAR, and 2 had APR. Among the 13 (25%) after chemo-radiotherapy (CRT), 4 had salvage AR. The time from TEM to RR was 47 days (range32-70). Of 16 salvage surgeries, 8 (50%) were laparoscopic. The median operative time was 210 minutes (range165-360). Five patients had protective ileostomy. Rectal perforation occurred in 2 (12%) patients; both had a posterior location, one after CRT. Two (12%) postoperative small-bowl obstruction and three wound infections occurred. There was no perioperative mortality in any of the patients who underwent RR. The final pathology was no residual disease in 9, T3N1 in 1, T3N0 in 3, T2N1 in 1, and T2N0 in 2 patients. Eight (50%) had adjuvant chemotherapy.

CONCLUSION

Laparoscopic total mesorectal excision following TEM seems to be safe, and with no negative impact of the completeness of the resection. The concern of intraoperative specimen perforation is real, and should be dealt with meticulous technique and careful dissection, particularly after CRT.

Is the pathological regression level of metastatic lymph nodes associated with oncologic outcomes following preoperative chemoradiotherapy in rectal cancer?

Purpose

The oncologic impact of the lymph node (LN) regression level after preoperative chemoradiotherapy (PCRT) has not been thoroughly evaluated. Hence, this study aimed to examine whether the regression level of metastatic LNs following PCRT is associated with oncologic outcomes in rectal cancer.

Results

The optimal number of cut points for LRG sum was determined to be three. The three LRG groups demonstrated different distributions according to the ypT and ypN stages (p < 0.001 for both). However, the distribution of the LRG groups was not associated with the TRG of the primary tumor (p = 0.527). The RFS significantly differed according to the LRG groups (p = 0.001). Moreover, the differences in RFS remained when the LRG groups were analyzed within each separate ypN stage. The LRG group was confirmed as a factor associated with RFS in the multivariate analysis (p=0.018), while the ypN stage was not (p=0.4).

Patients and Methods

We analyzed the outcomes of 142 rectal cancer patients diagnosed with ypN1 disease after PCRT followed by radical resection. The pathological responses of the primary tumor and LNs to PCRT were evaluated using the tumor regression grade (TRG) and LN regression grade (LRG), respectively. The impact of LRG on recurrence-free survival (RFS) was analyzed. The K-adaptive partitioning for survival data method was applied to determine the optimal number of cut points for the LRG-sum and the optimal number of subgroups.

Conclusion

The LRG as an indicator of response to PCRT should be considered as a prognostic determinant in rectal cancer patients. Future large-scale prospective studies are needed to confirm this finding.

A scoring system basing pathological parameters to predict regional lymph node metastasis after preoperative chemoradiotherapy for locally advanced rectal cancer: implication for local excision

Local excision is an alternative to radical surgery that is indicated in patients with locally advanced rectal cancer (LARC) who have a good response to chemoradiotherapy (CRT). Regional lymph node status is a major uncertainty during local excision of LARC following CRT. We retrospectively reviewed clinicopathologic variables for 244 patients with LARC who were treated at our institute between December 2000 and December 2013 in order to identify independent predictors of regional lymph node metastasis. Multivariate analysis of the training sample demonstrated that histopathologic type, tumor size, and the presence of lymphovascular invasion were significant predictors of regional nodal metastasis. These variables were then incorporated into a scoring system in which the total scores were calculated based on the points assigned for each parameter. The area under the curve in the receiver operating characteristic analysis was 0.750, and the cutoff value for the total score to predict regional nodal metastasis was 7.5. The sensitivity of our system was 73.2% and the specificity was 69.4%. The sensitivity was 77.8% and the specificity was 51.2% when the scoring system was applied to the testing sample. Using this system, we could accurately predict regional nodal metastases in LARC patients following CRT, which may be useful for stratifying patients in clinical trials and selecting potential candidates for organ-sparing surgery following CRT for LARC.

Evidence of intermetastatic heterogeneity for pathological response and genetic mutations within colorectal liver metastases following preoperative chemotherapy

BACKGROUND

In patients receiving preoperative chemotherapy, colorectal liver metastases (CLM) are expected to demonstrate a similar behaviour because of similar organ microenvironment and tumour cell chemosensitivity. We focused on the occurrence of pathological and genetic heterogeneity within CLM.

METHODS

Patients resected for multiple CLM between 2004 and 2011 after > three cycles of chemotherapy were included. Pathological heterogeneity was arbitrarily defined as a > 50% difference in the percentage of remaining tumour cells between individual CLM. In patients with pathological heterogeneity, the mutational genotyping (KRAS, NRAS, BRAF and PIK3CA) was determined from the most heterogeneous CLM.

RESULTS

Pathological heterogeneity was observed in 31 of 157 patients with multiple CLM (median = 4, range, 2-32) (19.7%). In 72.4% of them, we found a concordance of the mutation status between the paired CLM: both wild-type in 55%, and both mutated in 17.2%. We observed a discordance of the mutation status of 27.6% between CLM: one mutated and the other wild-type. The mutated CLM was the less florid one in 75% of patients with genetic heterogeneity.

CONCLUSIONS

Pathological heterogeneity is present in 19.7% of patients with multiple CLM. Genetic heterogeneity is present in 27.6% of patients with pathological heterogeneity. Heterogeneity could refine guide management for tissue sampling.

Pathologic response grade after long-course neoadjuvant chemoradiation does not influence morbidity in locally advanced mid-low rectal cancer resected by laparoscopy

PURPOSE

Patients with locally advanced rectal cancer and pathologic complete response to neoadjuvant chemoradiation therapy have lower rates of recurrence compared to those who do not. However, the influences of the pathologic response on surgical complications and survival remain unclear. This study aimed to investigate the influence of neoadjuvant therapy for rectal cancer on postoperative morbidity and long-term survival.

METHODS

This was a comparative study of consecutive patients who underwent laparoscopic total mesorectal excision for rectal cancer in two European tertiary hospitals between 2004 and 2014. Patients with and without pathologic complete responses were compared in terms of postoperative morbidity, mortality, and survival.

RESULTS

Fifty patients with complete response (ypT0N0) were compared with 141 patients who exhibited non-complete response. No group differences were observed in the postoperative mortality or morbidity rates. The median follow-up time was 57 months (range 1-121). Over this period, 11 (5.8 %) patients, all of whom were in the non-complete response group, exhibited local recurrence. The 5-year overall survival and disease-free survival were significantly better in the complete response group, 92.5 vs. 75.3 % (p = 0.004) and 89 vs. 73.4 % (p = 0.002), respectively.

CONCLUSIONS

Postoperative complication rate after laparoscopic total mesorectal excision is not associated with the pathologic response grade to neoadjuvant chemoradiation therapy.

DWI for Assessment of Rectal Cancer Nodes After Chemoradiotherapy: Is the Absence of Nodes at DWI Proof of a Negative Nodal Status?

OBJECTIVE

When considering organ preservation in patients with rectal cancer with good tumor response, assessment of a node-negative status after chemoradiation therapy (CRT) is important. DWI is a very sensitive technique to detect nodes. The study aim was to test the hypothesis that the absence of nodes at DWI after CRT is concordant with a ypN0 status.

MATERIALS AND METHODS

A retrospective study was performed of 90 patients with rectal cancer treated with CRT followed by restaging MRI at 1.5 T, including DWI (highest b value, 1000 s/mm²). Two independent readers counted the number of nodes visible in the mesorectal compartment on DW images obtained after CRT. The number of nodes on DWI (0 vs ≥ 1) was compared with the number of metastatic nodes at histopathology or long-term clinical follow-up (yN0 vs yN-positive status).

RESULTS

Seventy-one patients had a yN0 status, and 19 had a yN-positive status. For 10 patients, no nodes were observed at DWI, which was concordant with a yN0 status in 100% of cases. In the other 61 patients with a yN0 status, the median number of nodes detected at DWI was three (range, 1-17 nodes). To differentiate between yN0 and yN-positive status, sensitivity was 100%, specificity was 14%, the positive predictive value was 24%, and the negative predictive value was 100%.

CONCLUSION

Although the absence of nodes at DWI is not a frequent finding, it appears to be a reliable predictor of yN0 status after CRT in patients with rectal cancer. DWI may thus be a helpful adjunct in assessing response after CRT and may help select patients for organ-saving treatment.

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.

Oncologic Safety of Local Excision Compared With Total Mesorectal Excision for ypT0-T1 Rectal Cancer: A Propensity Score Analysis

Good oncologic outcomes, demonstrated by a complete pathologic response after preoperative chemoradiotherapy (PCRT), have led to local excision (LE) in selected patients with rectal cancer. We evaluated the oncologic safety of LE compared with total mesorectal excision (TME) in patients with ypT0-T1 rectal cancer.A retrospective review of 304 patients who underwent PCRT, followed by LE or TME, for ypT0-T1 rectal cancer was performed. Propensity scores were computed and used to match groups (LE:TME = 1:1), and analysis of disease-free survival (DFS) and overall survival (OS) was made by comparing patients who underwent LE or TME. Prognostic factors of relapse were analyzed for all patients.Tumor categories were ypT0 in 25 (61.9%) cases, ypTis in 6 (14.3%) cases, and ypT1 in 11 (26.2%) cases for the LE group, and ypT0 in 28 (66.7%) cases, ypTis in 4 (9.5%) cases, and ypT1 in 10 (23.8%) cases for the matched TME patients. There was no significant difference between the matched LE and TME groups in relapse (4.8% and 7.14%, respectively; P = 0.646), 5-year DFS (95.2% vs 91.6%; P = 0.33) and 5-year OS (96.6% vs 88.0%; P = 0.238). In the multivariate Cox regression analysis, tumor distance from the anal verge (hazard ratio [HR] = 0.78; 95% confidence interval (CI) = 0.616-0.992) and the tumor grade (HR = 4.29; 95% CI = 1.430-12.886) were significantly associated with the recurrence risk.LE results in oncologic outcomes that are comparable to those achieved by TME in selected patients with ypT0-T1 rectal cancer after PCRT.

Nodal involvement in luminal complete response after neoadjuvant treatment for rectal cancer

BACKGROUND

Pathological complete response (pCR) after neoadjuvant therapy in rectal cancer is correlated with improved survival. There is limited knowledge on the incidence of pCR at a national level with uniform guidelines. The aim of this prospective register-based study was to investigate the incidence and outcome of pCR in relation to neoadjuvant therapy in a national cohort.

METHOD

All patients abdominally operated for rectal cancer between 2007 and 2012 (n = 7885) were selected from The Swedish Colo-rectal Cancer Register. Twenty-six per cent (n = 2063) had neoadjuvant therapy with either long or short course radiotherapy with >4 weeks delay with the potential to achieve pCR. The primary endpoints were pCR and survival in relation to neoadjuvant therapy.

RESULTS

Complete eradication of the luminal tumor, ypT0 was found in 161 patients (8%). In 83% of the ypT0 the regional lymph nodes were tumor negative (ypT0N0), 12% had 1-3 positive lymph nodes (ypT0N1) and 4% had more than three positive lymph nodes (ypT0N2). There was significantly greater survival with ypT0 compared to ypT+ (hazard ratio 0.38 (C.I 0.25-0.58)) and survival was significantly greater in patients with ypT0N0 compared to ypT0N1-2 (hazard ratio 0.36 (C.I 0.15-0.86)). In ypT0, cT3-4 tumors had the greater risk of node-positivity. The added use of chemotherapy resulted in 10% ypT0 compared to 5.1% in the group without chemotherapy (p < 0.00004).

CONCLUSION

Luminal pathological complete response occurred in 8%, 16% of them had tumor positive nodes. The survival benefit of luminal complete response is dependent upon nodal involvement status.

The accuracy of MRI, endorectal ultrasonography, and computed tomography in predicting the response of locally advanced rectal cancer after preoperative therapy: A metaanalysis

BACKGROUND

To perform a metaanalysis to determine and compare the diagnostic performance of MRI, endorectal ultrasonography (ERUS), and computed tomography (CT) in predicting the response of locally advanced rectal cancer after preoperative therapy.

METHODS

All previously published articles on the role of MRI, CT, and/or ERUS in predicting the response of rectal cancer to preoperative therapy were collected. We divided the objective in 3 parts: the accuracy to assess (i) complete response, (ii) to detect T4 tumors with invasion to the circumferential resection margin (CRM), and (iii) to predict the presence of lymph node metastasis. The pooled estimates of, sensitivity, specificity, positive predictive value, negative predictive value, and accuracy were calculated using a bivariate mixed effect analysis.

RESULTS

Forty-six studies comprising 2,224 patients were included. (i) The pooled accuracy to assess complete tumor response were (a) 75% for MRI, (b) 82% for ERUS, (c) and 83% for CT. (ii) Pooled accuracy to detect T4 tumors with invasion to the CRM were (a) 88% and (b) 94% for ERUS. (iii) Pooled accuracy to predict the presence of lymph node metastasis was (a) 72% for MRI, (b) 72% for ERUS, (c) and 65% for CT.

CONCLUSION

MRI, CT, and ERUS cannot be used to predict complete response of locally advanced rectal cancer after CRT. In addition, the positive predictive value for these imaging techniques is low for the assessment of tumor invasion in the CRM. The accuracy of the modalities to predict the presence of metastatic lymph node disease is also low.

Transanal Minimally Invasive Surgery

Transanal minimally invasive surgery (TAMIS) was first described in 2010 as a crossover between single-incision laparoscopic surgery and transanal endoscopic microsurgery (TEM) to allow access to the proximal and mid-rectum for resection of benign and early-stage malignant rectal lesions. The TAMIS technique can also be used for noncurative intent surgery of more advanced lesions in patients who are not candidates for radical surgery. Proper workup and staging should be done before surgical decision-making. In addition to the TAMIS port, instrumentation and set up include readily available equipment found in most operating suites. TAMIS has proven its usefulness in a wide range of applications outside of local excision, including repair of rectourethral fistula, removal of rectal foreign body, control of rectal hemorrhage, and as an adjunct in total mesorectal excision for rectal cancer. TAMIS is an easily accessible, technically feasible, and cost-effective alternative to TEM.

Transanal Endoscopic Microsurgery After Neoadjuvant Chemoradiotherapy for Rectal Cancer

BACKGROUND

Radical rectal resection following neoadjuvant chemoradiation therapy (CRT) for locally advanced rectal cancer is accompanied by relatively high morbidity. Local excision of rectal cancer may be more appropriate for some frail patients with severe comorbidities. Transanal endoscopic microsurgery (TEM), consisting of local excision of selected rectal cancers, has been associated with low rates of postoperative complications. Because neoadjuvant CRT for rectal cancer may be associated with increased complications, the suitability of TEM following CRT is still unclear. In this study we aimed to assess the clinical outcomes of patients undergoing TEM following neoadjuvant CRT.

PATIENTS AND METHODS

This study retrospectively analyzed all patients undergoing TEM for malignant rectal tumor in our institution between 2004 and 2010. They were divided into those who received CRT (CRT group) and those without CRT (non-CRT group). Demographics and clinical data were compared.

RESULTS

Forty-four of 97 patients who underwent TEM were included: 13 CRT and 31 non-CRT. Age, comorbidities, and the duration of the procedure were similar for both groups. There were no significant group differences in tumor diameter (2.1 cm [range, 0.5-3.5 cm] and 2.9 cm [range, 0.5-4.2 cm], respectively; P=.125) or distance of the lower part of the tumor from the anal verge (6.7 cm [range, 5-10 cm] and 7.7 cm [range, 5-15 cm], respectively; P=.285). Two non-CRT patients had peritoneal entry, and 1 of them underwent protective ileostomy because of insecure rectal defect closure. One non-CRT patient underwent a re-operation for postoperative bleeding. The other perioperative complications were minor and included urinary retention requiring catheter placement (2 patients in each group), pulmonary edema (1 non-CRT patient), and pneumonia (1 non-CRT patient). All complications were managed conservatively. There was no wound disruption, major complication, or mortality in either group.

CONCLUSIONS

With proper patient selection, TEM can be performed safely following CRT, without major complication or increased postoperative morbidity.

Rectal cancer: An evidence-based update for primary care providers

Rectal adenocarcinoma is an important cause of cancer-related deaths worldwide, and key anatomic differences between the rectum and the colon have significant implications for management of rectal cancer. Many advances have been made in the diagnosis and management of rectal cancer. These include clinical staging with imaging studies such as endorectal ultrasound and pelvic magnetic resonance imaging, operative approaches such as transanal endoscopic microsurgery and laparoscopic and robotic assisted proctectomy, as well as refined neoadjuvant and adjuvant therapies. For stage II and III rectal cancers, combined chemoradiotherapy offers the lowest rates of local and distant relapse, and is delivered neoadjuvantly to improve tolerability and optimize surgical outcomes, particularly when sphincter-sparing surgery is an endpoint. The goal in rectal cancer treatment is to optimize disease-free and overall survival while minimizing the risk of local recurrence and toxicity from both radiation and systemic therapy. Optimal patient outcomes depend on multidisciplinary involvement for tailored therapy. The successful management of rectal cancer requires a multidisciplinary approach, with the involvement of enterostomal nurses, gastroenterologists, medical and radiation oncologists, radiologists, pathologists and surgeons. The identification of patients who are candidates for combined modality treatment is particularly useful to optimize outcomes. This article provides an overview of the diagnosis, staging and multimodal therapy of patients with rectal cancer for primary care providers.

Avoiding radical surgery improves early survival in elderly patients with rectal cancer, demonstrating complete clinical response after neoadjuvant therapy: results of a decision-analytic model

BACKGROUND

In elderly and comorbid patients with rectal cancer, radical surgery is associated with significant perioperative mortality. Data suggest that a watch-and-wait approach where a complete clinical response is obtained after neoadjuvant chemoradiotherapy might be oncologically safe.

OBJECTIVE

This study aimed to determine whether patient age and comorbidity should influence surgeon and patient decision making where a complete clinical response is obtained.

DESIGN

Decision-analytic modeling consisting of a decision tree and Markov chain simulation was used. Modeled outcome parameters were elicited both from comprehensive literature review and from a national patient outcomes database.

SETTINGS

Outcomes for 3 patient cohorts treated with neoadjuvant therapy were modeled after either surgery or watch and wait.

PATIENTS

Patients included 60-year-old and 80-year-old men with mild comorbidities (Charlson score <3) and 80-year-old men with significant comorbidities (Charlson score >3).

MAIN OUTCOME MEASURES

Absolute survival, disease-free survival, and quality-adjusted life years were measured.

RESULTS

The model found that absolute survival was similar in 60-year-old patients but was significantly improved in fit and comorbid 80-year-old patients at 1 year after treatment where watch and wait was implemented instead of radical surgery, with a survival advantage of 10.1% (95% CI, 7.9-12.6) and 13.5% (95% CI, 10.2-16.9). At all of the other time points, absolute survival was equivalent for both techniques. There were no short- or long-term differences among any patient groups managed either by radical surgery or watch and wait in terms of either disease-free survival or quality-adjusted life years.

LIMITATIONS

Oncologic data for the watch-and-wait approach used for this study is derived from only a small number of studies pertaining to a highly selected group of patients. The 90-day postoperative mortality rate derived from the United Kingdom population-based study might be lower in other countries or individual institutions.

CONCLUSIONS

This study suggests competing effects of oncologic and surgical risk when using watch-and-wait management and that elderly and comorbid patients have the most to gain from this approach.

Reduction in the size of enlarged pelvic lymph nodes after chemoradiation therapy is associated with fewer lymph node metastases in locally advanced rectal carcinoma

PURPOSE

We hypothesized that a reduction in the size of the lymph nodes after neoadjuvant therapy for locally advanced rectal carcinoma would be associated with decreased lymph node metastases and/or a better prognosis.

METHODS

Between March 2006 and April 2012, 71 patients with primary rectal cancer received neoadjuvant chemoradiation therapy (CRT). For all lymph nodes 5 mm or larger in size, the major and minor axes were measured on CT scan images, and the product was calculated. The lymph node size was determined before and after CRT. The patients were divided into three groups based on the lymph node size before and after treatment. Group A exhibited a reduction in size of 60% or more, Group B a reduction of less than 60% and Group C had no lymph node enlargement before treatment.

RESULTS

The incidence of lymph node metastases on pathological examination was 15% in Group A and 50% in Group B (p = 0.006). The five-year disease-free survival in Group A was 84% compared with 78% in Group B (log rank p = 0.34). The five-year overall survival in Group A was 92% compared with 74% in Group B (log rank p = 0.088).

CONCLUSIONS

A reduction in the size of enlarged lymph nodes after neoadjuvant therapy may be a useful prognostic factor for recurrence and survival.

Does pathologic response of rectal cancer influence postoperative morbidity after neoadjuvant radiochemotherapy and total mesorectal excision?

BACKGROUND

A pathologic complete response (pCR) can be observed in up to 25% of patients after preoperative chemoradiotherapy for rectal cancer and is associated with an improved long-term prognosis. However, few data are available regarding the effect of pCR on postoperative morbidity. This study aimed to assess the impact of the pCR on postoperative outcomes after laparoscopic total mesorectal excision (TME).

METHODS

A prospectively maintained database (2006-2011) was reviewed for all consecutive patients (n = 143) undergoing laparoscopic TME for mid or low rectal cancer after neoadjuvant chemoradiotherapy. Postoperative data were compared for pCR-group and non-pCR-group. A pCR was defined as the absence of gross and microscopic tumor in the specimen, irrespective of the nodal status (ypT0).

RESULTS

Thirty-three patients (23%) had a pCR. Median operating time was greatly shorter in the pCR-group (230 minutes, 180-360), compared with the non-pCR-group (240 minutes, 130-420, P = .02). Lymph node involvement was noted for 12% of the patients in the pCR-group and 33% of the patients in the non-pCR-group (P = .91). Clavien Dindo grade 3 and 4 complications (6% vs 22%, P = .04), infection related morbidity (47% vs 76%, P = .04), and clinical anastomotic leakage rates (9% vs 29%, P = .02) were lesser in the pCR group compared with the non-pCR group. Mean duration of hospital stay was lesser in the pCR-group (9 vs 12 days, P = .01).

CONCLUSION

This study showed that Clavien Dindo grade 3 and 4 complications, including anastomosis leakage, and infection related complications rates were lesser in patients with pathologic complete response after RCT and laparoscopic TME for rectal cancer.

Local excision after neoadjuvant chemoradiation therapy in advanced rectal cancer: a national multicenter analysis

BACKGROUND

The aim of the current study was to evaluate the clinical availability of local excision (LE) for advanced rectal cancer without lymph node metastasis after neoadjuvant chemoradiation therapy (nCRT) in Korea.

METHODS

From June 2000 to October 2009, 40 patients with cT2-3N0M0 rectal cancer underwent nCRT followed by LE according to a retrospective multicenter analysis.

RESULTS

Of the 40 patients, 22 were men and 18 were women. Eighteen patients were cT2, and 22 patients were cT3. The median follow-up duration was 38 months. Three patients (7.5%) had morbidity after LE. Four patients (10%) had recurrence (local recurrence [1 patient] and systemic metastasis [3 patients]). The 3-year disease-free survival rate was 85.9%. Only pCR was a recurrence-related prognostic factor (P = .040).

CONCLUSIONS

Although the current study was not a randomized controlled study, LE after nCRT in T2-3N0 rectal cancer patients appears to be a safe and effective treatment, especially in pCR patients.

Modern rectal cancer multidisciplinary treatment: the role of radiation and surgery

INTRODUCTION

Treatment of rectal cancer has evolved during the last few decades due to more in-depth knowledge of rectal cancer biology and major advances in the field of preoperative staging, medical management and surgical techniques. Consequently, treatment strategies are shifting moving towards a more personalized approach based on the response to treatment. Currently topics of controversy are centered around the indication for neoadjuvant radiation therapy in locally advanced rectal cancer and the role of surgery in patients with complete clinical response after neoadjuvant combined modality therapy. This manuscript aims to critically evaluate the evolution of treatment of rectal cancer during the last three decades and future directions.

METHODS

A review of the literature has been performed in PubMed/Medline electronic databases.

RESULTS

Treatment modalities are moving towards a tailored approach to rectal cancer patients based on the response to chemoradiation. A "wait-and-see" approach and local excision by Transanal Endoscopic Microsurgery (TEM) are strategies recently proposed in case of complete clinical response.

CONCLUSIONS

The standard of care still requires that locally advanced rectal cancer should be treated by neoadjuvant chemoradiation therapy followed by total mesorectal excision, including patients with a clinical complete response. Further evidence is needed to endorse a "wait-and-see" strategy and to define the role of TEM.

Transanal endoscopic microsurgery: what indications in 2013?

Thanks to major advances in the field of surgical techniques and neoadjuvant chemoradiation therapy, along with more accurate pre-operative staging tools and the widespread introduction of population-based screening programs, treatment of rectal cancer has been evolving over the past few decades, moving towards a more tailored approach. This has brought a shift in the treatment algorithm of benign rectal lesions and selected early rectal cancers, for which today transanal endoscopic microsurgery (TEM) is accepted as an effective alternative to abdominal surgery.

In 2013, topics of controversy are the role of TEM in the treatment of more advanced rectal cancers, in cases of complete pathological response after chemoradiation therapy and the role of TEM as a platform for single-port surgery and NOTES. This article reviews the current indications for TEM and the future perspectives of this approach in the treatment of rectal tumors.

Long-term outcome of local excision after complete pathological response to neoadjuvant chemoradiation therapy for rectal cancer

BACKGROUND

Neoadjuvant chemoradiotion therapy (CRT) for advanced rectal cancer has improved local disease. Complete rectal wall tumor regression may be associated with the absence of viable cancer cells in the mesorectum, and thus local excision (LE) of such lesions as an alternative to radical surgery has recently gained interest. We report the long-term outcome of LE in patients with a mural pathological complete response (ypT0) after CRT.

METHODS

A retrospective review of patients with rectal cancer treated by CRT and followed by LE with pathological complete response in the specimen between 1998 and 2009 was performed.

RESULTS

A total of 174 patients had neoadjuvant CRT, and 68 (39 %) showed complete clinical response (cCR). Thirty-one of the cCR patients underwent LE; 23 of them resulted in ypT0 and 8 had residual disease. The ypT0 group included 12 men and 11 women with a median age of 66. The pretreatment stage was T3N1 in 4 (17 %) patients, T3N0 in 11 (48 %), T2N1 in 3 (13 %), and T2N0 in 5 (22 %). The median tumor distance from the anal verge was 6 cm. Sixteen patients (70 %) underwent transanal excision, and 7 (30 %) were treated by transanal-endoscopic microsurgery. Three patients died: one of pneumonia, one of melanoma of the rectum, and one of lung carcinoma. No local or distant recurrences were detected in the remaining 20 patients. The median follow-up was 87 months.

CONCLUSIONS

Although radical rectal resection is the treatment of choice, LE of complete rectal tumor regression could be a safe alternative with an acceptable result in selected patients.

Transanal minimally invasive surgery (TAMIS) for local excision of benign neoplasms and early-stage rectal cancer: efficacy and outcomes in the first 50 patients

BACKGROUND

Since its inception in 2009, transanal minimally invasive surgery has been used increasingly in the United States and internationally as an alternative to local excision and transanal endoscopic microsurgery for local excision of neoplasms in the distal and mid rectum. Despite its increasing acceptance, the clinical benefits of transanal minimally invasive surgery have not yet been validated.

OBJECTIVE

The aim of this study is to assess the adequacy of transanal minimally invasive surgery for the local excision of benign and malignant lesions of the rectum.

DESIGN

This is a retrospective analysis of consecutive patients who underwent transanal minimally invasive surgery for local excision of neoplasms at a single institution.

SETTINGS

The study was conducted by a single group of colorectal surgeons at a tertiary referral center.

PATIENTS

Eligible patients with early-stage rectal cancer and benign neoplasms were offered transanal minimally invasive surgery as a means for local excision. Data from these patients were collected prospectively in a registry.

MAIN OUTCOME MEASURES

The primary outcome measures included the feasibility of transanal minimally invasive surgery for local excision, resection quality, and short-term clinical results.

RESULTS

: Fifty patients underwent transanal minimally invasive surgery between July 2009 and December 2011. Twenty-five benign neoplasms, 23 malignant lesions, and 2 neuroendocrine tumors were excised. All lesions were excised using transanal minimally invasive surgery without conversion to an alternate transanal platform. The average length of stay was 0.6 days (range, 0-6), and 68% of patients were discharged on the day of surgery. The average distance from the anal verge was 8.1 cm (range, 3-14 cm). All lesions were excised completely with only 2 fragmented specimens (4%). All specimens were removed with grossly negative margins, although 3 (6%) were found to have microscopically positive margins on final pathology. There were 2 recurrences (4%) at 6- and 18-month follow-up. Early complications occurred in 3 patients (6%). No long-term complications were observed at a median follow-up of 20 months.

LIMITATIONS

The study was limited by its retrospective nature and midterm follow-up.

CONCLUSIONS

Transanal minimally invasive surgery is an advanced transanal platform that provides a safe and effective method for resecting benign neoplasms, as well as carefully selected, early-stage malignancies of the mid and distal rectum.

Comparative analysis of lymph node metastases in patients with ypT0-2 rectal cancers after neoadjuvant chemoradiotherapy

BACKGROUND

Neoadjuvant chemoradiotherapy before total mesorectal excision for rectal cancer is associated with improved local tumor control, primary tumor regression, and pathologic downstaging. Therefore, tumor response in the bowel wall has been proposed to be used to identify patients for organ-preserving strategies.

OBJECTIVE

The aim of this study was to determine the rate of residual lymph node involvement following neoadjuvant chemoradiotherapy among patients with ypT0-2 residual bowel wall tumor and to comparatively assess their oncologic outcomes following total mesorectal excision.

DESIGN

This is a retrospective consecutive cohort study, 1993 to 2008.

SETTING AND PATIENTS

Patients with stage cII to III rectal carcinoma treated with preoperative chemoradiotherapy and total mesorectal excision were included.

MAIN OUTCOME MEASURES

The primary outcomes measured were the rate of lymph node metastasis by ypT stage, recurrence-free survival, and the frequencies of distant metastasis and local recurrence.

RESULTS

Among all 406 ypT0-2 patients, 66 (16.3%) had lymph node metastasis: 20.8% among ypT2, 17.1% among ypT1, and 9.1% among ypT0 patients. Local recurrences (2.0% vs 5.5%; p = 0.038) but not distant metastases (9.3% vs 13.5%; p = 0.38) occurred more frequently in ypN+ than in ypN0 patients. Recurrence-free survival was 85.2% among ypT0-2N0 and 79.6% for ypT0-2N+ patients (p = 0.28). The lack of difference in recurrence-free survival persisted after covariate adjustment (HR, 1.29; 95% CI, 0.77-2.16; p = 0.37). However, among ypT3-4 patients, 5-year recurrence-free survival was significantly lower with lymph node metastasis (HR, 1.51; 95% CI, 1.07-2.12; p = 0.019).

LIMITATIONS

Low local recurrence event rate limited further comparison by ypT0-2 subgroups.

CONCLUSIONS

Residual mesorectal lymph node metastasis risk remains high even with good neoadjuvant chemoradiotherapy response within the bowel wall. Complete removal of the mesorectal burden results in excellent disease control. Given the uniquely good outcomes with standard therapy among patients with ypT0-2 disease, the use of ypT stage to stratify patients for local excision risks undertreatment of an unacceptably high proportion of patients.

Distribution of residual cancer cells in the bowel wall after neoadjuvant chemoradiation in patients with rectal cancer

BACKGROUND

The standard treatment for locally advanced rectal cancer is preoperative chemoradiation and total mesorectal excision. After surgery, tumors are classified according to the depth of tumor invasion, nodal involvement, and tumor regression grade. However, these staging systems do not provide information about the distribution of residual cancer cells within the bowel wall.

OBJECTIVE

This study aimed to determine the distribution of residual cancer cells in each layer of the bowel wall in rectal cancer specimens.

DESIGN

This was a secondary analysis of data from a prospective phase II study.

SETTING

This study was performed in a multi-institutional setting.

PATIENTS

Included were 153 patients with stage II or stage III rectal cancer.

INTERVENTIONS

Patients were treated with chemoradiation and surgery. The surgical specimen tumor tissue was analyzed, and the distribution of residual cancer cells in each layer of the bowel wall was determined.

MAIN OUTCOME MEASURES

Statistical analysis was used to examine the correlation of residual cancer cells in each layer of the bowel wall with the clinical/pathologic stage and tumor regression grade.

RESULTS

Forty-two of 153 (27%) patients had complete response in the bowel wall (ypT0). Of the remaining 111 patients who had residual cancer cells, 5 (3%) were ypTis, 12 (8%) were ypT1, 41 (27%) were ypT2, 50 (33%) were ypT3, and 3 (2%) were ypT4. Of the 94 patients with ypT2-4 tumors, 12 (13%) had cancer cells in the mucosa, and 53 (56%) had cancer cells in the submucosa; 92 (98%) had cancer cells in the muscularis propria. Pretreatment cT correlated with the distribution of residual cancer cells. Tumor regression grade was not associated with the distribution of residual cancer cells after chemoradiation.

LIMITATIONS

: Patients received different chemotherapy regimens.

CONCLUSIONS

Residual cancer cells in rectal cancer specimens after chemoradiation are preferentially located close to the invasive front. This should be considered when designing strategies to diagnose complete pathologic response and when investigating the mechanisms of tumor resistance to chemoradiation.

Update and debate issues in surgical treatment of middle and low rectal cancer

Based on a review of the literature, this paper provides an update on surgical treatment of middle and low rectal cancer and discusses issues of debate surrounding that treatment. The main goal of the surgical treatment of rectal cancer is radical resection of the tumor and surrounding lymphatic tissue. Local excision of early rectal cancer can be another treatment option, in which the patient can avoid possible complications related to radical surgery. Neoadjuvant chemoradiation therapy (CRT) has been recommended for patients with cT3-4N0 or any T N+ rectal cancer because CRT shows better local control and less toxicity than adjuvant CRT. However, recent clinical trials showed promising results for local excision after neoadjuvant CRT in selected patients with low rectal cancer. In addition, the "wait and see" concept is another modality that has been reported for the management of tumors that show complete clinical remission after neoadjuvant CRT. Although radical surgery for middle and low rectal cancer is the cornerstone therapy, an ultralow anterior resection with or without intersphincteric resection (ISR) has become an alternative standard surgical method for selected patients. Many studies have reported on the oncological safety of the ISR, but few of them have addressed the issue the functional outcome. Furthermore, an abdominoperineal resection (APR) has problems with high rates of tumor perforations and positive circumferential resection margins, and those factors have contributed to its having a high rate of local recurrence and a poor survival rate for rectal cancer compared with sphincter-saving procedures. Recently, great efforts have been made to reduce these problems, and the total levator excision or the extended APR concept has emerged. Surgical management for low rectal cancer should aim to radically excise the tumor and to preserve as much of the sphincter function as possible by using multidisciplinary approaches. However, further prospective clinical trials are needed for tailored treatment of rectal cancer patients.

Complete pathologic response after combined modality treatment for rectal cancer and long-term survival: a meta-analysis

BACKGROUND

Complete pathologic response (CPR) after neoadjuvant chemoradiotherapy (combined modality treatment, CMT) for rectal cancer seems associated with improved survival compared to partial or no response (NPR). However, previous reports have been limited by small sample size and single-institution design.

METHODS

A systematic literature review was conducted to detect studies comparing long-term results of patients with CPR and NPR after CMT for rectal cancer. Variables were pooled only if evaluated by 3 or more studies. Study end points included rates of CPR, local recurrence (LR), distant recurrence (DR), 5-year overall survival (OS), and disease-free survival (DFS).

RESULTS

Twelve studies (1,913 patients) with rectal cancer treated with CMT were included. CPR was observed in 300 patients (15.6%). CPR and NPR patient groups were similar with respect to age, sex, tumor size, distance of tumor from the anus, and stage of disease before treatment. Median follow-up ranged from 23 to 46 months. CPR patients had lower rates of LR [0.7% vs. 2.6%; odds ratio (OR) 0.45, 95% confidence interval (CI) 0.22-0.90, P = 0.03], DR (5.3% vs. 24.1%; OR 0.15, 95% CI 0.07-0.31, P = 0.0001), and simultaneous LR + DR (0.7% vs. 4.8%; OR 0.32, 95% CI 0.13-0.79, P = 0.01). OS was 92.9% for CPR versus 73.4% for NPR (OR 3.6, 95% CI 1.84-7.22, P = 0.002), and DFS was 86.9% versus 63.9% (OR 3.53, 95% CI 1.62-7.72, P = 0.002).

CONCLUSIONS

CPR after CMT for rectal cancer is associated with improved local and distal control as well as better OS and DFS.

Avoiding radical surgery after pre-operative chemoradiotherapy: a possible therapeutic option in rectal cancer?

BACKGROUND

In this modern era of multi-modality treatment there is increasing interest in the possibility of avoiding radical surgery in complete responders after neo-adjuvant long-course chemoradiotherapy (LCPRT). In this article, we present a systematic review of such treatments and discuss their therapeutic applicability for the future.

METHODS

We searched the PubMed online libraries to identify studies that reported on the long-term surgical and pathological outcomes after local excision together with those that explored the possibility of clinical observation only in patients achieving a complete clinical response after LCPRT.

RESULTS

Several retrospective (n = 10), one single-arm prospective, and one small randomised series have reported on the use of local excision after LCPRT and demonstrated acceptably low levels of local recurrence with survival comparable to patients progressing to conventional surgery. One prospective series allocated patients to observation or radical surgery based on histological parameters after local excision (ypT0 and ypT1) and showed no differences in outcomes. Two retrospective series from the same group on a Brazilian cohort of patients reported excellent long-term outcomes after "wait and watch" in complete clinical responders. However, other reports have shown no direct correlation between clinical and pathological response.

CONCLUSION

Local excision may be an appropriate option for selected patients developing good clinical response after LCPRT. In our opinion, a policy of clinical observation in complete clinical responders after LCPRT may not be a safe strategy, unless we had robust predictive models for accurate identification of pathological complete response. In order to identify patients that may be potentially appropriate for such an approach we propose a clinical algorithm incorporating important clinical, radiological, and pathological parameters. The proposed model will require validation in a prospective study. Finally, we need randomised data for demonstrating the non-inferiority of clinical observation compared to conventional surgery before this can be considered as standard possible therapeutic option.

Systematic review and meta-analysis of outcomes following pathological complete response to neoadjuvant chemoradiotherapy for rectal cancer

BACKGROUND

Following neoadjuvant chemoradiotherapy (CRT) and interval proctectomy, 15-20 per cent of patients are found to have a pathological complete response (pCR) to combined multimodal therapy, but controversy persists about whether this yields a survival benefit. This systematic review evaluated current evidence regarding long-term oncological outcomes in patients found to have a pCR to neoadjuvant CRT.

METHODS

Three major databases (PubMed, MEDLINE and the Cochrane Library) were searched. The systematic review included all original articles reporting long-term outcomes in patients with rectal cancer who had a pCR to neoadjuvant CRT, published in English, from January 1950 to March 2011.

RESULTS

A total of 724 studies were identified for screening. After applying inclusion and exclusion criteria, 16 studies involving 3363 patients (1263 with pCR and 2100 without) were included (mean age 60 years, 65·0 per cent men). Some 73·4 per cent had a sphincter-saving procedure. Mean follow-up was 55·5 (range 40-87) months. For patients with a pCR, the weighted mean local recurrence rate was 0·7 (range 0-2·6) per cent. Distant failure was observed in 8·7 per cent. Five-year overall and disease-free survival rates were 90·2 and 87·0 per cent respectively. Compared with non-responders, a pCR was associated with fewer local recurrences (odds ratio (OR) 0·25; P = 0·002) and less frequent distant failure (OR 0·23; P < 0·001), with a greater likelihood of being alive (OR 3·28; P = 0·001) and disease-free (OR 4·33, P < 0·001) at 5 years.

CONCLUSION

A pCR following neoadjuvant CRT is associated with excellent long-term survival, with low rates of local recurrence and distant failure.

Long-term outcome of patients with complete pathologic response after neoadjuvant chemoradiation for cT3 rectal cancer: implications for local excision surgical strategies

BACKGROUND

Neoadjuvant chemoradiotherapy (CRT) followed by radical surgery including total mesorectal excision (TME) is standard treatment in patients with locally advanced rectal cancer. Emerging data indicate that patients with complete pathologic response (ypCR) after CRT have favorable outcome, suggesting the possibility of less invasive surgical treatment. We analyzed long-term outcome of cT3 rectal cancer treated by neoadjuvant CRT in relation to ypCR and type of surgery.

METHODS

The study population comprised 139 patients (93 men, 46 women; median age 62 years) with cT3N0-1M0 mid and distal rectal adenocarcinoma treated by CRT and surgery (110 TME and 29 local excision) at our institution between 1996 and 2008. At pathology, ypCR was defined as no residual cancer cells in the primary tumor.

RESULTS

Tumors of 42 patients (30.2%) were classified as ypCR. After a median follow-up of 55.4 months, comparing patients with ypCR to patients with no ypCR, 5-year disease-specific survival was 95.8% versus 78.0% (P = 0.004), and 5-year disease-free survival was 90.1% vs. 64.0% (P = 0.004). In patients with ypCR, no statistically significant outcome difference was observed between TME and local excision. In patients treated by local excision, comparing patients with ypCR to patients with no ypCR, 5-year disease-free survival was 100% vs. 65.5% (P = 0.024), and 5-year local recurrence-free survival was 92.9% vs. 66.7% (P = 0.047).

CONCLUSIONS

With retrospective analysis limitations, our data confirm favorable long-term outcome of cT3 rectal cancer with ypCR after CRT and warrant clinical trials exploring local excision surgical strategies.

Serum biomarkers which correlate with failure to respond to immunotherapy and tumor progression in a murine colorectal cancer model

PURPOSE

To advance our understanding of mechanisms involved in tumor progression/regression, a CT26 colorectal mouse model treated intra-tumorally with DISC-herpes simplex virus as immunotherapy was used in the discovery and validation phases to investigate and ultimately identify biomarkers correlating with the failure to respond to immunotherapy.

EXPERIMENTAL DESIGN

For the discovery phase, serum protein/peptide profiles of a retrospective sample collection (total n=70) were analyzed using MALDI-TOF-MS combined with artificial neural networks. Following identification of the key predictive peptides using ESI-MS/MS, validation of the identified proteins was carried out on serum and tissues collected in an independent sample set (total n=60).

RESULTS

Artificial neural network analysis resulted in four discriminatory peaks with an accuracy of 86%, sensitivity of 90% and specificity of 81% between the progressor/regressor groups. Three of the identified discriminatory markers were upregulated and demonstrated a positive correlation with tumor progression following DISC-herpes simplex virus therapy. Immunovalidation studies corroborated the MALDI-TOF-MS findings. Immunohistochemistry revealed that serum amyloid A-1 and serum amyloid P produced in the liver localized intracellularly in CT26 tumor tissue.

CONCLUSIONS

MALDI-TOF-MS and BI analysis of the serum proteome of tumor-bearer mice undergoing immunotherapy, identified biomarkers associating with "failure to respond" and biological arrays confirmed these findings.

Sphincter preservation for distal rectal cancer - a goal worth achieving at all costs?

To assess the merits of currently available treatment options in the management of patients with low rectal cancer, a review of the medical literature pertaining to the operative and non-operative management of low rectal cancer was performed, with particular emphasis on sphincter preservation, oncological outcome, functional outcome, morbidity, quality of life, and patient preference. Low anterior resection (AR) is technically feasible in an increasing proportion of patients with low rectal cancer. The cost of sphincter preservation is the risk of morbidity and poor functional outcome in a significant proportion of patients. Transanal and endoscopic surgery are attractive options in selected patients that can provide satisfactory oncological outcomes while avoiding the morbidity and functional sequelae of open total mesorectal excision. In complete responders to neo-adjuvant chemoradiotherapy, a non-operative approach may prove to be an option. Abdominoperineal excision (APE) imposes a permanent stoma and is associated with significant incidence of perineal morbidity but avoids the risk of poor functional outcome following AR. Quality of life following AR and APE is comparable. Given the choice, most patients will choose AR over APE, however patients following APE positively appraise this option. In striving toward sphincter preservation the challenge is not only to achieve the best possible oncological outcome, but also to ensure that patients with low rectal cancer have realistic and accurate expectations of their treatment choice so that the best possible overall outcome can be obtained by each individual.

Time to locoregional recurrence after curative resection of rectal carcinoma is prolonged after neoadjuvant treatment: a systematic review and meta-analysis

AIM

A systematic review of the literature with meta-analysis was performed to evaluate the time to locoregional recurrence after curative resection of rectal carcinoma, assuming that this time is prolonged after neoadjuvant radiochemotherapy and/or present day surgery.

METHOD

English and German language peer-reviewed articles published between 1980 and 2007 were selected. Twenty-five of 118 studies fulfilled the defined inclusion and exclusion criteria. For some special questions, data of the Erlangen Registry of Colorectal Carcinoma (ERCRC) from 1985 to 1997 are reported.

RESULTS

After conventional surgery of rectal carcinoma, 75% (range 66-84%) of locoregional recurrence presented during the first 2 years after resection. Following the introduction of total mesorectal excision surgery and the use of neoadjuvant treatment, a general reduction of the frequency of local recurrence combined with a prolongation of the time to local recurrence was observed. In the practice of today, in particular after neoadjuvant long-course radiochemo-or radiotherapy, 24% (range 8-40%) of all local recurrences present later than 5 years after primary therapy. In contrast, such late local recurrences are observed in only 8% (range 5-9%) following primary surgery alone.

CONCLUSION

For a definite assessment of the therapeutic results regarding local control, a minimal follow up of 7-8 years either after neoadjuvant long-course radiochemo- or radiotherapy and a minimum of 5 years after surgery alone is necessary. For patients with primary surgery followed by adjuvant therapy, it is not possible to make a clear statement.

Multidisciplinary approach to recurrent/unresectable rectal cancer: how to prepare for the extent of resection

Local recurrence from rectal cancer is a complex problem that should be managed by a multidisciplinary team. Pelvic re-irradiation and intraoperative radiation should be considered in the management of these patients. Long-term survival can be achieved in patients who undergo radical surgery with negative margins of resections. The morbidity of these procedures is high and at times may compromise quality of life. Palliative surgical procedures can be considered; however, in some cases, palliative resections may not be better than nonsurgical palliation.

Is local excision after complete pathological response to neoadjuvant chemoradiation for rectal cancer an acceptable treatment option?

PURPOSE

The role of local excision in patients with good histological response to neoadjuvant chemoradiation for locally advanced rectal cancer is unclear, mainly because of possible regional nodal involvement. This study aims to evaluate the correlation between pathological T and N stages following neoadjuvant chemoradiation for locally advanced rectal cancer and the outcome of patients with mural pathological complete response undergoing local excision.

METHODS

This investigation was conducted as a retrospective analysis. Between January 1997 and December 2007, 320 patients with T3 to 4Nx, TxN+ or distal (≤ 6 cm from the anus) T2N0 rectal cancer underwent neoadjuvant concurrent chemoradiation followed by surgery. Radiotherapy was standard and chemotherapy consisted of common fluoropyrimidine-based regimens.

RESULTS

After chemoradiation, 93% patients had radical surgery, 6% had local excision, and 3% did not have surgery. In the 291 patients undergoing radical surgery, the pathological T stage correlated with the N stage (P = .036). We compared the outcome of patients with mural complete pathological response (n = 37) who underwent radical surgery (group I) and those (n = 14) who had local excision only (group II). With a median follow-up of 48 months, 4 patients in group I had a recurrence and none in group II had a recurrence; one patient died in group I and none died in group II. Disease-free survival, pelvic recurrence-free survival, and overall survival rates were similar in both groups.

CONCLUSION

In this retrospective study, nodal metastases were rare in patients with mural complete pathological response following neoadjuvant chemoradiation (3%), and local excision did not compromise their outcome. Therefore, local excision may be an acceptable option in these patients.