Ex vivo sentinel lymph node mapping in patients undergoing proctectomy for rectal cancer

Disparities in Clinical Trial Enrollment and Reporting in Rectal Cancer: A Systematic Review and Demographic Comparison to the National Cancer Database

BACKGROUND

Cancer care guidelines based on clinical trial data in homogenous populations may not be applicable to all rectal cancer patients. The aim of this study was to evaluate whether patients enrolled in rectal cancer clinical trials (CTs) are representative of United States (U.S.) rectal cancer patients.

METHODS

Prospective rectal cancer CTs from 2010 to 2019 in the United States were systematically reviewed. In trials with multiple arms reporting separate demographic variables, each arm was considered a separate CT group in the analysis. Demographic variables considered in the analysis were age, sex, race/ethnicity, facility location throughout the United States, rural vs urban geography, and facility type. Participant demographics from trial and the National Cancer Database (NCDB) participants were compared using chi-squared goodness of fit and one-sample t-test where applicable.

RESULTS

Of 50 CT groups identified, 42 (82%) studies reported mean or median age. Trial participants were younger compared to NCDB patients (P < .001 all studies). All but three trials had fewer female patients than NCDB (48.2% female, P < .001). Less than half the CT groups reported on race or ethnicity. Eighteen out of 22 trials (82%) had a smaller percentage of Black patients and 4 out of 8 (50%) trials had fewer Hispanic or Spanish origin patients than the NCDB. No CTs reported comorbidities, socioeconomic factors, or education. CT primary sites were largely at academic centers and in urban areas.

CONCLUSION

The present study supports the need for improved demographic representation and transparency in rectal cancer clinical trials.

Sentinel lymph node mapping for metastasis detection in colorectal cancer: a systematic review and meta-analysis

INTRODUCTION

controversy exists on the diagnostic performance of sentinel lymph node (SLN) mapping in colorectal cancer. This study aimed to provide a more precise estimation of its clinical significance.

MATERIALS AND METHODS

a systematic search of electronic databases was conducted to retrieve all relevant studies up to August 31st, 2019. Detection rate, sensitivity, and upstaging rate were pooled together, and a subgroup analysis was performed to identify factors that affect diagnostic performance. The prognostic value of upstaging was also explored.

RESULTS

sixty-eight studies were eligible and included. The pooled SLN detection rate was 0.93 (95 % CI, 0.91-0.94), with a significant higher rate in colon cancer or in studies including more than 100 patients. The overall sensitivity of the SLN procedure in colorectal cancer was 0.72 (95 % CI, 0.67-0.77). The tracers used were found to influence sensitivity. A mean weighted upstaging of 0.22 (95 % CI, 0.18-0.25) was identified. True upstaging, defined as micro-metastases, was 14 %. Upstaged patients were associated with worse overall survival (OS) when compared with node-negative patients (HR = 2.60, 95 % CI, 0.16-4.63). In addition, upstaged patients had a lower 5-year disease-free survival (DFS) rate than node-negative patients.

CONCLUSION

based on the results of the present meta-analysis, the SLN mapping procedure should focus on early stage patients to refine staging, since upstaging appeared to be a prognostic factor for DFS and OS. The SLN procedure can be recommended for colorectal cancer patients in addition to conventional resection.

Pathological nodal staging score for rectal cancer patients treated with radical surgery with or without neoadjuvant therapy: a postoperative decision tool

Background

Lymph node status can predict the prognosis of patients with rectal cancer treated with surgery. Thus, we sought to establish a standard for the minimum number of lymph nodes (LNs) examined in patients with rectal cancer by evaluating the probability that pathologically negative LNs prove positive during surgery.

Patients and methods

We extracted information of 31,853 patients with stage I–III rectal carcinoma registered between 2004 and 2013 from the Surveillance, Epidemiology, and End Results database and divided them into two groups: the first group was SURG, including patients receiving surgery directly and the other group was NEO, encompassing those underwent neo-adjuvant therapy. Using a beta-binomial model, we developed nodal staging score (NSS) based on pT/ypT stage and the number of LNs retrieved.

Results

In both cohorts, the false-negative rate was estimated to be 16% when 12 LNs were examined, but it dropped to 10% when 20 LNs were evaluated. In the SURG cohort, to rule out 90% possibility of false staging, 3, 7, 28, and 32 LNs would be necessarily examined in patients with pT1–4 disease, respectively. While in the NEO cohort, 4, 7, 12, and 16 LNs would be included for examination in patients with ypT1–4 disease to guarantee an NSS of 90%.

Conclusion

By determining whether a rectal cancer patient with negative LNs was appropriately staged, the NSS model we developed in this study may assist in tailoring postoperative management.

Sentinel lymph node biopsy as a prognostic factor in non-metastatic colon cancer: a prospective study

PURPOSE

Around a third of node-negative patients with colon cancer experience a recurrence after surgery, suggesting poor staging. Sentinel lymph node techniques combined with immunochemistry could improve colon cancer staging. We prospectively assessed the effect of Sentinel node mapping on staging and survival in patients with non-metastatic colon cancer.

METHODS

An observational and prospective study was designed. 105 patients with colon cancer were selected. Patients were classified according to node involvement as: N1, with node invasion detected by the conventional techniques; up-staged, with node invasion detected only by sentinel node mapping; and N0, with negative lymph node involvement by both techniques. Five-year survival and disease-free survival rates were analysed. Multivariate regression analyses were performed to identify prognostic factors for disease-free and overall survival.

RESULTS

Sentinel node mapping was successfully applied in 78 patients: 33 % were N1; 24.5 % were up-staged (18 patients with isolated tumour cells and 1 patient with micrometastases); and 42.5 % were N0. N1 patients had the poorest overall 5-year survival (65.4 %) and 5-year disease-free survival (69.2 %) rates compared with the other two groups. No significant 5-year survival differences were observed between N0 patients (87.9 %) and up-staged patients (84.2 %).

CONCLUSIONS

Patients up-staged after sentinel node mapping do not have a poorer prognosis than patients without node involvement. Detection of isolated cancer cells was not a poor prognosis factor in these patients.

Replacing Transanal Excision with Transanal Endoscopic Microsurgery and/or Transanal Minimally Invasive Surgery for Early Rectal Cancer

The use of local resection of rectal polyps and early rectal cancer has progressed to become the standard of care in most institutions with a colorectal surgery specialist. The use of transanal excision (TAE) with anorectal retractors and standard instrumentation has been supplanted by the application of endoscopic techniques which allow direct video augmented visualization. The transanal endoscopic microsurgery method provides a 3D view and works under a constant flow of air to keep the rectal vault open. Instruments capable of accomplishing a surgical excision and suture closure work through a long 4 cm tube set at the anal canal. The newest version of TAE is transanal minimally invasive surgery which is similar to a single-site laparoscopic technique using a hand access port at the anal canal to maintain a seal for insufflation of the rectum, regular 2D video camera for visualization, and laparoscopic instrumentation through the port in the anus. Each of these techniques is described in detail and the outcomes compared, which show the progress being made in this area of colorectal surgery.

Ex vivo localization and immunohistochemical detection of sentinel lymph node micrometastasis in patients with colorectal cancer can upgrade tumor staging

BACKGROUND

It is not clear if sentinel lymph node (SLN) mapping can improve outcomes in patients with colorectal cancers. The purpose of this study was to determine the prognostic values of ex vivo sentinel lymph node (SLN) mapping and immunohistochemical (IHC) detection of SLN micrometastasis in colorectal cancers.

METHODS

Colorectal cancer specimens were obtained during radical resections and the SLN was identified by injecting a 1% isosulfan blue solution submucosally and circumferentially around the tumor within 30 min after surgery. The first node to stain blue was defined as the SLN. SLNs negative by hematoxylin and eosin (HE) staining were further examined for micrometastasis using cytokeratin IHC.

RESULTS

A total of 54 patients between 25 and 82 years of age were enrolled, including 32 males and 22 females. More than 70% of patients were T3 or above, about 86% of patients were stage II or III, and approximately 90% of patients had lesions grade II or above. Sentinel lymph nodes were detected in all 54 patients. There were 32 patients in whom no lymph node micrometastasis were detected by HE staining and 22 patients with positive lymph nodes micrometastasis detected by HE staining in non-SLNs. In contrast only 7 SLNs stained positive with HE. Using HE examination as the standard, the sensitivity, non-detection rate, and accuracy rate of SLN micrometastasis detection were 31.8% (7/22), 68.2% (15/22), and 72.2%, respectively. Micrometastasis were identified by ICH in 4 of the 32 patients with HE-negative stained lymph nodes, resulting in an upstaging rate 12.5% (4/32). The 4 patients who were upstaged consisted of 2 stage I patients and 2 stage II patients who were upstaged to stage III. Those without lymph node metastasis by HE staining who were upstaged by IHC detection of micrometastasis had a significantly poorer disease-free survival (p = 0.001) and overall survival (p = 0.004).

CONCLUSION

Ex vivo localization and immunohistochemical detection of sentinel lymph node micrometastasis in patients with colorectal cancer can upgrade tumor staging, and may become a factor affecting prognosis and guiding treatment.

Systematic review of sentinel lymph node mapping procedure in colorectal cancer

BACKGROUND

The clinical impact of sentinel lymph node (SN) biopsy in colorectal cancer is still controversial. The aim of our study was to determine the accuracy of this procedure from published data and to identify factors that contribute to the conflicting reports.

METHODS

A systematic search of the Medline, Embase, and Cochrane databases up to July 2011 revealed 98 potentially eligible studies, of which 57 were analyzed including 3,934 patients (3,944 specimens).

RESULTS

The pooled SN identification rate was 90.7% (95% CI 88.2-93.3), with a significant higher identification rate in studies including more than 100 patients or studies using the ex vivo SN technique. The pooled sensitivity of the SN procedure was 69.6% (95% CI 64.7-74.6). Including the immunohistochemical findings increased the pooled sensitivity of SN procedure to 80.2% (95% CI 4.7-10.7). Subgroups with significantly higher sensitivity could be identified: ≥4 SNs versus <4 SNs (85.2 vs. 66.3%, p = 0.003), colon versus rectal cancer (77.6 vs. 65.7%, p = 0.04), early T1 or T2 versus advanced T3 or T4 carcinomas (93.4 vs. 58.8%, p = 0.01). Serial sectioning and immunohistochemistry resulted in a mean upstaging of 18.9% (range 0-50%). True upstaging defined as micrometastases (pN1mi+) rather than isolated tumor cells (pN0itc+) was 7.7%.

CONCLUSIONS

The SN procedure in colorectal cancer has an overall sensitivity of 70%, with increased sensitivity and refined staging in early-stage colon cancer. Because the ex vivo SN mapping is an easy technique it should be considered in addition to conventional resection in colon cancer.

Sentinel-lymph-node procedure in colon and rectal cancer: a systematic review and meta-analysis

BACKGROUND

No consensus exists on the validity of the sentinel-lymph-node procedure for assessment of nodal status in patients with colorectal cancer. We aimed to assess the diagnostic performance of this procedure.

METHODS

We searched Embase and PubMed databases for studies published before March 20, 2010. Eligible studies had a prospective design, a sample size of at least 20 patients, and reported the rate of sentinel-lymph-node positivity. Individual patient data were requested for localisation and T-stage stratification. A subset of reports with high methodological quality was selected and analysed.

FINDINGS

We identified 52 eligible studies, which included 3767 sentinel-lymph-node procedures (2961 [78·6%] colon and 806 [21·4%] rectal carcinomas). Most tumours 2339 (62·1%) were stage T3 or T4. 1887 (50·1%) of patients were male, 1880 (49·9%) female. Mean overall weighted-detection rate was 0·94 (95% CI 0·92-0·95), at a pooled sensitivity of 0·76 (0·72-0·80) with limited heterogeneity (χ(2)=286·08, degrees of freedom=51; p=0·003). A mean weighted upstaging of 0·15 (95% CI 0·12-0·19) was noted. Individual patient data were available from 19 studies that included 1168 patients. Analysis of these data showed no significant difference in sensitivity between colon (0·86 [95% CI 0·83-0·90]) and rectal cancer (0·82 [0·77-0·88]; p=0·23). Also, there was no dependency of sensitivity on T stage for both colon (pT1: 0·79 [95% CI 0·73-0·84], pT2: 0·76 [0·62-0·90], pT3: 0·73 [0·59-0·87], pT4: 0·73 [0·53-0·93]) and rectal cancer (T1 or T2: 0·81 [0·52-0·94] vs T3 or T4: 0·80 [0·51-0·93]). The subgroup of eight studies with high methodological quality showed a mean detection rate of 0·96 (95% CI 0·90-0·99) for colonic tumours and 0·95 (0·75-0·99) for rectal tumours, and a mean sensitivity of 0·90 (95% CI 0·86-0·93) for colonic tumours and 0·82 (0·60-0·93) for rectal tumours.

INTERPRETATION

The sentinel-lymph-node procedure shows a low sensitivity, regardless of T stage, localisation, or pathological technique. For every patient diagnosed with colon or rectal cancer without clinical evidence of lymph-node involvement or metastatic disease, this procedure in addition to conventional resection should be considered, since the prognostic information provided by this technique could be clinically significant.

FUNDING

Cancer Center Amsterdam Foundation, Amsterdam, Netherlands.