Sentinel lymph node biopsy in rectal cancer--not yet ready for routine clinical use

Usefulness of histological superstudy of sentinel lymph nodes detected with radioisotopes in colon cancer

INTRODUCTION

Adjuvant chemotherapy (CT) significally reduces the rate of relapse in +pN (stage III) colon cancer (CC) and in some pN0 (stage II) with risk factors such as pT4, vascular invasion V1, perineural invasion Pn1, and complicated tumors. However, unexpectedly, 20%-30% of pN0 present a relapse in the follow-up, which may suggest that the lymph node involvement was not discovered in the conventional histological study (CS), and its finding with a superstudy (SS) could increase the number of patients who would benefit from neoadjuvant CT. It is not possible to perform this SS in every lymph node (LN) from the specimen, but it is possible in a small group of LN which are representative of the N status (definition of sentinel node SN). The aim of our work is to state the representativeness of the SN and to analyze de number of patients who are suprastaged after the SS of the SN.

MATERIAL AND METHODS

Prospective study of a series of patients who have undergone curative surgery for CC, to whom we perform selective biopsy of sentinel node (SBDN). Identification of SN was carried out with in vivo injection of the radiotracer, with ex vivo isolation of SN. Once the specimen is out, we take pictures of the surgical bed to rule out the presence of aberrant drainage routes, out of the routine oncological resection area. We performed the histological CS (Hematoxilin-Eosin stain (H-E) in conventional sections) in the rest of the LN from the mesocolon. In the SN we performed the CS and a SS with H-E in serial sections, immunohistochemistry (IHC) and molecular study with OSNA® (One Step Nucleic Acid Amplification). Diagnostic validity study od SBSN was carried out, defining the false negative (FN) as the negativity of the SN while other LN are positive (N+), as well as a valuation of the suprastaging due to the SS of the SN.

RESULTS

We performed lymphatic map in 72 patients, finding the SN in 62 of them (87.3%). The 9 identification failures happened in the first 17 cases. We have not found aberrant drainage routes. A total of 1.164 LN were studied in the 62 patients (18.8 LN/patient), from which 145 are SN (2,34 SN/patient), having found 103 positive LN with the CS and 112 positive with the SS of SN (9+ LN more in 8 patients than detected with the CS). Positivity after CS in the SN group is 17.24% (25/145), while it is 8.53% in the rest (87/1.019) (P < .001). With the CS, 50% of the patients (31/62) were pN+ (4 are N+ exclusively in the SN), and after the SS of the SN, only 1 of the 31 pN0 patients (3.2%) becomes pN1a, with a definitive 51.6% of N+ in the whole series (32 N+ in the 62 patients) (5 are N+ exclusively in the SN). Exclusively with the SS of the SN, FN rate ("-SN, +others", meaning patients who are N+ having -SN) is 54.8% (17/31). With the SS of the SN, 8 of the 62 patients (12.9%) increase their total number of +LN: apart from the patient who turns from pN0 to pN1a, suprastaging from IIA to IIIB (and therefore increasing the total number of pN+ to 32), 5 of the 17 FN in the CS turns into positive (2 change the pN subindex and one is suprastaged from IIIB to IIIC), decreasing FN to 37.5% (12/32 cases). Besides, 2 patients whose SN is already positive in the CS increase the number of +SN after the SS of the SN, therefore both changing their pN subindex and one of them suprastaging from IIIB to IIIC. In summary, 8 patients increase the total number of positive SN after the SS (8/62, 12.9%), 5 of them changing the pN subindex (5/62, 12.9%), even if only 3 of them get suprastaged (3/62, 4.8%), among them the one who turns from pN0 to pN1a.

CONCLUSION

Technique is valid and reproducible, with a high detection rate even with a high learning curve. It globally increases the number of affected LN in 12.9% of patients, having prognostic implications in 4.8% (suprastaging rate). Only 3.2% of pN0 patients in the CS turn to be +pN after the SS of the SN, with its therapeutic implications (prescription of adjuvant CT), which could be relevant when extrapolated to a big number of patients. The high FN rate (37.5%) prevents us from accepting the representativeness of SN as the global N status, but it is not clinically relevant in CC, as its aim is not to avoid lymphadenectomy, which remains mandatory (opposite to breast cancer or melanoma in which SN detection decides upon whether to perform or not the lymphadenectomy), but to decide which patients would benefit from adjuvant CT.

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.

Usefulness of histological superstudy of sentinel node detected with radioisotope in colon cancer

INTRODUCTION

Adjuvant chemotherapy (CT) significally reduces the rate of relapse in +pN (stage III) colon cancer and in some pN0 (stage II) with risk factors such as pT4, vascular invasion V1, perineural invasion Pn1, and complicated tumors. However, unexpectedly, 20-30% of pN0 present a relapse in the follow-up, which may suggest that the lymph node involvement was not discovered in the conventional histological study (CS), and its finding with a superstudy (SS) could increase the number of patients who would benefit from neoadjuvant CT. It is not possible to perform this SS in every lymph node (LN) from the specimen, but it is possible in a small group of LN which are representative of the N status (definition of sentinel node SN). The aim of our work is to state the representativeness of the SN and to analyze de number of patients who are suprastaged after the SS of the SN.

MATERIAL AND METHODS

Prospective study of a series of patients who have undergone curative surgery for colon cancer, to whom we perform selective biopsy of sentinel node. Identification of SN was carried out with in vivo injection of the radiotracer, with ex vivo isolation of SN. Once the specimen is out, we take pictures of the surgical bed to rule out the presence of aberrant drainage routes, out of the routine oncological resection area. We performed the histological CS (hematoxilin-eosin stain in conventional sections) in the rest of the LN from the mesocolon. In the SN we performed the CS and a SS with hematoxilin-eosin in serial sections, immunohistochemistry (IHC) and molecular study with One Step Nucleic Acid Amplification (OSNA®). Diagnostic validity study od selective biopsy of sentinel node was carried out, defining the false negative (FN) as the negativity of the SN while other LN are positive (N+), as well as a valuation of the suprastaging due to the SS of the SN.

RESULTS

We performed lymphatic map in 72 patients, finding the SN in 62 of them (87.3%). The 9 identification failures happened in the first 17 cases. We have not found aberrant drainage routes. A total of 1.164 LN were studied in the 62 patients (18.8 LN/ patient), from which 145 are SN (2,34 SN/ patient), having found 103 positive LN with the CS and 112 positive with the SS of SN (9 +LN more in 8 patients than detected with the CS). Positivity after CS in the SN group is 17.24% (25/145), while it is 8.53% in the rest (87/1.019) (p<.001). With the CS, 50% of the patients (31/62) were pN+ (4 are N+ exclusively in the SN), and after the SS of the SN, only 1 of the 31 pN0 patients (3.2%) becomes pN1a, with a definitive 51.6% of N+ in the whole series (32 N+ in the 62 patients) (5 are N+ exclusively in the SN). Exclusively with the SS of the SN, FN rate ("-SN, +others", meaning patients who are N+ having -SN) is 54.8% (17/31). With the SS of the SN, 8 of the 62 patients (12.9%) increase their total number of +LN: apart from the patient who turns from pN0 to pN1a, suprastaging from IIA to IIIB (and therefore increasing the total number of pN+ to 32), 5 of the 17 FN in the CS turns into positive (2 change the pN subindex and one is suprastaged from IIIB to IIIC), decreasing FN to 37.5% (12/32 cases). Besides, 2 patients whose SN is already positive in the CS increase the number of +SN after the SS of the SN, therefore both changing their pN subindex and one of them suprastaging from IIIB to IIIC. In summary, 8 patients increase the total number of positive SN after the SS (8/62, 12.9%), 5 of them changing the pN subindex (5/62, 12.9%), even if only 3 of them get suprastaged (3/62, 4.8%), among them the one who turns from pN0 to pN1a.

CONCLUSION

Technique is valid and reproducible, with a high detection rate even with a high learning curve. It globally increases the number of affected LN in 12.9% of patients, having prognostic implications in 4.8% (suprastaging rate). Only 3.2% of pN0 patients in the CS turn to be +pN after the SS of the SN, with its therapeutic implications (prescription of adjuvant CT), which could be relevant when extrapolated to a big number of patients. The high FN rate (37.5%) prevents us from accepting the representativeness of SN as the global N status, but it is not clinically relevant in colon cancer, as its aim is not to avoid lymphadenectomy, which remains mandatory (opposite to breast cancer or melanoma in which SN detection decides upon whether to perform or not the lymphadenectomy), but to decide which patients would benefit from adjuvant CT.

Sentinel lymph node mapping in colon cancer using radiocolloid as a single tracer: a feasibility study

OBJECTIVE

Evaluation of the feasibility and safety of radiocolloid as a tracer for sentinel lymph node (SLN) mapping in colon cancer.

METHODS

A feasibility study was conducted in consecutive colon cancer patients who were surgically treated at our institute. During preoperative colonoscopy, radiocolloid was injected around the tumour, followed by scintigraphic imaging to identify SLNs. SLNs were identified intraoperatively by a gamma probe and postoperatively by additional ex-vivo scintigraphy of the resection specimen. All retrieved SLNs were examined by histopathological ultrastaging. Standard oncologic laparoscopic resections with lymphadenectomy were performed following the identification of SLNs in all patients.

RESULTS

Fourteen patients were included. At least one SLN was identified in 86% of patients. In one patient (7%) SLNs could be detected intraoperatively. In 83% of patients, the SLNs accurately reflected the tumour status of the remaining lymph nodes. Aberrant lymphatic drainage was preoperatively identified in one patient (7%), but this could not be confirmed intraoperatively. Sensitivity was 67% and the false-negative rate was 33%. Seventeen per cent of patients were upstaged because of SLN micrometastases.

CONCLUSION

SLN mapping in colon cancer using radiocolloid as a single tracer is feasible and safe. However, it was difficult to identify SLNs intraoperatively because of high radioactivity at the injection site. Furthermore, the protocol is labour intensive, especially because of the additional colonoscopic tracer injection. Sensitivity is not better than when blue dye is used, and aberrant lymphatic drainage patterns are scarce. Therefore, this technique is not preferred for SLN mapping in colon cancer.

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.

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

PURPOSE

Controversy exists over the utility of sentinel lymph node mapping in the treatment of rectal cancer. The purpose of this study was to evaluate the use of ex vivo sentinel lymph node mapping in the setting of proctectomy for rectal cancer, with and without multilevel sectioning and immunohistochemistry.

METHODS

A prospective phase 2 clinical study of subjects undergoing proctectomy for rectal cancer from 2003 to 2008 was conducted. Sentinel lymph node mapping was performed with ex vivo injection of isosulfan blue. Sentinel lymph nodes were examined by hematoxylin and eosin evaluation, and when the results were negative, they were examined by multilevel sectioning and immunohistochemistry.

RESULTS

The study population consisted of 58 subjects; 88% received neoadjuvant therapy. Tumors were downstaged in 25 (49%) subjects receiving neoadjuvant therapy, 24% were clinical complete responders, and 20% were pathologic complete responders. The mean total lymph node harvest was 12.1 nodes per patient. Twenty-five subjects had positive nodal disease on final pathology. The sentinel lymph node detection rate was 85%, with a mean sentinel lymph node harvest of 2.2 nodes per subject. Fifteen (26%) subjects had sentinel lymph node nodal metastasis on routine hematoxylin and eosin examination. Neither multilevel sectioning nor immunohistochemistry evaluation improved detection of sentinel lymph node positivity. The accuracy of sentinel lymph node mapping was 71%, the sensitivity was 53%, the negative predictive value was 79%, and the false negative rate was 47%. Seven subjects were determined to have nodal disease only in the sentinel lymph node.

CONCLUSION

Ex vivo sentinel lymph node mapping is feasible after proctectomy for rectal cancer but did not improve staging. Neither multilevel sectioning nor immunohistochemistry improved the sensitivity of sentinel lymph node mapping.

Comparison of ex vivo and in vivo injection of blue dye in sentinel lymph node mapping for colorectal cancer

BACKGROUND

The technique of sentinel lymph node (SLN) mapping in patients with colorectal cancer varies between reports, and the optimal method has not been established. The purpose of this study was to determine the optimal injection technique for SLN mapping.

METHODS

Sixty-nine consecutive patients who underwent curative surgery for colorectal cancer were enrolled. The SLNs was identified intraoperatively by subserosal blue dye injection (in vivo) or by submucosal injection after standard colectomy (ex vivo). If negative by conventional hematoxylin and eosin staining analysis, all lymph nodes, SLNs and non-SLNs, were subjected to further analysis by multi-level section and immunohistochemical examination.

RESULTS

The in vivo and ex vivo injected groups were similar in demographic character, tumor size, and histological grade. The mean number of SLNs identified was 2.3 in the in vivo group and 2.6 in the ex vivo group (p = 0.192). The detection rate of SLNs by blue dye injection was somewhat higher in the ex vivo group than in the in vivo group: 90.6 vs. 81.1% (p = 0.219). The false-negative rate was 23.5% for the in vivo group and 13.3% for the ex vivo group (p = 0.392). The upstaging rate, which was 18.5% overall, was similar in both groups (p = 0.538).

CONCLUSIONS

These findings suggest that ex vivo blue dye injection is an effective alternative to in vivo injection for identifying SLNs in patients with colorectal cancer. Because of its simplicity and applicability in routine clinical settings, further investigation of the ex vivo mapping technique is warranted.

A comprehensive overview of radioguided surgery using gamma detection probe technology

The concept of radioguided surgery, which was first developed some 60 years ago, involves the use of a radiation detection probe system for the intraoperative detection of radionuclides. The use of gamma detection probe technology in radioguided surgery has tremendously expanded and has evolved into what is now considered an established discipline within the practice of surgery, revolutionizing the surgical management of many malignancies, including breast cancer, melanoma, and colorectal cancer, as well as the surgical management of parathyroid disease. The impact of radioguided surgery on the surgical management of cancer patients includes providing vital and real-time information to the surgeon regarding the location and extent of disease, as well as regarding the assessment of surgical resection margins. Additionally, it has allowed the surgeon to minimize the surgical invasiveness of many diagnostic and therapeutic procedures, while still maintaining maximum benefit to the cancer patient. In the current review, we have attempted to comprehensively evaluate the history, technical aspects, and clinical applications of radioguided surgery using gamma detection probe technology.

Lymph node evaluation in early-stage colon cancer

Accurate nodal staging is of crucial importance in patients with nonmetastatic colon cancer, because it affects patient prognosis and delivery of adjuvant chemotherapy. In this article, we review the role of 2 controversial aspects of lymph node staging in colon cancer: the number of lymph nodes evaluated and sentinel lymph node (SLN) biopsy. Although it is clear that the number of lymph nodes assessed correlates with patient survival, the underlying mechanisms are far more uncertain, and thus, more research is warranted to determine whether interventions to increase nodal assessment will lead to improved patient outcomes. Sentinel lymph node biopsy does not appear to have the same advantages in the treatment of patients with colon cancer as in the treatment of patients with breast cancer or melanoma. Also, it might not improve colon cancer staging above standard pathology, and should be restricted to use in research settings.

Technique and clinical consequences of sentinel lymph node biopsy in colorectal cancer

Sentinel lymph node biopsy (SLNB) in colorectal cancer (CRC) is a controversial issue. Different detection techniques, various protocols for the histopathological work-up of the SLN and a greatly differing experience between the investigators make the comparison of the available studies problematic. Nevertheless, it is clear, that the successful clinical application of SLNB in breast cancer and melanoma cannot simply be transferred into colorectal cancer treatment. In this paper we try to define the current status of clinical application of this technique in CRC by means of a literature review and our own experience. Moreover, the background and the potential clinical implications of additionally small tumor deposits in the SLN (so-called "upstaging") is critically reviewed. Summarizing the results, it is clear, that the value of SLNB in CRC is still unclear. If current techniques are to be applied outside a study protocol and no patient selection is performed the correct identification of macrometastases needs further investigation. Although still under debate, there is otherwise growing evidence, that -at least if RT-PCR-techniques are used- the detection of small tumor deposits in the SLN may be of prognostic and therefore clinical value. Future studies should focus on two subjects: First, alternative detection techniques and careful patient selection may clarify, if an improvement of the sensitivity to detect macrometastases is feasible. Second, large prospective trials using a standardized histopathological lymph node assessment should compare SLN and Non-SLN for its incidence to bear small tumor deposits. If SLNB proves to be sensitive, the prognostic and predictive value of these additional findings should be clarified.

Management of early rectal cancer

BACKGROUND

Early rectal cancer (ERC) is adenocarcinoma that has invaded into, but not extended beyond, the submucosa of the rectum (that is a T1 tumour). Local excision is curative for low-risk ERCs but for high-risk cancers such management is controversial.

METHODS

This review is based on published literature obtained by searching the PubMed and Cochrane databases, and the bibliographies of extracted articles.

RESULTS AND CONCLUSION

ERC presents as a focus of malignancy within an adenoma, as a polyp, or as a small ulcerating adenocarcinoma. Preoperative staging relies on endorectal ultrasonography and magnetic resonance imaging. Pathological staging uses the Haggitt and Kikuchi classifications for adenocarcinoma in pedunculated and sessile polyps respectively. Lymph node metastases increase with the Kikuchi level, with a 1-3 per cent risk for submucosal layer (Sm) 1, 8 per cent for Sm2 and 23 per cent for Sm3 lesions. Low-risk ERCs may be treated endoscopically or by a transanal procedure. Transanal excision or transanal endoscopic microsurgery may be inadequate for high-risk ERCs and adjuvant chemoradiotherapy may be appropriate. There is a low rate of recurrence after local surgery for low-risk ERCs but this increases to up to 29 per cent for high-risk cancers.

Lymphoscintigraphic localization of sentinel node in early colorectal cancer: results of a monocentric study

BACKGROUND AND OBJECTIVES

Evaluation of the feasibility of the sentinel node technique in early colorectal neoplasms and its overall accuracy in predicting nodal metastases.

METHODS

Thirty-five patients with colon or rectal lesions or degenerate polyps not radically excised by endoscopy were included. Lymphatic mapping was performed with 99mTc labeled albumin colloid injected submucosally by an endoscopic route the afternoon before the surgical procedure. The day of the intervention, 2.5% patent blue V dye (S.A.L.F: Italy) was injected circumferentially around the tumor. A hand held gamma detecting probe (Scintiprobe m100, Pol-Hi-Tech, Italy) was employed to detect "hot" nodes, in vivo and ex vivo. All sentinel nodes were embedded separately for haematoxylin and eosin staining. No IHC or PCR techniques were employed.

RESULTS

Sentinel lymph nodes (SLN) were successfully identified in 35 out of 35 patients. Concordance between SLN and nodal status was observed in 32 out of 35 cases (91.4%); four patients (11.4%) were upstaged. Three skip nodal metastases were observed (false-negative rate: 8.5%).

CONCLUSIONS

The sentinel node technique with blue dye and radiotracer seems valuable in early colorectal cancers detected by screening programs: a good organization and a learning curve are needed, as further multicentric studies.

Sentinel lymph node biopsy for gastrointestinal cancers

Sentinel lymph node biopsy (SLNB) in gastrointestinal-(GI)-tract cancer is not yet of clinical relevance. Nevertheless, the results in the upper GI-tract promise to be helpful to individualize the indication for surgical therapy. SLNB in colon cancer still fails to show high validity to predict the nodal status, but may be helpful to clarify the prognostic role of micrometastases/isolated tumor cells. In anal cancer SLNB is able to guide the indication for groin irradiation.

Is sentinel lymph node mapping in colorectal cancer a future prognostic factor? A meta-analysis

The diagnostic value of sentinel lymph node mapping (SLNM) in patients with colorectal cancer (CRC) is controversial. Prognostic factors for CRC must be detected to improve its treatment. A PubMed query (key words: colorectal cancer, sentinel node) provided 182 studies on the sentinel lymph node (SLN) for CRC, the abstracts of which were reviewed. Altogether, 48 studies dealing with the diagnostic value of SLNM were selected from PubMed, and 6 other studies were retrieved from reviews. We compared the diagnostic value of SLNM with that of conventional histopathologic examination. We used the diagnostic accuracy odds ratio (DAOR) method. Because of significant heterogeneity, we chose the random effect model (Der Simonian and Laird). Statistics were performed on 33 studies, including 1794 patients (1201 colon and 332 rectum cancers). The mean SLNM failure rate was 10%. The global sensitivity and specificity of the SLNM were, respectively, 70% and 81%. The pooled DAOR was 10.7 (95% confidence interval 7.0-16.5). That means that a patient whose SLN is invaded has 10.7 times more risk to be node-positive than an SLN-negative patient. Lymphatic mapping appears to be readily applicable to CRC. One of the main reasons for the heterogeneity is the performance of the SLNM by Saha et al., whose data had better sensitivity (90%) than those in other studies. The SLNM technique should be better standardized in future studies. Understanding the cause of false-negative SLNs (9%) is a major issue to resolve before routinely using this technique in CRC management. The prognostic implication of micrometastases found in SLNs requires further evaluation.

Sentinel lymph node mapping in colon cancer: current status

BACKGROUND

The primary role of sentinel lymph node (SLN) mapping in colon cancer is to increase the accuracy of nodal staging by identifying those lymph nodes with the greatest potential for harbouring metastatic disease. Ultrastaging techniques aim to identify the otherwise undetected metastases. Until now, no consensus exists as to the most optimal procedure in patients with colon cancer.

METHODS

A systematic literature search on the value of different SLN mapping techniques in patients with colon cancer was performed using the electronic search engine PubMed. Prospective studies published before 1 December 2005 were included and further articles were selected by cross-referencing. The results of different techniques using either blue dye or radiocolloid, were investigated.

RESULTS

The literature search yielded 17 relevant articles. SLN mapping using blue dye was described in 15 studies. Two studies reported the results of SLN mapping using a combination of blue dye and radiocolloid. The reported results on identification rate varied between 71 and 100%. Accuracy rates were between 78 and 100%, sensitivity rates between 25 and 100% and true upstaging rates between 0 and 26%. The results were not affected by the addition of radiocolloid to blue dye.

CONCLUSIONS

Sentinel lymph node mapping in patients with colon cancer remains an experimental procedure with varying results. Further evaluation may lead to a standardized technique that offers the potential for significant upstaging of stage II patients. This may have important implications as to tailor adjuvant chemotherapeutic regimens in these patients.

Current status of sentinel lymph node navigation surgery in breast and gastrointestinal tract

Sentinel lymph node biopsy (SLNB) has been developed as a new diagnostic and therapeutic modality in melanoma and breast cancer surgery. The purpose of the SLNB include preventing the operative morbidity and improving the pathologic stage by focusing on fewer lymph nodes using immunocytochemic and molecular technology has almost achieved in breast cancer surgery. The prognostic meaning of immunocytochemically detected micrometastases is also evaluating in the SLN and bone marrow aspirates of women with early-stage breast cancer. SLNB using available techniques have suggested that the lymphatic drainage of the gastrointestinal tract is much more complicated than other sites, skip metastasis being rather frequent because of an aberrant lymphatic drainage outside of the basin exist. At the moment, the available data does not justify reduced extent of lymphadenectomy, but provides strong evidence for an improvement in tumor staging on the basis of SLNB. Two large scale prospective multi-center trials concerning feasibility of gamma-probe and dye detection for gastric cancer are ongoing in Japan. Recent studies have shown favorable results for identification of SLN in esophageal cancer. CT lymphography with endoscopic mucosal injection of iopamidol was applicable for SLN navigation of superficial esophageal cancer. The aim of surgical treatment is complete resection of the tumor-infiltrated organ including the regional lymph nodes. Accurate detection of SLN can achieve a selection of a more sophisticated tailor made approach. The patient can make a individualized choice from a broader spectrum of therapeutic options including endoscopic, laparoscopic or laparoscopy-assisted surgery, modified radical surgery, and typical radical surgery with lymph node dissection. Ultrastaging by detecting micrometastasis at the molecular level and the choice of an adequate treatment improve the postoperative quality of life and survival. However these issues require further investigation.

Morphological characteristics of lateral pelvic lymph nodes in rectal carcinoma

AIM

Macroscopic and imaging indicators for lymph node metastasis have been documented not in lateral pelvic lymph nodes but in mesorectal lymph nodes in patients with rectal carcinoma. We conducted this study to uncover morphological characteristics of lateral pelvic lymph nodes in patients with rectal carcinoma.

MATERIALS AND METHODS

Fifty-eight patients with locally advanced rectal carcinoma who had total mesorectal excision and lateral pelvic lymph node dissection were studied. Total number of lateral pelvic lymph nodes evaluated was 462, with 538 mesorectal lymph nodes being used for comparison. Factors of lymph nodes evaluated were size (long- and short-axes diameters), shape (ovoid and irregular), and heterogeneity of internal structure. Receiver operating characteristic (ROC) curve analysis was used to compare the diagnostic accuracy of each factor.

RESULTS

Lateral pelvic lymph node at non-metastatic status appeared to be longer (4.5 vs 3.5 mm) and thinner (2.2 vs 2.6 mm) than mesorectal lymph nodes. ROC curve analysis, for discriminating non-metastatic and metastatic lateral pelvic lymph nodes, revealed that a short-axis diameter appeared to be the most prominent factor with highest area under curve (0.907) and was more reliable than either long-axis diameter (0.811) or shape (0.527) other than internal structure (1.00). A short-axis diameter was an independent risk factor for metastasis by multivariate analysis with an odds ratio of 1.29 (p < 0.0001, 95% confident interval, 1.22-1.36). The most reliable cut-off value was 4 mm with 96% of sensitivity, 68% of specificity, and 82% of overall accuracy.

CONCLUSION

Lateral pelvic lymph nodes tended to be longer and thinner than mesorectal lymph nodes at non-metastatic status. A short-axis diameter of 4 mm or larger was the prominent indicator of metastasis in lateral pelvic lymph nodes.

Preliminary Study on Radioguided Sentinel Node Identification in Colon Cancer

The purpose of this study was to prove the prognostic value of the sentinel node (SN) in colon tumors, and to validate radioguided surgery in identifying the SN. Nodal metastases are a strong prognostic factor in patients operated on for colon or rectal cancer, decreasing the 5-year survival rate by approximately 20 per cent and dropping it to 30 per cent. Unfortunately, of 50 per cent of patients judged to be nodal disease-free at surgery, about 20 to 30 per cent will die from a local tumor relapse or distant metastases within 5 years of diagnosis. These data suggest that other steps are needed for more precise staging of patients, and specifically, to accurately harvest and study the nodes on which to base the prognosis. Mapping lymph nodes predictive of the whole basin status, referred to as SN, may help focus the pathologist's attention on a small but representative target, and achieve correct nodal harvesting, which includes atypical drainage pathways, when present. Twenty selected patients with colon tumor were administered a subserosal, peritumoral, intraoperative injection of blue dye and 99mTc-marked colloidal particles. The SN was identified visually and with a handheld gamma probe and was subsequently stitch-labeled. The operation was then conducted after standard surgical procedures, and the required lymphadenectomy was performed. Later, the probe was used to confirm radioactivity in the excised specimen and the absence of radioactivity in the operative field after resection; the purpose of the latter was to exclude the presence of aberrant routes of lymphatic drainage. The labeled SN were stained with hematoxylin and eosin and, in case of negative findings, cytokeratin immunostaining was performed. The remaining resected nodes were stained with hematoxylin and eosin. The probe identification of SN was 95 per cent overall (19/20); in 13 patients, a single SN was labeled, and two were labeled in six patients, harvesting 25 SN. In the 19 patients in whom a radio-emitting SN was labeled, we recorded only one false-negative; in one case, a micrometastasis in the SN was the only extracolonic site. The blue dye identified the SN in 14 cases; in some of them, the number of nodes was overestimated (five single, seven double, and two triple SN) in comparison with the radioisotope, but at least one of the dyed nodes was also radioemitting. SN identification in colon cancers is a safe, fast, and easy procedure for ultrastaging the nodal basin. The technique involves a relatively flat learning curve and could become standard care for identifying the presence of nodal micrometastases at a low cost, thereby also making it affordable at small health centers.

Surgical treatment of rectal cancer: radical resection

Currently, surgery is the only potentially curative treatment modality for rectal cancer. The major goals of surgery for rectal cancer are to optimize oncologic outcome and maintain anorectal and genitourinary function. This article reviews the surgical management of primary rectal cancer and discusses major surgical considerations in the treatment of this disease.

The feasibility and reliability of sentinel node mapping in colorectal cancer

AIMS

Sentinel node mapping (SNM) has been introduced in colorectal cancer (CRC) to improve staging by facilitating occult tumour cell (OTC) assessment in lymph nodes that are most likely to be tumour-positive. In this paper, studies on the feasibility and reliability of SNM in CRC are reviewed.

METHODS

A literature search was conducted in the National Library of Medicine by using the keywords colonic, rectal, colorectal, neoplasm, adenocarcinoma, cancer and sentinel. Additional articles were identified by cross-referencing from papers retrieved in the initial search.

RESULTS

There is a large variation in identification rates and false-negative rates mainly due to the learning curve effect, differences in SNM technique and tumour stage.

CONCLUSIONS

We conclude that SNM in CRC is technically feasible. Standardization of SNM procedures is mandatory to resolve the debate on the reliability of sentinel node status for predicting the tumour status of all lymph nodes. Only then can adjuvant treatment of patients upstaged by OTC detection in sentinel nodes be justified.

Is there any role for sentinel node mapping in colorectal cancer staging? Personal experience and review of the literature

BACKGROUND

We explored the role of lymphatic mapping and sentinel lymphadenectomy (originally described for melanoma and breast cancer) in colon cancer. Pathologic techniques can successfully identify micrometastatic disease in lymph nodes, but they are not suitable for clinical routine use. We evaluated the role of sentinel node (SN) mapping in refining the staging of colorectal cancer.

METHODS

A total of 56 open colorectal resections were performed, and Patent Blue V dye was injected under the serosa surrounding the tumor immediately after opening the abdomen. SNs were analysed by immunohistochemistry to find micrometastatic disease. A literature search for the role of SNs in colorectal cancer was also performed.

RESULTS

We identified the SN in 100% of patients, with a mean of 2.02 SNs/patient (range 1-5). After immunohistochemical staining, we could upstage 21 out of 56 patients (37.5%), and we observed 10.7% false negative SNs (6/56 patients). Fewer than half of the articles described false negative rates of <15%, and most articles showed an upstaging rate of >5% of patients. These differences are probably the result of different sensitivities of the methods used in identifying the lymph node micrometastases.

CONCLUSIONS

SN mapping is an easy and cost-effective technique that holds promise and warrants further investigations.

Radio-guided sentinel node detection during the surgical treatment of rectal cancer

OBJECTIVE

The detection of sentinel nodes is performed in various types of malignant disease. The aim of this study was to evaluate the results of the radiodetection of sentinel nodes, based on the use of Tc-colloid, during the surgical treatment of rectal cancer.

METHODS

In 2003-2004, 42 patients (24 males and 18 females; average ages of 62.4 and 67 years, respectively) were examined during rectal carcinoma surgical procedures. Miles abdominoperineal rectal resection was performed in nine cases; 33 patients underwent low anterior rectum resection by total mesorectal excision. On the day of the operation, a transanal submucosal infiltration of colloid labelled with radioactive 99mTc was performed; infiltration was performed strictly peritumorally. After the operation, radiodetection of the surgical specimens (using a hand-held gamma probe) was performed. The areas of higher radioactivity were marked. The specimens were then examined by a histopathologist. The nodes found closest to the marked areas were considered to be 'sentinel nodes'. The results of scintigraphy and postoperative radiodetection were checked by histological examination. All the discovered lymph nodes were examined by haematoxylin and eosin staining; when this was negative, immunohistochemical examination with cytokeratin was used for the sentinel nodes.

RESULTS

In 36 of the 42 patients, the data obtained by scintigraphy and radiodetection were in agreement with histopathological proof of a sentinel node. The sensitivity of the method in this group of patients was 86% (95% confidence limits: 70.75-94.05).

CONCLUSIONS

The scintigraphic method of detection of sentinel nodes in total mesorectal excision is not therapeutic, but diagnostic, and demonstrates a high level of reliability. It can be used to indicate the nodes that should be examined to detect the presence of possible micrometastases immunohistochemically. However, this method cannot be used for all detected nodes as it is very demanding. In the evaluated group of patients, there were no intraoperative or postoperative complications caused by this diagnostic method.

Sentinel nodes are identifiable in formalin-fixed specimens after surgeon-performed ex vivo sentinel lymph node mapping in colorectal cancer

BACKGROUND

In recent years, the technique of sentinel lymph node (SLN) mapping has been applied to colorectal cancer. One aim was to ultrastage patients who were deemed node negative by routine pathologic processing but who went on to develop systemic disease. Such a group may benefit from adjuvant chemotherapy.

METHODS

With fully informed consent and ethical approval, 37 patients with primary colorectal cancer and 3 patients with large adenomas were prospectively mapped. Isosulfan blue dye (1 to 2 mL) was injected around tumors within 5 to 10 minutes of resection. After gentle massage to recreate in vivo lymph flow, specimens were placed directly into formalin. During routine pathologic analysis, all nodes were bivalved, and blue-staining nodes were noted. These later underwent multilevel step sectioning with hematoxylin and eosin and cytokeratin staining.

RESULTS

SLNs were found in 39 of 40 patients (98% sensitivity), with an average of 4.1 SLNs per patient (range, 1-8). In 14 of 16 (88% specificity) patients with nodal metastases on routine reporting, SLN status was in accordance. Focused examination of SLNs identified occult tumor deposits in 6 (29%) of 21 node-negative patients. No metastatic cells were found in SLNs draining the three adenomas.

CONCLUSIONS

The ability to identify SLNs after formalin fixation increases the ease and applicability of SLN mapping in colorectal cancer. Furthermore, the sensitivity and specificity of this simple ex vivo method for establishing regional lymph node status were directly comparable to those in previously published reports.

[Optimization of staging in colon cancer using sentinel lymph node biopsy]

Routine determination of the nodal status in colon cancer is strongly dependent on the individual quality and technique of histopathological assessment and surgical lymph node dissection. We evaluated whether sentinel lymph node biopsy (SLNB) could contribute to an improvement in staging. At least one SLN (median n=2) was detected (detection rate 84%) in each of 38 of 45 patients with primary colon cancer. Ten of these 38 were found to have lymph node metastases by HE staining (26%), six of them in the SLN. Nine of the 28 patients that were initially nodal-negative by HE revealed one micrometastasis and eight cases of isolated tumor cells by immunohistochemical (IHC) staining (32% upstaging response). Including the IHC-positive cases, 19 of the 38 patients were nodal-positive (50%), 15 of them with tumor-infiltrated SLN (overall sensitivity of SLNB 79%). Using the dye method, SLNB is clinically practicable and leads in the majority of the patients to the detection of SLN. The selective, intensified histopathological assessment of SLN identifies small tumor cell deposits in a relevant percentage of patients with little and clinically practicable effort.

Colorectal cancer

Every year, more than 945000 people develop colorectal cancer worldwide, and around 492000 patients die. This form of cancer develops sporadically, in the setting of hereditary cancer syndromes, or on the basis of inflammatory bowel diseases. Screening and prevention programmes are available for all these causes and should be more widely publicised. The adenoma-carcinoma sequence is the basis for development of colorectal cancer, and the underlying molecular changes have largely been identified. Prognosis depends on factors related to the patient, treatment, and tumour, and the expertise of the treatment team is one of the major determinants of outcome. New information on the molecular basis of this cancer have led to the development of targeted therapeutic options, which are being tested in clinical trials. Further clinical progress will largely depend on the broader implementation of multidisciplinary treatment strategies following the principles of evidence-based medicine.

Sentinel node biopsy in gastrointestinal-tract cancer

Forty three years after Gould's first description of the sentinel lymph node (SN) technique in malignant tumours of the parotid, sentinel lymph node biopsy (SLNB) has become an invaluable tool for the treatment of solid tumours. In some tumour types, it has been shown to reliably reflect the lymph node (LN) status of the tumour-draining LN basin. In melanoma and breast cancers, it has become a widely accepted element in the routine surgical management of these malignant diseases. In gastrointestinal tumours, the technique is currently under intense investigation. First reports on its application in other solid tumours like non-small cell lung cancer, thyroid carcinoma, oropharyngeal carcinoma, vulvar carcinoma, and Merkel Cell carcinoma of the skin were published more recently. In the following review, we will give a synopsis of the fundamentals of the SN concept and will then proceed to an overview of recent advances of SLNB in gastrointestinal cancers.