Infrared ray electronic endoscopy combined with indocyanine green injection for detection of sentinel nodes of patients with gastric cancer

BACKGROUND: To avoid unnecessary lymphadenectomy in patients with cancer accurate diagnosis of the sentinel lymph node (SLN) is important. METHODS: This report examined the initial clinical use of infrared ray electronic endoscopy (IREE) combined with indocyanine green (ICG) injection for SLN detection in 84 patients with gastric cancer not invading the subserosa (75 T1 N0 M0 and nine T2 N0 M0 tumours, according to tumour node metastasis classification). RESULTS: There were no adverse events after injection of ICG. At least one SLN was detected in all but one patient by both ICG injection alone and by IREE with ICG. Eleven of the 84 patients had lymph node metastasis. SLNs detected by ICG injection alone did not include metastases in four of 11 patients, whereas IREE with ICG detected SLNs containing lymph node metastases in all 11 patients. Moreover, SLNs illuminated by IREE with ICG included all metastases among the 105 regional lymph nodes in the 11 patients; no metastatic lymph nodes were identified among 154 non-SLNs. CONCLUSION: IREE combined with ICG injection may efficiently detect SLNs that contain metastases in patients with gastric cancer.     

Prostate lymphoscintigraphy and radio-guided surgery for sentinel lymph node identification in prostate cancer. Technique and results of the first 350 cases

INTRODUCTION: Having in mind the promising results of lymphoscintigraphy and intraoperative gamma probe application for the detection of sentinel lymph nodes (SLN) in malignant melanoma, breast and penis cancer, we tried to identify the SLN in prostate cancer by applying a comparable technique. MATERIALS AND METHOD: 350 patients with prostate cancer were examined after providing informed consent. The day before pelvic lymphadenectomy technetium-99m nanocolloid was transrectally injected into the prostate under ultrasound guidance. A single central application was done per prostate lobe in most cases. Activity attained 90- 400 MBq, and the total injected volume was about 2-3 ml. Hereafter, lymphoscintigraphy was carried out. Those lymph nodes having been identified as SLN by means of gamma probe detection and lymphoscintigraphy were removed intraoperatively. Later, most of the cases had different types of pelvic lymphadenectomy. SLN received serial sections and immunohistochemistry, non-SLN step sections. RESULTS: 335 patients showed at least 1 SLN in lymphoscintigraphy. 24.7% had lymph node metastases. In 2 patients, metastases in non-SLN were found without at least one SLN being affected (false-negative patient). CONCLUSION: Our experience suggests that the SLN identification is not only feasible in breast cancer and malignant melanoma, but also in prostate cancer with a comparable technique.     

Evaluation of dynamic sentinel lymph node biopsy in patients with squamous cell carcinoma of the penis and palpable inguinal nodes

OBJECTIVE

To evaluate dynamic sentinel lymph node biopsy (DSLNB) in patients with squamous cell carcinoma (SCC) of the penis and palpable inguinal lymph nodes, using inguinal lymph node dissection (ILND) as the reference standard to assess the reliability of DSLNB, as using radioscintigraphy and colloidal blue‐dye injection to locate the SLN was reported to be a useful technique to avoid ILND in men with SCC of the penis and clinically impalpable nodes.

PATIENTS AND METHODS

The study included 23 consecutive men with SCC of the penis and clinically palpable inguinal nodes treated between August 1999 and July 2006. On the day before surgery the patient had the SLN located by subcutaneous injection of 60 MBq ^99mTc‐nanocolloid 2 cm proximal to the penile tumour. The following day the patient was taken to the operating room for DSLNB, resection of the penile tumour and simultaneous ILND, if considered indicated (G2‐3 and/or T3‐4 primary tumour). During surgery 2 mL of colloidal blue dye was injected in the same area as the previous ^99mTc‐nanocolloid injection. The SLNs were located during surgery using a γ‐probe and visualization of blue dye in the node(s), which were then surgically removed. After partial or total penectomy, selected patients had ILND through a 10‐cm subinguinal incision. The primary tumour, SLNs and ILND specimens were assessed histopathologically, using haematoxylin and eosin staining only.

RESULTS

Biopsy of the primary tumour showed SCC grade 1 in six, grade 2 in 13 and grade 3 in two patients. The clinical T stage was T1 in two, T2 in seven, T3 in 13 and T4 in one. There were clinically palpable inguinal lymph nodes bilaterally in 19 and unilaterally in four men. Scintigraphy before surgery showed inguinal nodes bilaterally in 12 and unilaterally in eight patients, while there were no nodes in three. Surgery comprised partial penectomy in 14, radical penectomy in eight and circumcision alone in one patient. Simultaneous bilateral ILND was done in 15 patients. Inguinal node metastases were present in four of the 23 (17%) patients; the SLN was falsely negative in three (13%), one of whom had a small focus of cancer in the SLN that was missed on initial histopathological examination, and in two the dynamically located SLN contained no cancer, but node metastases were found in the ILND specimen.

CONCLUSION

The relatively high false‐negative rate of DSLNB indicates that it is not sufficiently reliable to replace complete ILND in men with a high suspicion of nodal metastases, i.e. a high‐grade or high‐stage primary lesion with clinically palpable inguinal nodes.     

The Progression of Melanoma Nodal Metastasis Is Dependent on Tumor Thickness of the Primary Lesion

Background: Recent results of several clinical trials using the technique of intraoperative lymphatic mapping and sentinel lymph node (SLN) biopsy confirm the validity of the concept of there being an order to the progression of melanoma nodal metastases. This report reviews the H. Lee Moffitt Cancer Center experience with this procedure, one of the largest series described to date. These data demonstrate that the involvement of the SLNs, as well as higher-echelon nodes, is directly proportional to the melanoma tumor thickness, as measured by the method of Breslow.Methods: The investigators at the H. Lee Moffitt Cancer Center retrospectively reviewed their experience using lymphatic mapping and SLN biopsies in the treatment of malignant melanoma. All eligible patients with primary malignant melanomas underwent preoperative and intraoperative mapping of the lymphatic drainage of their primary sites, along with SLN biopsies. All patients with positive SLNs underwent complete regional basin nodal dissection. For 20 consecutive patients with one positive SLN, all of the nodes from the complete lymphadenectomy were serially sectioned and examined by S-100 immunohistochemical analysis, to detect additional metastatic disease.Results: Six hundred ninety-three patients consented to undergo lymphatic mapping and SLN biopsy. The SLNs were successfully identified and collected for 688 patients, yielding a 99% success rate. One hundred patients (14.52%) showed evidence of nodal metastasis. The rates of SLN involvement for primary tumors with thicknesses of <0.76 mm, 0.76–1.0 mm, 1.0–1.5 mm, 1.5–4.0 mm, and >4.0 mm were 0%, 5.3%, 8%, 19%, and 29%, respectively. Eighty-one patients underwent complete lymph node dissection after observation of a positive SLN, and only six patients with positive SLNs demonstrated metastatic disease beyond the SLN (7.4%). The tumor thicknesses for these six patients ranged from 2.8 to 6.0 mm. No patient with a tumor thickness of <2.8 mm was found to have evidence of metastatic disease beyond the SLN in complete lymph node dissection. All 20 patients with a positive SLN for whom all of the regional nodes were serially sectioned and examined by S-100 immunohistochemical analysis failed to show additional positive nodes.Conclusions: These results suggest that regional lymph node involvement may be dependent on the thickness of the primary tumor. As the primary tumor thickness increases, so does the likelihood of involvement of SLNs and higher regional nodes in the basin beyond the positive SLNs.Presented at the 51st Annual Meeting of The Society of Surgical Oncology, San Diego, California, March 26–29, 1998.     

Sentinel-Lymphknoten-Dissektion beim malignen Melanom

INTRODUCTION: In patients with cutaneous malignant melanoma, the sentinel lymph node (SLN) reflects the histopathological features of the lymphatic basin with high accuracy. MATERIAL AND METHODS: Three hundred eighty-one melanoma patients at the Hornheide clinic with an overall follow-up of 36 months (November 1998 to October 2001) underwent sentinel lymph node dissection (SLND). RESULTS: The SLNs were successfully found in 93% of truncal melanoma ( n=136), 97% of melanoma of the extremities ( n=184), and 86% of melanoma of the head and neck region ( n=61).Of truncal midline melanomas, 84% ( n=43) showed two or more regional basins, in contrast to 18% of nonmidline melanoma ( n=93). Histopathological analysis revealed occult nodal disease in 25% of all patients. Completion lymphadenectomy revealed residual nodal disease in 8% of all patients with low risk melanoma with a tumor thickness of 0-1.5 mm (two of 26 patients with positive SLN) and in 11% of all patients with high risk melanoma with tumor thickness above 1.5 mm (eight of 70 patients with positive SLN). Tumor relapse was noted in 5% of negative SLN patients and 14% of positive SLN patients. The results of the method were false negative in 2% with a sensitivity of 98%. CONCLUSION: Sentinel lymph node dissection is a reliable and accurate method of staging regional lymph nodes for all primary tumor sites. It can localize occult metastases in unexpected lymphatic basins and provides critical indications for completion lymphadenectomy. It represents an essential method of establishing stratification criteria for future adjuvant trials. Further long-term follow-up is needed to investigate its prognostic relevance to recurrence and overall survival.     

Sentinel lymph node mapping for patients with Merkel cell carcinoma—experience of 5 years

Merkel cell carcinoma (MCC) is a rare, highly malignant carcinoma of the neuroendocrinological system (Bayrou et al., J Am Acad Dermatol 24:198–207, 1992). It is a fast-growing, aggressive tumor with a high rate of local recurrence and early metastases. A radical surgical procedure is the therapy of choice. In case of lymph node metastases, regional lymphadenectomy is mandatory. Sentinel lymph node (SLN) mapping is a standard diagnostic technique to detect micrometastases in certain patients with malignant melanoma and breast cancer. The question is, can the SLN technique provide information as a prognostic factor and can the prognosis of the MCC be improved by detecting micrometastases in SLN at an early stage?     

Sentinel node procedure in low-stage/low-grade penile carcinomas

OBJECTIVE: To optimize the indication for sentinel lymph node (SLN) biopsy according to tumour size in penile carcinoma. MATERIAL AND METHODS: This was a retrospective analysis of 23 consecutive patients (median age 65 years; range 49-85 years) with primary penile carcinoma classified according to the TNM classification as stage T1-T3 who were identified as having SLNs in the groins. SLNs were detected by means of preoperative injection of a 99mTc nanocolloid around the tumour and peroperative use of a gamma detector probe. The average tumour size was 2.9+/-1.3 cm. RESULTS: In 7/25 patients with penile carcinoma examined with the SLN method, metastases to inguinal lymph nodes could be demonstrated. Two out of three patients with primary penile carcinomas classified as T1 according to the TNM classification and tumours > 3 cm in diameter had inguinal lymph node metastases. One of the patients had a micrometastasis, which was detected by means of immunohistochemical analysis. Seven out of eight patients with penile carcinomas > 3 cm in diameter had lymph node metastases. We did not observe any major surgical complications associated with the SLN procedure. CONCLUSION: These data indicate that penile carcinomas with a diameter of >3 cm should be investigated with SLN biopsy regardless of stage. However, multicentre studies are needed in order to obtain the appropriate number of patients.     

Is completion lymphadenectomy after a positive sentinel lymph node biopsy for cutaneous melanoma always necessary?

HYPOTHESIS: Completion lymph node dissection (CLND) has usually been recommended after metastatic disease is identified in the sentinel lymph node (SLN) biopsy to eradicate further metastases in nonsentinel nodes. We hypothesized that patients with negative lymph nodes included in the initial SLN specimen have low risk of metastases in the residual draining basin and may not require CLND. DESIGN: Chart review. SETTING: University-affiliated tertiary care referral center. PATIENTS: Between January 1, 1997, and May 31, 2003, 506 consecutive patients underwent SLN biopsy for staging of primary cutaneous melanoma. INTERVENTION: The SLN biopsy identified 87 patients (17.2%) with metastatic melanoma, of whom 80 underwent CLND. RESULTS: In 28 patients, all SLNs were found to contain metastatic melanoma. Seven (25%) of these patients had additional metastases identified in the CLND specimen. In 52 patients, 1 or more SLNs did not contain metastatic melanoma. Five (10%) of these patients had additional metastases in the CLND specimen (P =.02). CONCLUSIONS: Although no evidence of metastatic melanoma was found on CLND in most patients in whom negative nodes had been removed with positive SLNs at the initial biopsy, 10% of these patients did have further metastases. This subgroup of patients (positive SLNs and negative nodes in the SLN biopsy specimen) is at significantly lower risk for further metastasis, but CLND cannot be safely omitted even for these patients.     

Parotid selective lymphadenectomy in malignant melanoma.

Malignant melanoma of the head and neck can metastasize to lymph nodes within the parotid gland. Selective lymphadenectomy is the modern method of staging regional lymph node basins in clinically localized melanoma. This procedure involves intraoperative lymphatic mapping and directed, selective removal of the first draining nodes or sentinel lymph nodes (SLNs). Historically, the assessment of parotid lymph nodes would involve a superficial parotidectomy with facial nerve dissection. Since 1993, 28 patients with localized melanoma of the head and neck have demonstrated lymphatic drainage to parotid lymph nodes on preoperative lymphoscintigraphy. The overall success rate of parotid selective lymphadenectomy is 86% (24 of 28 patients). Of the 28 patients, there were 6 early patients in whom blue dye alone was utilized intraoperatively, and the success rate is 50% (3 of 6 patients). When blue dye and radiocolloid mapping techniques are combined, the parotid selective lymphadenectomy is successful in 95% of patients (21 of 22 patients). Four of the 24 patients (17%) had metastases to the SLNs and underwent therapeutic superficial parotidectomy and/or modified radical neck dissection. After completion of the therapeutic superficial parotidectomy, 1 of the 4 patients was found to have an additional parotid (nonsentinel) node with melanoma metastases. None of the patients incurred injury to the facial nerve by parotid selective lymphadenectomy. To date, 2 of 28 patients (7%) have had regional recurrence to the parotid gland. Failure of the SLN technique may occur when blue dye alone is used, when human serum albumin (not sulfur colloid) is the radiocolloid, when prior wide excision and skin graft is present before lymphatic mapping, and when all SLNs are not retrieved. We conclude that parotid selective lymphadenectomy is a safe and reliable alternative to superficial parotidectomy for staging clinically localized melanoma of the head and neck.     

Identification and evaluation of axillary sentinel lymph nodes in patients with breast carcinoma treated with neoadjuvant chemotherapy

Sentinel lymph node (SLN) biopsy has been shown to predict axillary metastases accurately in early stage breast cancer. Some patients with locally advanced breast cancer receive preoperative (neoadjuvant) chemotherapy, which may alter lymphatic drainage and lymph node structure. In this study, we examined the feasibility and accuracy of SLN mapping in these patients and whether serial sectioning and keratin immunohistochemical (IHC) staining would improve the identification of metastases in lymph nodes with chemotherapy-induced changes. Thirty-eight patients with stage II or III breast cancer treated with neoadjuvant chemotherapy were included. In all patients, SLN biopsy was attempted, and immediately afterward, axillary lymph node dissection was performed. If the result of the SLN biopsy was negative on initial hematoxylin and eosin-stained sections, all axillary nodes were examined with three additional hematoxylin and eosin sections and one keratin IHC stain. SLNs were identified in 31 (82%) of 38 patients. The SLN accurately predicted axillary status in 28 (90%) of 31 patients (three false negatives). On examination of the original hematoxylin and eosin-stained sections, 20 patients were found to have tumor-free SLNs. With the additional sections, 4 (20%) of these 20 patients were found to have occult lymph node metastases. These metastatic foci were seen on the hematoxylin and eosin staining and keratin IHC staining. Our findings indicate that lymph node mapping in patients with breast cancer treated with neoadjuvant chemotherapy can identify the SLN, and SLN biopsy in this group accurately predicts axillary nodal status in most patients. Furthermore, serial sectioning and IHC staining aid in the identification of occult micrometastases in lymph nodes with chemotherapy-induced changes.     

How many lymph nodes are enough during sentinel lymphadenectomy for primary melanoma?

BACKGROUND: Sentinel lymph node (SLN) biopsy has been shown to reliably identify nodal metastases and the subsequent need for further surgical and adjuvant therapy in patients with cutaneous melanoma. Although SLN identification rates have improved with the addition of radioactive colloid to the blue dye technique, it remains unclear how many lymph nodes should be removed to accurately determine the histologic status of the nodal basin. The objective of this study was to determine the optimal extent of SLN biopsy in these patients. METHODS: The records of 633 consecutive patients with melanoma (765 nodal basins) whose primary treatment included SLN biopsy with the use of a combination of blue dye and technetium Tc 99 labeled sulfur colloid were reviewed. SLN biopsy consisted of the removal of all of the blue-stained nodes and all nodes with radiotracer uptake activity of at least twice background. RESULTS: SLN biopsy was successful in 765 of 772 basins (99%). A mean of 1.9 SLNs (median, 2 SLNs) per basin were excised. At least 3 SLNs were removed in 176 basins (23%). The overall histologic status of a basin was always established by the first or second SLN harvested (ie, in no patient was the third or subsequent SLN positive when 1 of the first 2 was not). Of the 124 basins containing lymphatic metastases, the SLN that contained the maximal radiotracer uptake (hottest) and/or stained blue was pathologically positive in 118 basins (95%). In only 6 of the 124 positive basins (5%) was the sole evidence of occult nodal metastases identified in an SLN that was neither blue-stained nor the hottest. All but 1 of these SLNs had counts that were at least 66% of the hottest node in the basin. CONCLUSIONS: With a combined modality approach to SLN biopsy, removal of more than 2 SLNs did not provide information that upstaged any patient with primary melanoma. Removal of additional nonblue SLN(s) that contained radioactive counts of at least twice background but lower than two thirds of the SLNs with maximal radiotracer uptake affected patient management in less than 0.2% of all cases. These findings may be helpful in minimizing the extent of surgery and perhaps in reducing the costs and resource use associated with operating room time and pathologic examination.     

Intraoperative radio-lympho-scintigraphy improves sentinel lymph node identification for patients with melanoma.

BACKGROUND: The sentinel lymph node (SLN), the first node draining the primary tumor site, has been shown to reflect the histologic features of the remainder of the lymphatic basin in patients with melanoma. Intraoperative localization of the SLN, first proposed by Morton and colleagues, has been accomplished with the use of a vital blue dye mapping technique. Technical difficulties resulting in unsuccessful explorations have occurred in up to 20% of the dissections. OBJECTIVES: The authors aimed to define the SLN using gamma detection probe mapping and to determine whether intraoperative radiolymphoscintigraphy using technetium sulfur colloid and a hand-held gamma-detecting probe could be used to improve detection of all SLNs for patients with melanoma. METHODS: To ensure that all initial nodes draining the primary site were removed at the time of selective lymphadenectomy, the authors used intraoperative radiolymphoscintigraphy to confirm the location of the SLN, which was determined initially with the preoperative lymphoscintigram and the intraoperative vital blue dye injection. PATIENT POPULATION: The patient population consisted of 106 consecutive patients who presented with cutaneous melanomas larger than 0.75 mm in all primary site locations. RESULTS: The preoperative lymphoscintigram revealed that 22 patients had more than one lymphatic basin sampled. Two hundred SLNs and 142 neighboring non-SLNs were harvested from 129 basins in 106 patients. After the skin incision was made, the mean ratio of hot spot to background activity was 8.5:1. The mean ratio of ex vivo SLN-to-non-SLN activity for 72 patients who had SLNs harvested was 135.6:1. When correlated with the vital blue dye mapping, 139 of 200 (69.5%) SLNs demonstrated blue dye staining, whereas 167 of 200 (83.5%) SLNs were hot according to radioisotope localization. With the use of both intraoperative mapping techniques, identification of the SLN was possible for 124 of the 129 (96%) basins sampled. Micrometastases were identified in SLNs of 16 of the 106 (15%) patients by routine histologic analysis. CONCLUSION: The use of intraoperative radiolymphoscintigraphy can improve the identification of all SLNs during selective lymphadenectomy.     

Regional Nodal basin control is not compromised by previous sentinel lymph node biopsy in patients with melanoma

Background Regional nodal basin control is an important goal of lymphadenectomy in the management of melanoma patients with nodal disease. The purpose of this study was to determine if previous sentinel lymph node (SLN) biopsy compromises the ultimate regional nodal control achieved by subsequent therapeutic lymph node dissection in melanoma patients with microscopic lymph node metastases. Methods A surgical melanoma database and hospital records were reviewed for 602 patients with primary cutaneous melanoma who underwent successful lymphatic mapping and SLN biopsy between 1991 and 1997. Results A total of 105 (17%) of 602 patients had histologically positive SLNs and were offered therapeutic lymphadenectomy; 101 (96%) underwent this procedure. Thirty-six patients (36%) developed recurrent melanoma at one or more sites. The median follow-up period was 30 months. Recurrence in the previously dissected nodal basin was observed in 10 patients (10%); none had recurrence at only that site. Nodal basin disease appeared after local/in-transit (n=6) or distant (n=1) failure in seven patients and, as a component of the first site of failure, simultaneously with local/in-transit (n=2) or distant (n=1) recurrence in three patients. Conclusions Nodal basin failure after lymphadenectomy in patients who underwent previous biopsy of a histologically positive SLN is primarily a function of aggressive locoregional disease rather than of contamination from previous surgery. Because regional nodal control was comparable with that in other series, we conclude that SLN biopsy with selective lymphadenectomy does not compromise regional nodal basin control. J.E.G. and R.S.B contributed equally to this study. Presented at the 52nd Annual Meeting of the Society of Surgical Oncology, Orlando, Florida, March 4–7, 1999.     

Sentinel lymph node biopsy in oral cavity squamous cell carcinoma without clinically evident metastasis

BACKGROUND: The clinically N0 neck in patients with oral SCC is commonly treated by neck dissection because the existence of metastases cannot be excluded. To determine whether unnecessary treatment could be avoided, we evaluated the feasibility of sentinel lymph node (SLN) biopsy. METHODS: Fifteen previously untreated patients with T1 or T2 oral SCC without clinically or radiologically detectable metastasis were included. A blue dye and gamma probe were used to identify SLNs. SLNs were stained with cytokeratins. All nodes in neck dissection specimens were stained using H and E. RESULTS: SLNs were identified in 14 patients by lymphoscintigraphy and in all patients when probe and dye were combined. Four neck dissection specimens contained four metastatic lymph nodes. Three of the four lymph nodes were SLN. One SLN was found to be metastatic after immunostaining. However, although there was one blue sentinel node in one neck, a metastatic non-SLN was present. CONCLUSIONS: Our results show that SLN biopsy is a promising tool for use in patients with oral SCC. However, further studies are necessary.     

Size of sentinel node metastases predicts other nodal disease and survival in malignant melanoma

BACKGROUND: A positive sentinel lymph node (SLN) biopsy is an indication for completion lymph node dissection (CLND) in malignant melanoma; however, most CLNDs are negative. We hypothesized SLN metastatic size of < or =2 mm would predict CLND status and prognosis. METHODS: We evaluated 80 consecutive patients undergoing CLND for positive SLNs over a 10-year period. Incidence of positive nonsentinel nodes and survival were compared for patients with SLN metastases < or =2 mm and >2 mm. RESULTS: Of 504 patients undergoing SLN biopsy, 49 patients had SLN deposits < or =2 mm and a 6% incidence of positive CLNDs. Five-year survival was 85%, essentially the same as negative SLN biopsies. In contrast, 31 had SLN metastases >2 mm, a 45% incidence of addition disease at CLND, and 5-year survival of 47% (P < .0001). CONCLUSION: An SLN metastatic cut point of 2 mm is an efficient predictor of CLND status and survival in malignant melanoma.     

Interval sentinel lymph nodes in melanoma

HYPOTHESIS: For patients with melanoma, interval or in-transit sentinel lymph nodes (SLNs) have the same risk for nodal metastasis as SLN in traditional (ie, cervical, axillary, and inguinal) nodal basins. DESIGN: Prospective clinical trial. SETTING: Multicenter study. PATIENTS: Eligible patients were aged 18 to 70 years with melanomas of at least 1.0-mm Breslow thickness and nodes with clinically negative findings. INTERVENTION: Sentinel lymph node biopsy was guided by preoperative lymphoscintigraphy to identify all SLNs. MAIN OUTCOME MEASURES: We evaluated interval nodal sites, including epitrochlear, popliteal, and subcutaneous or intramuscular nodes outside of traditional basins, for the presence of metastases. RESULTS: The SLNs were identified in 2332 nodal basins from 2000 patients. In 62 patients (3.1%), interval SLNs were identified. We found SLN metastases in 442 (19.5%) of 2270 conventional nodal basins and 13 (21.0%) of 62 interval sites. In 11 (84.6%) of the 13 cases in which we found an interval node that was positive for metastatic disease, it was the only site of nodal metastasis. CONCLUSIONS: Although interval SLNs are identified infrequently, they contain metastatic disease at nearly the same frequency as SLNs in cervical, axillary, and inguinal nodal basins. Positive interval SLNs are likely to be the only site of nodal metastasis. Therefore, detailed preoperative lymphoscintigraphy and meticulous intraoperative search for interval nodes should be performed.     

Technical Details of Sentinel Lymph Node Mapping in Colorectal Cancer and Its Impact on Staging

Background: Sentinel lymph node (SLN) mapping for melanoma and breast cancer has greatly enhanced the identification of micrometastases in many patients, thereby upstaging a subset of these patients. The purpose of this study was to see if SLN mapping technique could be used to identify SLNs in colorectal cancer and to assess its impact on pathological staging and treatment.Methods: At the time of surgery, 1 ml of Lymphazurin 1% was injected subserosally around the tumor without injecting into the lumen. The first to fourth blue nodes identified were considered the SLNs, which have the highest probability to contain metastases. A standard oncological resection of the bowel was then performed. Multilevel microsections of the SLNs, including a detailed pathological examination of the entire specimen, was performed.Results: SLN was successfully identified in 85 (98.8%) of 86 patients. In 85 patients, there were 1367 (16 per patient) lymph nodes examined, of which 140 (1.6 per patient) were identified as SLNs. In 53 (95%) of 56, of whom the SLNs were without metastases (negative), all other non-SLNs also were negative. In 29 (34% of 85) patients, SLNs were positive for metastases; in 14 of the 29 patients, other non-SLNs also were positive in addition to the SLNs. In the other 15 of the 29 patients (18% of 85 patients), SLNs were the only site of metastases, and all other non-SLNs were negative. In 7 patients (8.2% of 85 patients), micrometastases were identified only in 1 or 2 of the 10 sections of a single SLN. In five of seven patients, such micrometastases were detected by hematoxylin and eosin staining and immunohistochemistry; in the other two patients, it was detected only by immunohistochemistry. In patients with negative SLNs, the rate of occurrence of micrometastases in non-SLNs was 5 (0.4%) of 1184 lymph nodes.Conclusions: SLN mapping can be performed easily in colorectal cancer patients, with an accuracy of more than 95%. The identification of submicroscopic lymph node metastases by this technique may have upstaged these patients (18%) from stage I/II to stage III disease, who may then benefit from further adjuvant chemotherapy.