Enhanced postoperative lymphatic staging of malignant melanoma by endoscopically assisted iliacoinguinal dissection.

Radical lymphadenectomy for malignant melanoma continues to be controversial. In order to reduce morbidity but preserve prognostic informations, a minimally invasive technique for the iliac part of dissection was developed. We evaluated the practicability of this intervention under routine conditions as well as its prognostic impact. A total of 106 patients with tumor cell involvement of at least one inguinal lymph node underwent open inguinal dissection combined with a minimally invasive iliac dissection. Perioperative and postoperative data on morbidity, survival, and histopathological features of the primary and the dissected specimens were collected. Histopathological data were evaluated statistically for their prognostic relevance. Of the 106 patients, 38 showed evidence of additional metastases in the resected specimen, of which 11 cases were related to the iliac portion. Detection of lymph node metastases in the specimen was significantly correlated with a poorer prognosis, while out of all factors implicated, a new prognostic factor comprising iliac tumor involvement and primary tumor ulceration showed the strongest statistical correlation with prognosis. The median dissection time was 137 min, 58 min devoted to the iliac part. Complications necessitating reoperation (n = 7) related only to the inguinal wound area. Minimally invasive iliac lymph node dissection is ready for clinical routine. The additional information obtained by the iliac dissection-in particular, in combination with primary tumor ulceration-is of important prognostic relevance. Further development of this technique performing a completely minimally invasive ilioinguinal dissection may confer additional advantages.

Current clinical status of sentinel lymph nodes in colon and proximal rectal cancer.

The postoperative report of the lymph node status of colorectal cancer in clinical practice is not a given fact. Among other factors, it is dependent on the experience and technique of the surgeon as well as the pathologist. Therefore a method like sentinel lymph node biopsy (SLNB) that identifies and provides for analysis the lymph node at highest risk for tumour involvement would be highly beneficial. Unlike in breast cancer or melanoma, SLNB is more difficult to apply in colorectal cancer and is still not ready for clinical routine application for these tumor entities. However, careful patient selection and expertise of the involved specialists can improve the quality and results of SLNB in colorectal cancer. Especially in the early stage cancer patients, SLNB may be helpful to identify the earliest signs of lymphatic dissemination (thereby upstaging the patient) or to encourage a limited extent of resection.

[Risk factors for the development of lymphatic fistula after ilioinguinal lymph node dissection before isolated limb perfusion and its potential clinical relevance]. / Risikofaktoren für Lymphfisteln nach ilioinguinaler Lymphadenektomie im Rahmen einer isolierten Extremitätenperfusion und deren potenzielle klinische Relevanz.

INTRODUCTION: After ilioinguinal radical lymph node dissection (RLND), the therapy for lymph fistulas constitutes a challenge. Risk factors for the genesis of lymph fistulas have not been sufficiently evaluated. We investigated possible factors that could influence the development of lymph fistulas in patients suffering from malignant melanoma after iloinguinal RLND. PATIENT AND METHODS: The analysis was related to patients with intransit and lymphonodal metastasised malignant melanoma of the lower limb, who underwent RLND and isolated limb perfusion (ILP). Prospective data acquisition from patients undergoing ilioinguinal RLND and ILP in a one-step approach was performed. The association of lymph fistulas to risk factors was calculated using chi-squared, linear-by-linear test and ROC curves. As possible risk factors we investigated the presence of prior surgery and diabetes mellitus type II in the medical history, chemotherapeutics, patient age and the body mass index (BMI). RESULTS: Postoperative lymph fistula occurred in 11 of 108 patients (10.2%). A significant association to lymph fistulas was found in BMI (30.2± 7.0 kg/m (2), p<0.02). Other parameters, such as prior surgery (82% vs. 71%), diabetes mellitus type II (9% vs. 11.7%), chemotherapeutics and patient age (mean 67.8 vs. 62.4 years) showed no influence. CONCLUSION: Our results indicate that the incidence of lymph fistulas after RLND and ILP of malignant melanoma of the lower limb was associated with an increased BMI. Thus, for the prevention of lymph fistulae, an initially alternative wound-closure dressing like vacuum assisted closure (V.A.C.) dressing could be of clinical relevance for obese patients.

Influence of urea fertilizer placement on nitrous oxide production from a silt loam soil.

Urea placement in band or nests has been shown to enhance N use efficiency, but limited work has been done to assess its affect on N(2)O emissions. This study compared N(2)O emissions from urea prills applied to an Amsterdam silt loam (fine-silty, mixed, superactive, frigid Typic Haplustolls) using broadcast, band, and nest placements. Experiments were conducted in greenhouse pots (200 kg N ha(-1)) and in canola (Brassica rapa L.) seeded fields using rates of 100 kg N ha(-1) (recommended) and 200 kg N ha(-1). Urea placement affected N(2)O emission patterns and cumulative N(2)O losses in the greenhouse and field. Urea prills placed in nests, and sometimes bands delayed N(2)O production with peak flux activity occurring later, and elevated emission activity being more prolonged than for broadcast applications. Differences were more obvious at 200 kg N ha(-1). These effects were attributed to a delay in urea hydrolysis and inhibition of nitrification. The fraction of applied urea-N lost as N(2)O for broadcast, band, and nest placements applied at the recommended rate averaged 2.0, 2.7, and 5.8 g N kg(-1) N, respectively. The fraction of applied urea-N lost as N(2)O averaged 2.9, 10.4, and 9.2 g N kg(-1) N for broadcast, band, and nest placements when urea-N rate was increased from 100 to 200 kg N ha(-1), respectively. Greater N(2)O production with nest placement may in part be due to significant soil NO(2)-N accumulations. Potential benefits to crop fertilizer use efficiency that come with placement of urea in concentrated zones may lead to enhanced N(2)O production.

[Diagnosis of and therapy for gastric cancer--work-flow]. / Diagnostik und Therapie des Magenkarzinoms--Workflow.

AIM: This review comments on the diagnosis and treatment of gastric cancer in the classical meaning--excluding adenocarcinoma of the -oesophagogastric junction. Algorithms of diagnosis and care with respect to tumour stage are presented. PREOPERATIVE DIAGNOSIS: Besides oesophagogastroduodenoscopy, endoscopic ultrasonography is necessary for the accurate diagnosis of T categories and as a selection criterion for neoadjuvant chemotherapy. Computed tomography is recommended for preoperative evaluation of tumours > T1, laparoscopy has become an effective stag-ing tool in T3 and T4 tumours avoiding unnecessary laparotomies and improving the detection of small -liver and peritoneal metastases. TREATMENT: Endoscopic mucosal resection and submucosal dissection are indicated in superficial cancer confined to the mucosa with special characteristics (T1 a / no ulcer / G1, 2 / Laurén intestinal / L0 / V0 / tumour size < 2 cm). In all other cases total gastrectomy or distal subtotal gastric resection are indicated, the latter in cases of tumours located in the distal two-thirds of the stomach. Standard lymphadenectomy (LAD) is the D2 LAD without distal pancreatectomy and splenectomy. The Roux-en-Y oesophagojejunostomy is still the preferred type of reconstruction. An additional pouch reconstruction should be considered in -patients with favourable prognosis, this also -applies for the preservation of the duodenal passage by jejunum interposition. Extended organ resections are only indicated in cases where a R0-resection is possible. Hepatic resection for metachronous or synchronous liver metastases is rarely advised since 50 % of patients with liver metastases show concomitant peritoneal dissemination of the disease. DISCUSSION AND CONCLUSIONS: Undergoing gastrectomy at a high-volume centre is associated with lower in-hospital mortality and a better prognosis, however, clear thresholds for case load cannot be given. Perioperative chemotherapy and postoperative chemoradiotherapy are based on the MAGIC and MacDonald trials. Perioperative chemotherapy should be performed in patients with T3 and T4 tumours with the aim to increase the likelihood of curative R0-resection by downsizing the tumour. Adjuvant postoperative chemotherapy cannot be recommended since its benefit has so far not been proven in randomised trials. In selected patients with incomplete lymph-node dissection and questionable R0-resection postoperative chemoradiotherapy may be debated.

Lymphatic mapping and sentinel lymph node biopsy in epidermoid carcinoma of the anal canal.

AIM: Although 15-25% of patients with anal cancer present with superficial inguinal lymph node metastases but the routine application of groin irradiation is controversial because of serious side effects. Inguinal sentinel lymph node biopsy (SLNB) can be used to select patients appropriately for inguinal radiation. The study evaluates the efficiency and clinical impact of SLNB. METHODS: Forty patients with anal cancer underwent 1 ml Tc(99m)-Nanocolloid injection in four sites around the tumour. Patients with inguinal radio colloid enrichment were selected for sentinel lymph node biopsy (SLNB). Lymph node status was examined by haematoxylin and eosin (H&E) as well as immunohistochemistry-staining. All SLN-positive patients were scheduled for inguinal radiation; SLN-negative patients with T1 and early T2 tumours were not scheduled for inguinal radiation. RESULTS: SLN were detected in 36/40 patients. Three common patterns of lymphatic drainage were observed: mesenterial, iliacal and inguinal. Twenty patients with inguinal SLN underwent SLN-biopsy. 6/20 patients were SLN-positive. In 10/20 patients SLNB altered the therapy plan--four patients with T1-tumours and positive SLN had additional groin irradiation, whereas 6 patients with small T2-tumors and tumour-free inguinal SLN did not undergo inguinal irradiation. CONCLUSIONS: Inguinal sentinel node biopsy in anal cancer is efficient and could assist in the decision for inguinal radiation. The validity and safety of the proposed therapeutic algorithm has to be proven by a larger, prospective study.

Presence of mature DC-Lamp+ dendritic cells in sentinel and non-sentinel lymph nodes of breast cancer patients.

AIM: Our study examined differences in the presence of mature, DC-Lamp+ DC in the SLN and non-SLN according to the extent of metastatic involvement. PATIENTS AND METHODS: Paraffin blocks of the SLN and non-SLN from patients with primary breast cancer who had undergone SLN biopsy and axillary dissection were separated into three groups: (Group A) no tumor cell involvement in the SLN and non-SLN; (Group B) isolated tumor cells or micrometastases in the SLN, and tumor cell-free non-SLN; and (Group C) macrometastases in the SLN. One section of all the SLN and non-SLN was examined with immunohistochemistry using an anti-DC-Lamp-antibody. The densest area occupied by the DC-Lamp+ cells on each slide was quantified and recorded by an electronic imaging system. In this regard, the SLN and non-SLN were compared within the patients of each group using the Wilcoxon signed rank-test (p<0.05). RESULTS: One hundred and fourteen SLN and 1258 non-SLN from 79 patients were examined. A significantly larger area was occupied by the DC-Lamp(+) cells in the SLN compared to the non-SLN in Groups A (p=0.024) and B (p=0.009), whereas no significant difference was found within Group C (p=0.107). CONCLUSIONS: This study suggests that the DC-dependent immune response is altered during the process of metastasis formation and is primarily activated before and during formation of micrometastasis.

The location of small tumor deposits in the SLN predicts Non-SLN macrometastases in breast cancer patients.

AIMS: The extent to which the location of micrometastases (MIC) or isolated tumor cells (ITC) in sentinel lymph nodes (SLNs) is correlated with the risk of downstream metastases is still unknown. This study examined this issue and compared the impact of MIC/ITC location with other established risk factors. METHODS: Paraffin slides of SLNs with MIC/ITC-involvement obtained from 68 breast cancer patients were evaluated for MIC/ITC location, lesion size, and various SLN morphologic features. These parameters, together with demographic data and primary tumor characteristics, were analyzed using univariate and multivariate analysis to determine their association with the presence of downstream macrometastases in Non-SLN. RESULTS: Eighteen of 68 patients with MIC (n=37) or ITC (n=31) had Non-SLN metastases. After multivariate analysis, the location of MIC/ITC in the SLN (parenchyma vs. sinus/vessel) had the strongest association with the presence of Non-SLN macrometastases (p<0.0001), followed by the pT-category (p=0.008). Sixteen of 18 patients with parenchymal involvement but only 2 of 31 without parenchymal involvement had Non-SLN macrometastases. The metric size of the primary tumor and the estrogen receptor status were significantly associated only on univariate analysis (p=0.041, 0.034), whereas the correlation to the size classification for tumor cell deposits (MIC vs. ITC) was not significant (p=0.077). CONCLUSIONS: The results indicate that lesion location is an important predictor of Non-SLN-macrometastases. This finding may simplify the decision for axillary treatment in patients with small tumor deposits in the SLN.

[Cutaneous melanoma]. / Kutanes Melanom.

While the incidence of cutaneous melanoma (CM) continues to rise steadily, the mortality has stabilized. Risk factors for the development of CM are UV light exposure and individual characteristics relating to pigmentation, and especially the number of melanocytic nevi. The most important prognostic factor in CM is the vertical thickness of the primary tumor in the histological specimen. Excision of the primary tumor with adequate safety margins is the treatment of choice. In the case of a tumor 1.0 mm or more thick biopsy of the sentinel node is recommended. Interferon-alpha is currently the only adjuvant therapy shown to have significant benefit in prospective randomized trials. When distant metastases are present treatment is palliative and is aimed primarily at achieving tumor remission by operative, radiological, and pharmacological means. Dacarbazine is considered the standard drug for systemic treatment. Follow-up depends on the initial tumor parameters and the current stage of the disease.

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.

Hepatic arterial Fotemustine chemotherapy in patients with liver metastases from cutaneous melanoma is as effective as in ocular melanoma.

AIM: Hepatic metastases from melanoma are associated with poor prognosis. Systemic chemotherapy and biological treatments remain unsatisfactory. This study investigated the impact of hepatic arterial chemotherapy in patients with ocular and cutaneous melanoma. METHODS: In a retrospectively analysed observational study, 36 consecutive patients with hepatic metastases from ocular or cutaneous melanoma were assigned for surgical hepatic port-catheter implantation. Fotemustine was delivered weekly for a 4-week period, followed by a 5-week rest and a maintenance period every 3 weeks until progression. Overall survival, response and toxicity were analysed and compared. RESULTS: After port-catheter implantation 30/36 patients were finally treated (18 with ocular and 12 with cutaneous melanoma). A median of 8 infusions per patient were delivered (range 3-24). 30% thrombocytopenia grade >or=3, 7% neutropenia grade >or=3 but no nausea or vomiting grade >or=3 were encountered. Nine out of 30 patients achieved partial remission, 10/30 stable disease; 11/30 patients were progressive. Median survival for all treated patients was 14 months. Partial remission and stable disease were associated with a survival advantage compared to progressive disease (19 vs. 5 months). No significant difference in survival was observed for ocular versus cutaneous melanoma. Serum LDH was a significant predictor of both response and survival. CONCLUSIONS: Hepatic arterial Fotemustine chemotherapy was well tolerated. Meaningful response and survival rates were achieved in ocular as well as cutaneous melanoma. Careful patient selection in consideration of extra-hepatic involvement is crucial for the effectiveness of this treatment. Independent from the primary melanoma site, it is debatable if patients with highly elevated serum-LDH may benefit from this approach.

Impact of patient- and disease-specific factors on SLNB in breast cancer patients. Are current guidelines justified?

BACKGROUND: The evidence on which to base guidelines for sentinel lymph node biopsy (SLNB) in breast cancer is still limited. In order to facilitate the further implementation of renewed guidelines, we evaluated patient- and disease-specific factors for their impact on the results of SLNB. MATERIALS AND METHODS: Prospective data acquisition from patients undergoing surgery for primary invasive breast cancer was performed. All patients underwent SLNB using the radiocolloid or the combined technique. The association of patient- and disease-specific factors to detection rate and false-negative rate was calculated using univariate and multivariate analyses (P < 0.05 considered as significant). Calculation of the false-negative rate was based on patients who underwent a backup axillary dissection. RESULTS: Among 455 consecutively enrolled patients, a significant inverse association to the detection rate was found for extracapsular extension of non-SLN metastases, body mass index (BMI), number of involved lymph nodes, pT category, tumor size, and age. A significant association to the false-negative rate to identify macrometastases was found for pT category, tumor size, and grading. Other factors, such as prior surgery, multicentric tumor growth, or vascular invasion, showed no influence. A cut-point analysis revealed that a tumor size of 2 cm separated the collective of patients with the highest significance in regard to the false-negative rate (9% vs. 25%). CONCLUSION: Our results indicate that SLNB can be safely used in elderly and obese patients with multicentric tumors and those having undergone prior surgery for benign breast disease. However, the method should be applied with caution in patients with tumors larger than 2 cm.

[Minimal residual tumor in gastrointestinal carcinoma. Relevance to prognosis and oncologic surgical consequences]. / Minimalresiduale Tumorerkrankung bei gastrointestinalen Karzinomen. Prognoserelevanz und onkologisch-chirurgische Konsequenzen.

Isolated tumor cells as a consequence of minimal residual disease are often not detectable by routine diagnostic procedures. However, before or after surgery, isolated tumor cells in lymph nodes, the peritoneal cavity, blood, or bone marrow can frequently be identified by immunohistochemical or molecular methods. Failure to reveal the presence of such cells results in under-staging of tumor patients and may constitute the source of unexpected tumor recurrence after radical surgery. These facts emphasize the importance of isolated tumor cells at least as a surrogate marker. The frequency of appearance of isolated tumor cells in different organ systems also depends on the type of primary tumor. Developments in modern detection methods have led to increasing sensitivity but at the expense of specificity. Isolated tumor cells demonstrate remarkable heterogeneity with respect to proliferative potential and tumorigenicity. This characteristic is also reflected by a striking variability in the expression of various genes conditioning the aforementioned biological behavior. Unfortunately there is also remarkable heterogeneity in methods used for sampling and processing patient material as well as for the enrichment and detection of isolated tumor cells. Despite the ongoing controversies concerning detection methods and biological significance of isolated tumor cells, several clinical trials providing data supporting the prognostic relevance of minimal residual disease should also be considered for gastrointestinal carcinoma. In future this finding should be integrated in the planning of trials in surgical oncology, and "minimal residual disease" should receive stronger attention as a stratification criterion in such clinical studies.

Prediction of gastric cancer lymph node status by sentinel lymph node biopsy and the Maruyama computer model.

AIMS: The extent of lymph node dissection in gastric cancer remains controversial. The Maruyama computer model and the sentinel lymph node biopsy (SLNB) are compared for their value to predict the nodal status and lead to stage-adapted surgery. METHODS: Thirty four patients with stage I-IV gastric cancer underwent both staging procedures. For SLNB, 15 patients underwent endoscopic, peri-tumoural injection of (99m)Tc-colloid, and 19 patients were injected of Patent blue V. All 'hot' or blue sentinel lymph nodes (SLNs) were separately excised and histopathologically assessed. If the SLN was negative after routine staining by H&E, it was processed completely and reanalysed after immunohistochemistry. RESULTS: At least, one SLN was detected by means of SLNB in 33/34 of the patients. The sensitivity to identify a positive nodal status was 22/33 and the specificity/positive predictive value was 10/10 and 22/22. Additional micrometastases or isolated tumour cells in the SLN led to 'upstaging' of 5/15, initially classified as nodal negative by H&E-staining. Using the Maruyama computer model, a sensitivity of 22/23 for the correct prediction of the lymph node involvement was associated with a specificity of 2/10 and a positive predictive value of 22/30. CONCLUSIONS: The clinical impact of the Maruyama computer model is limited due to low specificity and a low positive predictive value, rendering the method less useful as an indicator for individualised surgery.

[Optimization of staging in colon cancer using sentinel lymph node biopsy]. / Optimierung des Staging beim Kolonkarzinom durch Sentinel-Lymphknoten-Biopsie. Aktuelle Aspekte.

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.

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.

[Sentinel lymph node biopsy in colorectal carcinoma]. / Sentinel Lymph Node beim kolorektalen Karzinom.

Lymph node status as an important prognostic factor in colon and rectal cancer is affected by the selection and number of lymph nodes examined and by the quality of histopathological assessment. The multitude of influences is accompanied by an elevated risk of quality alterations. Sentinel lymph node biopsy (SLNB) is currently under investigation for its value in improving determination of the nodal status. Worldwide, the data of 800 to 1000 patients from about 20 relatively small studies are available that focus rather on colon than rectal cancer patients. SLNB may be of clinical value for the collective of patients that are initially node-negative after H&E staining but reveal small micrometastases or isolated tumor cells in the SLN after intensified histopathological workup. If further studies confirm that these patients benefit from adjuvant therapy, the method may have an important effect on the therapy and prognosis of colon cancer patients as well. Another potential application could be the determination of the nodal status after endoscopic excision of early cancer to avoid bowel resection and lymphonodectomy.

Sentinel lymph node biopsy progress in surgical treatment of cancer.

BACKGROUND: Forty-three years after the first description of the sentinel lymph node technique in malignant tumours of the parotid by Gould, sentinel lymph node biopsy (SNLB) has become a precious tool in the treatment of solid tumours. METHODS: In the following review we give a synopsis of the fundamentals of the sentinel lymph node concept and then proceed to an overview of recent advances of SNLB in gastrointestinal cancers. RESULTS: In some tumour entities, SNLB has been shown to reflect reliably the lymph node status of the tumour-draining lymph node basin. In melanoma and breast cancer, it became a widely accepted element of 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, such as non-small cell lung cancer, thyroid carcinoma, oropharyngeal carcinoma, vulvar carcinoma, and Merckel cell carcinoma of the skin, were published more recently. CONCLUSION: SNLB has become an important component of diagnosis and treatment of solid tumours. A growing number of publications on SNLB in gastrointestinal cancer documents the interest of many investigators in the application of this technique in this tumour entity. As long as imaging techniques like 18FDG PET or other molecular imaging techniques are limited by their spatial resolution, SNLB remains the technique of choice for lympho-nodal staging.

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

BACKGROUND: The value of sentinel node biopsy in visceral cancers is uncertain. We evaluated the feasibility and utility of radiocolloid lymphatic mapping and selective lymph node sampling in patients with rectal cancer. METHODS: Forty-eight patients with rectal cancer were investigated. Thirty-seven patients had already undergone preoperative radiochemotherapy for locally advanced tumors. Eleven patients underwent primary surgery. An endoscopic injection of 1 mL technetium 99m-sulfur-colloid into the peritumoral submucosa was performed 15 to 17 hours before surgery. Ex vivo identification of the nuclide-enriched "sentinel lymph nodes" (SLNs) was performed using a hand-held gamma-probe. The selected SLNs were then carefully and systematically examined using serial sections and immunohistochemistry. RESULTS: One or more SLNs were found in 46 of the 48 patients. The SLN detection rate was 96%. Sixteen of the 48 patients had lymph node metastases (35%). In 7 of the 16 patients, the SLNs correctly represented the nodal status. In 9 of the 16 patients, the SLN was tumor-free whereas non-SLN harbored metastases. This result represents a sensitivity of only 44%, and a false-negative rate of 56%. Further analysis showed that the method correctly predicted the nodal status only in the small subgroup of 5 patients with early cancer without preoperative radiation. In 4 patients, juxtaregional lymph nodes were excised on the basis of intraoperative radiocolloid detection, leading to upward staging in 1 patient. CONCLUSIONS: Sentinel lymph node biopsy using the radiocolloid technique with ex vivo lymph node identification shows a relatively high detection rate; however, the sensitivity in patients with locally advanced/irradiated rectal cancer is low. Nevertheless, the detection of juxtaregional metastases can improve staging in some patients. Further studies should focus on patients with early rectal cancers where the data were more promising.