Analysis of micrometastatic disease in sentinel lymph nodes from resectable colon cancer: results of Cancer and Leukemia Group B Trial 80001.

PURPOSE: To determine whether sentinel lymph node (LN) sampling (SLNS) could reduce the number of nodes required to characterize micrometastatic disease (MMD) in patients with potentially curable colon cancer. PATIENTS AND METHODS: Cancer and Leukemia Group B 80001 was a study to determine whether SLNS could identify a subset of LNs that predicted the status of the nodal basin for resectable colon cancer and, therefore, could be extensively evaluated for the presence of micrometastases. Patients enrolled onto this study underwent SLNS after injection of 1% isosulfan blue, and both sentinel nodes (SNs) and non-SNs obtained during primary tumor resection were sectioned at multiple levels and stained using anti-carcinoembryonic antigen and anticytokeratin antibodies. RESULTS: Using standard histopathology, SNs failed to predict the presence of nodal disease in 13 (54%) of 24 node-positive patients. Immunostains were performed for patients whose LNs were negative by standard histopathology. Depending on the immunohistochemical criteria used to assign LN positivity, SN examination resulted in either an unacceptably high false-positive rate (20%) or a low sensitivity for detection of MMD (40%). CONCLUSION: By examining both SNs and non-SNs, this multi-institutional study showed that SNs did not accurately predict the presence of either conventionally defined nodal metastases or MMD. As a result, SLNS is not a useful technique for the study of MMD in patients with colon cancer.

Sentinel node staging of resectable colon cancer: results of a multicenter study.

OBJECTIVE AND SUMMARY BACKGROUND DATA: Sentinel lymph node (LN) sampling, a technique widely used to manage breast cancer and melanoma, seeks to select LNs that accurately predict regional node status and can be extensively examined to identify nodal metastatic disease not detected by standard histopathological staging. For patients with resectable colon cancer, improved identification of LN disease would significantly advance patient care by identifying patients likely to benefit from adjuvant therapy. This study, conducted by 25 surgeons at 13 institutions, examined whether sentinel node (SN) sampling accurately predicted LN status for patients with resectable colon cancer. METHODS: SN sampling involved peritumor injection of 1% isosulfan blue, followed by identification of all LN visualized within 10 minutes. SN sampling was performed on 79 of 91 patients enrolled, followed by multilevel sectioning (MLS) of the nodes and examination by a single study pathologist. RESULTS: By standard histopathology, 7 patients had primary disease that was either benign or not colon cancer and were therefore excluded from further studies. Of 72 colon cancer cases studied, 48 (66%) were node-negative and 24 (33%) contained nodal metastases. SNs were successfully located in 66 cases (92%), with an average of 2.1 nodes per patient. SNs were negative in 14 of 24 node-positive cases (58%). MLS revealed tumor in a SN in 1 of these cases, bringing the false-negative rate of SN examination to 54%. CONCLUSION: This multi-institutional study found that for patients with node-positive colon cancer, SN examination with MLS failed to predict nodal status in 54% of cases. We conclude that SN sampling with MLS, used alone, is unlikely to improve risk stratification for resectable colon cancer.

Nerve blocks and neuroablative surgery for chronic pancreatitis.

Surgical decompressive procedures for "large-duct" chronic pancreatitis have been notably successful in relieving pain. However, management of patients with intractable pain from "small-duct" chronic pancreatitis has been difficult, often resulting in narcotic addiction and/or malnutrition from major pancreatic resection. In view of the disappointing results from extensive pancreatic resections in these cases, denervation of pancreatic sympathetic pain afferents has been suggested as an alternative. Although denervation procedures have been attempted at multiple anatomical levels, results have unfortunately been mixed. The observed variability in results has been attributed to poor patient selection, incomplete understanding of neurophysiology of pancreatic pain, and perhaps inadequate knowledge of pancreatic neuroanatomy. At present, the preferred form of neural ablation is splanchnicectomy. However, a consistent and reliable method for identifying candidates for splanchnicectomy is critical, as it is clinically difficult to distinguish true pancreatic pain from other nociceptive conditions masquerading as pancreatic pain. Differential epidural anesthesia (DEA) is a promising, safe test for initial evaluation and patient selection, although it is not as precise as sometimes claimed. Patients responding to sympathetic block during DEA seem to be the best candidates for operative sympathetic ablation. At the moment, the optimal surgical approach to splanchnic ablation, which offers the least morbid technique, most favorable results, and an attractive risk-benefit ratio, is bilateral thoracoscopic splanchnicectomy. More experience and longer follow-up will be necessary to evaluate this approach.