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Detection of aberrant drainage after sentinel lymph node mapping and its impact on staging and change of operation in colon cancer. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.4_suppl.500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
500 Background: Sentinel lymph node mapping in colon cancer leads to the detection of micrometastasis in 15- 20% of patients leading to upstaging to stage III disease. Methods: Between 1996-2010, patients diagnosed with colon cancer were enrolled in our study and underwent SLNM at the tim of surgery plus standard oncological resection including regional LN resection. After initial years of experience, exact locations of the SLNs were mapped in relation to the primary tumor. Aberrant drainage was observed when a SLN was detected outside the standard lymph node basin. The primary objective of this analysis is to identify the frequency of detection of such aberrant drainage and the rates of positive aberrant SLNs leading to change of operation and staging. Results: Between 1996-2010, 304 patients were included in the study. The overall success rates of SLNM was 99.7%. The average number of resected LNs was 15.4. SLNM had a sensitivity, negative predictive value, accuracy and false negative rates of 85.3%, 91.7%, 94.4% and 14.6% respectively. Micrometastatic disease was detected in 15.1% of patients with node positive disease. Since 2001, 150 patients were evaluated for the presence of aberrant drainage and potential change of planned surgery. In 27 patients (18%), extended surgery was performed due to aberrant drainage. The nodal positivity in these 27 patients was 59.5%, compared to 46% in the whole group. The average number of lymph nodes in this group was 16 and the average number of SLNs was 4.3. The most common location of the primary tumor was the right colon in 55.6% of patients with aberrant drainage. In 13 patients (8.7% of case), change of operation led to the detection of positive SLNs leading to upstaging to stage IIIA/B diseases. All of these 13 patients had T3 or T4 disease. All node positive patients underwent adjuvant chemotherapy. Conclusions: SLNM in colon cancer is highly successful, sensitive and overall accurate staging procedure. It leads to detection of SLNs outside the regional lymphatic basin and change of surgery in 18% of patients. This results in higher nodal positivity and significant change of planned surgery in 8.7% of cases. No significant financial relationships to disclose.
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Biological impact of skip metastasis in patients with gastrointestinal cancers undergoing sentinel lymph node mapping. J Clin Oncol 2011. [DOI: 10.1200/jco.2011.29.4_suppl.499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
499 Background: As in melanoma and breast cancers, sentinel lymph node (SLN) mapping has been successfully used in gastrointestinal (GI) cancers (Ca) for accurate nodal staging. However, due to variable incidence of skip metastasis between different parts of the GI tract, its usefulness has been questioned for the proper staging. Hence, we aimed to evaluate the rates of skip mets, its mechanism and its biological impact in GICa. Methods: A search of English literature was performed incorporating MEDLINE and Cochrane library database using the following terms: skip metastasis, sentinel node, colorectal, gastric, and esophageal cancer. The following were excluded: comments, case reports, reviews, fewer than 40 patients in the study. The remaining were used for data extraction. Results: Between 2000-2009, 27 studies including 3,589 patients (122 esophageal, 1,185 gastric, 2,113 colon, and 169 rectal cancers) were reviewed. The overall success rate of SLNM was 95% (96.6% in esophageal, 94% in gastric, 94.3% in colon, and 95.6% in rectal cancer). Nodal positivity (positive SLN and/or non-SLN) was 34% in esophageal, 36.6% in gastric, 48.1% in colon, and 41% in rectal cancers. Rates of skip mets were 18%, 14%, 20%, and 15% in esophageal, gastric, colon, and rectal cancers respectively. In patients with skip mets, T3/T4 disease was found in 65%, 44%, and 82.5% of patients with esophageal, gastric and colon cancers respectively. The average tumor size ranged between 3 cm in gastric to 4.4 cm in colon cancer. The most common primary site for skip mets in colon cancer was the right side (50%), and in LN basin 7, 8, 9 in gastric cancer. All node positive (true and false negative) patients were staged as stage III and were treated with adjuvant chemotherapy. Conclusions: Skip mets are common in T3/T4 disease, and in larger tumors suggesting difficulty injecting the dye circumferentially. All node positive patients (true positive and skip mets) are treated with chemotherapy. Hence, skip mets has no real clinical impact on either the staging, treatment, or the outcome of the disease. No significant financial relationships to disclose.
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