Hussein, Atif

e15581 Background: Sentinel lymph node (SLN) assessment is critical in colorectal cancer (CRC) for accurate staging and determining optimal treatment strategies. The one-step nucleic acid amplification (OSNA) assay, which measures cytokeratin 19 (CK19) mRNA expression, has shown potential as a molecular diagnostic tool for the intraoperative detection of SLN metastases. This study aims to evaluate the diagnostic accuracy of OSNA for SLN metastasis in CRC. Methods: A systematic search was conducted in PubMed, Cochrane Library, and Web of Science for studies published up to December 2024. Studies reporting diagnostic accuracy metrics for OSNA in detecting SLN metastases in CRC were included. R software (version 4.0.3) with the mada package was used to compute pooled sensitivity, specificity, false-positive rates, diagnostic odds ratios (DOR), and likelihood ratios (LR), all expressed within 95% confidence intervals (CI). Results: Six studies involving 3,016 patients, of whom 363 had SLNs, were included. The pooled sensitivity of OSNA was 91% (95% CI: 84.8–94.8%), while the specificity was 95.6% (95% CI: 91.7–97.8%). The diagnostic odds ratio (DOR) was 220.59 (95% CI: 74.02–657.43). The false-positive rate was 4.4% (95% CI: 2.2–8.3%). The positive likelihood ratio (LR+) was 20.8 (95% CI: 10.5–41.2), and the negative likelihood ratio (LR−) was 0.09 (95% CI: 0.05–0.16). These findings demonstrate that in diagnostic accuracy, OSNA outperforms traditional histopathological methods, such as hematoxylin and eosin (H&E) staining. Conclusions: OSNA demonstrates superior diagnostic accuracy for detecting SLN metastases in colorectal cancer, supporting its integration into clinical workflows. Its high diagnostic accuracy and rapid intraoperative turnaround time make it an invaluable resource for improving surgical decision-making. However, variability in CK19 expression across tissues and the lack of standardized assay thresholds remain challenges that require further investigation. However, its adoption has the potential to enhance staging accuracy and improve surgical and oncological outcomes, warranting broader implementation in CRC management.

e14564 Background: Recent long-term clinical trial follow-up suggests that adding Ox to a fluoropyrimidine (FP) may provide less benefit in adjuvant CC than originally believed (Tournigand JCO 2012). In addition, emerging data on tissue biomarkers such as microsatellite mismatch repair (MMR) and the 12-gene Recurrence Score (RS) suggest these assays may be helpful in better defining treatment benefit, and a new report provides evidence that RS may specifically predict the value of Ox (O'Connell ASCO 2012). In view of these developments we sought to document current use of adjuvant chemotherapy and physician perceptions about these decisions. Methods: U.S.-based oncologists were recruited to complete a survey and contribute treatment data for their last three patients (pts) with stage II disease and last pt with a stage III tumor. Results: 25 gastrointestinal cancer clinical investigators and 77 practicing oncologists participated, providing data from a total of 408 cases (92% treated since 2011). Findings from the two groups are similar and are presented in aggregate. A median of 9 and 15 pts annually were evaluated with Stage II and III tumors, respectively. Clinicians stated that they require a median of a 5% absolute reduction in relapse rate to use a FP alone and an additional 5% reduction to add Ox. Ox/FP was administered to 95 of 102 pts with stage III tumors (93%) and 85 of 306 pts with stage II disease (28%), particularly to those under age 70 or with T4 tumors (Table). MMR was evaluated in 127 pts (42%) with stage II and 20 pts (20%) with stage III disease. RS was obtained for 46 pts (15%) with stage II tumors, but only 2 pts (2%) with stage III. Conclusions: Adjuvant Ox is employed widely in spite of the fact that it may provide less benefit than many oncologists report requiring to initiate its use. However, several recent research developments may be laying the groundwork for a change in this treatment practice. [Table: see text]

479 Background: Recent long-term clinical trial follow-up suggests that adding Ox to a fluoropyrimidine (FP) may provide less benefit in adjuvant CC than originally believed (Tournigand JCO 2012). In addition, emerging data on tissue biomarkers such as microsatellite mismatch repair (MMR) and the 12-gene Recurrence Score (RS) suggest these assays may be helpful in better defining treatment benefit, and a new report provides evidence that RS may specifically predict the value of Ox. (O’Connell ASCO 2012) In view of these developments we sought to document current use of adjuvant chemotherapy and physician perceptions about these decisions. Methods: US-based oncologists were recruited to complete a survey and contribute treatment data for their last 3 patients (pts) with stage II disease and last pt with a stage III tumor. Results: 25 gastrointestinal cancer clinical investigators and 77 practicing oncologists participated, providing data from a total of 408 cases (92% treated since 2011). Findings from the 2 groups are similar and are presented in aggregate. A median of 9 and 15 pts annually were evaluated with stage II and III tumors, respectively. Clinicians stated that they require a median of a 5% absolute reduction in relapse rate to use a FP alone and an additional 5% reduction to add Ox. Ox/FP was administered to 95 of 102 pts with stage III tumors (93%) and 85 of 306 pts with stage II disease (28%), particularly to those under age 70 or with T4 tumors (Table). MMR was evaluated in 127 pts (42%) with stage II and 20 pts (20%) with stage III disease. RS was obtained for 46 pts (15%) with stage II tumors, but only 2 pts (2%) with stage III. Conclusions: Adjuvant Ox is employed extensively in spite of the fact that it may provide less benefit than many oncologists report requiring to initiate its use. However, several recent research developments may be laying the groundwork for a change in this treatment practice. [Table: see text]