Estadística e Investigación Operativa

Sentinel lymph node detection in gastric cancer using a dual tracer (Superparamagnetic iron oxide and methylene blue): a prospective study with histological and OSNA validation

2026-11-05T05:08:38Z

Sentinel lymph node detection in gastric cancer using a dual tracer (Superparamagnetic iron oxide and methylene blue): a prospective study with histological and OSNA validation Escalera Pérez, Raquel; Medina-Achirica, C.; García-Molina, F.J.; Del Rio-Ignacio, J.J.; Lagares Franco, Carolina María; Estella García, Ángel; Mateo Vallejo, Francisco de Asís Gastric cancer (GC) remains an oncological challenge, with lymph node involvement being a major prognostic factor. Sentinel lymph node (SLN) mapping may improve staging and reduce morbidity. This study evaluated a dual-tracer technique (superparamagnetic iron oxide: SPIO and methylene blue) for ex vivo detection; assessed one-step nucleic acid amplification (OSNA) versus conventional histology; and applied OSNA-pooling analysis in non-SLN. Prospective study of patients undergoing curative gastrectomy with lymphadenectomy (2017–2022). SLNs were identified in fresh specimens by Sentimag® and/or macroscopic staining. Each lymph node was bisected, with one half analyzed by hematoxylin–eosin (H&E) and the other by OSNA. Non-SLN were assessed using pooled OSNA to enhance diagnostic performance. Diagnostic performance metrics and agreement (Cohen’s κ) were calculated. Survival was estimated by Kaplan–Meier. Thirty-eight patients were included (mean age 64.3 years; 58% male); 71.1% received neoadjuvant therapy. SLN detection rate was 84.2% (32/38), with 80 SLNs identified. The dual-tracer approach demonstrated high sensitivity (93.1%) and moderate specificity (44.4%), resulting in an accuracy of 81.6%. Tracer concordance was moderate (κ = 0.42; p < 0.007). OSNA showed good agreement with H&E (sensitivity 80%, specificity 87%), and better performance for micrometastases. The pooling analysis evaluated 1155 non-SLN simultaneously; this novel strategy showed good concordance with conventional histology. After a median follow-up of 53 months, OSNA and H&E status were associated with overall survival in exploratory analyses; however, these findings should be interpreted with caution given the limited sample size and ex vivo proof-of-concept design. Combining SPIO and methylene blue is technically feasible for ex vivo SLN mapping. OSNA complements histology, and its pooled use represents an innovative methodological approach. These results are preliminary and hypothesis-generating; larger prospective in vivo studies are required before clinical applicability can be evaluated. Dual-tracer sentinel node mapping in gastric cancer proved feasible and accurate. OSNA complemented histology, pooled analysis improved detection efficiency, and neoadjuvant therapy did not affect diagnostic performance.

Multicompartmental prolapse: A comparative study between clinical examination and ultrasound

2026-10-31T05:05:38Z

Multicompartmental prolapse: A comparative study between clinical examination and ultrasound García-Mejido, José Antonio; Salas Álvarez, Olaya; Bugatto González, Fernando; Fernández-Palacín, A.; Fernández Palacín, Fernando; Sainz Bueno, José Antonio Objective: The accurate diagnosis of multicompartment pelvic organ prolapse (POP) is fundamental to surgical success. This study aims to compare the diagnostic performance of transperineal ultrasound against clinical examination (pelvic organ prolapse quantification, POP-Q) for the detection of compartmental defects in patients with multicompartment POP, using assessment under spinal anesthesia as the reference standard. Method: A prospective randomized diagnostic accuracy study was designed, including 129 patients scheduled for multicompartment POP surgery. Patients were randomly assigned to undergo either a preoperative POP-Q two-dimensional transperineal ultrasound assessment. The reference standard for all patients was the intraoperative POP-Q assessment, conducted under spinal anesthesia immediately before surgery. Sensitivity, specificity, and likelihood ratios (LR) were calculated for each method and compartment. Results: Both techniques demonstrated high sensitivity for the diagnosis of cystocele (100% vs 98.3%). However, their performance varied across the other compartments. Ultrasound showed superior specificity for uterine prolapse (73.4% vs 45.4%) and rectocele (86.3% vs 66.0%) and was particularly robust in confirming enterocele (LR+ of 10.5). In turn, clinical examination had a higher sensitivity for detecting rectocele (61.5% vs 21.4%) and was highly reliable for ruling out cystocele and uterine prolapse (LR− of 0). Conclusion: Clinical examination and ultrasound are complementary in the diagnosis of prolapse. Their combined use is key to accurate surgical planning.

Robust penalty function method for an uncertain multi-time control optimization problems

2026-10-22T04:06:46Z

Robust penalty function method for an uncertain multi-time control optimization problems Jayswal, Anurag; Preeti; Arana Jiménez, Manuel This paper gives some new results on multi-time first-order PDE constrained control optimization problem in the face of data uncertainty (MCOPU). We obtain the robust sufficient optimality conditions for (MCOPU). Further, we construct an unconstrained multi-time control optimization problem (MCOPU) corresponding to (MCOPU) via absolute value penalty function method. Then, we show that the robust optimal solution to the constrained problem and a robust minimizer to the unconstrained problem are equivalent under suitable hypotheses. Moreover, we give some non-trivial examples to validate the results established in this paper

Fréchet and Gateaux gH-differentiability for interval valued functions of multiple variables

2026-10-17T04:10:34Z

Fréchet and Gateaux gH-differentiability for interval valued functions of multiple variables Stefanini, Luciano; Arana Jiménez, Manuel; Sorini, Laerte In this work we extend concepts of differentiability for Interval-Valued functions (IVfunctions) of multiple variables, based on generalized Hukuhara gH-difference. In this context, we introduce a new concept of gH-linearity and characterize the class of gHlinear IV-functions, which are fundamental for a general approach to Fréchet-type and Gateaux-type gH-differentiability of the first order. We moreover consider vector IVfunctions and outline the definition of the gH-Jacobian; by representing intervals and IV-functions in midpoint-radius notation, we establish properties and relations between pointwise, Fréchet and Gateaux gH-differentiability. Finally, higher-order differentiability and gH-Hessian matrix are considered. These intuitive concepts are mathematically and computationally easy to work with.