• Montes, Ana Fernández
• Pericay, Carles
• Cordero, Marta González
• Falcó, Esther
• Astorga, Beatriz González
• Páez, David
• Anton-Pascual, Beatriz
• Toledo, Débora Contreras
• Tocino, Rosario Vidal
• Morales, Pilar
• Salas, Nuria Rodríguez
• Gil-Raga, Mireia
• Santos, Cristina
• Pereyra, Fernando Aguilar
• Alonso, Vicente
• Zoilo, Juan José Reina
• Garcia-Carbonero, Rocio

Abstract

<jats:title>Abstract</jats:title><jats:sec><jats:title>Purpose</jats:title><jats:p>Clinical practice guidelines recommend that all patients with metastatic colorectal cancer (mCRC) should be tested for mismatch repair deficiency (dMMR) or microsatellite instability-high (MSI-H). We aimed to describe the dMMR/MSI-H testing practice in patients with mCRC in Spanish centers.</jats:p></jats:sec><jats:sec><jats:title>Methods</jats:title><jats:p>Multicenter, observational retrospective study that included patients newly diagnosed with mCRC or who progressed to a metastatic stage from early/localized stages.</jats:p></jats:sec><jats:sec><jats:title>Results</jats:title><jats:p>Three hundred patients were included in the study from May 2020 through May 2021, with a median age of 68 years, and two hundred twenty-five (75%) had stage IV disease at initial diagnosis; two hundred eighty-four patients received first-line treatment, and dMMR/MSI-H testing was performed in two hundred fifty-one (84%) patients. The results of the dMMR/MSI-H tests were available in 61 (24%) of 251 patients before the diagnosis of metastatic disease and in 191 (81%) of 236 evaluable patients for this outcome before the initiation of first-line treatment. Among the 244 patients who were tested for dMMR/MSI-H with IHC or PCR, 14 (6%) were MMR deficient. The most frequent type of first-line treatment was the combination of chemotherapy and biological agent, that was received by 71% and 50% of patients with MMR proficient and deficient tumors, respectively, followed by chemotherapy alone, received in over 20% of patients in each subgroup. Only 29% of dMMR/MSI-H tumors received first-line immunotherapy.</jats:p></jats:sec><jats:sec><jats:title>Conclusion</jats:title><jats:p>Our study suggests that a high proportion of patients with mCRC are currently tested for dMMR/MSI-H in tertiary hospitals across Spain. However, there is still room for improvement until universal testing is achieved.</jats:p><jats:p><jats:italic>Trial registration</jats:italic>: Not applicable.</jats:p></jats:sec>

Topics

• impedance spectroscopy
• size-exclusion chromatography