Using the full PICO model as a search tool for systematic reviews resulted in lower recall for some PICO elements.

OBJECTIVES: The use of the four-part PICO model to facilitate search strategy development for a precise answer is recommended for structuring searches for systematic reviews. Existing guidelines generally recommend that a search strategy should include the population, intervention(s), and types of study design. Consequently, comparison and outcome are not recommended as a part of the search strategy. There is evidence that comparison and particularly outcome is not represented in enough detail, but this needs to be confirmed. STUDY DESIGN AND SETTING: The present study examines the presence of PICO elements in the records in two commonly used databases for health sciences research: Embase and PubMed. We examine the field of upper GI and pancreatic diseases as well as the field of pregnancy and childbirth by extracting the included studies as well as the related PICO elements from a random selection of Cochrane reviews within these two areas. RESULTS: We find that the PICO elements C and O had a lower retrieval potential across the two Cochrane groups and databases also when combining text words and subject headings. In particular, we find a lower retrieval when searching for both primary and secondary outcomes. CONCLUSION: Our results support the existing recommendation not to search for outcomes.

Frequency of mismatch repair deficiency in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) has an ominous prognosis and there are only few treatment options. It is therefore crucial to investigate possible predictive markers that may improve the treatment of this disease. Mismatch repair (MMR) deficiency (d-MMR), meaning MMR protein loss (l-MMR) and/or microsatellite instability (MSI), is predictive of response to immunotherapy, but its frequency has to our knowledge not been elucidated in Scandinavian PDACs. Our aims were to examine the frequency of d-MMR in a Danish cohort of PDACs. We constructed multi-punch tissue microarrays (TMAs) using primary tumor tissue. Immunohistochemistry (IHC) for the DNA MMR proteins MLH1, MSH2, MSH6 and PMS2 was performed, and their expression was evaluated using a scoring system from 0 to 4. If the overall score was between 0-2 or if IHC was inconclusive for technical reasons, IHC on whole-tissue sections and MSI using PCR was performed. A final score of 0, 1-2 or 3-4 defined the tumor as l-MMR, MMR reduced (r-MMR) or MMR proficient. In total, 4/164 (2.4 %), 2/164 (1.2 %) and 3/164 (1.8 %) were l-MMR, r-MMR, or inconclusive based on IHC. MSI testing of these specimens showed that two of the four l-MMR tumors were MSI-high, while the remaining cases were microsatellite stable (MSS). In conclusion, in this study of Danish PDACss, d-MMR was found in a small proportion of the tumors. For these patients, individualized treatment using immunotherapy could be considered.