Prognostic value of toll-like receptors in colorectal cancer

ABSTRACT Background and aims Colorectal cancer (CRC) is the third most commonly diagnosed cancer worldwide with 1.9 million new cases occuring globally in 2020. The prognosis of CRC patients has improved, although 30–50% of all local colon cancer patients treated develop recurrence. Biomarkers serve as diagnostic, prognostic, and predictive tools that help to detect disease without clinical symptoms, to identify early recurrence at follow-up, and to determine which patients might need more aggressive treatment. Subtyping cancers using biomarkers can enable targeted and personalized therapy. Chronic inflammation may promote cancer development and dissemination. Notably, cancer may cause both systemic and local inflammation. CRC patients with a strong systemic inflammatory response (SIR) indicated by an elevated C-reactive protein (CRP) value exhibit a worse prognosis, whereas CRC patients with high local immune cell infiltration have a better prognosis. Furthermore, CD3-positive and CD8-positive immune cells are critical in local adaptive immune responses. Toll-like receptors (TLRs) are transmembranous proteins crucial in initiating innate and adaptive immune responses after recognizing pathogen-associated or host-originating patterns. In malignancies, TLRs play pro- and antitumorigenic roles. Thus, this dissertation project aimed to evaluate the prognostic role of different TLRs in CRC. Moreover, this project aimed to assess the possible relationship between TLRs and CRP, and between local innate (TLRs) and adaptive (CD3-positive and CD8-positive cells) immune responses in CRC. Methods Expressions of TLR2, TLR4, TLR5, and TLR7 were assessed in tumor cells through the immunohistochemistry of tissue microarray (TMA) slides from 1308 CRC patients who underwent surgery in the Department of Surgery at Helsinki University Hospital, Finland, between 1982 and 2005. The associations between the immunoexpressions of TLRs in tumor cells, clinicopathological characteristics, and survival were evaluated. Among a subgroup of 549 patients surgically treated between 1998 and 2005, the relationship between tumor cell expressions of TLR2, TLR4, TLR5, and TLR7 and plasma CRP was analyzed. Blood samples were taken preoperatively, and plasma CRP levels were measured using a high-sensitivity method. Finally, the relationship between the tumor cell expressions of TLRs and the immunoexpression of CD3-positive and CD8-positive T-cell densities in the tumor and stroma in the same samples was analyzed. A CD3–CD8 tumor–stroma index was established based on the density levels of CD3-positive and CD8-positive T cells in the tumor and stroma, resembling the well-known Immunoscore®. Results Patients with a high TLR2 expression, a high TLR5 expression, and a positive TLR7 expression exhibited a better disease-specific survival (DSS) in the cohort of 1308 CRC patients. Furthermore, stage III subgroup patients with a high TLR2 immunoexpression exhibited a better outcome. A high TLR5 value served as a positive prognostic factor among younger patients, patients with a higher pT stage, patients with lymph node–negative disease, and patients with a lower WHO grade. A positive TLR7 immunoexpression emerged as a positive prognostic factor among higher pT stage and lower WHO grade patients. In a cohort of 549 CRC patients, individuals with a high preoperative CRP level exhibited a worse DSS. Among patients with a high CRP level, those with a low TLR4 immunoexpression exhibited a better prognosis. In the low CRP subgroup, patients with a high TLR2, a high TLR5, and a positive TLR7 immunoexpression exhibited a better survival. Interestingly, TLR4 immunoexpression carried no prognostic value in the entire cohort. Furthermore, none of the TLRs emerged as an independent prognostic factor in the multivariate analyses. High expressions of tumoral and stromal CD3-positive and CD8-positive T cells associated with high expressions of TLR2, TLR4, and TLR5. Among all TLR subgroups except the negative TLR7 subgroup, patients with a low CD3–CD8 tumor–stroma index exhibited a worse prognosis. Conclusions Survival was better among patients with a high expression of TLR2, TLR5, and TLR7 in the tumor cells. By contrast, survival was worse among patients with a high CRP level. Furthermore, survival was better among patients with a low CRP level and with high tumor cell expressions of TLR2, TLR5, and TLR7, as well as among patients with a high CRP level and a low TLR4 expression. High expressions of immune cell densities in the tumor and stroma associated with high expressions of TLRs in the tumor cells. Thus, TLRs may play a prognostic role either alone or in combination with CRP or immune cell densities. However, further studies are needed to more fully understand the prognostic value of TLRs in CRC.TIIVISTELMÄ (FINNISH ABSTRACT) Tausta ja tavoitteet Paksu- ja peräsuolisyöpä (kolorektaalisyöpä) on kolmanneksi tavallisin syöpätauti maailmassa ja vuonna 2020 todettiin 1,9 miljoonaa uutta tapausta. Kolorektaalisyöpää sairastavien potilaiden ennuste on parantunut, mutta silti 30–50 % hoidetuista paikallisista syövistä uusiutuu. Biomerkkiaineet ovat diagnostisia ja ennusteellisia molekyylejä, joiden avulla voi löytää aggressiivisemmasta hoidosta ja seurannasta hyötyvät potilaat. Syövän alatyypitys biomerkkiaineiden avulla voi auttaa löytämään apuvälineitä millä voi kohdentaa hoidot paremmin. Krooninen tulehdus voi edesauttaa syövän kehittymistä ja leviämistä. Osalle kolorektaalisyöpäpotilaista kehittyy syövän yhteydessä vahva systeeminen tulehdusvaste ja näillä potilailla on huonompi ennuste. C-reaktiivinen proteiini (CRP) on hyvin tunnettu systeemisen tulehdusvasteen merkkiaine. Korkea paikallinen T-imusolujen tiheys kasvainalueella taas liittyy hyvään ennusteeseen. CD3- ja CD8-positiiviset T-imusolut ovat keskeinen osa paikallista adaptiivisen immuunivastetta. Tollin kaltaiset reseptorit (TLR:t) ovat transmembraaniproteiineja, jotka tunnistavat mikrobiaalisista taudinaiheuttajista ja isännästä lähtöisin olevia tekijöitä ja ovat erittäin tärkeitä luontaisen ja adaptiivisen immuunijärjestelmän aktivoinnissa. Tollin kaltaisilla reseptoreilla on sekä syövän kehitystä edistäviä että syövän kehittymiseltä suojaavia vaikutuksia. Tämän tutkimuksen tavoitteena oli arvioida TLR:ien ennusteellista roolia kolorektaalisyövässä. Lisäksi oli tarkoitus arvioida TLR:ien ja systeemisen tulehdusvasteen yhteyttä sekä paikallisen luonnollisen (TLR:t) ja adaptiivisen (CD3- ja CD-8 positiiviset solut) immuunivasteen yhteyttä kolorektaalisyövässä. Potilaat ja menetelmät Tutkimuksessa mitattiin TLR2, TLR4, TLR5 ja TLR7 ilmentymätasoa kasvainsoluissa immunohistokemiallisen värjäyksen avulla 1308 kolorektaalisyöpäpotilaan kudosmikrosirublokeista (tissue microarray). Potilaat oli leikattu kolorektaalisyövän vuoksi Helsingin yliopistollisessa sairaalassa vuosina 1982–2005. Arvioitiin TLR:ien kudosilmentymän yhteyttä kliinispatologisiin tekijöihin ja elossaoloon. Pienemmässä 549 potilaan ryhmässä, jonka potilaat oli hoidettu vuosina 1998–2005, tukittiin TLR2, TLR4, TLR5 ja TLR7 sekä plasman CRP-tason yhteyttä. Potilailta oli otettu verinäytteitä ennen leikkausta ja plasman CRP määriteltiin herkällä mittausmenetelmällä (high-sensitivity method). Lopuksi arvioitiin samasta potilasryhmästä TLR:ien syöpäsoluilmentymän ja CD3-positiivisten ja CD8-positiivisten T-immuunisolujen tiheyden yhteyttä. Kasvainsolukon ja tukikudoksen (strooman) immuunisolujen tiheystasot laskettiin erikseen ja niiden perusteella muodostettiin CD3-CD8 kasvain-strooma indeksi (tumor-stroma index) vastaavalla tavalla kuin yleisesti tunnetussa Immunoscoressa®. Tulokset Havaitsimme 1308 kolorektaalisypää sairastavan potilaan ainaistossa, että korkeaan TLR2-, korkeaan TLR5- ja positiiviseen TLR7-ilmentymään liittyi pidempi tautispesifinen elossaolo. Levinneisyysasteen III (stage III) alaryhmän potilailla, joilla oli korkea TLR2-ilmentymä, oli parempi ennuste. Korkea TLR5 oli positiivinen ennusteellinen merkki seuraavissa alaryhmissä: nuoremmat potilaat, korkeamman kasvusyvyystason (pT) kasvain, imusolmukenegatiivinen tauti (pN0) ja hyvän erilaistumistason (gradus 1–2) syöpä. Positiivinen TLR7-ilmentymä oli positiivinen ennusteellinen merkki korkeassa pT-ryhmässä ja potilailla, joilla oli hyvän erilaistumistason syöpä. Pienemässä 549 potilaan aineistossa oli lyhyempi tautispesifinen elossaolo potilailla, joilla oli korkea leikkausta edeltävä CRP-taso,. Korkean CRP:n alaryhmässä oli huonompi ennuste niillä, joilla oli matala TLR4-ilmentymä kasvainsoluissa. Lisäksi matalan CRP:n alaryhmässä oli parempi ennuste potilailla, joilla oli korkea TLR2-, TLR5- ja TLR7-ilmentymä kasvainsoluissa. Yksikään tutkituista merkkiaineista ei noussut itsenäiseksi ennusteelliseksi tekijäksi monimuuttujaanalyysissä. Korkea CD3- ja CD8-positiivisten T-solujen ilmentymä kasvainkudoksessa ja vastaava stroomassa oli yhteydessä korkeaan TLR2-, TLR4- ja TLR5-ilmentymään kasvainsoluissa. Kaikissa TLR- alaryhmissä paitsi negatiivisessa TLR7-ryhmässä oli huonompi ennuste potilailla, joilla oli matala CD3-CD8 kasvain-strooma indeksi. Yhteenveto Tulosten perustella voi päätellä, että ennuste on parempi potilailla, joilla on korkea TLR2-, TLR5- ja TLR7-ilmentymä kasvainsoluissa. Korkea CRP on huonoon ennusteen merkki. Ennuste on parempi potilailla, joilla on matala CRP ja korkea TLR2-, TLR5- ja TLR7-ilmentymä kasvainsoluissa. Matala TLR4-ilmentymä kasvainsoluissa oli hyvän ennusteen merkki potilailla, joilla on korkea CRP-taso. T-immuunisolujen korkea tiheys kasvainkudoksessa liittyi tutkittujen TLR:ien korkeaan ilmentymään kasvainsoluissa. TLR:t voisivat toimia ennusteellisinä tekijöinä yksin tai yhdistettynä muihin merkkiaineisiin, mutta tarvitaan kuitenkin lisää tutkimuksia TLR:ien ennuisteellisen roolin selventämiseksi

Tumor-associated CD3- and CD8-positive immune cells in colorectal cancer : The additional prognostic value of CD8+-to-CD3+ ratio remains debatable

Funding Information: This study was financially supported by the Competitive State Research Financing of the Expert Responsibility of Helsinki University Hospital, Finland (CH), the Finnish Cancer Foundation (CH), Finska Läkaresällskapet (CH, CB, JK, IB-L), the Sigrid Jusélius Foundation (CH, JK), and the K Albin Johanssons Foundation (TK, IB-L). Funding Information: This study was financially supported by the Competitive State Research Financing of the Expert Responsibility of Helsinki University Hospital, Finland (CH), the Finnish Cancer Foundation (CH), Finska L?kares?llskapet (CH, CB, JK, IB-L), the Sigrid Jus?lius Foundation (CH, JK), and the K Albin Johanssons Foundation (TK, IB-L). Publisher Copyright: © 2022 - The authors. Published by IOS Press. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (CC BY-NC 4.0).BACKGROUND: A large number of infiltrating CD3- and CD8-positive inflammatory cells indicates an improved survival in colorectal cancer (CRC), similar to many other cancers. OBJECTIVE: We investigated the prognostic value of different combinations of CD3- and CD8-positive immune cells in CRC patients. METHODS: The densities of CD3- and CD8-positive cells in intratumoral and stromal tissues were evaluated from 539 patients, for which we calculated a CD3 tumor-stroma index, a CD8 tumor-stroma index, and a CD3-CD8 tumor-stroma index. RESULTS: High CD3 and CD8 tumor-stroma indices associated with stage I to II disease (p < 0.001 for both). The CD3 tumor-stroma index associated with a colonic tumor location (p = 0.006), while the CD8 tumor-stroma index associated with right-sided tumors (p < 0.001) and histological grade 3 tumors (p = 0.032). High intratumoral and stromal densities for CD3- and CD8-positive immune cells, the CD3 tumor-stroma index, the CD8 tumor-stroma index, and the CD3-CD8 tumor-stroma index all indicated a better DSS. CONCLUSIONS: The CD3 tumor-stroma index carries a strong prognostic value in CRC, and none of the CD3 and CD8 combinations we analyzed proved superior.Peer reviewe

High Tissue TLR5 Expression Predicts Better Outcomes in Colorectal Cancer Patients

Background: Colorectal cancer (CRC), the third most common cancer globally, caused 881,000 cancer deaths in 2018. Toll-like receptors (TLRs), the primary sensors of pathogen-associated molecular patterns and damage-associated molecular patterns, activate innate and adaptive immune systems and participate in the development of an inflammatory tumor microenvironment. We aimed to explore the prognostic value of TLR3, TLR5, TLR7, and TLR9 tissue expressions in CRC patients. Methods: Using immunohistochemistry, we analyzed tissue microarray samples from 825 CRC patients who underwent surgery between 1982 and 2002 at the Department of Surgery, Helsinki University Hospital, Finland. After analyzing a pilot series of 205 tissue samples, we included only TLR5 and TLR7 in the remainder of the patient series. We evaluated the associations between TLR5 and TLR7 tissue expressions, clinicopathologic variables, and survival. Using the Kaplan-Meier method, we generated survival curves, determining significance using the log-rank test. Univariate and multivariate survival analyses relied on the Cox proportional hazards model. Results: The 5-year disease-specific survival was 55.9% among TLR5-negative (95% confidence interval [CI] 50.6-61.2%) and 61.9% (95% CI 56.6-67.2%; p = 0.011, log-rank test) among TLR5-positive patients. In the Cox multivariate survival analysis adjusted for age, sex, stage, location, and grade, positive TLR5 immunoexpression (hazard ratio [HR] 0.74; 95% CI 0.59-0.92; p = 0.007) served as an independent positive prognostic factor. TLR7 immunoexpression exhibited no prognostic value in the survival analysis across the entire cohort (HR 0.97; 95% CI 0.78-1.20; p = 0.754) nor in subgroup analyses. Conclusions: We show for the first time that a high TLR5 tumor tissue expression associates with a better prognosis in CRC patients.Peer reviewe

The prognostic role of tissue TLR2 and TLR4 in colorectal cancer

Colorectal cancer (CRC), the second most common cancer globally, resulted in 881,000 deaths in 2018. Toll-like receptors (TLRs) are crucial to detecting pathogen invasion and inducing the host's immune response. This study aimed to explore the prognostic value of TLR2 and TLR4 tumor expressions in colorectal cancer patients. We studied the immunohistochemical expressions of TLR2 and TLR4 using tissue microarray specimens from 825 patients undergoing surgery in the Department of Surgery, Helsinki University Hospital, between 1982 and 2002. We assessed the relationships between TLR2 and TLR4 expressions and clinicopathological variables and patient survival. We generated survival curves using the Kaplan-Meier method, determining significance with the log-rank test. Among patients with lymph node-positive disease and no distant metastases (Dukes C), a strong TLR2 immunoactivity associated with a better prognosis (p <0.001). Among patients with local Dukes B disease, a strong TLR4 immunoactivity associated with a worse disease-specific survival (DSS; p = 0.017). In the multivariate survival analysis, moderate TLR4 immunoactivity compared with strong TLR4 immunoactivity (hazard ratio (HR) 0.66, 95% confidence interval (CI) 0.49-0.89, p = 0.007) served as an independent prognostic factor. In the multivariate analysis for the Dukes subgroups, moderate TLR2 immunoactivity (HR 2.63, 95% CI 1.56-4.44, p <0.001) compared with strong TLR2 immunoactivity served as an independent negative prognostic factor in the Dukes C subgroup. TLR2 and TLR4 might be new prognostic factors to indicate which CRC patients require adjuvant therapy and which could spare from an unnecessary follow-up, but further investigations are needed.Peer reviewe

Tumor-associated CD3- and CD8-positive immune cells in colorectal cancer: The additional prognostic value of CD8+-to-CD3+ ratio remains debatable

BackgroundA large number of infiltrating CD3- and CD8-positive inflammatory cells indicates an improved survival in colorectal cancer (CRC), similar to many other cancers.ObjectiveWe investigated the prognostic value of different combinations of CD3- and CD8-positive immune cells in CRC patients.MethodsThe densities of CD3- and CD8-positive cells in intratumoral and stromal tissues were evaluated from 539 patients, for which we calculated a CD3 tumor–stroma index, a CD8 tumor–stroma index, and a CD3–CD8 tumor–stroma index.ResultsHigh CD3 and CD8 tumor–stroma indices associated with stage I to II disease (p p = 0.006), while the CD8 tumor–stroma index associated with right-sided tumors (p p = 0.032). High intratumoral and stromal densities for CD3- and CD8-positive immune cells, the CD3 tumor–stroma index, the CD8 tumor–stroma index, and the CD3–CD8 tumor–stroma index all indicated a better DSS.ConclusionsThe CD3 tumor–stroma index carries a strong prognostic value in CRC, and none of the CD3 and CD8 combinations we analyzed proved superior.</p

Elevated tumor expression of Astroprincin (FAM171A1) is an independent marker of poor prognosis in colon cancer

Background Colon cancer (CC) is one of the most commonly diagnosed malignancies worldwide. Several biomarkers have been suggested for improved prognostic evaluation, but few have been implemented in clinical practice. There is a need for biomarkers that predict the tumor behavior in CC and allow stratification of patients that would benefit from adjuvant therapy. We recently identified and functionally characterized a previously unknown protein that we called ASTROPRINCIN (APCN) due to its abundance in astrocytes. APCN, also annotated as FAM171A1, is found in trophoblasts of early placenta. We demonstrated that high expression levels of APCN in cancer cells induced motility and ability of invasive growth in semisolid medium. Methods We screened by immunohistochemistry a tissue microarray material from the tumors of 429 CC patients with clinical follow-up in a test series and 255 CC patients in a validation series. Results We showed that low or absent APCN expression correlates with a favorable prognosis while high APCN expression was a sign of an adverse outcome. Cox uni- and multivariable analysis revealed that elevated tumor expression of APCN constitutes a robust marker of poor prognosis independent of stage, grade, patient's age, or gender. Conclusion Our findings demonstrate that APCN is a novel independent prognostic marker in CC and could potentially select patients for more intense postoperative adjuvant treatment and follow-up.Peer reviewe

Serum MMP-8 and TIMP-1 predict prognosis in colorectal cancer

Abstract Background Almost all of the extracellular matrix (ECM) components can be degraded by the endoproteinases matrix metalloproteinases (MMPs). Important regulators of MMPs, and thereby of the extracellular environment, are tissue inhibitors of metalloproteinases (TIMPs), and especially TIMP-1. Early tumor development, as well as distant metastasis, may be results of an MMP/TIMP ratio imbalance altering the ECM. MMPs are elevated in several inflammatory conditions. Our aim is to investigate the prognostic role of MMP-8, − 9, and TIMP-1 in colorectal cancer (CRC) and their relationship to inflammation. Methods We included 337 colorectal cancer patients and 47 controls undergoing surgery at Helsinki University Hospital in Finland, 1998–2011. Serum levels of MMP-8 and plasma levels of C-reactive protein (CRP) were determined with a time-resolved immunofluorometric assay (IFMA), and MMP-9 and TIMP-1 with commercial enzyme-linked immunosorbent assay (ELISA) kits. Association and correlation analyses were performed with the Mann-Whitney U, Kruskal-Wallis, and Spearman rank correlation tests. Survival curves were constructed according to the Kaplan-Meier method and compared with the log-rank test. Results Among patients with advanced disease, serum levels of MMP-8 and TIMP-1 were elevated. CRC patients with high MMP-8 (HR (hazard ratio) 1.72, 95% confidence interval (CI) 1.17–2.52, P = 0.005) and those with high TIMP-1 (HR 1.80, 95% CI 1.23–2.64, P = 0.002) had worse prognoses. MMP-9 level failed to serve as a prognostic factor. In multivariable survival analysis, Dukes stage, and low MMP-9/TIMP-1 molar ratio (HR 0.46, 95% CI 0.33–0.98, P = 0.042) were independently predicted prognosis. A weak correlation between CRP and MMP-8 (rS = 0.229, P < 0.001), and TIMP-1 (rS = 0.280, P < 0.001) was noted. Among patients showing no systemic inflammatory response, MMP-8 (HR 1.66, 95% CI 1.10–2.53, P = 0.017) and TIMP-1 (HR 1.59, 95% CI 1.05–2.42, P = 0.029) were prognostic factors. Conclusions MMP-8 and TIMP-1 in serum, but not MMP-9, identified CRC patients with bad prognosis. Among patients showing no systemic inflammatory response, MMP-8 and TIMP-1 may associate with poor prognosis

The Relationship between the Tissue Expression of TLR2, TLR4, TLR5, and TLR7 and Systemic Inflammatory Responses in Colorectal Cancer Patients

Background: Colorectal cancer (CRC) is the third most commonly diagnosed malignancy globally. CRC patients with elevated plasma C-reactive protein (CRP) levels exhibit compromised prognoses. Toll-like receptors (TLRs), activating the innate and adaptive immune systems, may contribute to pro- and antitumorigenic inflammatory responses. We aimed to identify a possible link between local and systemic inflammatory responses in CRC patients by investigating the association between tissue TLRs and plasma CRP. Methods: Tissue expressions of TLR2, TLR4, TLR5, and TLR7 were assessed using immunohistochemistry of tissue microarray slides from 549 CRC patients surgically treated between 1998 and 2005. Blood samples were drawn preoperatively, centrifuged, aliquoted, and stored at -80 degrees C until analysis. Plasma CRP was determined through high-sensitivity time-resolved immunofluorometric assay. We investigated the association of TLRs to clinicopathologic variables, plasma CRP, and survival. Results: High TLR2 expression (hazard ratio [HR] 0.59; 95% confidence interval [CI] 0.41-0.85; p = 0.005), high TLR5 expression (HR 0.60; 95% CI 0.45-0.83; p = 0.002), positive TLR7 expression (HR 0.49; 95% CI 0.33-0.72; p < 0.001), and low CRP (HR 1.48; 95% CI 1.08-2.11; p = 0.017) were associated with a better prognosis. A high TLR2 immunoexpression was associated with a better prognosis among low-CRP patients (HR 0.53; 95% CI 0.35-0.80; p = 0.002), high TLR4 expression among high-CRP patients (HR 2.04; 95% CI 1.04-4.00; p = 0.038), high TLR5 expression among low-CRP patients (HR 0.059; 95% CI 0.37-0.92; p = 0.021), and positive TLR7 expression among low-CRP patients (HR 0.53; 95% CI 0.28-1.00; p = 0.049). In multivariate analyses, no biomarkers emerged as significant independent variables. Conclusions: High tissue TLR2, TLR5, and TLR7 levels were associated with a better prognosis. Among low-CRP patients, those with high TLR2, TLR5, and TLR7 immunoexpressions exhibited a better prognosis. Among high CRP patients, a high TLR4 immunoexpression was associated with a better prognosis.Peer reviewe

Systematic reviews of observational studies of Risk of Thrombosis and Bleeding in General and Gynecologic Surgery (ROTBIGGS) : introduction and methodology

Funding Information: The Risk of Thrombosis and Bleeding in General and Gynecologic Surgery (ROTBIGGS) project was conducted by the Clinical Urology and Epidemiology (CLUE) Working Group and supported by the Academy of Finland (309387, 340957), Sigrid Jusélius Foundation and Competitive Research Funding of the Helsinki University Hospital (TYH2019321; TYH2020248). The sponsors had no role in the analysis and interpretation of the data or the manuscript preparation, review, or approval. Funding Information: KMA received a research grant from Astra Zeneca, and is consultant for Gedeon Richter, and received reimbursement for attending a scientific meeting from GSK (Tesaro Bio). RMT received reimbursement for attending a scientific meeting from Olympus. LIL, GHG, YL, RC, ALL, VJS, IEJK, PJK, RJC, RLA, KA, KMA, IB-L, MHB, JLC, SC, PJG, HAG-P, FZG, HAG, LH, MLI-K, KMJ, PKK, NK, TPK, AJK, TK, HL, AKM, BTN, TPN, CN, SMO, SP, NP, CBBR, ARR, TS, RMT, RWMV, YW, YX, LY, JH, and KAOT have no financial conflicts of interest. GHG and RC were panel members of the European Association of Urology (EAU) ad hoc Guideline on Thromboprophylaxis in Urological Surgery. KAOT was chair of the European Association of Urology (EAU) ad hoc Guideline on Thromboprophylaxis in Urological Surgery and panel member of the American Society of Hematology (ASH) Guideline Panel on Prevention of Venous Thromboembolism (VTE) in Surgical Hospitalized Patients. Publisher Copyright: © 2021, The Author(s).Background Venous thromboembolism (VTE) and bleeding are serious and potentially fatal complications of surgical procedures. Pharmacological thromboprophylaxis decreases the risk of VTE but increases the risk of major post-operative bleeding. The decision to use pharmacologic prophylaxis therefore represents a trade-off that critically depends on the incidence of VTE and bleeding in the absence of prophylaxis. These baseline risks vary widely between procedures, but their magnitude is uncertain. Systematic reviews addressing baseline risks are scarce, needed, and require innovations in methodology. Indeed, systematic summaries of these baseline risk estimates exist neither in general nor gynecologic surgery. We will fill this knowledge gap by performing a series of systematic reviews and meta-analyses of the procedure-specific and patient risk factor stratified risk estimates in general and gynecologic surgeries. Methods We will perform comprehensive literature searches for observational studies in general and gynecologic surgery reporting symptomatic VTE or bleeding estimates. Pairs of methodologically trained reviewers will independently assess the studies for eligibility, evaluate the risk of bias by using an instrument developed for this review, and extract data. We will perform meta-analyses and modeling studies to adjust the reported risk estimates for the use of thromboprophylaxis and length of follow up. We will derive the estimates of risk from the median estimates of studies rated at the lowest risk of bias. The primary outcomes are the risk estimates of symptomatic VTE and major bleeding at 4 weeks post-operatively for each procedure stratified by patient risk factors. We will apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate evidence certainty. Discussion This series of systematic reviews, modeling studies, and meta-analyses will inform clinicians and patients regarding the trade-off between VTE prevention and bleeding in general and gynecologic surgeries. Our work advances the standards in systematic reviews of surgical complications, including assessment of risk of bias, criteria for arriving at the best estimates of risk (including modeling of the timing of events and dealing with suboptimal data reporting), dealing with subgroups at higher and lower risk of bias, and use of the GRADE approach. Systematic review registration PROSPERO CRD42021234119Peer reviewe

Systematic reviews of observational studies of Risk of Thrombosis and Bleeding in General and Gynecologic Surgery (ROTBIGGS): introduction and methodology

Background: Venous thromboembolism (VTE) and bleeding are serious and potentially fatal complications of surgical procedures. Pharmacological thromboprophylaxis decreases the risk of VTE but increases the risk of major post-operative bleeding. The decision to use pharmacologic prophylaxis therefore represents a trade-off that critically depends on the incidence of VTE and bleeding in the absence of prophylaxis. These baseline risks vary widely between procedures, but their magnitude is uncertain. Systematic reviews addressing baseline risks are scarce, needed, and require innovations in methodology. Indeed, systematic summaries of these baseline risk estimates exist neither in general nor gynecologic surgery. We will fill this knowledge gap by performing a series of systematic reviews and meta-analyses of the procedure-specific and patient risk factor stratified risk estimates in general and gynecologic surgeries.Methods: We will perform comprehensive literature searches for observational studies in general and gynecologic surgery reporting symptomatic VTE or bleeding estimates. Pairs of methodologically trained reviewers will independently assess the studies for eligibility, evaluate the risk of bias by using an instrument developed for this review, and extract data. We will perform meta-analyses and modeling studies to adjust the reported risk estimates for the use of thromboprophylaxis and length of follow up. We will derive the estimates of risk from the median estimates of studies rated at the lowest risk of bias. The primary outcomes are the risk estimates of symptomatic VTE and major bleeding at 4 weeks post-operatively for each procedure stratified by patient risk factors. We will apply the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach to rate evidence certainty.Discussion: This series of systematic reviews, modeling studies, and meta-analyses will inform clinicians and patients regarding the trade-off between VTE prevention and bleeding in general and gynecologic surgeries. Our work advances the standards in systematic reviews of surgical complications, including assessment of risk of bias, criteria for arriving at the best estimates of risk (including modeling of the timing of events and dealing with suboptimal data reporting), dealing with subgroups at higher and lower risk of bias, and use of the GRADE approach.Systematic review registration: PROSPERO CRD42021234119</p