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OBJECTIVE: To describe the long-term consequences of necrotising pancreatitis, including complications, the need for interventions and the quality of life. DESIGN: Long-term follow-up of a prospective multicentre cohort of 373 necrotising pancreatitis patients (2005-2008) was performed. Patients were prospectively evaluated and received questionnaires. Readmissions (ie, for recurrent or chronic pancreatitis), interventions, pancreatic insufficiency and quality of life were compared between initial treatment groups: conservative, endoscopic/percutaneous drainage alone and necrosectomy. Associations of patient and disease characteristics during index admission with outcomes during follow-up were assessed. RESULTS: During a median follow-up of 13.5 years (range 12-15.5 years), 97/373 patients (26%) were readmitted for recurrent pancreatitis. Endoscopic or percutaneous drainage was performed in 47/373 patients (13%), of whom 21/47 patients (45%) were initially treated conservatively. Pancreatic necrosectomy or pancreatic surgery was performed in 31/373 patients (8%), without differences between treatment groups. Endocrine insufficiency (126/373 patients; 34%) and exocrine insufficiency (90/373 patients; 38%), developed less often following conservative treatment (p<0.001 and p=0.016, respectively). Quality of life scores did not differ between groups. Pancreatic gland necrosis >50% during initial admission was associated with percutaneous/endoscopic drainage (OR 4.3 (95% CI 1.5 to 12.2)), pancreatic surgery (OR 3.2 (95% CI 1.1 to 9.5) and development of endocrine insufficiency (OR13.1 (95% CI 5.3 to 32.0) and exocrine insufficiency (OR6.1 (95% CI 2.4 to 15.5) during follow-up. CONCLUSION: Acute necrotising pancreatitis carries a substantial disease burden during long-term follow-up in terms of recurrent disease, the necessity for interventions and development of pancreatic insufficiency, even when treated conservatively during the index admission. Extensive (>50%) pancreatic parenchymal necrosis seems to be an important predictor of interventions and complications during follow-up.
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Insuficiencia Pancreática Exocrina , Pancreatitis Aguda Necrotizante , Pancreatitis Crónica , Humanos , Pancreatitis Aguda Necrotizante/complicaciones , Pancreatitis Aguda Necrotizante/cirugía , Estudios de Seguimiento , Calidad de Vida , Estudios Prospectivos , Insuficiencia Pancreática Exocrina/etiología , Pancreatitis Crónica/complicaciones , Drenaje/efectos adversos , Necrosis , Resultado del TratamientoRESUMEN
BACKGROUND: The sole presence of deep submucosal invasion is shown to be associated with a limited risk of lymph node metastasis. This justifies a local excision of suspected deep submucosal invasive colon carcinomas (T1 CCs) as a first step treatment strategy. Recently Colonoscopy-Assisted Laparoscopic Wedge Resection (CAL-WR) has been shown to be able to resect pT1 CRCs with a high R0 resection rate, but the long term outcomes are lacking. The aim of this study is to evaluate the safety, effectiveness and long-term oncological outcomes of CAL-WR as primary treatment for patients with suspected superficial and also deeply-invasive T1 CCs. METHODS: In this prospective multicenter clinical trial, patients with a macroscopic and/or histologically suspected T1 CCs will receive CAL-WR as primary treatment in order to prevent unnecessary major surgery for low-risk T1 CCs. To make a CAL-WR technically feasible, the tumor may not include > 50% of the circumference and has to be localized at least 25 cm proximal from the anus. Also, there should be sufficient distance to the ileocecal valve to place a linear stapler. Before inclusion, all eligible patients will be assessed by an expert panel to confirm suspicion of T1 CC, estimate invasion depth and subsequent advise which local resection techniques are possible for removal of the lesion. The primary outcome of this study is the proportion of patients with pT1 CC that is curatively treated with CAL-WR only and in whom thus organ-preservation could be achieved. Secondary outcomes are 1) CAL-WR's technical success and R0 resection rate for T1 CC, 2) procedure-related morbidity and mortality, 3) 5-year overall and disease free survival, 4) 3-year metastasis free survival, 5) procedure-related costs and 6) impact on quality of life. A sample size of 143 patients was calculated. DISCUSSION: CAL-WR is a full-thickness local resection technique that could also be effective in removing pT1 colon cancer. With the lack of current endoscopic local resection techniques for > 15 mm pT1 CCs with deep submucosal invasion, CAL-WR could fill the gap between endoscopy and major oncologic surgery. The present study is the first to provide insight in the long-term oncological outcomes of CAL-WR. TRIAL REGISTRATION: CCMO register (ToetsingOnline), NL81497.075.22, protocol version 2.3 (October 2022).
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Carcinoma , Neoplasias del Colon , Neoplasias Colorrectales , Humanos , Calidad de Vida , Estudios Prospectivos , Neoplasias del Colon/cirugía , Colonoscopía , Endoscopía Gastrointestinal , Resultado del Tratamiento , Neoplasias Colorrectales/patología , Estudios Retrospectivos , Estudios Multicéntricos como AsuntoRESUMEN
OBJECTIVES: In the Dutch National colorectal cancer (CRC) screening program, patients with a positive faecal immunochemical test (FIT) are referred for a colonoscopy. In a small proportion, because of contraindications, a computed tomographic colonography (CTC) is performed to rule out advanced neoplasia. The aim of our study is to evaluate the intra- and extra-colonic yield of CTC and its clinical implications. MATERIALS AND METHODS: In this retrospective cohort study, all FIT positive patients who underwent primary (instead of colonoscopy) or secondary CTC (after incomplete colonoscopy) between January 2014 and January 2018 were included. Relevant intra-colonic lesions on CTC were defined as lesions suspected for CRC or >10 mm. Relevant extra-colonic findings were defined as E3 and E4 using the E-RADS classification. RESULTS: Of the 268 included patients, 66 (24.6%) were suspected to have CRC or 10 mm + lesion on CTC and 56 of them (84.8%) underwent an additional endoscopy. Another 20 patients with <10 mm lesions on CTC underwent additional endoscopy. Overall, 76/268 patients (28.4%) underwent confirmatory endoscopy of which 50 (18.7%) had histologic confirmed advanced neoplasia; 4.9% had CRC and 13.8% advanced adenoma. New relevant extra-colonic findings were detected in 13.8%. CONCLUSIONS: In the Dutch National CRC screening program, a CTC was followed by an endoscopic procedure in more than a quarter of patients, resulting in a significant number of advanced neoplasia. Overall, one out of seven CTCs showed new relevant extra-colonic findings which may lead to further diagnostic/therapeutic work-up. Our results can be important for the informed consent procedure.
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Colonografía Tomográfica Computarizada , Neoplasias Colorrectales , Neoplasias Colorrectales/diagnóstico por imagen , Detección Precoz del Cáncer , Humanos , Sangre Oculta , Estudios RetrospectivosRESUMEN
BACKGROUND: Current risk stratification models for early invasive (T1) colorectal cancer are not able to discriminate accurately between prognostic favourable and unfavourable tumours, resulting in over-treatment of a large (>80%) proportion of T1 colorectal cancer patients. The tumour-stroma ratio (TSR), which is a measure for the relative amount of desmoplastic tumour stroma, is reported to be a strong independent prognostic factor in advanced-stage colorectal cancer, with a high stromal content being associated with worse prognosis and survival. We aimed to investigate whether the TSR predicts clinical outcome in patients with non-pedunculated T1 colorectal cancer. METHODS: Haematoxylin and eosin (H&E)-stained tumour tissue slides from a retrospective multicentre case cohort of patients with nonpedunculated surgically treated T1 colorectal cancer were assessed for TSR by two independent observers who were blinded for clinical outcomes. The primary end point was adverse outcome, which was defined as the presence of lymph node metastasis in the resection specimen or colorectal cancer recurrence during follow-up. RESULTS: All 261 patients in the case cohort had H&E slides available for TSR scoring. Of these, 183 were scored as stroma-low, and 78 were scored as stroma-high. There was moderate inter-observer agreement κ = 0.42). In total, 41 patients had lymph node metastasis, 17 patients had recurrent cancer and five had both. Stroma-high tumours were not associated with an increased risk for an adverse outcome (adjusted hazard ratio = 0.66, 95% confidence interval 0.37-1.18; p = 0.163). CONCLUSIONS: Our study emphasises that existing prognosticators may not be simply extrapolated to T1 colorectal cancers, even though their prognostic value has been widely validated in more advanced-stage tumours.
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Advanced colorectal cancer (CRC) consensus molecular subtype 4 (CMS4) or CRC with a low immunoscore is associated with shorter survival times. Non-metastatic CRC with microsatellite instability (MSI) is associated with a lower risk of recurrence. We evaluated outcome (lymph node metastases [LNM] or cancer recurrence) in these tumor subtypes in patients with surgically-removed non-pedunculated T1 CRC by performing a multicenter case-cohort study. We included all patients in 13 hospitals in the Netherlands from 2000-2014 (n = 651). We randomly selected a subgroup of patients (n = 223) and all patients with LNM or recurrence (n = 63), and median follow-up of 44 months. We centrally reviewed tumor-slides, and constructed and immunostained tissue microarrays determining MSI, CMS (MSI/CMS1, CMS2/3, or CMS4), and immunoscore (I-low/I-high). We used weighted Cox proportional hazard models to evaluate the association of MSI, CMS, and immunoscore with LNM or recurrence, adjusting for conventional histologic risk factors. In the randomly selected subgroup of patients, 7.1% of tumors were MSI/CMS1, 91.0% CMS2/3, 1.8% CMS4, and 25% I-low. In the case-cohort, patients with CMS4 tumors had an increased risk for LNM or recurrence compared with patients with tumors of other CMSs (adjusted hazard ratio [HR], 3.97; 95% CI, 1.12-14.06; P = 0.03). Albeit not significant, tumors with MSI had a lower risk for LNM or recurrence than other tumor subtypes (adjusted HR, 0.52; 95% CI, 0.12-2.30; P = 0.39), whereas tumors with a low immunoscore had an increased risk for LNM or recurrence (adjusted HR, 1.30; 95% CI, 0.68-2.48; P = 0.43). In conclusion, in a case-cohort study of patients with non-pedunculated T1 CRC, MSI, and immunoscore were not significantly associated with adverse outcome after surgery. CMS4 substantially increased the risk of adverse outcome. However, CMS4 is rare in T1 CRCs, limiting its value for determining the risk in patients.
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Adenocarcinoma , Biomarcadores de Tumor/análisis , Neoplasias Colorrectales , Enzimas Reparadoras del ADN/análisis , Inmunohistoquímica , Inestabilidad de Microsatélites , Adenocarcinoma/química , Adenocarcinoma/genética , Adenocarcinoma/secundario , Adenocarcinoma/cirugía , Anciano , Estudios de Casos y Controles , Neoplasias Colorrectales/química , Neoplasias Colorrectales/genética , Neoplasias Colorrectales/patología , Neoplasias Colorrectales/cirugía , Femenino , Predisposición Genética a la Enfermedad , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia , Estadificación de Neoplasias , Países Bajos , Fenotipo , Valor Predictivo de las Pruebas , Factores de Tiempo , Análisis de Matrices Tisulares , Resultado del TratamientoRESUMEN
OBJECTIVE: This study evaluated the preresection accuracy of optical diagnosis of T1 colorectal cancer (CRC) in large non-pedunculated colorectal polyps (LNPCPs). DESIGN: In this multicentre prospective study, endoscopists predicted the histology during colonoscopy in consecutive patients with LNPCPs using a standardised procedure for optical assessment. The presence of morphological features assessed with white light, and vascular and surface pattern with narrow-band imaging (NBI) were recorded, together with the optical diagnosis, the confidence level of prediction and the recommended treatment. A risk score chart was developed and validated using a multivariable mixed effects binary logistic least absolute shrinkage and selection (LASSO) model. RESULTS: Among 343 LNPCPs, 47 cancers were found (36 T1 CRCs and 11 ≥T2 CRCs), of which 11 T1 CRCs were superficial invasive T1 CRCs (23.4% of all malignant polyps). Sensitivity and specificity for optical diagnosis of T1 CRC were 78.7% (95% CI 64.3 to 89.3) and 94.2% (95% CI 90.9 to 96.6), and 63.3% (95% CI 43.9 to 80.1) and 99.0% (95% CI 97.1 to 100.0) for optical diagnosis of endoscopically unresectable lesions (ie, ≥T1 CRC with deep invasion), respectively. A LASSO-derived model using white light and NBI features discriminated T1 CRCs from non-invasive polyps with a cross-validation area under the curve (AUC) of 0.85 (95% CI 0.80 to 0.90). This model was validated in a temporal validation set of 100 LNPCPs (AUC of 0.81; 95% CI 0.66 to 0.96). CONCLUSION: Our study provides insights in the preresection accuracy of optical diagnosis of T1 CRC. Sensitivity is still limited, so further studies will show how the risk score chart could be improved and finally used for clinical decision making with regard to the type of endoresection to be used and whether to proceed to surgery instead of endoscopy. TRIAL REGISTRATION NUMBER: NTR5561.
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Pólipos del Colon/diagnóstico por imagen , Neoplasias Colorrectales/diagnóstico por imagen , Imagen de Banda Estrecha/métodos , Anciano , Pólipos del Colon/patología , Colonoscopía , Neoplasias Colorrectales/patología , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Estudios Prospectivos , Medición de RiesgoRESUMEN
BACKGROUND & AIMS: HIV/hepatitis B virus (HBV) coinfected subjects are thought to have faster progression to end-stage liver disease (ESLD) than HBV mono-infected subjects. We assessed whether this remains in the current cART-era. METHODS: Data from subjects with follow-up completion post-2003 were compared between HIV/HBV coinfected subjects in the Dutch HIV Monitoring database and HBV mono-infected subjects from two centres. The primary outcomes of composite ESLD included portal hypertension, decompensated cirrhosis, hepatocellular carcinoma, liver transplantation and liver-related mortality. Outcomes were analysed using time-dependent cause-specific Cox regression models adjusted for follow-up time and relevant covariates. Subset-analyses were done in subjects with follow-up pre-2003. RESULTS: In the 1336 co- vs 742 mono-infected subjects, coinfected subjects had no increased probability for ESLD compared to mono-infected subjects (cHR 0.7 (95% CI 0.4-1.1), but had increased probabilities for all-cause (cHR 7.4 [4.9-11.1]) and liver-related mortality (cHR 3.4 [1.6-7.5]). In the current combined cohort, treatment with tenofovir or entecavir was inversely associated with ESLD, all-cause and liver-related mortality (cHR 0.4 [95% CI 0.3-0.7], cHR 0.003 [0.001-0.01]), cHR 0.007 [0.001-0.05]). Other predictors for ESLD were older age, being of Sub-Sahara African descent, increased alanine aminotransferase levels and hepatitis C virus coinfection. While the probability for all-cause mortality was increased in coinfected subjects, this rate decreased compared to pre-2003 (HR 40.2 (95% CI: 8.7-186.2). CONCLUSIONS: HIV/HBV coinfected patients no longer seem to be at increased risk for progression to ESLD compared to HBV mono-infected patients, likely due to widespread use of highly effective cART with dual HBV and HIV activity.
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Antirretrovirales/uso terapéutico , Coinfección , Enfermedad Hepática en Estado Terminal/epidemiología , Infecciones por VIH/tratamiento farmacológico , Hepatitis B/epidemiología , Adulto , Antirretrovirales/efectos adversos , Bases de Datos Factuales , Progresión de la Enfermedad , Quimioterapia Combinada , Enfermedad Hepática en Estado Terminal/diagnóstico , Enfermedad Hepática en Estado Terminal/mortalidad , Enfermedad Hepática en Estado Terminal/virología , Femenino , Infecciones por VIH/diagnóstico , Infecciones por VIH/mortalidad , Hepatitis B/diagnóstico , Hepatitis B/mortalidad , Humanos , Estudios Longitudinales , Masculino , Persona de Mediana Edad , Países Bajos/epidemiología , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Factores de TiempoRESUMEN
BACKGROUND & AIMS: Risk stratification for adverse events, such as metastasis to lymph nodes, is based only on histologic features of tumors. We aimed to compare adverse outcomes of pedunculated vs nonpedunculated T1 colorectal cancers (CRC). METHODS: We performed a retrospective study of 1656 patients diagnosed with T1CRC from 2000 through 2014 at 14 hospitals in The Netherlands. The median follow-up time of patients was 42.5 months (interquartile range, 18.5-77.5 mo). We evaluated the association between tumor morphology and the primary composite end point, adverse outcome, adjusted for clinical variables, histologic variables, resection margins, and treatment approach. Adverse outcome was defined as metastasis to lymph nodes, distant metastases, local recurrence, or residual tissue. Secondary end points were tumor metastasis, recurrence, and incomplete resection. RESULTS: Adverse outcome occurred in 67 of 723 patients (9.3%) with pedunculated T1CRCs vs 155 of 933 patients (16.6%) with nonpedunculated T1CRCs. Pedunculated morphology was independently associated with decreased risk of adverse outcome (adjusted odds ratio [OR], 0.59; 95% CI, 0.42-0.83; P = .003). Metastasis, incomplete resection, and recurrence were observed in 5.8%, 4.6%, and 3.9% of pedunculated T1CRCs vs 10.6%, 8.0%, and 6.6% of nonpedunculated T1CRCs, respectively. Pedunculated morphology was independently associated with a reduced risk of metastasis (adjusted OR, 0.62; 95% CI, 0.41-0.94; P = .03), incomplete resection (adjusted OR, 0.57; 95% CI, 0.36-0.91; P = .02), and recurrence (adjusted hazard ratio, 0.52; 95% CI, 0.32-0.85; P = .009). Metastasis, incomplete resection, and recurrence did not differ significantly between low-risk pedunculated vs nonpedunculated T1CRCs (0.8% vs 2.9%, P = .38; 1.5% vs 0%, P = .99; 1.5% vs 0%; P = .99). However, incomplete resection and recurrence were significantly lower for high-risk pedunculated vs nonpedunculated T1CRCs (6.5% vs 12.5%; P = .007; 4.4% vs 8.6%; P = .03). CONCLUSIONS: In a retrospective study of patients with T1CRC, we found pedunculated morphology to be associated independently with a decreased risk of adverse outcome in a T1CRC population at high risk of adverse outcome. Incorporating morphologic features of tumors in risk assessment could help predict outcomes of patients with T1CRC and help identify the best candidates for surgery.
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Colonoscopía/métodos , Neoplasias Colorrectales/diagnóstico , Recurrencia Local de Neoplasia/epidemiología , Estadificación de Neoplasias , Medición de Riesgo/métodos , Anciano , Neoplasias Colorrectales/epidemiología , Neoplasias Colorrectales/secundario , Femenino , Estudios de Seguimiento , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Recurrencia Local de Neoplasia/diagnóstico , Países Bajos/epidemiología , Pronóstico , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia/tendencias , Factores de TiempoRESUMEN
Colorectal cancer (CRC) screening is capable of reducing CRC-related morbidity and mortality. Colonoscopy is the reference standard to detect CRC, also providing the opportunity to detect and resect its precursor lesions: colorectal polyps. Therefore, colonoscopy is either used as a primary screening tool or as a subsequent procedure after a positive triage test in screening programs based on non-invasive stool testing or sigmoidoscopy. However, in both settings, colonoscopy is not fully protective for the occurrence of post-colonoscopy CRCs (PCCRCs). Because most PCCRCs are the result of colonoscopy-related factors, a high-quality procedure is of paramount importance to assure optimal effectiveness of CRC screening programs. For this reason, at the start of the Dutch fecal immunochemical test (FIT)-based screening program, quality criteria for endoscopists performing colonoscopies in FIT-positive screenees, as well as for endoscopy centers, were defined. In conjunction, an accreditation and auditing system was designed and implemented. In this report, we describe the quality assurance process for endoscopists participating in the Dutch national CRC screening program, including a detailed description of the evidence-based quality criteria. We believe that our experience might serve as an example for colonoscopy quality assurance programs in other CRC screening programs.
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Adenoma/diagnóstico , Carcinoma/diagnóstico , Colonoscopía/normas , Neoplasias Colorrectales/diagnóstico , Detección Precoz del Cáncer/normas , Humanos , Países Bajos , Sangre Oculta , Garantía de la Calidad de Atención de Salud , SigmoidoscopíaRESUMEN
BACKGROUND & AIMS: Most patients with pedunculated T1 colorectal tumors referred for surgery are not found to have lymph node metastases, and were therefore unnecessarily placed at risk for surgery-associated complications. We aimed to identify histologic factors associated with need for surgery in patients with pedunculated T1 colorectal tumors. METHODS: We performed a cohort-nested matched case-control study of 708 patients diagnosed with pedunculated T1 colorectal tumors at 13 hospitals in The Netherlands, from January 1, 2000 through December 31, 2014, followed for a median of 44 months (interquartile range, 20-80 months). We identified 37 patients (5.2%) who required surgery (due to lymph node, intramural, or distant metastases). These patients were matched with patients with pedunculated T1 colorectal tumors without a need for surgery (no metastases, controls, n = 111). Blinded pathologists analyzed specimens from each tumor, stained with H&E. We evaluated associations between histologic factors and patient need for surgery using univariable conditional logistic regression analysis. We used multivariable least absolute shrinkage and selection operator (LASSO; an online version of the LASSO model is available at: http://t1crc.com/calculator/) regression to develop models for identification of patients with tumors requiring surgery, and tested the accuracy of our model by projecting our case-control data toward the entire cohort (708 patients). We compared our model with previously developed strategies to identify high-risk tumors: conventional model 1 (based on poor differentiation, lymphovascular invasion, or Haggitt level 4) and conventional model 2 (based on poor differentiation, lymphovascular invasion, Haggitt level 4, or tumor budding). RESULTS: We identified 5 histologic factors that differentiated cases from controls: lymphovascular invasion, Haggitt level 4 invasion, muscularis mucosae type B (incompletely or completely disrupted), poorly differentiated clusters and tumor budding, which identified patients who required surgery with an area under the curve (AUC) value of 0.83 (95% confidence interval, 0.76-0.90). When we used a clinically plausible predicted probability threshold of ≥4.0%, 67.5% (478 of 708) of patients were predicted to not need surgery. This threshold identified patients who required surgery with 83.8% sensitivity (95% confidence interval, 68.0%-93.8%) and 70.3% specificity (95% confidence interval, 60.9%-78.6%). Conventional models 1 and 2 identified patients who required surgery with lower AUC values (AUC, 0.67; 95% CI, 0.60-0.74; P = .002 and AUC, 0.64; 95% CI, 0.58-0.70; P < .001, respectively) than our LASSO model. When we applied our LASSO model with a predicted probability threshold of ≥4.0%, the percentage of missed cases (tumors mistakenly assigned as low risk) was comparable (6 of 478 [1.3%]) to that of conventional model 1 (4 of 307 [1.3%]) and conventional model 2 (3 of 244 [1.2%]). However, the percentage of patients referred for surgery based on our LASSO model was much lower (32.5%, n = 230) than that for conventional model 1 (56.6%, n = 401) or conventional model 2 (65.5%, n = 464). CONCLUSIONS: In a cohort-nested matched case-control study of 708 patients with pedunculated T1 colorectal carcinomas, we developed a model based on histologic features of tumors that identifies patients who require surgery (due to high risk of metastasis) with greater accuracy than previous models. Our model might be used to identify patients most likely to benefit from adjuvant surgery.
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Colonoscopía/estadística & datos numéricos , Neoplasias Colorrectales/patología , Modelos Estadísticos , Selección de Paciente , Medición de Riesgo/estadística & datos numéricos , Anciano , Área Bajo la Curva , Estudios de Casos y Controles , Neoplasias Colorrectales/cirugía , Femenino , Humanos , Mucosa Intestinal/patología , Ganglios Linfáticos/patología , Masculino , Persona de Mediana Edad , Invasividad Neoplásica , Medición de Riesgo/métodos , Factores de Riesgo , Sensibilidad y EspecificidadRESUMEN
BACKGROUND: In patients with stage II colorectal cancer (CRC) the number of surgically retrieved lymph nodes (LNs) is associated with prognosis, resulting in a minimum of 10-12 retrieved LNs being recommended for this stage. Current guidelines do not provide a recommendation regarding LN yield in T1 CRC. Studies evaluating LN yield in T1 CRC suggest that such high LN yields are not feasible in this early stage, and a lower LN yield might be appropriate. We aimed to validate the cut-off of 10 retrieved LNs on risk for recurrent cancer and detection of LN metastasis (LNM) in T1 CRC, and explored whether this number is feasible in clinical practice. METHODS: Patients diagnosed with T1 CRC and treated with surgical resection between 2000 and 2014 in thirteen participating hospitals were selected from the Netherlands Cancer Registry. Medical records were reviewed to collect additional information. The association between LN yield and recurrence and LNM respectively were analyzed using 10 LNs as cut-off. Propensity score analysis using inverse probability weighting (IPW) was performed to adjust for clinical and histological confounding factors (i.e., age, sex, tumor location, size and morphology, presence of LNM, lymphovascular invasion, depth of submucosal invasion, and grade of differentiation). RESULTS: In total, 1017 patients with a median follow-up time of 49.0 months (IQR 19.6-81.5) were included. Four-hundred five patients (39.8%) had a LN yield ≥ 10. Forty-one patients (4.0%) developed recurrence. LN yield ≥ 10 was independently associated with a decreased risk for recurrence (IPW-adjusted HR 0.20; 95% CI 0.06-0.67; P = 0.009). LNM were detected in 84 patients (8.3%). LN yield ≥ 10 was independently associated with increased detection of LNM (IPW-adjusted OR 2.27; 95% CI 1.39-3.69; P = 0.001). CONCLUSIONS: In this retrospective observational study, retrieving < 10 LNs was associated with an increased risk of CRC recurrence, advocating the importance to perform an appropriate oncologic resection of the draining LNs and diligent LN search when patients with T1 CRC at high-risk for LNM are referred for surgical resection. Given that both gastroenterologists, surgeons and pathologists will encounter T1 CRCs with increasing frequency due to the introduction of national screening programs, awareness on the consequences of an inadequate LN retrieval is of utmost importance.