Recurrence-free survival as a surrogate endpoint for overall survival after neoadjuvant chemotherapy and surgery for oesophageal squamous cell carcinoma.

BACKGROUND: Overall survival is considered as one of the most important endpoints of treatment efficacy but often requires long follow-up. This study aimed to determine the validity of recurrence-free survival as a surrogate endpoint for overall survival in patients with surgically resectable advanced oesophageal squamous cell carcinoma (OSCC). METHODS: Patients with OSCC who received neoadjuvant cisplatin and 5-fluorouracil, or docetaxel, cisplatin and 5-fluorouracil, at 58 Japanese oesophageal centres certified by the Japan Esophageal Society were reviewed retrospectively. The correlation between recurrence-free and overall survival was assessed using Kendall's τ. RESULTS: The study included 3154 patients. The 5-year overall and recurrence-free survival rates were 56.6 and 47.7% respectively. The primary analysis revealed a strong correlation between recurrence-free and overall survival (Kendall's τ 0.797, 95% c.i. 0.782 to 0.812) at the individual level. Subgroup analysis showed a positive relationship between a more favourable pathological response to neoadjuvant chemotherapy and a higher τ value. In the meta-regression model, the adjusted R2 value at the institutional level was 100 (95% c.i. 40.2 to 100)%. The surrogate threshold effect was 0.703. CONCLUSION: There was a strong correlation between recurrence-free and overall survival in patients with surgically resectable OSCC who underwent neoadjuvant chemotherapy, and this was more pronounced in patients with a better response to neoadjuvant chemotherapy.

Outcomes of patients with esophageal squamous cell carcinoma who achieved a pathological complete response in the primary lesion by neoadjuvant treatment: a Japanese nationwide cohort study.

BACKGROUND: Minimal data was reported regarding the characteristics, risks of lymph node metastasis, and prognostic factors in esophageal cancer patients who achieved remarkable response in the primary lesion to neoadjuvant treatment (NAT). METHODS: This study evaluated the nationwide data of esophageal squamous cell carcinoma (ESCC) patients who underwent surgery following NAT in Japan. Of 4484 patients, 300 (6.7%) had ypT0 following NAT and curative esophagectomy. Factors associated with lymph node metastasis and prognosis were analyzed. RESULTS: Neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) were administered in 260 (86.2%) and 40 (13.8%) patients, respectively. Pathologically, 72 (24.0%) had lymph node metastasis (residual nodal disease; RND), and pretherapeutic lymph node metastasis was the independent risk factor for RND (odd ratio [OR]: 3.21; 95% confidence interval [CI]: 1.44-8.20; P = 0.008). The 5-year overall and relapse-free survivals were significantly longer in patients with pathological complete response (pCR) than in those with RND (both P < 0.001). Pretherapeutic cT3 or T4a tumors (hazard ratio [HR]: 1.71; 95% CI: 1.02-2.88; P = 0.043), RND (HR: 3.30; 95% CI: 1.98-5.50; P < 0.001), and operative blood loss (Liter, HR: 1.53; 95% CI: 1.07-2.19; P = 0.021) were independent risk factors affecting relapse-free survival in multivariable analysis. CONCLUSIONS: Of patients with ypT0 after NAT, 24.0% had RND, and pretherapeutic lymph node metastasis was the risk factor. In addition, pretherapeutic cT3, or T4a tumors, RND, and operative blood loss were the poor prognosticators in patients with ypT0 after NAT.

Real-world Evaluation of the Efficacy of Neoadjuvant DCF Over CF in Esophageal Squamous Cell Carcinoma: Propensity Score-matched Analysis From 85 Authorized Institutes for Esophageal Cancer in Japan.

OBJECTIVE: We aimed to evaluate the efficacy of neoadjuvant docetaxel, cisplatin, and 5-fluorouracil (DCF) therapy over cisplatin and 5-fluorouracil (CF) in patients with surgically resectable advanced esophageal squamous cell carcinoma (ESCC), using real-world data from 85 esophageal centers. BACKGROUND: JCOG1109 trial, which assessed the superiority of DCF over CF, and the superiority of chemoradiotherapy with CF over CF alone demonstrated the significant survival advantage of neoadjuvant DCF in overall survival (OS) over CF for ESCC. METHODS: The ESCC patients who received neoadjuvant CF or DCF at 85 Japanese esophageal centers certified by the Japan Esophageal Society were retrospectively reviewed. After propensity score (PS) matching, the OS and recurrence-free survival were compared between CF and DCF. RESULTS: We initially enrolled 4781 patients. After data cleaning and PS matching using pretreatment variables, 1074 patients for each group were selected for subsequent analysis. There was no significant difference in the incidence of postoperative pneumonia and anastomotic leakage. In the survival analysis, OS was significantly longer in DCF group than CF group (hazard ratio, 0.868; 95% confidence interval, 0.770-0.978; P =0.02), as well as recurrence-free survival (hazard ratio, 0.850; 95% confidence interval, 0.761-0.949; P =0.004). The survival advantage of DCF was not observed in patients with 76 years old or older. CONCLUSIONS: Neoadjuvant DCF therapy showed a remarkable survival advantage in surgically resectable ESCC patients, especially in patients who were 75 years old or younger. The current real-world evidence will encourage recommendations for DCF as a standard regimen in neoadjuvant chemotherapy-based treatment strategy for ESCC.

Nationwide Validation Study of the Prognostic Significance of Stratification Using Pathological Stage and Response to Neoadjuvant Chemotherapy for Esophageal Squamous Cell Carcinoma.

OBJECTIVE: This study aimed to validate the prognostic significance of stratification using pathological stage and response to neoadjuvant chemotherapy with a nationwide database from an authorized institute by the Japan Esophageal Society. BACKGROUND: We proposed the combined criteria using pStage and pathological response. Conducting a validation study using an expanded cohort in the clinical setting would be valuable since it was developed using retrospective data collection. METHODS: Patients with esophageal squamous cell carcinoma who underwent subtotal esophagectomy at 85 authorized institutes were retrospectively reviewed for esophageal cancer between 2010 and 2015. The prognostic value of the pathological response was evaluated within the same pStage. Moreover, risk stratification was developed to predict cancer-specific survival (CSS). RESULTS: The pathological response showed significant stratification of CSS in 3761 patients included in this analysis. We classified the patients into 7 groups as survival was significantly different between responders and nonresponders under the stratification with pStage, excluding pStage I comprising pStage 0-I/II responder/II nonresponder/III responder/III nonresponder/IV responder/IV nonresponder with the 5-year CSS of 83.7%/75.8%/68.9%/59.8%/44.4%/40.7%/23.1%, respectively. Furthermore, the area under the curve was significantly higher under the new classification than in the pStage alone ( P <0.001). CONCLUSIONS: The prognostic value of classification using pStage and the pathological response was successfully validated using real-world data in Japan. This result would guide appropriate treatment for patients with esophageal squamous cell carcinoma who received neoadjuvant chemotherapy followed by esophagectomy.

Stratification of Stage II Colon Cancer Using Recurrence Prediction Value: A Multi-institutional International Retrospective Study.

OBJECTIVE: To create a recurrence prediction value (RPV) of high-risk factor and identify the patients with high risk of cancer recurrence. SUMMARY BACKGROUND DATA: There are several high-risk factors known to lead to poor outcomes. Weighting each high-risk factor based on their association with increased risk of cancer recurrence can provide a more precise understanding of risk of recurrence. METHODS: We performed a multi-institutional international retrospective analysis of patients with Stage II colon cancer patients who underwent surgery from 2010 to 2020. Patient data from a multi-institutional database were used as the Training data, and data from a completely separate international database from two countries were used as the Validation data. The primary endpoint was recurrence-free survival (RFS). RESULTS: A total of 739 patients were included from Training data. To validate the feasibility of RPV, 467 patients were included from Validation data. Training data patients were divided into RPV low (n = 564) and RPV high (n = 175). Multivariate analysis revealed that risk of recurrence was significantly higher in the RPV high than the RPV low (Hazard ratio (HR) 2.628; 95% confidence interval (CI) 1.887-3.660; P < 0.001). Validation data patients were divided into two groups (RPV low, n = 420) and RPV high (n = 47). Multivariate analysis revealed that risk of recurrence was significantly higher in the RPV high than the RPV low (HR 3.053; 95% CI 1.962-4.750; P < 0.001). CONCLUSIONS: RPV can identify Stage II colon cancer patients with high risk of cancer recurrence world-wide.

Development and Validation of a Predictive Model of Therapeutic Effect in Patients with Esophageal Squamous Cell Carcinoma Who Received Neoadjuvant Treatment: A Nationwide Retrospective Study in Japan.

BACKGROUND: Neoadjuvant treatment has become the standard of care for patients with advanced esophageal cancer. However, few studies have elucidated the clinical factors that predict response to neoadjuvant therapy in a large multicenter cohort. We aimed to develop a predictive model of therapeutic effect in patients with esophageal squamous cell carcinoma (SCC) who received neoadjuvant treatment. METHODS: This nationwide study included 4078 patients from 85 institutions. Patients who received neoadjuvant treatment followed by surgery for esophageal SCC were eligible. We developed a logistic regression model to predict good pathological therapeutic effects, and a predictive nomogram was generated by applying the logistic regression formula. RESULTS: Among neoadjuvant regimens, cisplatin plus 5-fluorouracil (CF) was the most frequently used (60.2%), followed by docetaxel plus CF (DCF, 27.4%), CF with radiotherapy (CF-RT, 4.5%), adriamycin plus CF (3.6%), nedaplatin plus 5-fluorouracil (0.9%), and DCF-RT (0.5%). Multivariable analysis revealed that male sex, advanced cT category, and increased pretherapeutic SCC antigen level were independently associated with not achieving a good therapeutic effect. Moreover, intensified neoadjuvant regimens were independently associated with favorable therapeutic effects; DCF-RT elicited the best therapeutic effect, followed by CF-RT and DCF. A predictive model including nine commonly measured preoperative variables was generated, and the area under the curve was 0.679 (95% confidence interval: 0.658-0.700). This nomogram was also adequately validated internally. CONCLUSIONS: The model developed in this study was validated and predicts the therapeutic effect in patients with esophageal SCC who received neoadjuvant treatment. This model might contribute to individualized treatment strategies.

Neoadjuvant Chemotherapy or Neoadjuvant Chemoradiotherapy for Patients with Esophageal Squamous Cell Carcinoma: Real-World Data Comparison from A Japanese Nationwide Study.

BACKGROUND: Although neoadjuvant treatment has become the standard of care for patients with locally advanced esophageal cancer, previous studies comparing neoadjuvant chemotherapy (NAC) and neoadjuvant chemoradiotherapy (NACRT) have demonstrated inconclusive results. METHODS: Our study cohort included 3978 patients from 85 institutions. Those who underwent NAC or NACRT followed by surgery for esophageal squamous cell carcinoma (ESCC) were eligible for inclusion. We used the inverse probability of treatment weighting (IPTW) method to compare the outcomes between NAC and NACRT. RESULTS: Among the 3978 patients, 3777 (94.9%) received NAC and 201 (5.1%) received NACRT. After IPTW adjustment, the NACRT group had more patients with pathologically downstaged diseases and significantly better pathological response compared with the NAC group (p < 0.001); however, 5-year overall survival (OS), recurrence-free survival (RFS), and regional recurrence-specific survival (RRSS) were comparable between the groups. Subgroup analysis stratifying patients according to cT category showed that among cT1-2 patients, those in the NACRT group had significantly longer 5-year OS, RFS, and RRSS than those in the NAC group (P = 0.024, < 0.001, and 0.020, respectively). In contrast, no significant differences were observed among cT3-4a patients. The competing risks regression model showed comparable subdistribution hazard ratios for 10-year cancerous and noncancerous deaths between the NAC and NACRT groups. CONCLUSIONS: Compared with NAC, NACRT for ESCC did not promote better survival despite better therapeutic effects and did not increase noncancerous deaths.

Tumor Burden Monitoring with Circulating Tumor DNA During Treatment in Patients with Esophageal Squamous Cell Carcinoma.

BACKGROUND: To guide appropriate treatment strategy, an accurate tumor monitoring modality that reflects tumor burden during neoadjuvant treatment is required for esophageal squamous cell carcinoma (ESCC). We aimed to investigate the clinical utility of circulating tumor DNA (ctDNA) in plasma in patients who received neoadjuvant chemotherapy (NAC) followed by esophagectomy. PATIENTS AND METHODS: Longitudinally collected plasma samples for ctDNA combined with genomic DNA from primary lesions were obtained from patients with histologically confirmed ESCC who underwent NAC followed by subtotal esophagectomy. Next-generation sequencing was performed to identify mutations from the plasma and the primary tumor. The relationships between changes in ctDNA and the pathological response and recurrence were assessed in patients with locally advanced ESCC. RESULTS: In pretreatment samples from 13 patients, multiple concordant mutations in ctDNA and primary tumors were observed in 11 patients (85%), who were classified as ctDNA positive before treatment. The ctDNA positive rate after NAC correlated with the pathological response (responders, 25%; nonresponders, 100%; p = 0.007). The risk of recurrence increased significantly in patients with positive ctDNA after surgery in analysis of 16 patients; the 1-year recurrence-free survival rates were 90 and 0% in ctDNA-negative and ctDNA-positive groups, respectively (p = 0.0008). In two patients with postoperative recurrence, ctDNA was detected approximately 5.5 months earlier than the diagnosis using radiographical imaging. CONCLUSIONS: ctDNA is a promising biomarker for predicting pathological response and postoperative recurrence in ESCC. To demonstrate the external validity, we are currently preparing a multicenter prospective study.

Five-Year Outcomes of the Bioresorbable Peripheral Remedy Stent in the Treatment of Iliac Artery Disease.

PURPOSE: To evaluate the 5-year performance of a bioresorbable vascular scaffold, the Remedy stent, for the treatment of iliac artery atherosclerotic disease. MATERIALS AND METHODS: This prospective, multicenter, single-arm clinical study evaluated 97 patients (97 lesions) with symptomatic TransAtlantic Inter-Society Consensus II A/B iliac artery lesions for 5 years after stent placement. The primary efficacy end point was 12-month primary patency compared with the prespecified standard derived from historical data with metallic stents, and the primary safety end point was the occurrence of major adverse clinical events within 5 years. All angiographic and computed tomography angiographic findings were evaluated by an independent core laboratory for quantitative vessel analysis. RESULTS: The 12-month primary patency rate was 88.6% (95% CI, 80.1%-94.4%), which was lower than the prespecified standard. No significant difference was noted between the diameter stenosis at 9 and 12 months. There were no device- or procedure-related deaths, major amputation, or distal embolization during the follow-up period. The ankle-brachial index maintained significant improvement through the 5-year period compared with that at baseline. The Kaplan-Meier estimates of freedom from target lesion revascularization (TLR), major adverse cardiovascular events, and major adverse cardiovascular and limb events were 95.8%, 91.7%, and 87.5% at 12 months and 85.4%, 72.1%, and 62.5% at 5 years, respectively. CONCLUSIONS: The 5-year follow-up outcomes, including freedom from TLR, of the Remedy stent in iliac artery lesions were satisfactory, with a good safety profile. Nevertheless, the 12-month primary patency did not meet the expected standard compared with that of contemporary metallic stents.

The impact of thoracic duct resection on the long-term body composition of patients who underwent esophagectomy for esophageal cancer and survived without recurrence.

BACKGROUND: We have reported the possible benefits of radical esophagectomy with thoracic duct (TD) resection in elective esophageal cancer surgery. However, the effect of TD resection on the long-term nutrition status remains unclear. METHODS: Patients who underwent esophagectomy at Keio University between January 2006 and December 2018 were included, and those who had no recurrence for more than three years were evaluated. Changes in each body composition (muscle mass and body fat) were comparatively assessed between those who underwent TD resection or not, before and at, one, three and five years after surgery. Computed tomography images were analyzed on postoperative year 1, 3 and 5. RESULTS: This study included 217 patients categorized in the TD-resected (TD-R) (156 patients) and TD-preserved (TD-P) (61 patients) groups. The loss of muscle mass was comparable between the groups. On the other hand, the loss of adipose tissues was significantly greater in the TD-R group than in the TD-P group at one and three years after surgery, while there was no statistical difference five years after surgery. Additionally, among patients with cT1N0M0 disease in whom survival advantage of TD resection has been reported previously, the loss of muscle mass did not differ between each group. CONCLUSIONS: The change of muscle mass between the two groups was comparable. Although body fat mass was reduced by TD resection, it eventually recovered in the long term. In patients with esophageal cancer, TD resection may be acceptable without significant impact on body composition in the long term.

A nationwide validation of the prognostic impact of pathological response and the distribution of recurrence patterns in responders after neoadjuvant chemotherapy for esophageal squamous cell carcinoma.

BACKGROUND: We previously reported that postoperative recurrence in responders occurred in the regional field mostly as a solitary lesion without distant failure. However, further validation is necessary due to the low percentage of pathological responders, especially those with pCR. This study aimed to validate the prognostic impact of pathological response and the distribution of residual tumors in pathological responders using a nationwide database from 85 Japanese esophageal centers. METHODS: We retrospectively reviewed patients with esophageal squamous cell carcinoma (ESCC) who underwent subtotal esophagectomy at 85 authorized institutes for esophageal cancer between 2010 and 2015. The recurrence free survival (RFS), overall survival (OS), and recurrent tumor patterns were compared among the pathological responses. RESULTS: Of 4781 patients initially enrolled, 3840 were selected for subsequent analysis, including 237 patients with pathological complete response (pCR, 6%). The RFS and OS were significantly correlated with pathological response. When the recurrence pattern was classified into regional or distant recurrence, the incidence of distant failure was significantly lower in patients with pCR in cT1/2. Three percent of all patients with pCR in cT1/2 encountered postoperative recurrence in distant organs. CONCLUSION: The prognostic impact of pathological response was reproduced in the nationwide data. pCR in ESCC patients with cT1/2 provides a favorable prognosis with less incidence of distant failure. This finding may contribute to selecting appropriate candidates for an organ preservation approach based on the response to induction therapy.

Risk prediction of esophageal squamous cell carcinoma recurrence in patients who underwent esophagectomy after receiving neoadjuvant treatment: a nationwide retrospective study in Japan.

BACKGROUND: Although neoadjuvant treatment (NAT) has become the standard of care for patients with locally advanced esophageal cancer, the risk of recurrence remains high. The risk must be predicted accurately, so that appropriate adjuvant therapy can be planned. We aimed to develop a model predicting recurrence of esophageal squamous cell carcinoma (ESCC) in patients who received NAT before esophagectomy. METHODS: This nationwide study included 3874 patients from 85 institutions. Patients who underwent NAT and then surgery for ESCC were eligible. We developed a Cox proportional hazards model and created a nomogram to predict disease recurrence after NAT and curative esophagectomy. RESULTS: Of the patients, 268 (6.9%), 1280 (33.0%), 2006 (51.8%), and 320 (8.3%) had clinical stage I, II, III, and IV tumors, respectively. The 5-year recurrence rate was 45.1% (95% confidence interval 43.4%-46.7%). Multivariable analysis revealed that body mass index, type of neoadjuvant treatment, primary tumor location, operative blood loss, pathological tumor stage, pathological therapeutic effect, and leakage were independently associated with disease recurrence. Using 13 commonly measured perioperative variables, we created a predictive nomogram, and the area under the curve was 0.783 (95% confidence interval 0.766-0.800). This nomogram was also adequately validated internally and had excellent calibration capacity (calibration slope, 0.992). CONCLUSIONS: The model developed in this study adequately predicted ESCC recurrence in patients who underwent NAT and then esophagectomy. Further research with this nomogram is needed to assess the effect of adjuvant therapy in patients at high risk for recurrence.

Prognostic impact of endoscopic response evaluation after neoadjuvant chemotherapy for esophageal squamous cell carcinoma: a nationwide validation study.

BACKGROUND: Our previous study reported the prognostic significance of endoscopic response (ER) evaluation, defined ER, and revealed ER as an independent prognostic factor of overall survival (OS) and recurrence-free survival (RFS) for esophageal squamous cell carcinoma (ESCC) treated with neoadjuvant chemotherapy (NAC) and surgery. The present study aimed to validate the prognostic impact of ER using a nationwide database from the authorized institute for board-certified esophageal surgeons by the Japan Esophageal Society. METHODS: This study retrospectively reviewed patients with ESCC who underwent subtotal esophagectomy at 85 authorized institutes for esophageal cancer from 2010 to 2015. Patients were classified as ER when the tumor size was markedly reduced post-NAC compared to pre-NAC. The correlation between OS and RFS was investigated. RESULTS: Of 4781 patients initially enrolled, 3636 were selected for subsequent analysis. Of them, 642 (17.7%) patients were classified as the ER group. Patients with ER showed significantly better OS and RFS. Subgroup analysis revealed the statistical difference in OS and RFS in cStage II and III, while the magnitude of survival difference between ER and non-ER was not evident in cStage I and IV. The percentage of ER varied from 46 to 87% among groups when institutions were classified into 3 subgroups based on the hospital volume, which would indicate the interinstitutional inconsistency. CONCLUSIONS: The prognostic impact of ER was validated using a nationwide database. Standardization of ER evaluation is required to improve the interinstitutional consistency and clinical validity of the ER evaluation.

Old age and intense chemotherapy exacerbate negative prognostic impact of postoperative complication on survival in patients with esophageal cancer who received neoadjuvant therapy: a nationwide study from 85 Japanese esophageal centers.

BACKGROUND: The prognostic impact of docetaxel, cisplatin, and 5-FU (DCF) reported in JCOG1109 was successfully validated using real-world data in patients < 75 years old. However, DCF was not reported to be beneficial in elderly patients with a relatively higher postoperative complication incidence. This study aimed to clarify the impact of postoperative complications on the prognosis of ESCC and the difference in the magnitude of the impact by age and regimen. METHODS: Patients with esophageal squamous cell carcinoma (ESCC) who underwent subtotal esophagectomy at 85 authorized institutes were retrospectively reviewed from 2010 to 2015. The prognostic impact of postoperative anastomotic leakage (AL) and pneumonia on survival was evaluated. The prognostic value of the postoperative complications was assessed by stratifying patients according to age and neoadjuvant chemotherapy regimen. RESULTS: Patients with AL, pneumonia, and infectious complications (ICs: a combination of pneumonia and AL) showed significantly worse overall survival (OS). IC served as a negative prognostic factor of OS and recurrence-free survival, and its negative prognostic impact was more evident in patients aged > 75 years. When the patients were further stratified by chemotherapeutic regimens, using the CF/IC(-) group as a reference, the DCF/IC (+) group showed significantly shorter OS in patients aged > 75 years with a hazard ratio (HR) of 2.551. The HR of the CF/IC (+) group was 1.503. CONCLUSIONS: The negative impact of postoperative complications on survival was confirmed in this nationwide study. Furthermore, its magnitude was higher in elderly patients who received triplet chemotherapy.

Exposure to a Postoperative Hypercoagulable State Predicts Poor Prognosis After Transthoracic Esophagectomy in Patients with Esophageal Cancer.

PURPOSE: The contribution of postoperative coagulation-fibrinolysis status to prognosis is yet to be fully investigated. Thus, in this study, we aimed to elucidate the relationship between postoperative hypercoagulable state (PHS) after transthoracic esophagectomy and long-term outcome in patients with esophageal cancer. METHODS: Patients with esophageal cancer who underwent transthoracic esophagectomy were selected from a prospectively maintained database. Based on the trend of postoperative plasma fibrin-fibrinogen degradation product (FDP) levels, patients with PHS were identified. The prognostic significance of PHS was evaluated via multivariate analysis using the Cox regression model. RESULTS: Based on the plasma FDP levels of 172 patients that reached a plateau between POD5 and POD7, we calculated the mean FDP value of POD5, 6, and 7, setting a median value as a cutoff. Consequently, 87 patients were classified as PHS. The overall survival (OS) in the PHS group was determined to be significantly lower than in the non-PHS group (5-year OS; 68% and 80%, p = 0.012). Recurrence-free survival (RFS) in the PHS group was significantly lower than in the non-PHS group (5-year RFS; 60% and 79%, p = 0.017). Using the pathological stage as a covariate in the multivariate analysis, PHS was an independent prognostic factor of OS [hazard ratio (HR) 2.517, p = 0.009] and RFS (HR 1.905, p = 0.041). CONCLUSIONS: PHS was found to be an independent negative prognostic factor in patients with esophageal cancer. Possible improvement of the oncological outcome by early postoperative intervention with anticoagulants should be explored in clinical trials.

Early prediction model of organ/space surgical site infection after elective gastrointestinal or hepatopancreatobiliary cancer surgery.

BACKGROUND: Organ/space SSI is a significant clinical problem. However, early detection of organ/space SSI is difficult, and previous predictive models are limited in their prognostic ability. We aimed to develop and validate a prediction model of organ/space surgical site infection (SSI) using postoperative day 3 laboratory data in patients who underwent gastrointestinal or hepatopancreatobiliary cancer resection. METHODS: This retrospective cohort study using a single-center hospital data from April 2013 to September 2017 included all adult patients who underwent elective gastrointestinal or hepatopancreatobiliary cancer resection. The primary outcome was a presence of organ/space SSI including anastomotic leakage, pancreatic fistula, biliary fistula, or intra-abdominal abscess. We developed and validated a logistic regression model to predict organ/space SSI using laboratory data on postoperative day (POD) 3. Similar models using laboratory data on POD 1 or 5 were developed to compare the predictive ability of each model. RESULTS: A total of 1578 patients were included. Organ/space SSI was diagnosed in 107 patients, with median diagnosis days of 6 (interquartile range, 4-9 days) after surgery. A prediction model using five commonly measured variables on POD 3 was created with the area under the curve (AUC) of 0.883 (95%CI 0.819-0.946). The AUC of a model with POD 1 laboratory data was 0.751 (95%CI 0.655-0.848), while that of POD 5 laboratory data was 0.818 (95%CI 0.730-0.906). CONCLUSIONS: Laboratory data on POD 3 could forecast organ/space SSI precisely. Further prospective studies are warranted to investigate the clinical impact of this model.