Safety and efficacy of indocyanine green fluorescence imaging-guided laparoscopic para-aortic lymphadenectomy for left-sided colorectal cancer:A preliminary case-matched study.

AIM: This study is aimed to explore the safety and feasibility of indocyanine green (ICG) fluorescence imaging guidance in laparoscopic para-aortic lymph node (PALN) dissection for left-sided colorectal cancer (CRC) patients with clinically suspected PALN metastasis. METHOD: A total of 151 patients who underwent primary tumor resection and laparoscopic PALN dissection for left-sided CRC were included, with 20 patients in the ICG group and 131 patients in the non-ICG group. The surgical outcomes, postoperative complications, and pathological results, such as the number of harvested and metastatic lymph nodes were compared between groups after propensity score matching. RESULTS: Following propensity score matching, the ICG group had 20 patients, and the non-ICG group had 53 patients, and the two groups were similar in baseline characteristics. No significant differences were observed in overall intraoperative and postoperative complications between groups, except for chylous leakage, where the ICG group had a longer time to a normal diet. The number of harvested pericolic/perirectal and intermediate lymph nodes were comparable between the two groups, while the ICG group had a significantly higher number of total harvested lymph nodes (39 [14-78] vs. 29 [11-70], P = 0.001), inferior mesenteric artery lymph nodes (IMALN, 6 [0-17] vs. 3 [0-11], P = 0.006), and PALNs (9 [3-29] vs. 5 [1-37], P = 0.001). CONCLUSION: ICG fluorescence imaging could increase the retrieval of IMALN, PALN, and total lymph nodes, and potentially improve the completeness of laparoscopic PALN dissection in patients with left-sided CRC.

Unraveling variations and enhancing prediction of successful sphincter-preserving resection for low rectal cancer: A post hoc analysis of the multicenter LASRE randomized clinical trial.

BACKGROUND: Accurate prediction of successful sphincter-preserving resection (SSPR) for low rectal cancer enables peer institutions to scrutinize their own performance and potentially avoid unnecessary permanent colostomy. The aim of this study is to evaluate the variation in SSPR and present the first artificial intelligence (AI) models to predict SSPR in low rectal cancer patients. STUDY DESIGN: This was a retrospective post hoc analysis of a multicenter, noninferiority randomized clinical trial (LASRE, NCT XXXXXX) conducted in 22 tertiary hospitals across China. A total of 604 patients who underwent neoadjuvant chemoradiotherapy (CRT) followed by radical resection of low rectal cancer were included as the study cohort, which was then split into a training set (67%) and a testing set (33%). The primary end point of this post hoc analysis was SSPR, which was defined as meeting all the following criteria: (1) sphincter-preserving resection; (2) complete or nearly complete TME, (3) a clear CRM (distance between margin and tumor of 1 mm or more), and (4) a clear DRM (distance between margin and tumor of 1 mm or more). Seven AI algorithms, namely, support vector machine (SVM), logistic regression (LR), extreme gradient boosting (XGB), light gradient boosting (LGB), decision tree classifier (DTC), random forest (RF) classifier, and multilayer perceptron (MLP), were employed to construct predictive models for SSPR. Evaluation of accuracy in the independent testing set included measures of discrimination, calibration, and clinical applicability. RESULTS: The SSPR rate for the entire cohort was 71.9% (434/604 patients). Significant variation in the rate of SSPR, ranging from 37.7% to 94.4%, was observed among the hospitals. The optimal set of selected features included tumor distance from the anal verge before and after CRT, the occurrence of clinical T downstaging, post-CRT weight and clinical N stage measured by magnetic resonance imaging. The 7 different AI algorithms were developed and applied to the independent testing set. The LR, LGB, MLP and XGB models showed excellent discrimination with AUROC values of 0.825, 0.819, 0.819 and 0.805, respectively. The DTC, RF and SVM models had acceptable discrimination with AUROC values of 0.797, 0.766 and 0.744, respectively. LR and LGB showed the best discrimination, and all 7 AI models had superior overall net benefits within the range of 0.3-0.8 threshold probabilities. Finally, we developed an online calculator based on the LGB model to facilitate clinical use. CONCLUSIONS: The rate of SSPR exhibits substantial variation, and the application of AI models has demonstrated the ability to predict SSPR for low rectal cancers with commendable accuracy.

Early recurrence after complete mesocolic excision for right-sided colon cancer with D3 lymphadenectomy: pattern, risk factors, prognostic impact, and individualized follow-up.

The definition of early recurrence (ER) for right-sided colon cancer patients after complete mesocolic excision (CME) with D3 lymphadenectomy remains unclear. This study aimed to define the optimal time for ER and clarify risk factors for ER and post-recurrence survival (PRS). A total of 578 right-sided colon cancer patients who underwent CME with D3 lymphadenectomy were included. The minimum p value method was used to evaluate theme optimal time of recurrence-free survival to discriminate between ER and late recurrence (LR). Risk factors for ER were determined by a logistics regression model. The PRS was compared between ER and LR. The optimal time to define ER was 15 months (P = 1.8697E-7). 93 patients developed tumor recurrence, 46 patients had ER (≤15 months) and 47 patients had LR (>15 months). Preoperative serum CA19-9 > 37 U/mL (OR = 3.185, P = 0.001), pathological N+ stage (OR = 3.042, P = 0.027), and lymphovascular invasion (OR = 2.182, P = 0.027) were identified as independent risk factors associated with ER. Age > 75 years (HR = 1.828, P = 0.040), pathological N2 stage (HR = 1.850, P = 0.009), multiple sites of recurrence (HR = 1.680, P = 0.024), and time to recurrence ≤15 months (HR = 2.018, P = 0.043) were significantly associated with worse PRS in patients with recurrence. 15 months was the optimal time to distinguish ER and LR. ER was associated with a poor PRS. Elevated preoperative serum CA19-9 level, pathological N+ stage, and lymphovascular invasion were significantly predictive of ER.

Minimally invasive para-aortic lymph node dissection in left-sided colonic and rectal cancer: experience based on a high-volume centre.

AIM: There is no established consensus on the optimal surgical approach to para-aortic lymph node (PALN) dissection in patients with colorectal cancer. This study aimed to demonstrate the technical and oncological safety of minimally invasive PALN dissection for left-sided colonic and rectal cancer patients with clinically suspected infrarenal PALN metastasis. METHOD: One hundered and one patients who underwent primary tumour resection and minimally invasive (laparoscopic n = 92, robotic n = 9) PALN dissection for left-sided colonic and rectal cancer were included. Logistic regression analysis was used to identify risk factors for PALN metastasis. Survival outcomes were evaluated using the Kaplan-Meier (log-rank) method. RESULTS: Para-aortic lymph node metastasis was pathologically confirmed in 23 patients (22.8%). Postoperative complications occurred in 22 patients (21.8%). Pathological N2 stage (OR = 9.337, p = 0.003) and inferior mesenteric artery LN metastasis (OR = 7.499, p = 0.009) were independently associated with PALN metastasis. The median follow-up time was 32 months (range 3-92 months). In all patients, the 5-year overall survival (OS) and progression-free survival (PFS) rates were 76.1% and 69.5%, respectively. The 5-year OS and PFS rates in patients with PALN metastasis were 49.8% and 47.5%, respectively. Patients with PALN metastasis had lower 5-year OS (p = 0.023) and PFS rates (p = 0.035) than those without PALN metastasis. CONCLUSION: Minimally invasive PALN dissection had acceptable postoperative complications and may be oncologically beneficial in selected patients with clinically suspicious PALN metastasis.

A refined prediction of early recurrence combining tumor deposits in patients with resected rectal mucinous adenocarcinoma.

PURPOSE: Early recurrence (ER) of rectal mucinous adenocarcinoma (MAC) has yet to be defined. We therefore explored risk factors for ER and constructed a predictive nomogram. METHOD: A total of 145 rectal MAC patients undergoing radical surgery were included. The minimum P value method was used to determine the optimal cut-off point to discriminate between ER and late recurrence (LR). Risk factors for ER were determined by a logistic regression analysis, and a predictive nomogram was constructed. RESULTS: A total of 62 (42.8%) patients developed tumor recurrence. The optimal time to define ER was 12 months. A pre-treatment tumor distance from the anal verge ≤ 7 cm, pathological N stage, lymphovascular invasion, tumor deposits, and time to recurrence ≤ 12 months were significantly associated with a poor post-recurrence survival in patients with recurrence. A pre-treatment serum carcinoembryonic antigen (CEA) level > 10 ng/ml, pre-treatment tumor distance from the anal verge ≤ 7 cm, pathological N + stage, perineural invasion, and tumor deposits were identified as independent risk factors associated with ER. A nomogram predicting ER was constructed (C-index 0.870). CONCLUSION: The pre-treatment serum CEA level, pre-treatment tumor distance from the anal verge, pathological N + stage, perineural invasion, and tumor deposits were significantly predictive of ER for rectal MAC patients.

The impact of prophylactic oophorectomy on the survival for postmenopausal patients with pT4a colorectal cancer.

PURPOSE: This study aimed to evaluate the prognostic effect of prophylactic oophorectomy (PO) in postmenopausal patients with pT4 colorectal cancers (CRC) in terms of overall survival (OS), disease-free survival (DFS), and peritoneal metastasis. METHODS: The data of postmenopausal female patients with pT4 CRC undergoing surgical resection between 2000 and 2019 were analyzed. Kaplan-Meier analysis was used to evaluate survival outcomes between patients treated with and without PO. Risk factors for DFS and peritoneal metastasis were evaluated using Cox regression analysis. p-values <0.05 were considered statistically significant. RESULTS: Totally, 176 (34.3%) patients received PO. There was no significant difference in estimated blood loss, rates of postoperative complications, and hospitalization between the PO and non-PO groups. The 5-year OS and DFS rates were similar in the two groups (47.9% vs. 54.1%, p = 0.278; 53.5% vs. 50.5%, p = 0.161, respectively). In the subgroup analysis of patients with peritoneal metastasis, the median survival was significantly longer for the PO group compared with the non-PO group (14 vs. 11 months, p < 0.001). CONCLUSION: Undertaking PO in pT4 CRC female patients did not confer a survival benefit. Indication of PO even for advanced CRC patients should require caution. It has potential survival benefit only when the patients developed metachronous peritoneal metastases.

Clinical implication of the advanced lung cancer inflammation index in patients with right-sided colon cancer after complete mesocolic excision: a propensity score-matched analysis.

BACKGROUND: This study aimed to assess the clinical implications of the advanced lung cancer inflammation index (ALI) in patients with right-sided colon cancer (RCC) after complete mesocolic excision (CME). METHODS: A total of 441 patients with RCC who underwent CME were included. The optimal cut-off value for the ALI was determined using the X-tile software. Logistic and Cox regression analyses were used to identify risk factors for postoperative complications and long-term outcomes. Predictive nomograms for overall survival (OS) and disease-free survival (DFS) were constructed after propensity score matching (PSM), and their performance was assessed using the net reclassification improvement index (NRI), integrated discrimination improvement index (IDI), and time-dependent receiver operating characteristic (time-ROC) curve analysis. RESULTS: The optimal preoperative ALI cut-off value was 36.3. After PSM, ASA classification 3/4, operative duration, and a low ALI were independently associated with postoperative complications in the multivariate analysis (all P<0.05). Cox regression analysis revealed that an age >60 years, a carbohydrate antigen 19-9 (CA19-9) level >37 U/mL, pathological N+ stage, and a low ALI were independently correlated with OS (all P<0.05). A CA19-9 level >37 U/mL, pathological N+ stage, lymphovascular invasion, and a low ALI were independent predictors of DFS (all P<0.05). Predictive nomograms for OS and DFS were constructed using PSM. Furthermore, a nomogram combined with the ALI was consistently superior to a non-ALI nomogram or the pathological tumor-node-metastasis classification based on the NRI, IDI, and time-ROC curve analysis after PSM (all P<0.05). CONCLUSION: The ALI was an effective indicator for predicting short- and long-term outcomes in patients with RCC.

Preoperative combination score of neutrophils, monocytes, and lymphocytes as a predictor for locally advanced rectal cancer.

OBJECTIVE: The aim of this study was to investigate the prognostic value of baseline peripheral blood neutrophils, monocytes, and lymphocytes on locally advanced rectal cancer (LARC) patients. METHODS: Clinicopathologic data of 317 LARC patients during July 2010 and October 2016 were retrospectively gathered. X-tile software was used to acquire the optimal cutoff values of neutrophils, monocytes, and lymphocytes. Peripheral blood immune score (PBIS) system was proposed and built based on neutrophils, monocytes, and lymphocytes. The Cox model was used to analyze the associations between clinicopathological characteristics and potential outcomes. C-index was used to assess model performance. A nomogram was constructed to predict prognosis, and a calibration plot was used to verify the accuracy of the nomogram prediction model. RESULTS: Cutoff values of neutrophils, lymphocytes, and monocytes were 4.46 (× 109/L), 1.66 (× 109/L), and 0.39 (× 109/L), respectively. PBIS was related to sex (P < 0.001), tumor length (P = 0.003), and tumor thickness (P = 0.014). Multivariate Cox regression analysis revealed that PBIS (HR = 0.707, 95% CI: 0.549-0.912, P = 0.008) was an independent predictor of DFS. High PBIS (HR = 0.697, 95% CI: 0.492-0.988, P = 0.043) and high lymphocyte count (HR = 0.511, 95%CI: 0.273-0.958, P = 0.036) were favorable factors of OS. Both C-index (0.74, 95% CI: 0.549-0.912) and the calibration plot showed good prediction ability of the nomogram for DFS. CONCLUSION: PBIS, composed of baseline peripheral blood neutrophils, monocytes, and lymphocytes, is an independent predictor of the prognosis of LARC. Combination of PBIS and ypTNM stage may be a promising marker to guide adjuvant therapy after the operation.

Combined laparoscopic lymphoadenectomy of lateral pelvic and inguinal nodal metastases using indocyanine green fluorescence imaging guidance in low rectal cancer after preoperative chemoradiotherapy: a case report.

BACKGROUND: Intraoperative near-infrared fluorescence (NIR) imaging with indocyanine green (ICG) can demonstrate real-time lymphatic drainage and thus improve the accuracy and completeness of lymphadenectomy in colorectal cancer surgery. However, it has not been utilized in the inguinal lymphadenectomy in rectal cancer. This study aimed to describe a case of combined laparoscopic lymphadenectomy of left lateral pelvic and inguinal nodal metastases using NIR imaging with ICG imaging guidance for a rectal cancer patient with left lateral pelvic and inguinal lymph node metastases. CASE PRESENTATION: A 26-year-old man presented rectal cancer located 7 cm from the anal verge and enlarged lymph nodes in the left inguinal area. Pretreatment workup revealed rectal cancer with left lateral pelvic and inguinal lymph node metastases. The patient received preoperative chemoradiotherapy (pCRT), including radiation (total dose of 50.4 Gy in 28 fractions) to the whole pelvis and bilateral inguinal regions together with eight cycles of FOLFOX (oxaliplatin, fluoropyrimidine, and leucovorin) and three cycles of bevacizumab targeted chemotherapy. After pCRT, both colonoscopy and MR scan revealed a significant response of the primary tumor to pCRT, while MR scan revealed enlarged left lateral pelvic and inguinal lymph nodes. After four months from the completion of radiation (2 months after the last course of bevacizumab targeted therapy), the patient underwent laparoscopic-assisted ultra-low anterior resection and lymphadenectomy of left lateral pelvic and inguinal nodal metastases using ICG-NIR fluorescence imaging. The combined procedure was performed successfully without perioperative complication. Total operative time was 480 min and estimated blood loss 50 mL. Totally 34 lymph nodes were retrieved. CONCLUSIONS: This is the first report of the safety and feasibility of ICG-NIR fluorescence imaging-guided laparoscopic lymphadenectomy of left lateral pelvic and inguinal nodal metastases in managing low rectal cancer with lateral pelvic and inguinal LNs metastases.

Para-aortic lymph node dissection in left-sided colorectal cancer: Risk factors, prognostic impact, and therapeutic value.

AIM: This study aimed to clarify risk factors, prognostic impact, and the therapeutic value of para-aortic lymph node (PALN) dissection in left-sided colorectal cancer. METHOD: One hundred and fifty-four patients who underwent primary tumor resection and PALN dissection for left-sided colorectal cancer were included. Logistic regression analysis was used to identify risk factors for PALN metastasis. Cox regression analysis was performed to identify risk factors for overall survival (OS). RESULTS: PALN metastasis was pathologically confirmed in 47 patients (30.5%). Postoperative complications occurred in 42 patients (27.3%). Pathological N stage (OR = 4.661, p = 0.034) and inferior mesenteric artery LNs metastasis (OR = 6.048, p = 0.003) remained to be independently associated with PALN metastasis, the 5-year OS rate and median survival in patients with PALN metastasis was 37.7% and 24 months. Elevated preoperative serum CA19-9 level (HR = 1.006, p = 0.007), number of positive LNs > 7 (HR = 7.263, p = 0.001), and mucinous adenocarcinoma or signet ring cell carcinoma (HR = 6.511, p = 0.001) were independently associated with OS in patients with PALN metastasis. CONCLUSION: PALN dissection in addition to primary tumor resection have acceptable postoperative complications and may be oncologically beneficial in selected left-sided colorectal cancer patients with clinically suspicious PALN metastasis.

Identification of proteins associated with treatment response of neoadjuvant chemoradiotherapy in rectal mucinous adenocarcinoma by co-expression network analysis based on proteomic analysis.

For rectal mucinous adenocarcinoma (MAC), identifying biomarkers of neoadjuvant chemoradiotherapy (NCRT) response has become imperative. This study applied label-free mass spectrometry and weighted gene co-expression network analysis to identify hub proteins in association with the NCRT response in 20 rectal MAC patients. We identified 131 differentially abundant proteins and 7 candidate proteins associated with the NCRT response. The immunostaining expressions of six proteins (ENOA, ILEU, MDHM, RM11, PTGDS, and RL3) were significantly associated with the NCRT response. Logistic regression analysis revealed that ENOA (OR = 6.275, P = 0.006) was independent risk hub protein for the NCRT response. Tow hub proteins (ENOA and PTGDS) were identified as significant risk factors by Cox regression analysis. A prognostic risk score system was constructed: risk score = (0.910 × EXPENOA) + (-1.519 × EXPPTGDS), and found to be an independent predictor of DFS in rectal MAC patients (HR = 10.308, P < 0.001). Our study suggested that ENOA may be a novel biomarker for the NCRT response and prognosis in rectal MAC patients. A two-hub-protein-based risk score system might be used for predicting tumor recurrence in rectal MAC patients. SIGNIFICANCE: NCRT resistance is a major problem in the treatment of rectal MAC patients. Identifying robust predictive biomarkers for NCRT resistance is beneficial to the stratified treatment of rectal MAC patients. In this study, label-free mass spectrometry and weighted gene co-expression network analysis identified ENOA as a potential novel biomarker for the NCRT response and prognosis. ENOA may be involved in the process of the NCRT resistance and tumor recurrence through the carbon metabolism pathway.

Prediction of prolonged resolution of chylous ascites after radical D3 resection for colorectal cancer: A population-based experience from a high-volume center.

AIM: This study was aimed to analyze the incidence, risk factors, and management of chylous ascites (CA) after radical D3 resection for colorectal cancer, and to construct a predicting nomogram for prolonged resolution of CA. METHOD: Consecutive colorectal cancer patients who underwent radical D3 resection were included. Logistic analysis was used to identify risk factors of postoperative CA, as well as prolonged CA resolution. A predictive nomogram for prolonged resolution of CA was developed and validated internally. RESULTS: Among 7167 patients included, 277 (3.8%) patients developed CA. Logistic regression analysis demonstrated that laparoscopic operation (OR 1.507; P = 0.017) and tumors fed by the superior mesenteric artery (SMA, OR 2.456; P < 0.001) were independent risk factors of postoperative CA following radical D3 surgery for colorectal cancer. Open operation (OR 0.422; P = 0.027), drainage output on the first day of treatment (OR 1.004; P = 0.016), time to oral intake (OR 1.273; P = 0.042), and time to onset (OR 1.231; P = 0.024) were independently associated with prolonged resolution of postoperative CA (≥7 days). A predictive nomogram for prolonged CA resolution was developed with a C-index of 0.725. CONCLUSION: The incidence of CA after radical D3 surgery of colorectal cancer was 3.8%. Open operation, drainage output on the first day of treatment, time to oral intake, and time to onset were independently associated with prolonged resolution of postoperative CA. A nomogram may assist in tailored treatment decision-making and counseling patient with treatment strategies.

Chylous ascites after complete mesocolic excision for right-sided colon cancer with D3 lymphadenectomy: A retrospective cohort-study.

AIM: This retrospective study was designed to evaluate risk factors of the occurrence and severity of chylous ascites after complete mesocolic excision (CME) and D3 lymphadenectomy in patients with right-sided colon cancer. METHODS: Consecutive patients receiving CME and D3 lymphadenectomy for right-sided colon cancer were included. Risk factors of the occurrence and severity of chylous ascites by using logistic analysis were assessed. A nomogram predicting chylous ascites was constructed. RESULTS: Among 661 patients included in the study, postoperative chylous ascites occurred in 48 (7.3%) patients. Logistic regression analysis demonstrated that prognostic nutritional index (PNI ≤ 47, OR = 2.172, p = 0.016), laparoscopic surgery (OR = 2.798, p = 0.034), operating time (>225 min, OR = 2.645, p = 0.002), and apical lymph node (APN) metastasis (OR = 3.698, p = 0.034) were correlated with the occurrence of postoperative chylous ascites. A nomogram predicting postoperative chylous ascites was constructed (C-index 0.701). 31.2% (15/48) of patients with chylous ascites were resolved in more than 7 days. The number of retrieved lymph nodes (OR = 1.074, 95% CI: 1.002-1.152, p = 0.044) and PNI ≤ 47 (OR = 7.890, 95% CI: 1.224-50.869, p = 0.030) were independently predictive of prolonged chylous ascites resolution (≥7 days). CONCLUSIONS: In our series, 7.3% of patients developed chylous ascites after right hemicolectomy with CME and D3 lymphadenectomy. Laparoscopic surgery, PNI, operation time, and APN metastasis were independently predictive of postoperative chylous ascites. Lower PNI and more retrieved lymph nodes were correlated with prolonged resolution of chylous ascites.

A PCR assay with high sensitivity and specificity for the detection of swine toxoplasmosis based on the GRA14 gene.

Toxoplasma gondii, an intracellular apicomplexan protozoan parasite, can infect all warm-blooded animals. Infected swine are considered one of the most important sources of T. gondii infection in humans. Rapidly and effectively diagnosing T. gondii infection in swine is essential. PCR-based diagnostic tests have been fully developed, and very sensitive and specific PCR is crucial for the diagnosis of swine toxoplasmosis. In this study, we used the T. gondii dense granule protein 14 (GRA14) gene as a target to design specific primers and established a high-specificity and high-sensitivity PCR detection method for swine toxoplasmosis. Notably, this PCR method could detect T. gondii tachyzoite DNA in the acute infection phase. The GRA14 gene PCR assay detected a minimum of 2.35 tachyzoites of T. gondii and can be used for T. gondii detection in blood, tissue, semen, urine and waste feed specimens. A total of 5462 blood specimens collected from pigs in 5 provinces and autonomous regions in southern China during 2016-2017 were assessed by the newly established GRA14 gene PCR method. The overall T. gondii infection rate was 18.9 % (1033/5462). According to the statistical analysis of different regions in China, the positive rates of swine toxoplasmosis from 2016 to 2017 were highest in the Shaanxi, Fujian and Guangdong areas, at 31.7 % (44/139), 21.9 % (86/391) and 18.8 % (874/4645), respectively. Specimens collected in 2017 had a higher positive rate (19.1 %) than those collected in 2016 (16.1 %). In addition, specimens collected in autumn (39.4 %), spring (22.8 %) and winter (18.2 %) had higher positive rates than those collected in summer (3.8 %). These results indicate that the new PCR method based on the T. gondii GRA14 gene has utility for the diagnosis of swine toxoplasmosis and can facilitate the diagnosis of toxoplasmosis in clinical laboratories.

A nomogram predicting the difficulty of laparoscopic surgery for rectal cancer.

PURPOSE: This study aimed to identify the risk factors associated with performing a difficult laparoscopic radical resection of rectal cancer, and to establish a predictive nomogram to help individual clinical treatment decisions. METHODS: A total of 977 patients with rectal cancer who underwent laparoscopic radical resection between January 2014 and December 2016 were enrolled in this study. The difficulty of laparoscopic-assisted rectal resection (LARR) was defined according to the scoring criteria reported by Escal. A logistic regression analysis was performed to identify the variables that may affect the difficulty of LARR, and a nomogram predicting the surgical difficulty was created. RESULTS: A multivariate analysis demonstrated that a BMI > 28 kg/m2, the distance between the tumor and the anal margin ≤ 5 cm, the maximum transverse tumor diameter > 3 cm tumor, interspinous distance < 10 cm, history of abdominal surgery, and preoperative radiotherapy were independent risk factors and they were, therefore, included in the predictive nomogram for identifying a difficult LARR. CONCLUSIONS: This study defined a difficult LARR and identified independent risk factors for a difficult operation and created a predictive nomogram for difficult LARR. This nomogram may facilitate the stratification of patients at risk for being associated with a difficult LARR for rectal cancer.

Pelvimetric and Nutritional Factors Predicting Surgical Difficulty in Laparoscopic Resection for Rectal Cancer Following Preoperative Chemoradiotherapy.

AIM: Laparoscopic total mesorectal excision (LaTME) following preoperative chemoradiotherapy (PCRT) in locally advanced rectal cancer (LARC) is technically demanding. The present study is intended to evaluate predictive factors of surgical difficulty of LaTME following PCRT by using pelvimetric and nutritional factors. METHOD: Consecutive LARC patients receiving LaTME after PCRT were included. Surgical difficulty was classified based upon intraoperative (operation time, blood loss, and conversion) and postoperative outcomes (postoperative hospital stay and morbidities). Pelvimetry was performed using preoperative T2-weighted MRI. Nutritional factors such as albumin-to-globulin ratio (AGR) and prognostic nutritional index (PNI) were calculated. Multivariable logistic analysis was used to identify predictors of high surgical difficulty. A predictive nomogram was developed and validated internally. RESULTS: Among 294 patients included, 36 (12.4%) patients were graded as high surgical difficulty. Logistic regression analysis demonstrated that previous abdominal surgery (OR = 6.080, P = 0.001), tumor diameter (OR = 1.732, P = 0.003), intersphincteric resection (vs. low anterior resection, OR = 13.241, P < 0.001), interspinous distance (OR = 0.505, P = 0.009), and preoperative AGR (OR = 0.041, P = 0.024) were independently predictive of high surgical difficulty of LaTME after PCRT. Then, a predictive nomogram was built (C-index = 0.867). CONCLUSION: Besides previous abdominal surgery, type of surgery (intersphincteric resection), tumor diameter, and interspinous distance, we found that preoperative AGR could be useful for the prediction of surgical difficulty of LaTME after PCRT. A predictive nomogram for surgical difficulty may aid in planning an appropriate approach for rectal cancer surgery after PCRT.