Investigation of Expanded Human Adipose-derived Stem Cell Dosage and Timing for Improved Defecation Function.

BACKGROUND/AIM: Although certain treatment options exist for intestinal incontinence, none are curative. Adipose-derived stem cells (ADSCs) have emerged as promising therapeutic agents, but most preclinical studies of their effectiveness for anal function have used autologous or allogeneic ADSCs. In this study, the effectiveness, timing of administration, and required dosage of human ADSCs were investigated for clinical application. MATERIALS AND METHODS: A 10-mm balloon catheter was used to induce anal sphincter injury in immunodeficient mice in the following experimental groups (n=4 per group): ADSC (injected ADSCs after injury), PBS (injected phosphate-buffered saline after injury), and control (uninjured). The effects of different timing (immediately after injection and 30 days following injury) and number of human ADSCs administered was compared among groups based on defecation status and pathological evaluation. RESULTS: In terms of defecation status, groups receiving ≥1×104 human ADSCs after injection showed improvement. Pathological images showed that compared to the PBS group, the thinnest part of the sphincter was thicker for animals that received ≥1×104 human ADSCs, and fibrosis of the sphincter was notable in those treated with 1×103 human ADSCs or PBS. Furthermore, defecation status was improved by administration of human ADSCs, not only immediately after injury, but also at 30 days following injury. CONCLUSION: Human ADSC administration in a mouse model of anal sphincter injury was effective. Injection of ≥1×104 human ADSCs was the amount necessary to improve defecation status, an effect detected in both the acute and chronic phases.

Metastases and treatment-resistant lineages in patient-derived cancer cells of colorectal cancer.

Circulating tumor cells (CTCs) play an important role in metastasis and recurrence. However, which cells comprise the complex tumor lineages in recurrence and are key in metastasis are unknown in colorectal cancer (CRC). CRC with high expression of POU5F1 has a poor prognosis with a high incidence of liver metastatic recurrence. We aim to reveal the key cells promoting metastasis and identify treatment-resistant lineages with established EGFP-expressing organoids in two-dimensional culture (2DOs) under the POU5F1 promotor. POU5F1-expressing cells are highly present in relapsed clinical patients' blood as CTCs. Sorted POU5F1-expressing cells from 2DOs have cancer stem cell abilities and abundantly form liver metastases in vivo. Single-cell RNA sequencing of 2DOs identifies heterogeneous populations derived from POU5F1-expressing cells and the Wnt signaling pathway is enriched in POU5F1-expressing cells. Characteristic high expression of CTLA4 is observed in POU5F1-expressing cells and immunocytochemistry confirms the co-expression of POU5F1 and CTLA4. Demethylation in some CpG islands at the transcriptional start sites of POU5F1 and CTLA4 is observed. The Wnt/ß-catenin pathway inhibitor, XAV939, prevents the adhesion and survival of POU5F1-expressing cells in vitro. Early administration of XAV939 also completely inhibits liver metastasis induced by POU5F1-positive cells.

Triclosan-coated sutures to reduce surgical site infection in abdominal gastrointestinal surgery: A meta-analysis and systematic review.

Background: Previous randomized trials evaluated the effectiveness of triclosan-coated sutures for fascial closure in preventing surgical site infection (SSI). However, available evidence remains still inconclusive. We aimed to evaluate the effectiveness of triclosan-coated sutures in fascia closure in preventing postoperative SSI in elective gastrointestinal surgery. Meta-analysis: A meta-analysis included present outcomes, evaluating the advantages of triclosan-coated compared with non-coated sutures in preventing SSIs for fascia closure of laparotomy in abdominal gastrointestinal surgery. To identify prospective randomized trials regarding this topic, we searched Cochrane Central Register of Controlled Trials (Central) and PubMed with the following search terms: "triclosan or triclosan coated;" "surgical site infection;" and "randomized controlled trial" was searched, respectively. To avoid the evaluation of the heterogenous group of patients, the following studies were excluded; only emergency surgery, or not including gastroenterological surgery. The Mantel-Haenszel random-effects model was performed with R software (CRAN, R3·6·2; https://cran.r-project.org/). Results: This meta-analysis included eleven phase-III and two prospective studies, which comprised 9588 patients. The aggregated phase-III results of the trials demonstrate a significant superiority of triclosan-coated sutures compared with non-coated sutures (random-effect model, OR 0.71, 95 % CI 0.56-0.90, P = 0.0052). Conclusion: The meta-analysis showed benefit with triclosan-coated sutures in preventing SSI after gastrointestinal surgery.

Treatment response prediction of neoadjuvant chemotherapy for rectal cancer by deep learning of colonoscopy images.

In current clinical practice, several treatment methods, including neoadjuvant therapy, are being developed to improve overall survival or local recurrence rates for locally advanced rectal cancer. The response to neoadjuvant therapy is usually evaluated using imaging data collected before and after preoperative treatment or postsurgical pathological diagnosis. However, there is a need to accurately predict the response to preoperative treatment before treatment is administered. The present study used a deep learning network to examine colonoscopy images and construct a model to predict the response of rectal cancer to neoadjuvant chemotherapy. A total of 53 patients who underwent preoperative chemotherapy followed by radical resection for advanced rectal cancer at the Osaka University Hospital between January 2011 and August 2019 were retrospectively analyzed. A convolutional neural network model was constructed using 403 images from 43 patients as the learning set. The diagnostic accuracy of the deep learning model was evaluated using 84 images from 10 patients as the validation set. The model demonstrated a sensitivity, specificity, accuracy, positive predictive value and area under the curve of 77.6% (38/49), 62.9% (22/33), 71.4% (60/84), 74.5% (38/51) and 0.713, respectively, in predicting a poor response to neoadjuvant therapy. Overall, deep learning of colonoscopy images may contribute to an accurate prediction of the response of rectal cancer to neoadjuvant chemotherapy.

Surgery for Rectal Cancer With Mixed Reality of 3D Model During Operation: A Case Report.

Background/Aim: Recently, robotic surgery for rectal cancer has become a common minimally invasive surgery. In addition, the technology of augmented and mixed reality is applied in various living environments, including medicine. We successfully performed robotic surgery for rectal cancer with three-dimensional (3D) images as mixed reality (MR) using HoloLens2. Case Report: The patient was diagnosed with rectal cancer by colonoscopy and a positron-emission computed-tomography scan, and we performed robot-assisted anterior resection. The operator used HoloLens2 and performed the surgery while visualizing 3D images of pelvic anatomy with the location of the rectal cancer as hologram. The operation was performed completely and safely, and she was discharged 11 days after surgery with no postoperative complications. Conclusion: This case presents the usefulness of a MR system offering organ visualization as hologram during surgery.

Cancer Stem Cells Persist Despite Cellular Damage, Emergence of the Refractory Cell Population.

PURPOSE: Cancer stem cells (CSCs) are responsible for chemotherapy resistance and have unique properties that protect them from chemotherapy. Investigating CSCs may help to identify the population that is more resistant to treatments, leading to recurrence. We evaluated persisting CSCs, emerging after chemotherapy that cause tumor recurrence. METHODS: Using human colorectal cancer organoids prepared from surgical specimens, we looked at changes in CSCs, the emergence and changes in the original population, which single-cell analysis identified. RESULTS: With regards to changes in cancer stem cell markers, CD44 showed low levels after 5-fluorouracil administration. Once the CD44-ve population was sorted and cultured, the CD44+ve population gradually emerged, and the CD44-ve population decreased. Compared with the CD44-ve population of an organoid parent, the CD44-ve population proliferated after chemotherapeutic agent stimulation. The CD44-ve population was derived from the CD44+ve population before chemotherapeutic agents. In addition, when the CD44 variants were evaluated, the CD44v9 population remained. In single-cell analysis, we found that POU5F1 was highly expressed in the CD44low population. Velocity analysis showed that the CD44-ve population was induced after chemotherapy and expressed POU5F1. POU5F1-EGFP-Casp9 transfected organoids resulted in the appearance of a CD44-ve population after administration of a chemotherapeutic reagent. Both in vivo and in vitro, the dimerizer administration inhibited tumor growth significantly. CONCLUSIONS: POU5F1 is involved in chemotherapy resistance in relation to stemness. For the treatment against refractory tumors, such as the recurrence after chemotherapy, the treatment should target the emerging specific population such as CD44 (or CD44v9) and proliferative cancer cells.

Efficacy of transanal drainage tube in preventing anastomotic leakage after surgery for rectal cancer: A meta-analysis.

BACKGROUND: Anastomotic leakage (AL) following rectal cancer surgery is an important cause of mortality and recurrence. Although transanal drainage tubes (TDTs) are expected to reduce the rate of AL, their preventive effects are controversial. AIM: To reveal the effect of TDT in patients with symptomatic AL after rectal cancer surgery. METHODS: A systematic literature search was performed using the PubMed, Embase, and Cochrane Library databases. We included randomized controlled trials (RCTs) and prospective cohort studies (PCSs) in which patients were assigned to two groups depending on the use or non-use of TDT and in which AL was evaluated. The results of the studies were synthesized using the Mantel-Haenszel random-effects model, and a two-tailed P value > 0.05 was considered statistically significant. RESULTS: Three RCTs and two PCSs were included in this study. Symptomatic AL was examined in all 1417 patients (712 with TDT), and TDTs did not reduce the symptomatic AL rate. In a subgroup analysis of 955 patients without a diverting stoma, TDT reduced the symptomatic AL rate (odds ratio = 0.50, 95% confidence interval: 0.29-0.86, P = 0.012). CONCLUSION: TDT may not reduce AL overall among patients undergoing rectal cancer surgery. However, patients without a diverting stoma may benefit from TDT placement.

Lymph node metastasis in T1 colorectal cancer: Risk factors and prediction model.

Endoscopic resection is typically performed for early T1 stage colorectal cancer (T1 CRC). Additional surgery is subsequently recommended based on pathological findings; however, the current criteria may result in overtreatment. The present study aimed to re-examine the reported risk factors for lymph node (LN) metastasis in T1 CRC and develop a prediction model using a large multi-institutional dataset. In this retrospective study, the medical records of 1,185 patients with T1 CRC who underwent surgery between January 2008 and December 2020 were investigated. Slides pathologically re-assessable for additional risk factors were re-examined. A total of 251 patients with inadequate data were excluded, and 934 patients were randomly assigned at a ratio of 3:1 to the training and validation datasets. In the univariate analysis, left-sided CRC (P=0.003), deep submucosal invasion depth (P=0.005), poor histological grade (P=0.020), lymphatic invasion (P<0.001), venous invasion (P<0.001) and tumor budding grade 2/3 (P<0.001) were significant risk factors for LN metastasis. A nomogram predicting LN metastasis was developed using these variables, with an area under the received operating characteristic curve (AUC) of 0.786. The nomogram was validated using a validation set with an AUC of 0.721, indicating moderate accuracy. No LN metastases were observed in patients with <90 points using the nomogram; therefore, patients with a low nomogram score may avoid undergoing surgical resection. Prediction of LN metastasis using this developed nomogram may help identify patients who are at high-risk who require surgery.

Ischemia prediction score (IsPS) in patients with strangulated small bowel obstruction: a retrospective cohort study.

BACKGROUNDS: Intestinal ischemia of strangulated small bowel obstruction (SSBO) requires prompt identification and early intervention. This study aimed to evaluate the risk factors and develop a prediction model of intestinal ischemia requiring bowel resection in SSBO. METHODS: This was a single-center, retrospective cohort study of consecutive patients underwent emergency surgery for SSBO from April 2007 to December 2021. Univariate analysis was performed to identify the risk factors for bowel resection in these patients. Two clinical scores (with contrasted computed tomography [CT] and without contrasted CT) were developed to predict intestinal ischemia. The scores were validated in an independent cohort. RESULTS: A total of 127 patients were included, 100 in the development cohort (DC) and 27 in the validation cohort (VC). Univariate analysis showed that high white blood cell count (WBC), low base excess (BE), ascites and reduced bowel enhancement were significantly associated with bowel resection. The ischemia prediction score (IsPS) comprised 1 point each for WBC ≥ 10,000/L, BE ≤ -1.0 mmol/L, ascites, and 2 points for reduced bowel enhancement. The simple IsPS (s-IsPS, without contrasted CT) of 2 or more had a sensitivity of 69.4%, specificity of 65.4%. The modified IsPS (m-IsPS, with contrasted CT) of 3 or more had a sensitivity of 86.7%, specificity of 76.0%. AUC of s-IsPS was 0.716 in DC and 0.812 in VC, and AUC of m-IsPS was 0.838 and 0.814. CONCLUSION: IsPS predicted possibility of ischemic intestinal resection with high accuracy and can help in the early identification of intestinal ischemia in SSBO.

[A Case of Long-Term Survival with Tumor Resection and DOX plus DTIC Therapy for Desmoid Tumor after FAP Surgery].

The patient is a 22-year-old, female. She had a family history of familial adenomatous polyposis(FAP)and a prophylactic total colorectal resection was performed for FAP at age of 18. She presented with fever and abdominal distention and palpated a mass with tenderness in the right lower abdomen. Contrast-enhanced CT scan of the abdomen showed a heterogeneous contrast effect around the tumor margins. With the diagnosis of intra-abdominal desmoid tumor, a partial duodenal resection, small bowel mass resection, and right fallopian tube resection were performed along with the tumor, and an artificial anus was created with the jejunum. Contrast-enhanced CT scan of the abdomen 16 months after resection of desmoid tumor showed a 6.5 cm long desmoid tumor recurrence in the mesentery. She received 5 courses of doxorubicin (DOX)plus dacarbazine(DTIC)therapy followed by continued NSAIDs. Seven years after the operation, she has been able to maintain the shrinkage of the recurrent tumor and is still on medication. Long-term surveillance is necessary because of the possibility of the appearance of other associated lesions in the future.

Tumor-infiltrating T cells as a risk factor for lymph node metastasis in patients with submucosal colorectal cancer.

Approximately 10% of patients with colorectal cancer with submucosal invasion have lymph node metastasis. Pathological risk factors for lymph node metastasis have varying sensitivities and specificities. To predict the risk of lymph node metastasis, the identification of new risk factors is vital. Tumor-infiltrating T cells have been reported to improve the prognosis of many solid tumors. Therefore, the purpose of this study was to examine the relationship between lymph node metastasis and tumor-infiltrating T cells in patients with colorectal cancer with submucosal invasion. We examined CD8+ tumor-infiltrating T cells level as a risk factor for lymph node metastasis in patients with colorectal cancer with submucosal invasion. Using immunohistochemical staining, we identified CD8 + T cells in surgically resected specimens from 98 patients with SM-CRC. We showed that low CD8+ tumor-infiltrating T cells levels are positively correlated with lymph node metastasis. Furthermore, by combining the number of CD8+ tumor-infiltrating T cell and the number of CD103+ tumor-infiltrating T cells, the results showed a high positive predictive value for lymph node metastasis in cases with low numbers of both types of tumor-infiltrating T cells and a high negative predictive value in cases with high numbers of both types of tumor-infiltrating T cells.

Fibroblast Activation Protein and Tertiary Lymphoid Structure in Colorectal Cancer Recurrence.

BACKGROUND/AIM: Fibroblast activation protein (FAP) is known to have prognostic significance in colorectal cancer (CRC). However, FAP and tertiary lymphoid structures (TLSs) have not been associated with each other in predicting the prognosis of CRC recurrence. PATIENTS AND METHODS: FAP expression was evaluated by real-time reverse transcription polymerase chain reaction in 195 CRC patients at Osaka International Cancer Institute (first data set). Immunohistochemistry (IHC) was then performed to stain FAP at the invasive margin (IM) and in the central tumour (CT) in 159 CRC patients at Osaka University Hospital (second data set). Consecutive slides were used to evaluate the presence of TLSs in 159 CRC patients from Osaka University Hospital. RESULTS: The high FAP mRNA expression group (n=82) was associated with poor recurrence-free survival (RFS) compared with the low FAP expression group (n=83) (p=0.004). In the second data set, patients with high FAP expression in CT and TLS absence (n=49) showed significantly poorer RFS compared with those with low expression of FAP in CT and presence of TLSs (n=101) (p=0.002). CONCLUSION: FAP in the CT combined with TLSs was shown to have significant prognostic value in predicting CRC recurrence after curative resection.

Diagnosis of Depth of Submucosal Invasion in Colorectal Cancer with AI Using Deep Learning.

The submucosal invasion depth predicts prognosis in early colorectal cancer. Although colorectal cancer with shallow submucosal invasion can be treated via endoscopic resection, colorectal cancer with deep submucosal invasion requires surgical colectomy. However, accurately diagnosing the depth of submucosal invasion via endoscopy is difficult. We developed a tool to diagnose the depth of submucosal invasion in early colorectal cancer using artificial intelligence. We reviewed data from 196 patients who had undergone a preoperative colonoscopy at the Osaka University Hospital and Osaka International Cancer Institute between 2011 and 2018 and were diagnosed pathologically as having shallow submucosal invasion or deep submucosal invasion colorectal cancer. A convolutional neural network for predicting invasion depth was constructed using 706 images from 91 patients between 2011 and 2015 as the training dataset. The diagnostic accuracy of the constructed convolutional neural network was evaluated using 394 images from 49 patients between 2016 and 2017 as the validation dataset. We also prospectively tested the tool from 56 patients in 2018 with suspected early-stage colorectal cancer. The sensitivity, specificity, accuracy, and area under the curve of the convolutional neural network for diagnosing deep submucosal invasion colorectal cancer were 87.2% (258/296), 35.7% (35/98), 74.4% (293/394), and 0.758, respectively. The positive predictive value was 84.4% (356/422) and the sensitivity was 75.7% (356/470) in the test set. The diagnostic accuracy of the constructed convolutional neural network seemed to be as high as that of a skilled endoscopist. Thus, endoscopic image recognition by deep learning may be able to predict the submucosal invasion depth in early-stage colorectal cancer in clinical practice.

Combined Inflammation and Nutrition Factors Reinforce the Prognostic Prediction for Stage III Colorectal Cancer Patients.

BACKGROUND/AIM: Previous studies have shown that postoperative adjuvant chemotherapy improves overall survival in patients with stage III colorectal cancer (CRC). However, adjuvant chemotherapy may not be necessary for some patients. This study aimed to develop a new nutritional-inflammation score, which would be useful in identifying a favorable prognosis group among stage III CRC patients. PATIENTS AND METHODS: This retrospective study included 262 patients with stage III CRC who underwent curative surgery and were divided into two groups: a training set (TS) of 162 patients and a validation set (VS) of 100 patients. In the TS, clinicopathological factors were tested using a Cox regression model, and a new prognostic model was developed. RESULTS: Multivariate analyses in TS revealed that lymph node metastasis (N2) (p=0.002), low albumin (p=0.017), high monocyte counts (p=0.008), and low platelet counts (p=0.018) were independent risk factors for disease free survival (DFS). The Kansai prognostic score (KPS) was assessed by 1 point each for <3.5 g/dl albumin level, >450 monocyte counts, and <1.65×105 platelet counts. Using KPS, DFS and overall survival (OS) were validated in VS. The C-indices of KPS to predict DFS and OS in TS were 0.707 and 0.772. It was validated in VS that the C-indices of KPS to predict DFS and OS were 0.618 and 0.708, respectively. A high KPS was a significant predictor of DFS and OS. CONCLUSION: KPS serves as a new model for the prognosis of patients with stage III CRC.

Robotic complete mesocolic excision of right-sided colon cancer with bulky lymph node metastases using the da Vinci® Si™ system: A case report.

Reports on robotic surgery in the treatment of right-sided colorectal cancer most commonly use the da Vinci® Xi™ system; however, with the increasing popularity of robotic surgery for the treatment of colon cancer, it is likely to be performed using the da Vinci Si™ and X™ systems. The present study reported the case of a 63-year-old woman who underwent complete mesocolic excision (CME) with the da Vinci Si system involving a rotation technique for ascending colon cancer with bulky lymph node metastasis to the anterior pancreas. Robot-assisted right hemicolectomy was planned for this patient with T4aN2bM0, stage IIIc cancer. A lap protector and EZ access (Hakko Co. Ltd.) were fixed in the umbilical incision, and the da Vinci camera port was placed just off-center at the EZ access to allow the camera port to be repositioned by rotating it. The medial approach was used. The bulky metastatic lymph nodes at the head of the pancreas were dissected after ligating the right colic artery and vein. During CME, rotation of the EZ access was used to avoid interference between the robotic arms. The right colon was released from the retroperitoneum and resected. A functional end-to-end anastomosis was created, and right colectomy was successfully completed. The total operation time was 271 min and the console time with the da Vinci Si system was 140 min. The patient was discharged on postoperative day 8 without complications. In conclusion, robotic right colectomy was successfully performed and rotation of the EZ access facilitated robotic surgery using the da Vinci Si system.

PLXND1/SEMA3E Promotes Epithelial-Mesenchymal Transition Partly via the PI3K/AKT-Signaling Pathway and Induces Heterogenity in Colorectal Cancer.

Colorectal cancer (CRC) is a major cause of cancer-related deaths. Metastasis is enhanced through epithelial-mesenchymal transition (EMT), a process primarily induced by the transforming growth factor beta (TGF-ß)-mediated canonical Smad pathway. This study focused on plexin D1 (PLXND1), a chemoreceptor for the ligand SEMA3E to mechanosensory, showing that PLXND1 induces EMT via activation of the PI3K/AKT pathway in CRC cells. The findings showed that PLXND1-knockdown decreases cell migration and invasion significantly, and that the binding of p61-SEMA3E to the PLXND1 enhances the invasiveness and migration through EMT. Furin inhibitor suppresses EMT, decreasing cell migration and invasion. Furin cleaves full-length SEMA3E and converts it to p61-SEMA3E, suggesting that furin inhibitors block PLXND1 and p61-SEMA3E binding. Furin is a potential therapeutic target for the purpose of suppressing EMT by inhibiting the binding of p61-SEMA3E to PLXND1. In vivo experiments have shown that PLXND1-knockdown suppresses EMT. Mesenchymal cells labeled with ZEB1 showed heterogeneity depending on PLXND1 expression status. The high-expression group of PLXND1 in 182 CRC samples was significantly associated with poor overall survival compared with the low-expression group (P = 0.0352, median follow-up period of 60.7 months) using quantitative real-time polymerase chain reaction analysis. Further research is needed to determine whether cell fractions with a different expression of PLXND1 have different functions.

Risk Factors for Predicting Lymph Node Metastasis in Submucosal Colorectal Cancer.

Objectives: The cornerstone of treating colorectal cancer (CRC) is generally a surgical resection with lymph node (LN) dissection. The tools for predicting lymph node metastasis (LNM) in submucosal (SM) CRC are useful to avoid unnecessary surgical resection. Methods: Retrospectively, we analyzed 526 consecutive patients with SM CRC who underwent surgical resection at the Osaka International Cancer Institute, Osaka University Hospital, and Minoh City Hospital, Japan, between 1984 and 2012. The Osaka International Cancer Institute group and the Osaka University Hospital group were randomly divided into a training set and a test set of 2:1. The prediction model was validated in Minoh City Hospital. Results: We partitioned patients using three risk factors involved in the presence or absence of LNM in SM CRC: lymphatic invasion (Ly), budding grade (BD) and the depth of submucosal invasion (DSI) (cut-off value 2789 µm) that were significantly different in the multivariate analysis. As a result, a predictive model of "LNM <5%" when "Ly negative and DSI <2789 µm" was evaluated. We similarly partitioned by DSI 3000 µm as easy-to-evaluate values in clinical use. We developed the additional model for predicting LNM is 1.05%, that is, LNM <5%, when there are "Ly negative and DSI <3000 µm." Conclusions: As a limitation, only patients who underwent surgical resection were included in this study. This predictive model could help clinicians and CRC patients decide on the additional surgery required after endoscopic resection.

The Geriatric Nutritional Risk Index as a Prognosis Predictor in Patients With Rectal Cancer Receiving Neoadjuvant Chemotherapy.

BACKGROUND/AIM: There are few reports on the clinical significance of the geriatric nutritional risk index (GNRI) in patients with locally advanced rectal cancer who undergo preoperative chemotherapy (NAC, neoadjuvant chemotherapy) followed by radical resection; this study examined the relationship between preoperative GNRI, postoperative complications, and prognosis in these patients. PATIENTS AND METHODS: Fifty-seven patients with rectal cancer who underwent radical resection after NAC at Osaka University Hospital between November 2011 and May 2018 were included. The GNRI was calculated as follows: GNRI= [1.489×serum albumin level (g/l)]+[41.7×present/ideal body weight (kg)]. Patients were classified into high (GNRI ≥96.74; n=36) and low GNRI (GNRI <96.74; n=21) groups, based on the results of the receiver operating characteristic curve analysis. RESULTS: The Kaplan-Meier analysis showed that the low GNRI group had a significantly poorer cancer-specific survival (CSS) and a poorer overall survival tendency than the high GNRI group. In the univariate analysis, venous invasion, lymphatic vessel invasion, and low GNRI were significantly correlated with CSS; depth of tumor invasion, lymph node metastasis, and lymphatic vessel invasion were significantly correlated with disease-free survival (DFS). In the multivariate analysis, there were no significantly poor prognostic factors for CSS and DFS. CONCLUSION: Preoperative GNRI may be a useful predictor for recurrence and poor prognosis in elderly patients with rectal cancer who undergo radical resection after NAC. Further studies and accumulation of cases should investigate the relationship between preoperative GNRI and prognosis after NAC in elderly patients.

Postoperative pain management after concomitant sacrectomy for locally recurrent rectal cancer.

PURPOSE: To assess pain management in patients post-sacrectomy, focusing on opioid use, and to identify the factors associated with postoperative pain. METHODS: Patients who underwent resection of locally recurrent rectal cancer (LRRC) with concomitant sacrectomy at one of two hospitals between 2007 and 2020 were reviewed retrospectively. We examined the use of opioids preoperatively and postoperatively. Patients were classified into high and low sacrectomy groups based on the sacral bone resection level passing through the S3 vertebra. RESULTS: Sixty-four patients were enrolled. Opioid use was significantly higher in the high sacrectomy group than in the low sacrectomy group at all times assessed: on postoperative days 7, 14, 30, 90, 180, and 365. Opioid use 3 months after locally recurrent rectal cancer surgery was significantly higher in patients with local re-recurrence of the tumor than in those without re-recurrence (p < 0.05), and the median morphine-equivalent opioid use 3 months postoperatively was significantly higher in the high sacrectomy group (30 vs. 0 mg/day; p < 0.05). CONCLUSIONS: Opioid use after concomitant sacrectomy for LRRC was higher in the high sacrectomy group. Prolonged postoperative pain or increasing pain was associated with local recurrence.