Locally Advanced Rectal Cancer Invading the Gluteus Maximus Muscle Completely Responded to Total Neoadjuvant Therapy.

A 70-year-old male with anal pain and fever was diagnosed with rectal cancer perforation and abscess in the right gluteus maximus (GM) muscle. He underwent a transverse colon colostomy followed by preoperative capecitabine+oxaliplatin. Some local control was achieved but a residual abscess was observed in the right GM muscle. To secure circumferential resection margin by tumor reduction, he received chemoradiotherapy as total neoadjuvant therapy (TNT) and underwent laparoscopic abdominoperineal resection, D3 lymph node dissection, combined coccyx resection, and partial resection of the right GM muscle. The skin defect and pelvic dead space were filled with a right lateral vastus lateral great muscle flap. Histopathologically, the resected specimen showed no tumor cells in the primary tumor or lymph nodes, indicating a pathological complete response (pCR). This case suggests that TNT might improve the R0 resection and pCR rates and overall survival.

A Case Report of Non-typical Annular Pancreas Diagnosed during Laparoscopic Gastric Surgery.

An annular pancreas is a rare anomaly of the pancreas, defined as pancreatic tissue that totally or partly encircles the duodenum, usually the descending portion. A 76-year-old man who was diagnosed with gastric cancer cT3N0M0 Stage IIB underwent laparoscopic distal gastrectomy with D2 lymph node dissection. Intraoperatively, the dorsal half of the duodenal bulb was seen to be half surrounded by the pancreas, and a non-typical annular pancreas was diagnosed. Because of the risk to the pancreas, it was considered impossible to perform anastomosis by a linear stapler as in the usual laparoscopic procedure. Therefore, we performed laparoscopically assisted distal gastrectomy and Billroth-I reconstruction using a circular stapler, and the surgery was completed without difficulties. His postoperative course was good despite the development of a pancreatic fistula, which was an International Study Group for Pancreas Fistula biochemical leak. Some APs can be diagnosed preoperatively, but the rarer subtypes such as ours are more difficult to visualize on imaging. In gastrectomy, it is both oncologically important and technically challenging to perform lymph node dissection around the pancreas. In this case with an especially proximal pancreas, a circular stapler was considered better suited for gastroduodenal anastomosis and required a broader field than that afforded by laparoscopy. A case of non-typical annular pancreas diagnosed during laparoscopic gastric surgery is described.

Tumor-targeted fluorescence labeling systems for cancer diagnosis and treatment.

Conventional imaging techniques are available for clinical identification of tumor sites. However, detecting metastatic tumor cells that are spreading from primary tumor sites using conventional imaging techniques remains difficult. In contrast, fluorescence-based labeling systems are useful tools for detecting tumor cells at the single-cell level in cancer research. The ability to detect fluorescent-labeled tumor cells enables investigations of the biodistribution of tumor cells for the diagnosis and treatment of cancer. For example, the presence of fluorescent tumor cells in the peripheral blood of cancer patients is a predictive biomarker for early diagnosis of distant metastasis. The elimination of fluorescent tumor cells without damaging normal tissues is ideal for minimally invasive treatment of cancer. To capture fluorescent tumor cells within normal tissues, however, tumor-specific activated target molecules are needed. This review focuses on recent advances in tumor-targeted fluorescence labeling systems, in which indirect reporter labeling using tumor-specific promoters is applied to fluorescence labeling of tumor cells for the diagnosis and treatment of cancer. Telomerase promoter-dependent fluorescence labeling using replication-competent viral vectors produces fluorescent proteins that can be used to detect and eliminate telomerase-positive tumor cells. Tissue-specific promoter-dependent fluorescence labeling enables identification of specific tumor cells. Vimentin promoter-dependent fluorescence labeling is a useful tool for identifying tumor cells that undergo epithelial-mesenchymal transition (EMT). The evaluation of tumor cells undergoing EMT is important for accurately assessing metastatic potential. Thus, tumor-targeted fluorescence labeling systems represent novel platforms that enable the capture of tumor cells for the diagnosis and treatment of cancer.

Regulatory T cells induce a suppressive immune milieu and promote lymph node metastasis in intrahepatic cholangiocarcinoma.

BACKGROUND: Emerging evidence indicates that immunogenicity plays an important role in intrahepatic cholangiocarcinoma (ICC). Herein, we systematically evaluated the clinical relevance of immunogenicity in ICC. METHODS: Highly immunogenic ICCs identified in the public dataset and the Cancer Immunome Atlas (TCIA) were assessed to determine the prognostic impact of immunogenicity in ICC and key components after curative resection. We also investigated the clinical relevance of the immune milieu in ICC. RESULTS: Using the Gene Expression Omnibus dataset 89749 and TCIA, we identified CD8+/forkhead box P3 (FoxP3)+ tumour-infiltrating lymphocytes (TILs), T-cell immunoglobulin and mucin domain 3 (TIM-3) and human leukocyte antigen-A (HLA-A) in highly immunogenic ICCs. Immunohistochemical analysis of the in-house cohort showed that intratumoral FoxP3+ TILs correlated with CD8+ TILs (P = 0.045, Fisher's exact test) and that high FoxP3+/CD8+ ratio (FCR) was an important marker for poor survival (P < 0.001, log-rank test). Furthermore, the FCR was higher in tumour-free lymph nodes in ICCs with lymph node metastases than in those without lymph node metastases (P = 0.003, Mann-Whitney U test). CONCLUSIONS: FCR should be considered an important biomarker that represents the immune environment of ICC based on its potentially important role in tumour progression, especially lymph node metastasis.

ADAR1 and AZIN1 RNA editing function as an oncogene and contributes to immortalization in endometrial cancer.

OBJECTIVE: Adenosine-to-inosine (A-to-I) RNA editing is a recently described epigenetic modification, which is believed to constitute a key oncogenic mechanism in human cancers. However, its functional role and clinical significance in endometrial cancer (EC) remain unclear. METHODS: Adenosine Deaminase family Acting on RNA1 (ADAR1) expression and Antizyme inhibitor 1 (AZIN1) RNA editing were examined to clarify the correlation with clinicopathological parameters and prognosis in EC patients. The biological functions and inhibitory effects of ADAR1 knockdown were investigated in JHUCS-1 and TU-ECS-1 EC cell lines. RESULTS: ADAR1 showed significant association with worse histology (P = 0.006), and lymph vascular space involvement (P = 0.049) in EC. The level of AZIN1 RNA editing was also significantly associated with worse histology (P = 0.012). ADAR1 expression was significantly correlated with AZIN1 RNA editing level (R = 0.729, R2 = 0.547, P < 0.001). Multivariate analysis indicated that higher ADAR1 expression along with AZIN1 RNA editing is an independent predictor of prognosis in EC patients (P = 0.015). Knockdown of ADAR1 led to increased MDA-5, RIG-I, PKR, and IRF-7 expression, which in turn resulted in increased levels of Bak and apoptosis in EC cells. CONCLUSIONS: High ADAR1 expression along with AZIN1 RNA editing could be a predictor of worse prognosis in EC. ADAR1 could be a potential therapeutic target in EC patients.

Long-term Survival with a Rare Advanced Primary Gastrointestinal Malignant Melanoma Treated with Laparoscopic Surgery/Immune Checkpoint Inhibitor.

Targeted therapies for malignant melanoma have improved patients' prognoses. A primary gastrointestinal malignant melanoma is very rare, with no standard treatment strategy. We treated a 78-year-old Japanese female with advanced primary gastrointestinal melanoma of the descending colon and gallbladder. We administered a multidisciplinary treatment: surgical resection of the descending colon and gallbladder tumors, resection of the metastatic lymph nodes behind the pancreas head, and immune checkpoint antibody-blockade therapy (nivolumab) for ~4 years. PET/CT demonstrated no recurrent lesion for > 3 years. Multidisciplinary therapies (e.g., surgery, chemotherapy, radiotherapy, target therapy, and immune checkpoint antibody-blockade therapy) can successfully treat primary gastrointestinal malignant melanoma.

The PVT1 lncRNA is a novel epigenetic enhancer of MYC, and a promising risk-stratification biomarker in colorectal cancer.

Accumulating evidence suggests that dysregulation of transcriptional enhancers plays a significant role in cancer pathogenesis. Herein, we performed a genome-wide discovery of enhancer elements in colorectal cancer (CRC). We identified PVT1 locus as a previously unrecognized transcriptional regulator in CRC with a significantly high enhancer activity, which ultimately was responsible for regulating the expression of MYC oncogene. High expression of the PVT1 long-non-coding RNA (lncRNA) transcribed from the PVT1 locus was associated with poor survival among patients with stage II and III CRCs (p < 0.05). Aberrant methylation of the PVT1 locus inversely correlated with the reduced expression of the corresponding the PVT1 lncRNA, as well as MYC gene expression. Bioinformatic analyses of CRC-transcriptomes revealed that the PVT1 locus may also broadly impact the expression and function of other key genes within two key CRC-associated signaling pathways - the TGFß/SMAD and Wnt/ß-Catenin pathways. We conclude that the PVT1 is a novel oncogenic enhancer of MYC and its activity is controlled through epigenetic regulation mediated through aberrant methylation in CRC. Our findings also suggest that the PVT1 lncRNA expression is a promising prognostic biomarker and a potential therapeutic target in CRC.

Integrated fluorescent cytology with nano-biologics in peritoneally disseminated gastric cancer.

Gastric cancer patients positive for peritoneal cytology are at increased risk of tumor recurrence, but although a certain proportion of cytology-positive patients relapse rapidly with aggressive progression, others survive longer with conventional chemotherapies. This heterogeneity makes it difficult to stratify patients for more intensive therapy and poses a substantial challenge for the implementation of precision medicine. We developed a new approach to identify biologically malignant subpopulations in cytology-positive gastric cancer patients, using a green fluorescent protein (GFP)-expressing attenuated adenovirus in which the telomerase promoter regulates viral replication (TelomeScan, OBP-401). The fluorescence emitted from TelomeScan-positive cells was successfully quantified using a multi-mode microplate reader. We then analyzed clinical peritoneal washes obtained from 68 gastric cancer patients and found that patients positive for TelomeScan had a significantly worse prognosis. In 21 cytology-positive patients, the median survival time of those who were TelomeScan positive (235 days) was significantly shorter than that for those who were TelomeScan negative (671 days; P = 0.0062). This fluorescent virus-guided cytology detects biologically malignant cancer cells from the peritoneal washes of gastric cancer patients and may thus be useful for both therapy stratification and precision medicine approaches based on genetic profiling of disseminated cells.

Enhanced AZIN1 RNA editing and overexpression of its regulatory enzyme ADAR1 are important prognostic biomarkers in gastric cancer.

BACKGROUND: Adenosine-to-inosine (A-to-I) RNA editing is catalyzed by adenosine deaminases acting on RNA (ADAR) enzymes. Recent evidence suggests that RNA editing of antizyme inhibitor 1 (AZIN1) RNA is emerging as a key epigenetic alteration underlying cancer pathogenesis. METHODS: We evaluated AZIN1 RNA editing levels, and the expression of its regulator, ADAR1, in 280 gastric tissues from 140 patients, using a RNA editing site-specific quantitative polymerase chain reaction assays. We also analyzed the clinical significance of these results as disease biomarkers in gastric cancer (GC) patients. RESULTS: Both AZIN1 RNA editing levels and ADAR1 expression were significantly elevated in GC tissues compared with matched normal mucosa (P < 0.0001, 0.0008, respectively); and AZIN1 RNA editing was positively correlated with ADAR1 expression. Elevated expression of ADAR1 significantly correlated with poor overall survival (P = 0.034), while hyper-edited AZIN1 emerged as an independent prognostic factor for OS and disease-free survival in GC patients [odds ratio (OR):1.98, 95% CI 1.17-3.35, P = 0.011, OR: 4.55, 95% CI 2.12-9.78, P = 0.0001, respectively]. Increased AZIN1 RNA editing and ADAR1 over-expression were significantly correlated with key clinicopathological factors, such as advanced T stage, presence of lymph node metastasis, distant metastasis, and higher TNM stages in GC patients. Logistic regression analysis revealed that hyper-editing status of AZIN1 RNA was an independent risk factor for lymph node metastasis in GC patients [hazard ratio (HR):3.03, 95% CI 1.19-7.71, P = 0.02]. CONCLUSIONS: AZIN1 RNA editing levels may be an important prognostic biomarker in GC patients, and may serve as a key clinical decision-making tool for determining preoperative treatment strategies in GC patients.

Fluorescence virus-guided capturing system of human colorectal circulating tumour cells for non-invasive companion diagnostics.

BACKGROUND: Molecular-based companion diagnostic tests are being used with increasing frequency to predict their clinical response to various drugs, particularly for molecularly targeted drugs. However, invasive procedures are typically required to obtain tissues for this analysis. Circulating tumour cells (CTCs) are novel biomarkers that can be used for the prediction of disease progression and are also important surrogate sources of cancer cells. Because current CTC detection strategies mainly depend on epithelial cell-surface markers, the presence of heterogeneous populations of CTCs with epithelial and/or mesenchymal characteristics may pose obstacles to the detection of CTCs. METHODS: We developed a new approach to capture live CTCs among millions of peripheral blood leukocytes using a green fluorescent protein (GFP)-expressing attenuated adenovirus, in which the telomerase promoter regulates viral replication (OBP-401, TelomeScan). RESULTS: Our biological capturing system can image epithelial and mesenchymal tumour cells with telomerase activities as GFP-positive cells. After sorting, direct sequencing or mutation-specific PCR can precisely detect different mutations in KRAS, BRAF and KIT genes in epithelial, mesenchymal or epithelial-mesenchymal transition-induced CTCs, and in clinical blood samples from patients with colorectal cancer. CONCLUSIONS: This fluorescence virus-guided viable CTC capturing method provides a non-invasive alternative to tissue biopsy or surgical resection of primary tumours for companion diagnostics.

Early detection of metachronous bile duct cancer in Lynch syndrome: report of a case.

Lynch syndrome is an autosomal dominant disease associated with a high incidence of colorectal, endometrial, stomach, ovarian, pancreatic, ureter and renal pelvis, bile duct and brain tumors. The syndrome can also include sebaceous gland adenomas and keratoacanthomas, and carcinoma of the small bowel. The lifetime risk for bile duct cancer in patients with Lynch syndrome is approximately 2 %. The present report describes a case of Lynch syndrome with metachronous bile duct cancer diagnosed at an early stage. The patient was a 73-year-old Japanese male who underwent a successful left lobectomy of the liver, and there was no sign of recurrence for 2 years postoperative. However, this patient harbored a germline mutation in MLH1, which prompted diagnostic examinations for noncolorectal tumors when a periodic surveillance blood examination showed abnormal values of hepatobiliary enzymes. Although most patients with bile duct cancer are diagnosed at an advanced stage, the bile duct cancer was diagnosed at an early stage in the present patient due to the observation of the gene mutation and the preceding liver tumor. This case illustrates the importance of continuous surveillance for extracolonic tumors, including bile duct cancer, in patients with Lynch syndrome.

[Tumor-infiltrating lymphocytes can be used to screen for lynch syndrome - a case report].

Lynch syndrome is an inherited syndrome associated with the development of colorectal and various other cancers. A 65- year-old male underwent a laparoscopic-assisted right hemi-colectomy for ascending colon cancer (cStage II). Histologically, his tumor was diagnosed as a poorly differentiated adenocarcinoma. Lymphocytic reactions, such as tumor-infiltrating lymphocytes (TIL), and Crohn's-like reactions, were observed. Genetic testing revealed the presence of a pathogenic mutation in the MLH1. In the Lynch syndrome, the most frequently observed findings include the accumulation of mutations, and an early onset of familial colon cancer. Although the case presented here did not show the typical clinical findings of Lynch syndrome, histological examination of the lymphocytic reactions proved useful for screening for Lynch syndrome. Herein, we establish the important role of the pathologist in alerting the clinician to the possibility of Lynch syndrome when the findings of TIL and Crohn's-like reactions are detected.

[A case of gastric cancer developed after pylorus-preserving gastrectomy in a patient with lynch syndrome].

Lynch syndrome is an inherited autosomal dominant disorder caused by germ-line mutation of mismatch repair genes, in which a malignant tumor develops at a young age in the colon, endometrium, stomach, or other tissues. A 54-year-old patient with gastric cancer received pylorus-preserving gastrectomy, and a genetic examination confirmed a pathological variation of the MLH1 gene. Five years after surgery, an upper gastrointestinal endoscopy revealed a residual 0 -IIa+IIc gastric tumor approximately 2 cm in size extending from the anastomotic site to the lesser curvature side of the stomach. The remaining stomach was completely removed. The final diagnosis was T1b (SM) N1M0, StageIB gastric cancer. Microsatellite instability was positive, and we attributed the cancer to Lynch syndrome. In Lynch syndrome, the risk of multicentric gastric cancer is higher than normal, and for the initial therapy, preventive total gastrectomy should be considered as an option.

The adenosine deaminase family acting on RNA 1 can be a useful diagnostic biomarker in chorioamnionitis.

INTRODUCTION: Chorioamnionitis (CAM) involves infection and inflammation of the chorion and amniotic membrane, but there are still no effective diagnostic biomarkers for CAM. METHODS: We investigated the correlation between RNA editing enzyme Adenosine deaminase family acting on RNA 1 (ADAR1) and CAM in chorion and amniotic membrane specimens derived from premature rupture of the membrane (PROM), CAM (pathologically diagnosed), and clinical CAM (clinically diagnosed) patients using reverse transcription polymerase chain reaction (RT-PCR). RESULTS: ADAR1 was upregulated in the chorion and amniotic membrane specimens of CAM and clinical CAM patients (p < 0.001 and p = 0.005). ADAR1 had a significantly higher area under the curve (AUC) (0.735 and 0.828) than markers of inflammation characteristics in diagnosing CAM and clinical CAM patients. ADAR1 also had significantly higher AUC (0.701 and 0.837) than clinical characteristics for CAM and clinical CAM patients. DISCUSSION: ADAR1 can be a useful diagnostic biomarker in CAM patients.

Adenosine Deaminase Family Acting on RNA 1 (ADAR1) May Be a De Novo Target for Endometriosis Treatment.

BACKGROUND/AIM: Adenosine deaminase family acting on RNA 1 (ADAR1) expression was examined to determine its correlation with endometriosis. The biological functions and inhibitory effects of ADAR1 knockdown were investigated in a human endometriotic cell line. MATERIALS AND METHODS: ADAR1 was examined in patients with and without endometriosis using reverse transcription polymerase chain reaction (RT-PCR), and the apoptotic expression of ADAR1 small interfering RNA (siRNA) was confirmed using flow cytometry. The biological functions and inhibitory effects of ADAR1 knockdown were investigated using RT-PCR in a 12Z immortalized human endometriotic cell line. RESULTS: ADAR1 expression was significantly higher in patients with endometriosis than in those without (p<0.001). ADAR1 siRNA increased early and late apoptosis, compared to the mock (24.83%) and control (19.96%) cells. ADAR1 knockdown led to apoptosis through MDA5, RIG-I, IRF3, IRF7, caspase 3, caspase 7, and caspase 8 expression in the cell lines. CONCLUSION: ADAR1 is a potential novel therapeutic target in endometriosis.

BRAF-mutant microsatellite-stable rectal cancer with acquired KRAS mutation leading to drug resistance in liver metastasis.

BRAF-mutant microsatellite-stable colorectal cancer (CRC), metastasized to distant sites, is associated with a poor prognosis. However, the BEACON CRC regimen, comprising a BRAF inhibitor, MEK inhibitor, and anti-EGFR antibody, offered a prolonged prognosis. Nonetheless, resistance to this regimen may occur, as observed in our reported case of CRC, where a KRAS mutation was identified in addition to the BRAF V600E mutation. Here, we present a case of 74-year-old woman with rectal cancer (pT4bN1bM0 Stage IIIc) harboring the BRAF V600E mutation. After resection of the primary tumor and during adjuvant chemotherapy using CAPOX (capecitabine and oxaliplatin), liver and lung metastases became apparent, and a companion diagnosis test revealed the presence of a BRAF V600E mutation. The new lesions were deemed resistant to the CAPOX regimen, and we decided to introduce encorafenib and cetuximab. After resection of liver metastases, encorafenib and cetuximab were reintroduced, but a new lesion appeared in hepatic S7, indicating resistance to the encorafenib and cetuximab regimen. The resistant liver metastasis was subsequently resected. To elucidate the resistance mechanism, we conducted a comprehensive analysis using the FoundationOne CDx cancer gene panel test, revealing the presence of a KRAS Q61H mutation alongside the BRAF V600E mutation. Subsequent liquid biopsy after liver recurrence confirmed the persistence of the KRAS Q61H mutation. Our results highlight the significance of cancer genome profiling tests (CGP tests) and liquid biopsies in guiding treatment strategies for BRAF-mutant colorectal cancer. Therefore, CGP testing offers valuable information for treatment, even if it does not lead to new drug administrations.

BNCT pancreatic cancer treatment strategy with glucose-conjugated boron drug.

Multidisciplinary therapy centered on radical surgery for resectable pancreatic cancer is expected to prolong prognosis, but relies on CA19-9 biomarker levels to determine treatment strategy. Boron neutron capture therapy (BNCT) is a chemoradiotherapy using tumor hyperaccumulator boron drugs and neutron irradiation. The purpose of this study is to investigate novel boron drug agents for BNCT for pancreatic cancer. Bioinformatics was used to evaluate the uptake of current boron amino acid (BPA) drugs for BNCT into pancreatic cancer. The expression of the amino acid transporter LAT1, a BPA uptake transporter, was low in pancreatic cancer and even lower in high CA19-9 pancreatic cancer. In contrast, the glucose transporter was high in high CA19-9 pancreatic cancers and inversely correlated with LAT1 expression. Considering the low EPR effect in pancreatic cancer, we synthesized a small molecule Glucose-BSH, which is boron BSH bound to glucose, and confirmed its specific uptake in pancreatic cancer. uptake of Glucose-BSH was confirmed in an environment compatible with the tumor microenvironment. The therapeutic efficacy and safety of Glucose-BSH by therapeutic neutron irradiation were confirmed with BNCT. We report Glucose-BSH boron drug discovery study of a Precision Medicine BNCT with application to high CA19-9 pancreatic cancer.

Advanced hepatocellular carcinoma with lymph node metastases showing epithelial to mesenchymal transition effectively treated with systemic chemotherapy: Report of a case.

We present a case in which combination chemotherapy was used to successfully treat hepatocellular carcinoma (HCC) with rapid progression of lymph node (LN) metastases after liver resection. In addition, epithelial to mesenchymal transition (EMT) markers were examined immunohistochemically. A 43-year-old man who had been diagnosed with HCC showed an enlarged LN near the hepatic artery proper. After extended left lobectomy with lymphadenectomy in the hepatoduodenal ligament, he experienced rapid progression of metastases to the para-aortic and mediastinal LN. Partial remission was achieved after induction and maintenance of combination chemotherapy using etoposide, carboplatin, epirubicin and 5-fluorouracil. As a consequence of this treatment, the patient survived 10 months. Immunohistochemical studies demonstrated that HCC cells in the metastatic LN showed low expression of E-cadherin and high expression of N-cadherin and vimentin, indicating EMT. Combination chemotherapy may prove effective for patients with HCC accompanied by LN metastases that show features of EMT.

ADAR1 has an oncogenic function and can be a prognostic factor in cervical cancer.

Adenosine deaminase acting on RNA 1 (ADAR1), a recently described epigenetic modifier, is believed to play a critical oncogenic role in human cancers. However, its functional role and clinical significance in cervical cancer (CC) remain unclear. ADAR1 knockdown was performed to investigate its oncogenic functions in SiHa (HPV16), HeLa (HPV18), and Yumoto (non-HPV) CC cell lines. Cytoplasmic and nuclear ADAR1 expression were examined to clarify their correlation with clinicopathological parameters and prognosis in patients with CC. This resulted in increased apoptosis and necroptosis in HPV16 -type SiHa, HPV18-type HeLa, and non-HPV-type Yumoto CC cell lines. Progression-free survival (PFS) rates of patients exhibiting high cytoplasmic and nuclear ADAR1 expression were poorer than those in the other groups (P = 0.016). Multivariate analysis indicated that the combination of higher cytoplasmic and nuclear ADAR1 expression was an independent predictor of prognosis in patients with CC (P = 0.017). ADAR1 could be a potential therapeutic target for HPV-positive or HPV-negative CC. The combination of cytoplasmic and nuclear ADAR1 comprises a better prognostic factor for CC.

Clinical Impact of Prehabilitation on Elective Laparoscopic Surgery in Frail Octogenarians With Colorectal Cancer.

BACKGROUND/AIM: The aim of the present study was to clarify the clinical impact of prehabilitation by the perioperative management center (PERIO) at our hospital in severely frail octogenarians with colorectal cancer. PATIENTS AND METHODS: We compared the clinicopathological characteristics of octogenarians who underwent surgery for colorectal cancer before the establishment of PERIO intervention (Control group) with those who received prehabilitation (PERIO group). All patients were classified as American Society of Anesthesiologists (ASA) class 3 or higher. The primary outcome was the incidence of postoperative complications. RESULTS: There were 21 patients in the Control group and 19 patients in the PERIO group. Operative time was significantly longer in the PERIO group (Control group, 200 min vs. PERIO group, 230 min; p=0.03) and blood loss was significantly higher in the PERIO group (Control group, 5 ml vs. PERIO group, 30 ml; p=0.02). Postoperative complications occurred in 10 patients (47.6%) in the Control group and 3 patients (15.8%) in the PERIO group and were significantly lower in the PERIO group (p=0.03). Postoperative hospital stay was 13 days (range=7-31 days) in the Control group and 11 days (range=8-70 days) in the PERIO group (p=0.39). The rate of discharge directly to home was 81% in the Control group and 93.3% in the PERIO group (p=0.29). CONCLUSION: In frail octogenarians with colorectal cancer of ASA class 3 or higher, the incidence of postoperative complications was significantly lower after PERIO intervention.