Implementable assay for monitoring minimum residual disease after radical treatment for colorectal cancer.

Considering the cost and invasiveness of monitoring postoperative minimal residual disease (MRD) of colorectal cancer (CRC) after adjuvant chemoradiotherapy (ACT), we developed a favorable approach based on methylated circulating tumor DNA to detect MRD after radical resection. Analyzing the public database, we identified the methylated promoter regions of the genes FGD5, GPC6, and MSC. Using digital polymerase chain reaction (dPCR), we termed the "amplicon of methylated sites using a specific enzyme" assay as "AMUSE." We examined 180 and 114 pre- and postoperative serial plasma samples from 28 recurrent and 19 recurrence-free pathological stage III CRC patients, respectively. The results showed 22 AMUSE-positive of 28 recurrent patients (sensitivity, 78.6%) and 17 AMUSE-negative of 19 recurrence-free patients (specificity, 89.5%). AMUSE predicted recurrence 208 days before conventional diagnosis using radiological imaging. Regarding ACT evaluation by the reactive response, 19 AMUSE-positive patients during their second or third blood samples showed a significantly poorer prognosis than the other patients (p = 9E-04). The AMUSE assay stratified four groups by the altered patterns of tumor burden postoperatively. Interestingly, only 34.8% of cases tested AMUSE-negative during ACT treatment, indicating eligibility for ACT. The AMUSE assay addresses the clinical need for accurate MRD monitoring with universal applicability, minimal invasiveness, and cost-effectiveness, thereby enabling the timely detection of recurrences. This assay can effectively evaluate the efficacy of ACT in patients with stage III CRC following curative resection. Our study strongly recommends reevaluating the clinical application of ACT using the AMUSE assay.

Prognostic significance of a novel index score based on the inflammation-based prognostic scores of patients with colorectal cancer.

BACKGROUND AND AIM: This study aimed to clarify the prognostic value of various inflammation-based prognostic scores (IBPSs) in patients who underwent radical surgery for colorectal cancer (CRC) and to develop a novel prognostic index using IBPSs and other predictive factors. METHODS: Data of 1157 patients who underwent radical surgery for CRC were reviewed. The predictive value of various IBPSs in determining the CRC prognosis was compared. A novel index score based on the IBPSs and other parameters that were associated with survival in patients with CRC was established, and its usefulness was evaluated. RESULTS: The patients were randomly divided into the training (n = 694) and validation (n = 463) sets. Male sex (P = 0.0001), age ≥ 75 years (P < 0.0001), a carcinoembryonic antigen (CEA) level of > 5 (P = 0.0009), a C-reactive protein/albumin ratio (CAR) of ≥ 0.04 (P = 0.0033), and a prognostic nutritional index (PNI) of < 43.1 (P = 0.0004) were poor independent prognostic factors of overall survival. The novel index score was calculated based on the scores of these five prognostic factors. The Kaplan-Meier survival curves showed that the CRC patients with higher novel index scores in the training and validation datasets had poorer overall survival. CONCLUSIONS: CAR and PNI were superior to other IBPSs for predicting the prognosis of CRC patients. The novel index score established based on sex, age, CEA level, CAR, and PNI can predict the prognosis of CRC with more precise and clearer stratification than the individual parameters alone.

Primary esophageal malignant melanoma without recurrence after surgery and adjuvant therapy with nivolumab.

Primary malignant melanoma of the esophagus is a rare disease with a severely poor prognosis. Here, we report a patient with primary malignant melanoma of the esophagus surviving without recurrence after surgery and adjuvant therapy with nivolumab. The patient was a 60-year-old female with dysphagia. Esophagogastroscopy showed an elevated dark brown tumor in the lower thoracic esophagus. A histological examination of the biopsy revealed human melanoma black 45 and melan-A positivity. The patient was diagnosed with primary malignant melanoma of the esophagus and was treated with radical esophagectomy. As postoperative treatment, the patient was given nivolumab (240 mg/body) every 2 weeks. Although bilateral pneumothorax occurred after 2 courses, she recovered after chest drainage. Nivolumab treatment is still ongoing over 1 year after the surgery, and the patient has survived without recurrence. We conclude that nivolumab is an optimal option as a postoperative adjuvant treatment for PMME.

Comparison of Laparoscopic and Open Emergency Surgery for Colorectal Perforation: A Retrospective Study.

Background: This study aimed to clarify the safety and efficacy of laparoscopic surgery for colorectal perforation by comparing the clinical outcomes between laparoscopic and open emergency surgery for colorectal perforation. Materials and Methods: We retrospectively reviewed the data of 116 patients who underwent surgery for colorectal perforation. The patients were categorized into two groups: the open group included patients who underwent laparotomy, and the laparoscopic group included those who underwent laparoscopic surgery. Clinical and operative characteristics and postoperative outcomes were evaluated. Results: The open and laparoscopic groups included 67 and 49 patients, respectively. More than half of the patients in both groups developed perforation in the sigmoid colon (open, 58.2%; laparoscopic, 61.2%). The most common cause of perforation was diverticulum, followed by colorectal cancer. The mean intraoperative blood loss was significantly lower in the laparoscopic group than in the open group (70.0 mL versus 160.3 mL; P = .0290). The incidence of surgical site infection was lower in the laparoscopic group than in the open group (2.0% versus 13.4%; P = .0430). There were no significant differences in either the short- or long-term outcomes between the two groups. Univariate and multivariate analyses showed that the choice of surgical approach (open versus laparoscopic) did not affect overall survival in patients with colorectal perforation. Conclusion: The laparoscopic approach for colorectal perforation in an emergency setting can be safely performed and provides certain advantages over an open approach in suitable patients.

A case of undifferentiated pleomorphic sarcoma in esophagus after multiple cancer treatments of surgery and chemoradiotherapy.

BACKGROUND: Undifferentiated pleomorphic sarcoma (UPS) in the esophagus is extremely rare. Therefore, there are few reports of UPS in the esophagus (UPSE). We present a case of UPSE after multiple cancer treatments. CASE PRESENTATION: A 73-year-old man with a history of cancer treatment, including distal gastrectomy, transverse colectomy, and chemoradiotherapy, was diagnosed with an elevated lesion such as a submucosal tumor in the lower esophagus by regular endoscopy. A boring biopsy was performed, and the specimen showed features of sarcoma. The patient underwent a partial esophagectomy without lymph node dissection. Histopathological findings confirmed an undifferentiated pleomorphic sarcoma. Adjuvant therapy was not administered, and the patient survived without recurrence 1 year after surgery. CONCLUSIONS: Currently, complete resection is the only treatment option for UPSE. An optimal treatment strategy using chemotherapy or radiotherapy should be established.

Association Between Anti-Helicobacter pylori Antibody Seropositive and De Novo Gallstone Formation After Laparoscopic Sleeve Gastrectomy for Japanese Patients with Severe Obesity.

PURPOSE: Patients who have undergone bariatric surgery are at risk for gallstone formation. However, the incidence of gallstone formation after bariatric surgery has not been adequately studied in the Japanese population. We aimed to elucidate the incidence and risk factors for gallstone formation after laparoscopic sleeve gastrectomy (LSG) for Japanese patients with severe obesity. METHODS: We conducted a retrospective cohort study among patients with severe obesity treated with LSG between April 2017 and June 2020 at two institutions. Patients who had received previous cholecystectomy, had preoperative gallstones, and had received postoperative prophylactic ursodeoxycholic acid were excluded. Body weight, body mass index, and blood data were collected at each follow-up visit before and after the surgery. Follow-up abdominal ultrasonography was performed 6-12 months after surgery, and the incidence of gallstones was calculated. The association between the data and gallstone formation was evaluated. RESULTS: During the study period, we performed LSG for 98 patients. Of these, 61 cases remained by above conditions and were examined using abdominal ultrasonography over 6 months after surgery. The incidence of gallstones was 23.0% and that of symptomatic gallstones was 3.3%. Anti-Helicobacter pylori antibody seropositive and titer were the only factors that showed significant association with de novo gallstone formation after LSG. CONCLUSIONS: Anti-Helicobacter pylori antibody seropositive may be associated with de novo gallstone formation after LSG for Japanese patients with severe obesity.

New index combining multiple inflammation-based prognostic scores for predicting the prognosis of gastric cancer patients.

Background and Aim: Several inflammation-based scores have prognostic value for patients diagnosed with various cancers. However, using only a single inflammation-based prognostic score may be unreliable, as the cut-off values and relative usefulness among various inflammation-based prognostic scores vary. We established a new combined index of four inflammation-based prognostic scores, namely the neutrophil/lymphocyte ratio, platelet/lymphocyte ratio, prognostic index, and prognostic nutritional index, and assessed its usefulness to predict the prognosis of gastric cancer. Methods and Results: We reviewed the data of 635 patients who underwent surgical resection for gastric cancer. We calculated the combined index as the total value of each of the four included inflammation-based prognostic scores and analyzed the relationship between the combined index and postoperative prognosis of gastric cancer. The new combined index was represented as a value between 0 and 6 in each patient. The Kaplan-Meier survival curves showed that patients whose combined index was 0 had good long-term outcomes, while the prognosis of patients whose combined index ranged from 4 to 6 was poor. Conclusion: This new combined index was strongly associated with poor prognosis in patients who underwent surgery for gastric cancer. It is inferred that it can predict patient prognosis after surgical resection for gastric cancer with a stronger correlation and clearer stratification than a single inflammation-based prognostic score.

Prediction of hospital mortality after colorectal perforation surgery from inflammation-based prognostic scores.

Background: Inflammation-based prognostic scores have prognostic value in cancer or cardiovascular disease patients. This study evaluated the prognostic value of inflammation-based prognostic scores in colorectal perforation patients. Methods: Data of 97 patients who underwent surgery for colorectal perforation were reviewed. We calculated various inflammation-based prognostic scores and analyzed the relationship between inflammation-based prognostic score and hospital mortality due to colorectal perforation. Results: Multivariate analyses of hospital mortality revealed neutrophil-lymphocyte ratio (P = .0021), C-reactive protein/albumin ratio (P = .0224), and prognostic nutritional index (P = .0078) as independent predictive factors. The Kaplan-Meier analysis showed that patients who met all of the following parameters avoided hospital death: neutrophil-lymphocyte ratio < 30, prognostic nutritional index ≥ 27.2, age < 75 years, and perforation of the left colon. Conclusion: Neutrophil-lymphocyte ratio, C-reactive protein/albumin ratio, and prognostic nutritional index were superior to other inflammation-based prognostic scores in predicting mortality of colorectal perforation. Neutrophil-lymphocyte ratio, prognostic nutritional index, patient's age, and sidedness of the perforation site may be useful parameters to identify subgroups in which a favorable prognosis can be expected.

Combined laparoscopic and thoracoscopic surgical repair of Bochdalek hernia in an adult: a case report.

BACKGROUND: Bochdalek hernia is a rare disease in adults. Diaphragmatic hernia in adults has been repaired using minimally invasive surgery through laparoscopy or thoracoscopy. However, the literature regarding the combined use of laparoscopy and thoracoscopy for the repair of Bochdalek hernia is limited. CASE PRESENTATION: A 26-year-old man diagnosed with Bochdalek hernia was managed through combined abdominal and thoracic endoscopic surgery. On laparoscopy, the omentum prolapsed into the left thoracic cavity through the posterolateral area of the left diaphragm. On thoracoscopy, no adhesions of the omentum were seen in the thoracic cavity. The omentum was drawn back to the abdominal cavity, and a 4 × 3-cm hernial orifice was identified. The hernia orifice was repaired through simple closure with sutures laparoscopically. The patient's postoperative course was uneventful with no recurrences within the first year post-surgery. CONCLUSION: Combined laparoscopic and thoracoscopic surgery is a safe and effective method for Bochdalek hernial repair in adults.

Gastric glomus tumor with a preoperative diagnosis by endoscopic ultrasonography-guided fine needle aspiration: a case report.

A gastric glomus tumor (GGT) is a rare gastric submucosal tumor that can become malignant. A preoperative diagnosis would allow for a more informed decision regarding the treatment strategy. We present the case of an asymptomatic man with a GGT that was diagnosed during a preoperative examination. Upper gastrointestinal endoscopy was performed in a 64-year-old man and revealed a submucosal tumor at the lesser curvature of the antrum of the stomach. Endoscopic ultrasonography showed a 12-mm-sized hypoechoic tumor in the second and third layers of the stomach wall. A histologic diagnosis of GGT was made using endoscopic ultrasonography-guided fine needle aspiration (EUS-FNA). Abdominal contrast-enhanced computed tomography was performed, but the identification of the tumor was difficult owing to poor enhancement. The gradual growth of the tumor made it necessary to perform an operation. Laparoscopy and endoscopy cooperative surgery was performed without any complications. The tumor cells were immunohistochemically positive for alpha-smooth muscle actin, h-caldesmon, and collagen type IV but were negative for desmin, discovered on GIST-1, S-100 protein, cluster of differentiation 34, epithelial membrane antigen, and cytokeratin AE1/AE3. The final diagnosis was identical to the preoperative diagnosis made using EUS-FNA. EUS-FNA is a useful method for the preoperative diagnosis of small submucosal tumors, including GGTs.

Comparison of Inflammation-Based Prognostic Scores Associated with the Prognostic Impact of Adenocarcinoma of Esophagogastric Junction and Upper Gastric Cancer.

BACKGROUND: Several inflammation-based prognostic scores have a prognostic value in patients with various cancers. This study investigated the prognostic value of various inflammation-based prognostic scores in patients who underwent a surgery for adenocarcinoma of the esophagogastric junction (AEG) and upper gastric cancer (UGC). METHODS: We reviewed data of 206 patients who underwent surgery for AEG and UGC. We calculated neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), Glasgow Prognostic Score (GPS), modified GPS (mGPS), C-reactive protein (CRP)/albumin (Alb) ratio, prognostic index (PI), and prognostic nutritional index (PNI) and analyzed the relationship between these biomarkers and postoperative prognosis. RESULTS: In multivariate analyses for overall survival, mGPS (P = 0.0337, hazard ratio [HR] = 5.211), PI (P = 0.0002, HR = 21.20), and PNI (P < 0.0001, HR = 6.907) were identified as independent predictive factors. A multivariate analysis for recurrence-free survival showed that only PI (P = 0.0006, HR = 11.89) and PNI (P = 0.0002, HR = 4.972) were independent predictive factors among the above-mentioned inflammation-based prognostic scores. CONCLUSIONS: In various inflammation-based prognostic scores, PI and PNI were more strongly associated with poor prognosis in patients who underwent surgery for AEG and UGC.

Efficacy of endoscopic ultrasound with artificial intelligence for the diagnosis of gastrointestinal stromal tumors.

BACKGROUND: Although endoscopic ultrasound (EUS) is reported to be suitable for determining the layer from which subepithelial lesions (SELs) originate, it is difficult to distinguish gastrointestinal stromal tumor (GIST) from non-GIST using only EUS images. If artificial intelligence (AI) can be used for the diagnosis of SELs, it should provide several benefits, including objectivity, simplicity, and quickness. In this pilot study, we propose an AI diagnostic system for SELs and evaluate its efficacy. METHODS: Thirty sets each of EUS images with SELs ≥ 20 mm or < 20 mm were prepared for diagnosis by an EUS diagnostic system with AI (EUS-AI) and three EUS experts. The EUS-AI and EUS experts diagnosed the SELs using solely the EUS images. The concordance rates of the EUS-AI and EUS experts' diagnoses were compared with the pathological findings of the SELs. RESULTS: The accuracy, sensitivity, and specificity for SELs < 20 mm were 86.3, 86.3, and 62.5%, respectively for the EUS-AI, and 73.3, 68.2, and 87.5%, respectively, for the EUS experts. In contrast, accuracy, sensitivity, and specificity for SELs ≥ 20 mm were 90.0, 91.7, and 83.3%, respectively, for the EUS-AI, and 53.3, 50.0, and 83.3%, respectively, for the EUS experts. The area under the curve for the diagnostic yield of the EUS-AI for SELs ≥ 20 mm (0.965) was significantly higher than that (0.684) of the EUS experts (P = 0.007). CONCLUSION: EUS-AI had a good diagnostic yield for SELs ≥ 20 mm. EUS-AI has potential as a good option for the diagnosis of SELs.

CTDSP1 inhibitor rabeprazole regulates DNA-PKcs dependent topoisomerase I degradation and irinotecan drug resistance in colorectal cancer.

Irinotecan specifically targets topoisomerase I (topoI), and is used to treat various solid tumors, but only 13-32% of patients respond to the therapy. Now, it is understood that the rapid rate of topoI degradation in response to irinotecan causes irinotecan resistance. We have published that the deregulated DNA-PKcs kinase cascade ensures rapid degradation of topoI and is at the core of the drug resistance mechanism of topoI inhibitors, including irinotecan. We also identified CTD small phosphatase 1 (CTDSP1) (a nuclear phosphatase) as a primary upstream regulator of DNA-PKcs in response to topoI inhibitors. Previous reports showed that rabeprazole, a proton pump inhibitor (PPI) inhibits CTDSP1 activity. The purpose of this study was to confirm the effects of rabeprazole on CTDSP1 activity and its impact on irinotecan-based therapy in colon cancer. Using differentially expressing CTDSP1 cells, we demonstrated that CTDSP1 contributes to the irinotecan sensitivity by preventing topoI degradation. Retrospective analysis of patients receiving irinotecan with or without rabeprazole has shown the effects of CTDSP1 on irinotecan response. These results indicate that CTDSP1 promotes sensitivity to irinotecan and rabeprazole prevents this effect, resulting in drug resistance. To ensure the best chance at effective treatment, rabeprazole may not be a suitable PPI for cancer patients treated with irinotecan.

Primary anorectal malignant melanoma with laparoscopic abdominoperineal resection: a case study and review of the relevant literature.

ARMM is a disease with a poor prognosis. ARMM is often diagnosed at an advanced stage, and the 5-year survival rate of ARMM is < 20%. Although the number of case reports on ARMM is gradually increasing, the optimal treatment strategy for ARMM remains controversial. We report the case of an 81-year-old woman who had experienced bloody stool for 6 months before her diagnosis and who had been initially diagnosed with hemorrhoids. The pathological diagnosis of a biopsy specimen was malignant melanoma. Other examinations showed no evidence of lymph node or distant metastasis. Based on these results, laparoscopic abdominoperineal resection was performed. Three months later on her first follow-up examination, distant metastasis to the lung and liver was detected. Immunotherapy using Nivolumab was initiated to treat the recurrent disease. We reviewed the characteristics of a total of 1834 ARMM patients described in previous reports on ARMM for which the full text was available on PubMed. We experienced a case of ARMM. The prognosis of ARMM is still poor, regardless of the surgical procedure. Previous studies and our case report suggest that systemic therapy, such as immunotherapy using an anti-PD-1 ligand may be more important than reinforcement of local control for improving the prognosis of ARMM patients.

Reintroduction of nivolumab in a patient with gastric cancer after improvement of nivolumab-induced acute interstitial nephritis: a case report.

Nivolumab, an anti-programmed cell death-1 (PD-1) antibody, has attracted increasing attention as a new treatment modality for gastric cancer. Herein, a case of acute kidney injury in a 66-year-old man with gastric cancer treated with nivolumab is presented. Kidney biopsy revealed severe acute interstitial nephritis and mild immunoglobulin A nephropathy. The cause of acute kidney injury was considered as acute interstitial nephritis because the main site of the lesion was the tubulointerstitium. Cessation of nivolumab and oral prednisolone administration rapidly improved the patient's renal function. Nivolumab was then restarted without worsening of renal function. To the best of the authors knowledge, this is the first case in which reintroduction of nivolumab was successfully performed in a patient with gastric cancer. Further, the relevant literature was reviewed on nivolumab-induced acute interstitial nephritis.

Postoperative C-reactive protein/albumin ratio is a biomarker of risk of recurrence and need for adjuvant chemotherapy for stage III colorectal cancer.

BACKGROUND: Adjuvant chemotherapy is generally recommended for patients with stage III colorectal cancer. Even with adjuvant chemotherapy, 20-30% of such patients develop recurrences; the risk factors for recurrence are currently unclear. The preoperative systemic inflammation index has been linked to poor prognoses in patients with colorectal cancer; however, the relationship between postoperative systemic inflammation index and recurrence is unclear. We aimed to evaluate the association between preoperative and postoperative systemic inflammation indexes and recurrence in patients with stage III colorectal cancer. METHODS: The following laboratory data of 133 patients with stage III colorectal cancer were analyzed: preoperative and postoperative C-reactive protein/albumin ratios (CAR); neutrophil to lymphocyte ratios (NLR); and platelet to lymphocyte ratios (PLR) and their relationships with recurrence analyzed. RESULTS: The optimal cutoff values for systemic inflammation indexes were determined by examining receiver operating characteristic curves. Multivariate analyses indicated that N-stage, postoperative complications, preoperative NLR, and postoperative CAR were independent predictors of recurrence-free survival (RFS). Postoperative CAR was also an independent predictor of overall survival (OS). Patients with postoperative CAR ≥ 0.035 who did not receive adjuvant chemotherapy had shorter RFS and OS than those who did. There were no significant differences in RFS and OS between patients with postoperative CAR < 0.035 who did and did not receive adjuvant chemotherapy. CONCLUSIONS: Postoperative CAR is strongly associated with poor prognosis in patients with stage III colorectal cancer and is a useful biomarker for determining whether adjuvant chemotherapy should be administered.

Skeletal Muscle Loss After Esophagectomy Is an Independent Risk Factor for Patients with Esophageal Cancer.

BACKGROUND: Postoperative changes in skeletal muscle and their influence on outcomes after esophagectomy for patients with esophageal cancer have not been fully investigated. This study aimed to confirm that postoperative skeletal muscle decrease influences long-term patient outcomes. METHODS: Data were collected from 218 patients who underwent curative esophagectomy for esophageal cancer whose data were available before and 6 months after surgery. The skeletal muscle index (SMI) was measured at the level of the L3 vertebrae, and the postoperative change in the SMI compared with preoperative values was calculated as the delta SMI. RESULTS: The mean SMI value was - 11.64%, and the median delta SMI value was - 11.88%. The first and third quartiles were defined as cutoffs, and 218 patients were classified as the mild-loss group (54 patients), moderate-loss group (110 patients), and severe-loss group (54 patients). The patients with a more severely reduced SMI had a worse prognosis (5-year overall survival rates: mild loss, 66.6%; moderate loss, 58.8%; and severe loss, 48.5%; p = 0.0314). This correlation between reduced SMI and prognosis also was observed for the patients with preoperative sarcopenia (p < 0.0001), but not for those without preoperative sarcopenia. CONCLUSIONS: Postoperative reduced SMI and worse prognosis were significantly associated in esophageal cancer patients.

Comparison of computed tomography imaging analyses for evaluation after chemotherapy in patients with colorectal cancer: a retrospective pooled analysis of six phase II clinical trials.

BACKGROUND: There are several methods for analyzing computed tomography (CT) images to evaluate chemotherapy efficacy in clinical studies. However, the optimal analysis method for each drug is still under debate. We conducted a pooled analysis using data from six phase II studies to evaluate four analysis methods in colorectal cancers (CRCs): morphological responses (MRs), early tumor shrinkage (ETS), depth of response (DpR), and response evaluation criteria in solid tumors (RECIST) ver.1.1. METHODS: We included 249 patients in this analysis. Pretreatments and findings of subsequent CT imaging were analyzed based on the MR, ETS, DpR, and RECIST ver.1.1. Differences in overall survival (OS) between the responders and non-responders according to each method were evaluated using survival analysis. RESULTS: The responders had significantly better hazard ratios (HRs) for OS, in terms of DpR (≥ median), ETS, objective response rate (ORR) [complete response (CR) + partial response (PR)], and disease control rate [CR + PR + stable disease (SD)]. Patients with right-sided colon cancers showed better HRs for DpR, but not for ETS and ORR. Contrastingly, patients with left-sided CRCs had better HRs for ETS, DpR, and ORR. MR was not associated with outcomes in this study, even in cases where bevacizumab was used. In patients with liver metastasis, ETS, DpR, and ORR showed better HRs, but not in those with lung metastasis. CONCLUSION: Early tumor shrinkage and DpR might be predictive markers only in left-sided CRCs with liver metastasis. Each imaging analysis has a different value based on the primary and metastatic sites.

Skeletal muscle loss during systemic chemotherapy for colorectal cancer indicates treatment response: a pooled analysis of a multicenter clinical trial (KSCC 1605-A).

BACKGROUND: Sarcopenia or degenerative loss of skeletal muscle mass is related to poor prognosis in patients with cancer. This study aimed to clarify the clinical significance of skeletal muscle loss (SML) during chemotherapy for metastatic colorectal cancer (mCRC). METHODS: A total of 249 patients who were secondarily registered in a pooled database of mCRC patients with the first-line systemic chemotherapy and prospectively enrolled in six clinical trials of Kyushu Study Group of Clinical Cancer were included in this study. Skeletal muscle area was calculated from computed tomography images before and 3 and 6 months after treatment. Baseline sarcopenia and SML (cut-off value = 9%) were evaluated. RESULTS: Baseline sarcopenia was observed in 135 of 219 patients who were evaluated before treatment. They tended to be male; older; and have lower body mass index, lower visceral and subcutaneous fat contents, and a lower waist circumference (P < 0.01); however, baseline sarcopenia was not associated with prognosis. SML at 3 months was associated with an incidence of adverse events (P = 0.01), poor objective response rate (ORR) (P < 0.01), and poor progression-free survival (PFS) (P = 0.03), and it was an independent predictive factor for poor ORR (P < 0.01) and PFS (P = 0.04). CONCLUSION: SML at 3 months after systemic chemotherapy for mCRC was associated with poor treatment response. Thus, clarifying the importance of SML prevention guarantees a more effective chemotherapy.