Impaired tumor immune response in metastatic tumors is a selective pressure for neutral evolution in CRC cases.

A Darwinian evolutionary shift occurs early in the neutral evolution of advanced colorectal carcinoma (CRC), and copy number aberrations (CNA) are essential in the transition from adenoma to carcinoma. In light of this primary evolution, we investigated the evolutionary principles of the genome that foster postoperative recurrence of CRC. CNA and neoantigens (NAG) were compared between early primary tumors with recurrence (CRCR) and early primary tumors without recurrence (precancerous and early; PCRC). We compared CNA, single nucleotide variance (SNV), RNA sequences, and T-cell receptor (TCR) repertoire between 9 primary and 10 metastatic sites from 10 CRCR cases. We found that NAG in primary sites were fewer in CRCR than in PCRC, while the arm level CNA were significantly higher in primary sites in CRCR than in PCRC. Further, a comparison of genomic aberrations of primary and metastatic conditions revealed no significant differences in CNA. The driver mutations in recurrence were the trunk of the evolutionary phylogenic tree from primary sites to recurrence sites. Notably, PD-1 and TIM3, T cell exhaustion-related molecules of the tumor immune response, were abundantly expressed in metastatic sites compared to primary sites along with the increased number of CD8 expressing cells. The postoperative recurrence-free survival period was only significantly associated with the NAG levels and TCR repertoire diversity in metastatic sites. Therefore, CNA with diminished NAG and diverse TCR repertoire in pre-metastatic sites may determine postoperative recurrence of CRC.

Comparison of the subtotal and narrow gastric conduit for cervical esophagogastrostomy after esophagectomy in esophageal cancer patients: a propensity score-matched analysis.

BACKGROUND: Several reports have compared narrow gastric conduit (NGC) with subtotal gastric conduit (SGC) for cervical esophagogastrostomy after esophagectomy; however, whether which one is more beneficial in terms of postoperative complications remains unclear. To determine the optimal gastric conduit type, we retrospectively investigated and compared the postoperative complications between NGC and SGC used in cervical circular-tapered esophagogastrostomy after esophagectomy through a propensity score-matched analysis. METHODS: Between 2008 and 2022, 577 consecutive esophageal cancer patients who underwent esophagectomy and cervical circular-stapled esophagogastrostomy were enrolled in this study. RESULTS: Of the 577 patients, 77 were included each in the SGC and NGC groups, after propensity score matching. Clinical characteristics did not differ between the two groups. The anastomotic leakage rate was significantly lower in the SGC group than in the NGC group (5% vs. 22%, p < 0.01). The anastomotic stenosis rate was significantly higher in the SGC group (16% vs. 5%, p = 0.03). Multivariate logistic analysis showed that NGC, subcutaneous route, and age were significant independent factors associated with anastomotic leakage (odds ratios, 8.58, 6.49, and 5.21; p < 0.01, < 0.01 and 0.03, respectively) and that SGC was a significant independent factor associated with anastomotic stricture (odds ratios, 4.91; p = 0.04). CONCLUSIONS: In cervical circular-stapled esophagogastrostomy after esophagectomy, SGC was superior to NGC in terms of reducing the risk of anastomotic leakage, although the risk of anastomotic stricture needs to be resolved.

Clinical Significance of Eligibility Criteria Determined by the SPIRITS Trial in Patients with Advanced Gastric Cancer.

INTRODUCTION: This study aimed to assess the clinical significance of eligibility criteria determined by phase 3 clinical trials in the clinical practice of patients with advanced gastric cancer who underwent chemotherapy. METHODS: Patients with stage IV gastric cancer who received chemotherapy between February 2002 and December 2021 were retrospectively enrolled and divided into two groups (the eligible vs. ineligible group) based on eligibility criteria determined by the SPIRITS (S-1 vs. S-1 plus cisplatin) trial. RESULTS: Among the 207 patients, 103 (49.8%) and 104 (50.2%) patients were classified into eligible and ineligible groups, respectively. Eligibility criteria were significantly correlated with age, the first-line regimen of chemotherapy, the presence or absence of conversion surgery, and tumor response to the first-line chemotherapy (all p < 0.01). The eligible group had a significantly higher induction of post-progression chemotherapy after first- and second-line chemotherapy than did the ineligible group (all p < 0.01). The ineligible group had significantly poorer prognoses than the eligible group (p < 0.0001). Multivariate analysis showed that peritoneal dissemination, tumor response, conversion surgery, and eligibility criteria were independent prognostic factors (all p < 0.05). CONCLUSION: Eligibility criteria determined by the SPIRITS trial may have clinical utility for predicting tumor response, the induction of conversion surgery, and prognosis in patients with advanced gastric cancer who underwent chemotherapy.

Clinical significance of intraperitoneal paclitaxel combined with systemic chemotherapy for gastric cancer with peritoneal metastasis.

BACKGROUND: Despite investigations of intraperitoneal paclitaxel as a personalized treatment for peritoneal metastasis of gastric cancer, few studies have evaluated its prognostic impact on conversion surgery for unresectable gastric cancer with peritoneal metastasis. Our study aimed to close this gap in knowledge. METHODS: We retrospectively enrolled 128 patients who underwent chemotherapy for peritoneal metastasis from gastric cancer and assigned them into intraperitoneal (IP) (n = 36) and non-IP (n = 92) groups, based on the use of intraperitoneal paclitaxel plus systemic chemotherapy. RESULTS: Disease control rates were 94% and 69% in the IP and non-IP groups, respectively, with the former having a significantly higher tumor response rate than the latter (p < 0.01). The median survival times in the IP and non-IP groups were 665 and 359 days, respectively, with the former having significantly better prognosis than the latter (p = 0.02). Fifteen (42%) and sixteen (17%) patients underwent conversion surgery after chemotherapy in the IP and non-IP groups, respectively, with the former having a significantly higher conversion surgery induction rate than the latter (p < 0.01). Although the prognosis of the conversion surgery group was significantly better than that of the non-conversion surgery group (p < 0.01), there was no significant difference in prognosis between patients in the IP and non-IP groups who underwent conversion surgery (p = 0.22). Multivariate analysis identified performance status and conversion surgery as independent prognostic factors (all p < 0.01). CONCLUSION: Our study demonstrated that the IP chemotherapy was one of important factors for conversion surgery induction, while it was not a risk factor for prognosis.

A prognostic scoring system for conversion surgery after trastuzumab-based chemotherapy for human epidermal growth factor receptor 2-positive advanced gastric cancer.

PURPOSE: To investigate the clinical indications and prognostic significance of surgical interventions after chemotherapy using trastuzumab-containing regimens for patients with human epidermal growth factor receptor 2 (HER2)-positive advanced gastric cancer (AGC). METHODS: A total of 146 patients with AGC who underwent chemotherapy were enrolled in this retrospective study. Tumors with an immunohistochemistry (IHC) score of 3 + or an IHC score of 2 + plus fluorescence in situ hybridization positivity were defined as HER2-positive AGC. We devised a scoring system for predicting prognosis associated with conversion surgery. RESULTS: Thirty-three patients received trastuzumab-based chemotherapy for HER2-positive tumors. Multivariate analyses identified advanced age, peritoneal dissemination, histologically undifferentiated tumors, and tumor response of progressive disease as independent prognostic factors for a worse prognosis. Twelve patients with HER2-positive AGC underwent conversion surgery. The conversion surgery group of patients with HER2-positive AGC had a better prognosis than the chemotherapy-alone group. A prognostic scoring system based on age, peritoneal dissemination, and histological type was significantly correlated with the presence or absence of conversion surgery and the prognosis of patients with HER2-positive AGC. CONCLUSIONS: Our scoring system has the clinical potential to predict prognosis associated with conversion surgery after trastuzumab-containing chemotherapy for patients with HER2-positive AGC.

A comparison of the surgical invasiveness and short-term outcomes between thoracoscopic and pneumatic mediastinoscopic esophagectomy for esophageal cancer.

PURPOSE: Minimally invasive esophagectomy (MIE) has been widely accepted as a treatment for esophageal cancer. This retrospective study compared the short-term outcomes and surgical invasiveness between thoracoscopic esophagectomy (TE) and mediastinoscopic esophagectomy with pneumomediastinum (pneumatic mediastinoscopic esophagectomy [PME]). METHODS: A total of 72 patients who underwent TE or PME were included and assessed for their surgical findings, postoperative complications, and inflammatory responses on postoperative day (POD) 1, 3, 5, and 7. RESULTS: The PME group exhibited a significantly shorter operative time and fewer lymph nodes retrieved than the TE group. Furthermore, the PME group tended to have greater incidences of recurrent laryngeal nerve palsy and lower incidences of atelectasis than the TE group. The PME group had significantly lower white blood cell counts on POD 5, serum C-reactive protein (CRP) levels on POD 3 than the TE group. CONCLUSION: PME seems to be less invasive than TE and can be considered the preferred option for patients with lower-stage esophageal cancer expected to have severe pleural adhesion or who cannot tolerate TE.

Clinical Impact of the Prognostic Nutritional Index as a Predictor of Outcomes in Patients with Stage II/III Gastric Cancer: A Retrospective Cohort Study.

BACKGROUND: The Japanese Gastric Cancer Treatment Guidelines recommend S-1 and S-1 plus docetaxel as postoperative chemotherapy for pathological stage II and III gastric cancer (GC). There is currently no strategy for using chemotherapy to treat high-risk recurrent pathological stage II/III. Previous studies reported that the several nutritional, immunological, and inflammatory markers examined the association with clinical outcomes after surgery for GC. METHODS: Ninety patients with GC (stage II, n = 48; stage III, n = 42) for whom gastrectomy was performed at our institution between November 2009 and September 2018 were examined. Nutritional, immunological, and inflammatory markers were calculated from blood samples within 1 week before surgery. RESULTS: The prognostic nutritional index (PNI) status correlated with the pathological stage and disease recurrence after surgery (p = 0.015 and p < 0.0001, respectively). Thirty-three patients had disease recurrence after gastrectomy (stage II, n = 11; stage III, n = 22). The PNI was significantly lower in the recurrent group than in the non-recurrent group (p = 0.0003). The PNI correlated with overall survival and recurrence-free survival after gastrectomy (p = 0.0021 and p = 0.0001, respectively). A multivariate analysis identified the PNI as an independent prognostic factor (p = 0.006). CONCLUSION: The PNI may be useful for predicting the outcomes of patients with pathological stage II/III GC and may contribute to the selection of an appropriate adjuvant chemotherapy regimen.

Comparison of greater curvature and lesser curvature circular-stapled esophagogastrostomy after esophagectomy in patients with esophageal cancer: a prospective randomized controlled trial.

PURPOSE: Using a circular stapler to create an anastomosis for esophagogastrostomy after esophagectomy is well accepted; however, it remains uncertain if the greater curvature (GC) or lesser curvature (LC) of the gastric conduit is better for the anastomosis. We conducted this prospective study to compare the integrity of esophagogastrostomy between the esophagus and the GC or LC side of the gastric conduit. METHODS: The subjects of this study were 70 patients who underwent esophagectomy and were randomized to a "GC" group and an "LC" group (n = 35 each). The primary and secondary end points were anastomotic leakage (AL) and anastomotic stricture (AS), respectively. RESULTS: The overall AL rate was 22.1%, without a significant difference between the groups. Stump leakage developed in eight of nine patients in the GC group, whereas leakage developed at the esophagogastric anastomosis in five of six patients in the LC group. The rate of stump leakage was significantly higher than that of esophagogastric AL in the GC group. The overall AS rate was 4.4%, with a significant difference between the groups (0% in the GC group vs. 9.1% in the LC group). CONCLUSIONS: AL rates were comparable in the two groups, but the sites of leakage were significantly different.

Drug repositioning in cancer: The current situation in Japan.

Cancer is a leading cause of death worldwide, and the incidence continues to increase. Despite major research aimed at discovering and developing novel and effective anticancer drugs, oncology drug development is a lengthy and costly process, with high attrition rates. Drug repositioning (DR, also referred to as drug repurposing), the process of finding new uses for approved noncancer drugs, has been gaining popularity in the past decade. DR has become a powerful alternative strategy for discovering and developing novel anticancer drug candidates from the existing approved drug space. Indeed, the availability of several large established libraries of clinical drugs and rapid advances in disease biology, genomics/transcriptomics/proteomics and bioinformatics has accelerated the pace of activity-based, literature-based and in silico DR, thereby improving safety and reducing costs. However, DR still faces financial obstacles in clinical trials, which could limit its practical use in the clinic. Here, we provide a brief review of DR in cancer and discuss difficulties in the development of DR for clinical use. Furthermore, we introduce some promising DR candidates for anticancer therapy in Japan.

N-Cadherin mRNA Levels in Peripheral Blood Could Be a Potential Indicator of New Metastases in Breast Cancer: A Pilot Study.

BACKGROUND: There is growing evidence that patients with metastatic breast cancer whose disease progresses from a new metastasis (NM) have a worse prognosis than that of patients whose disease progresses from a pre-existing metastasis. The aim of this pilot study is to identify a blood biomarker predicting NM in breast cancer. METHODS: The expression of epithelial (cytokeratin 18/19) or mesenchymal (plastin-3, vimentin, and N-cadherin) markers in the peripheral blood (PB) of recurrent breast cancer patients undergoing chemotherapy with eribulin or S-1 was measured over the course of treatment by RT-qPCR. The clinical significance of preoperative N-cadherin expression in the PB or tumor tissues of breast cancer patients undergoing curative surgery was assessed by RT-qPCR or using public datasets. Finally, N-cadherin expression in specific PB cell types was assessed by RT-qPCR. RESULTS: The expression levels of the mesenchymal markers N-cadherin and vimentin were high in the NM cases, whereas that of the epithelial marker cytokeratin 18 was high in the pre-existing metastasis cases. High preoperative N-cadherin expression in PB or tumor tissues was significantly associated with poor recurrence-free survival. N-cadherin was expressed mainly in polymorphonuclear leukocytes in PB. CONCLUSION: N-cadherin mRNA levels in blood may serve as a novel prognostic biomarker predicting NM, including recurrence, in breast cancer patients.

[Axillary Arterial Bleeding with Administration of Bevacizumab plus Paclitaxel in a Patient with Recurrent Breast Cancer-A Case Report].

We report a case of axillary arterial bleeding after administration of bevacizumab plus paclitaxel in a patient with recurrent breast cancer.A 50-year-old woman with invasive ductal carcinoma of the left breast underwent mastectomy and sentinel node biopsy.She was administered 4 courses of docetaxel and cyclophosphamide as adjuvant chemotherapy.Twenty -eight months after the surgery, she developed axillary lymph node recurrence with pain and upper-limb paralysis.Initially, radiation therapy was performed in the axilla combined with the oral administration of TS-1.However, the response was inadequate. Subsequently, bevacizumab plus paclitaxel was administered.After 2 courses, we observed remarkable shrinkage of the axillary tumor.However, she experienced massive bleeding from the axillary artery.As the bleeding recurred, we ligated the axillary artery.Caution is required while administrating bevacizumab in cases of tumors located close to the major blood vessels.

Oncogenic splicing abnormalities induced by DEAD-Box Helicase 56 amplification in colorectal cancer.

Alternative splicing, regulated by DEAD-Box Helicase (DDX) families, plays an important role in cancer. However, the relationship between the DDX family and cancer has not been fully elucidated. In the present study, we identified a candidate oncogene DDX56 on Ch.7p by a bioinformatics approach using The Cancer Genome Atlas (TCGA) dataset of colorectal cancer (CRC). DDX56 expression was measured by RT-qPCR and immunochemical staining in 108 CRC patients. Clinicopathological and survival analyses were carried out using three CRC datasets. Biological roles of DDX56 were explored by gene set enrichment analysis (GSEA), and cell proliferation in vitro and in vivo, cell cycle assays, and using DDX56-knockdown or overexpressed CRC cells. RNA sequencing was carried out to elucidate the effect of DDX56 on mRNA splicing. We found that DDX56 expression was positively correlated with the amplification of DDX56 and was upregulated in CRC cells. High DDX56 expression was associated with lymphatic invasion and distant metastasis and was an independent poor prognostic factor. In vitro analysis, in vivo analysis and GSEA showed that DDX56 promoted proliferation ability through regulating the cell cycle. DDX56 knockdown reduced intron retention and tumor suppressor WEE1 expression, which functions as a G2-M DNA damage checkpoint. We have identified DDX56 as a novel oncogene and prognostic biomarker of CRC that promotes alternative splicing of WEE1.

A clinical trial of somatic and germline analyses for healthy longevity in a postoperative cancer patient.

PURPOSE: Recent developments in molecular-targeted therapies have improved the clinical outcome of cancer patients; however, the issue of adverse effects due to treatments has often gone unconsidered. We herein report the results of a clinical trial of dual genomic analyses for healthy longevity in a postoperative cancer patient. METHODS: We performed dual genomic analyses for a representative 79-year-old rectal cancer patient who relapsed with liver metastasis. First, we determined single-nucleotide polymorphisms according to the constitution and disease risk in the genomic DNA from the patient's saliva by referring to the data of 10,000 Japanese patients obtained from Yahoo Japan Corporation. Second, we conducted whole-exome sequencing to detect druggable mutations in the primary tumour. RESULTS: Forty of 59 determinable characters related to the constitution were consistent with the clinical phenotype. Several diseases classified as 'high risk' diseases actually occurred during the patient's clinical course. Of the 129 significant mutations, we identified somatic mutations in BRAF, PIK3CA, and SMAD4 as targets. CONCLUSION: The dual genomic examination will improve the follow-up observation system to support primary care doctors in the social community for taking care of postoperative cancer patients.

[A Case of Adult Undifferentiated Sarcoma of the Liver with Intraatrial Metastasis].

A 24-year-old woman was admitted to the hospital for abdominal pain. Abdominal contrast-enhanced computed tomography( CT)revealed a cystic mass measuring 11×8 cm in the left lobe of the liver with extravasation. Vascular embolization was performed, but extravasation remained on CT images. She was then transferred to our hospital. We performed an emergency extended left hepatectomy. Histopathological examination revealed solid proliferation of spindle-shaped cells. Immunohistochemical staining showed that the tumor cells were positive for vimentin and negative for AE1/AE3. Thus, a diagnosis of undifferentiated sarcoma was confirmed. Multiple recurrent tumors were recognized on CT images of the lung and right atrium taken 1 year and 10 months post-surgery. Partial resection of the tumor was performed for the right atrial mass, the left lingular segment, the left inferior lobe, and the right middle lobe. Pathological diagnosis confirmed metastasis of undifferentiated sarcoma from the liver. Chemotherapy consisting of vincristine, actinomycin D, and cyclophosphamide(VAC) was not effective, and the patient died 31 months after the primary surgery. Undifferentiated sarcoma of the liver is a rare malignant mesenchymal tumor, whose occurrence is extremely rare in adults. Although surgical treatment is the first choice, outcomes remain poor. Multimodality treatment should be used to improve the outcome.

[Case Report of an Acute Focal Bacterial Nephritis Associated with Adjuvant Chemotherapy in Esophageal Cancer Patient].

We report a case of acute focal bacterial nephritis(AFBN)as a complication of chemotherapy in esophageal cancer patient. A 54-year-old woman underwent thoracoscopic esophagectomy for thoracic esophageal cancer. The final pathological diagnosis was a squamous cell carcinoma, pT1b, N2(No. 110), M0, pStage II . She received adjuvant chemotherapy with docetaxel, CDDP and 5-FU(mDCF)in our hospital from February, 2016. There was no complication in first course. She visited our hospital with complaints of a fever and right flank pain on the 22 nd day after second course of chemotherapy. There was a severe inflammation reaction in the laboratory test. An enhanced CT revealed swelling and partial low density area in the right kidney. Therefore, we diagnosed AFBN, and administrated antibiotic levofloxacin for 16 days. Her symptom improved immediately, and renal function was normal when followed up 10 months later.

[A Case of Recurred Gastric Cancer of the Anastomosis Completely Responding to Docetaxel, Cisplatin, and S-1 Triplet Therapy].

A 51-year-old man who had undergone distal gastrectomy for gastric cancer was admitted in Kagoshima University Hospital under the diagnosis of anastomotic recurrence of gastric cancer. From abdominal CT results, the recurred tumor was suspected to invade into the pancreas with regional node metastases. Because of the intense radicality of surgical intervention, we planned 3 courses of docetaxel, cisplatin, and S-1 triplet therapy(DCS therapy). After the chemotherapy, the recurred tumor and lymph node metastases shrunk drastically. Segmental gastrectomy with lymph node dissection was performed with curative intent. Final pathology revealed complete regression of both the recurred tumor and lymph node metastases. The patient's postoperative course was uneventful without tumor relapse. DCS therapy seems to be suitable to obtain drastic tumor regression before surgical intervention as a neoadjuvant chemotherapy for locally advanced gastric cancer.

[A Case of Advanced Esophageal Cancer Patient with Schizophrenia Successfully Treated with Chemoradiation Therapy with S-1 and CDDP].

A 67-year-old man who was hospitalized at a mental hospital because of schizophrenia was admitted to our hospital with a complaint of dysphagia and vomiting. He was found to have advanced cancer in the middle thoracic esophagus. With the cooperation of a radiologist, a psychiatrist, and a nurse, we successfully performed chemoradiation therapy with S-1 and CDDP. The patient had adverse events of esophagitis and anuria during chemoradiation therapy. However, such adverse events were well controlled through the cooperation with a palliative care team and a urologist. Finally, we were able to enforce chemoradiation therapy with S-1 and CDDP without interruption.

Clinical Significance of Body Weight Loss During Chemotherapy for Advanced Gastric Cancer Undergoing Conversion Surgery.

BACKGROUND/AIM: The purpose of the present study was to assess the clinical impact of body weight loss (BWL) during chemotherapy in patients with initially unresectable advanced gastric cancer who underwent conversion surgery. PATIENTS AND METHODS: This retrospective study included 61 patients with stage IV gastric cancer who underwent conversion surgery after chemotherapy, and body weight changes during chemotherapy were examined. Based on receiver operating characteristic (ROC) curve analysis of body weight change for disease recurrence, the cutoff value of BWL was determined. Based on the BWL cutoff value, patients were classified into two groups. RESULTS: Body weight change ranged from 28.2% to -21.8%. The cut-off value of BWL was set at 6% based on the ROC analysis. Of the 61 patients, 45 (74%) and 16 (26%) had <6% and ≥6% BWL, respectively. Patients with ≥6% BWL had peritoneal dissemination, pathological lymph node metastasis, residual tumor status of R1-2, and disease recurrence compared with those with <6% BWL (all p<0.05). The median survival times after conversion surgery were 21 and 63 months in the ≥6% and <6% BWL groups, respectively (p<0.01). Univariate analysis identified BWL as an independent prognostic factor (p=0.01), although histological response alone was significantly associated with survival in the multivariate analysis (p=0.02). CONCLUSION: Patients with severe BWL during chemotherapy may be excluded from the indication of conversion surgery.

Evaluation of Quality of Life and Prognosis of Gastric Cancer Patients After Laparoscopic Subtotal Gastrectomy.

BACKGROUND/AIM: The clinical significance of laparoscopic subtotal gastrectomy (LsTG) with a small remnant stomach remains unclear in patients with gastric cancer, including at an advanced stage. The present study assessed postoperative quality of life (QOL) and survival after LsTG compared with laparoscopic total gastrectomy (LTG). PATIENTS AND METHODS: We retrospectively analyzed consecutive patients with gastric cancer who underwent LsTG (n=26) or LTG (n=26). Surgical outcome, postoperative nutritional status, QOL, and prognosis were compared between the LsTG and LTG groups. The Postgastrectomy Syndrome Assessment Scale was used to evaluate postoperative QOL. RESULTS: Operating time was significantly shorter (p<0.01) and postoperative morbidity was significantly lower (p=0.04) in the LsTG than in the LTG group. The reduction in body weight after surgery was significantly greater in the LTG than in the LsTG group (p<0.01). The Postgastrectomy Syndrome Assessment Scale revealed that, compared with LTG, LsTG significantly improved postoperative QOL (p<0.05). There was no significant difference in relapse-free survival and cancer-specific survival between the two groups. Three patients in the LTG group died of pneumonia and overall survival was significantly longer in the LsTG group (p=0.01). CONCLUSION: This study demonstrated the efficacy of LsTG with a small remnant stomach to prevent a decline in postoperative QOL and non-cancer-related death.

Successful subtotal gastrectomy and hepatectomy for HER2-positive gastric cancer with liver metastasis after trastuzumab-based chemotherapy: a case report.

BACKGROUND: Conversion surgery (CS) after chemotherapy is weakly recommended as a promising tool for improving prognoses in patients with unresectable gastric cancer. Moreover, several investigators have demonstrated the clinical efficacy of subtotal gastrectomy (sTG) with a small remnant stomach for the nutritional status and surgical outcome compared with total gastrectomy. Here, we report a patient with liver metastasis from human epidermal growth factor receptor 2 (HER2)-positive gastric cancer who underwent sTG and hepatectomy after trastuzumab-based chemotherapy. CASE PRESENTATION: An 84-year-old male patient was diagnosed with HER2-positive gastric cancer with a single liver metastasis. He was treated with eight courses of trastuzumab in combination with S-1 and oxaliplatin as first-line chemotherapy. The primary tumor and liver metastasis shrank significantly. The metastatic liver lesion's reduction rate was 65%. According to the Response Evaluation Criteria in Solid Tumors, the patient had a partial response. Therefore, he underwent an sTG with D2 lymphadenectomy and partial hepatectomy of segment 2. Histopathological examination revealed a grade 3 histological response without lymph node metastases from the primary tumor. No viable cancer cells were observed in the resected liver specimens. The patient received adjuvant chemotherapy with S-1. The postoperative quality of life (QOL) evaluated using the Postgastrectomy Syndrome Assessment Scale-45 was maintained, and the patient was still alive 8 months after the CS without recurrence. CONCLUSIONS: An sTG with a small remnant stomach might be clinically useful for preventing a decline in QOL and improving prognoses in patients with stage IV gastric cancer after chemotherapy.