Clinical application of targeted tumour sequencing tests for detecting ERBB2 amplification and optimizing anti-HER2 therapy in gastric cancer.

BACKGROUND: Evaluation of human epidermal growth factor receptor 2 (HER2) overexpression caused by erb-b2 receptor tyrosine kinase 2 (ERBB2) amplification (AMP) by immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) is essential for treating unresectable metastatic gastric cancer (GC). A targeted tumour sequencing test enables comprehensive assessment of alterations in cancer-related genes, including ERBB2. This study aimed to evaluate the concordance between the targeted tumour sequencing test and IHC/FISH for detecting HER2-positive GC and to clarify the significance of ERBB2 AMP and concomitant genetic alterations in HER2 downstream pathways (DPs) in anti-HER2 therapy for unresectable metastatic GC patients. METHODS: ERBB2 copy number alteration (CNA) was examined via a targeted tumour sequencing test in 152 formalin-fixed paraffin-embedded (FFPE) GC tissues. ERBB2 CNA was compared to HER2 status evaluated by IHC/FISH in FFPE block sections, which were identical to those subjected to the targeted tumour sequencing test. Treatment outcomes of anti-HER2 therapy in 11 patients with unresectable metastatic GC was evaluated. RESULTS: ERBB2 AMP (≥ 2.5-fold change) was detected by the targeted tumour sequencing test in 15 patients (9.9%), and HER2 positivity (IHC 3 + or IHC 2+/FISH positive) was detected in 21 patients (13.8%). The overall percent agreement, positive percent agreement, negative percent agreement and Cohen's kappa between ERBB2 CNA and HER2 status were 94.7%, 66.7%, 99.2% and 0.75, respectively. Progression-free survival for trastuzumab therapy in patients with ERBB2 AMP was significantly longer than that in patients with no ERBB2 AMP detected by the targeted tumour sequencing test (median 14 months vs. 4 months, P = 0.007). Treatment response to trastuzumab therapy was reduced in patients with ERBB2 AMP and concomitant CNAs of genes in HER2 DPs. One patient with ERBB2 AMP and concomitant CNAs of genes in HER2 DPs achieved a durable response to trastuzumab deruxtecan as fourth-line therapy. CONCLUSIONS: A targeted tumour sequencing test is a reliable modality for identifying HER2-positive GC. ERBB2 AMP and concomitant genetic alterations detected through the targeted tumour sequencing test are potential indicators of treatment response to trastuzumab therapy. The targeted tumour sequencing test has emerged as a plausible candidate for companion diagnostics to determine indications for anti-HER2 therapy in the era of precision medicine for GC.

Histological differentiation between sporadic and colitis-associated intestinal cancer in a nationwide study: A propensity-score-matched analysis.

BACKGROUND AND AIM: Colitis-associated intestinal cancer (CAC) can develop in patients with inflammatory bowel disease; however, the malignant grade of CAC may differ from that of sporadic colorectal cancer (CRC). Therefore, we compared histological findings distinct from cancer stage between CAC and sporadic CRC to evaluate the features of CAC. METHODS: We reviewed the clinical and histological data collected from a nationwide database in Japan between 1983 and 2020. Patient characteristics were compared to distinguish ulcerative colitis (UC), Crohn's disease (CD), and sporadic CRC. Comparisons were performed by using all collected data and propensity score-matched data. RESULTS: A total of 1077 patients with UC-CAC, 297 with CD-CAC, and 136 927 with sporadic CRC were included. Although the prevalence of well or moderately differentiated adenocarcinoma (Tub1 and Tub2) decreased according to tumor progression for all diseases (P < 0.01), the prevalence of other histological findings, including signet ring cell carcinoma, mucinous carcinoma, poorly differentiated adenocarcinoma, or squamous cell carcinoma, was significantly higher in CAC than in sporadic CRC. Based on propensity score-matched data for 982 patients with UC and 268 with CD, the prevalence of histological findings other than Tub1 and Tub2 was also significantly higher in those with CAC. At pT4, mucinous carcinoma occurred at a significantly higher rate in patients with CD (45/86 [52.3%]) than in those with sporadic CRC (13/88 [14.8%]) (P < 0.01). CONCLUSION: CAC, including early-stage CAC, has a higher malignant grade than sporadic CRC, and this difference increases in significance with tumor progression.

Macroscopic type is implicated in the prognostic impact of initial chemotherapy on peritoneal lavage cytology-positive gastric cancer with no other noncurative factors.

BACKGROUND: Initial chemotherapy (Initial-C) followed by surgery is a promising treatment strategy for peritoneal lavage cytology-positive gastric cancer (CY1 GC) with no other noncurative factors. The aim of this study was to investigate the survival advantage of Initial-C compared to initial surgery (Initial-S) for this disease according to the macroscopic type, which was associated with prognosis and the efficacy of chemotherapy in GC. METHODS: One hundred eighty-nine patients who were diagnosed with CY1 GC with no other noncurative factors at four institutions from January 2007 to December 2018 were enrolled. The patients were divided into a macroscopic type 4 group (N = 48) and a non-type 4 group (N = 141). The influence of initial treatment on overall survival (OS) in each group was evaluated. RESULTS: In the type 4 group, the 5-year OS rates of Initial-C (N = 35) and Initial-S (N = 13) were 11.6% and 0%, respectively (P = 0.801). The multivariate analysis could not show the survival advantage of Initial-C. In the non-type 4 group, the 5-year OS rates of Initial-C (N = 41) and Initial-S (N = 100) were 48.4% and 29.0%, respectively (P = 0.020). The multivariate analysis revealed that Initial-C was independently associated with prolonged OS (hazard ratio, 0.591; 95% confidence interval, 0.375-0.933: P = 0.023). CONCLUSIONS: Initial-C improves the prognosis of non-type 4 CY1 GC with no other noncurative factors. On the other hand, further development of effective chemotherapeutic regimens and innovative treatment strategies are required for type 4 CY1 GC.

Risk factors for death from other diseases after curative gastrectomy and lymph node dissection for gastric cancer.

BACKGROUND: Recent advances in treatment are expected to bring a cure to more patients with gastric cancer (GC). Focusing on the risk of death from other diseases (DOD) has become a crucial issue in patients cured of GC. The aim of this study was to elucidate the risk factors for DOD in patients who underwent curative gastrectomy with lymph node dissection for GC. METHODS: We enrolled 810 patients who underwent curative gastrectomy with lymph node dissection for GC from January 1990 to December 2014 and had no recurrence or death of GC until December 2019. We investigated the risk factors for DOD defined as death excluding death from a malignant neoplasm, accident, or suicide after gastrectomy, focusing on the perioperative characteristics at gastrectomy. RESULTS: Among 315 deaths from any cause, 210 died from diseases other than malignancy, accidents and suicide. The leading cause of DOD was pneumonia in 54 patients (25.7%). The actual survival period in 167 patients (79.5%) with DOD was shorter than their estimated life expectancy at gastrectomy. Multivariate analysis revealed that a high Charlson Comorbidity Index score (score 1-2: hazard ratio [HR] 2.192, 95% confidence interval [CI] 1.713-2.804, P < 0.001 and score ≥ 3: HR 4.813, 95% CI 3.022-7.668, P < 0.001), total gastrectomy (HR 1.620, 95% CI 1.195-2.197, P = 0.002) and the presence of postoperative complications (HR 1.402, 95% CI 1.024-1.919, P = 0.035) were significant independent risk factors for DOD after gastrectomy for GC, in addition to age of 70 years or higher, performance status of one or higher and body mass index less than 22.0 at gastrectomy. CONCLUSIONS: Pneumonia is a leading cause of DOD after curative gastrectomy and lymph node dissection for GC. Paying attention to comorbidities, minimizing the choice of total gastrectomy and avoiding postoperative complications are essential to maintain the long-term prognosis after gastrectomy.

[Long-Term Survival after Liver and Pulmonary Metastasectomy Following Chemotherapy for Metastatic Pancreatic Ductal Adenocarcinoma-A Case Report].

The patient was a 61-year-old man with a diagnosis of carcinoma of the pancreatic head. Abdominal computed tomography( CT)showed no distant metastasis, and he underwent subtotal stomach-preserving pancreatoduodenectomy. Immediately after surgery, he received liver perfusion chemotherapy with 5-fluorouracil followed by systemic gemcitabine. Eighteen months after surgery, CT revealed liver metastasis in the S6 segment, and partial hepatectomy was performed. The pathological diagnosis was liver metastasis of pancreatic cancer. Postoperatively, the patient was treated with gemcitabine and S-1 therapy for 1 year and then switched to S-1 monotherapy for about 6 months. Four years after the initial surgery, CT showed 2 metastases in the right lung. After 2 months of S-1 monotherapy, wedge resection of the upper and lower lobes of the right lung was performed. Gemcitabine and nab-paclitaxel therapy were administered, after the metastasectomy, but pleural dissemination appeared on CT 5 years after the initial surgery. Modified FOLFIRINOX therapy was started and continued for 8 months, but CT revealed further disseminated lesions in the diaphragm. Palliative irradiation was provided, but the disease gradually progressed. After multidisciplinary treatment, the patient survived for 6 years and 3 months after the initial surgery.

Crohn's Disease-Associated Anorectal Cancer Has a Poor Prognosis With High Local Recurrence: A Subanalysis of the Nationwide Japanese Study.

INTRODUCTION: Colorectal cancer (CRC) is one of the major life-threatening complications in patients with Crohn's disease (CD). Previous studies of CD-associated CRC (CD-CRC) have involved only small numbers of patients, and no large series have been reported from Asia. The aim of this study was to clarify the prognosis and clinicopathological features of CD-CRC compared with sporadic CRC. METHODS: A large nationwide database was used to identify patients with CD-CRC (n = 233) and sporadic CRC (n = 129,783) over a 40-year period, from 1980 to 2020. Five-year overall survival (OS), recurrence-free survival (RFS), and clinicopathological characteristics were investigated. The prognosis of CD-CRC was further evaluated in groups divided by colon cancer and anorectal cancer (RC). Multivariable Cox regression analysis was used to adjust for confounding by unbalanced covariables. RESULTS: Compared with sporadic cases, patients with CD-CRC were younger; more often had RC, multiple lesions, and mucinous adenocarcinoma; and had lower R0 resection rates. Five-year OS was worse for CD-CRC than for sporadic CRC (53.99% vs 71.17%, P < 0.001). Multivariable Cox regression analysis revealed that CD was associated with significantly poorer survival (hazard ratio 2.36, 95% confidence interval: 1.54-3.62, P < 0.0001). Evaluation by tumor location showed significantly worse 5-year OS and RFS of CD-RC compared with sporadic RC. Recurrence was identified in 39.57% of CD-RC cases and was mostly local. DISCUSSION: Poor prognosis of CD-CRC is attributable primarily to RC and high local recurrence. Local control is indispensable to improving prognosis.

Rational Extent of Regional Lymphadenectomy and the Prognostic Impact of the Number of Positive Lymph Nodes for Perihilar Cholangiocarcinoma.

BACKGROUND: The definition and classification of regional nodes are not standardized for perihilar cholangiocarcinoma. This study aimed to clarify the rational extent of regional lymphadenectomy and to elucidate the impact of number-based regional nodal classification on survival of patients with this disease. METHODS: Data of 136 patients with perihilar cholangiocarcinoma who underwent surgery were reviewed. The incidence of metastasis and the survival of patients with metastasis were calculated for each node group. RESULTS: The incidence of metastasis for the node groups in the hepatoduodenal ligament (denoted as no. 12) ranged from 3.7% to 25.4%, with 5-year disease-specific survival of 12.9% to 33.3% for patients with metastasis. The incidences of metastasis in the common hepatic artery (no. 8) and posterior superior pancreaticoduodenal (no. 13a) node groups were 14.4% and 11.2%, respectively, with 5-year disease-specific survival rates of 16.7% and 20.0% for the patients with metastasis. When these node groups were defined as regional nodes, the 5-year disease-specific survival rates for the patients with pN0 (n = 80), pN1 (1-3 positive nodes, n = 38), and pN2 (≥ 4 positive nodes, n = 18) were 61.4%, 22.9%, and 17.6%, respectively (p < 0.001). The pN classification was independently associated with disease-specific survival (p < 0.001). When only the no. 12 node groups were regarded as regional nodes, pN classification failed to stratify the patients prognostically. CONCLUSIONS: No. 8 and no. 13a node groups should be considered regional nodes in addition to no. 12 node groups and should be dissected. The number-based regional nodal classification allows patients with this disease to be stratified prognostically.

Clinical significance of metastatic tumor deposit foci in rectal cancer in the lateral pelvic lymph node area.

BACKGROUND: Although previous studies have demonstrated that tumor deposits (TDs) are associated with worse prognosis in colon cancer, their clinical significance in rectal cancer has not been fully elucidated, especially in the lateral pelvic lymph node (LPLN) area. This study aimed to clarify the clinical significance of TDs, focusing on the number of metastatic foci, including lymph node metastases (LNMs) and TDs, in the LPLN area. METHODS: This retrospective study involved 226 consecutive patients with cStage II/III low rectal cancer who underwent LPLN dissection. Metastatic foci, including LNM and TD, in the LPLN area were defined as lateral pelvic metastases (LP-M) and were evaluated according to LP-M status: presence (absence vs. presence), histopathological classification (LNM vs. TD), and number (one to three vs. four or more). We evaluated the relapse-free survival of each model and compared them using the Akaike information criterion (AIC) and Harrell's concordance index (c-index). RESULTS: Forty-nine of 226 patients (22%) had LP-M, and 15 patients (7%) had TDs. The median number of LP-M per patient was one (range, 1-9). The best risk stratification power was observed for number (AIC, 758; c-index, 0.668) compared with presence (AIC, 759; c-index, 0.665) and histopathological classification (AIC, 761; c-index, 0.664). The number of LP-M was an independent prognostic factor for both relapse-free and overall survival, and was significantly associated with cumulative local recurrence. CONCLUSION: The number of metastatic foci, including LNMs and TDs, in the LPLN area is useful for risk stratification of patients with low rectal cancer.

Prediction of visceral pleural invasion of clinical stage I lung adenocarcinoma using thoracoscopic images and deep learning.

PURPOSE: To develop deep learning models using thoracoscopic images to identify visceral pleural invasion (VPI) in patients with clinical stage I lung adenocarcinoma, and to verify if these models can be applied clinically. METHODS: Two deep learning models, one based on a convolutional neural network (CNN) and the other based on a vision transformer (ViT), were applied and trained via 463 images (VPI negative: 269 images, VPI positive: 194 images) captured from surgical videos of 81 patients. Model performances were validated via an independent test dataset containing 46 images (VPI negative: 28 images, VPI positive: 18 images) from 46 test patients. RESULTS: The areas under the receiver operating characteristic curves of the CNN-based and ViT-based models were 0.77 and 0.84 (p = 0.304), respectively. The accuracy, sensitivity, specificity, and positive and negative predictive values were 73.91, 83.33, 67.86, 62.50, and 86.36% for the CNN-based model and 78.26, 77.78, 78.57, 70.00, and 84.62% for the ViT-based model, respectively. These models' diagnostic abilities were comparable to those of board-certified thoracic surgeons and tended to be superior to those of non-board-certified thoracic surgeons. CONCLUSION: The deep learning model systems can be utilized in clinical applications via data expansion.

[Radical Resection Followed by Chemotherapy for Intrahepatic Cholangiocarcinoma with Lymph Node Metastases-Report of a Long-Term Survivor].

We report a case of intrahepatic cholangiocarcinoma(ICC)with lymph node metastases in which long-term survival was achieved after surgery followed by chemotherapy. A 69-year-old man underwent left hepatectomy, extrahepatic bile duct resection, and lymph node dissection for ICC located mainly in segment 4 of the liver with enlarged lymph nodes in the hepatoduodenal ligament. The histopathologically confirmed diagnosis was ICC(T2N1M0, Stage ⅣA)with 3 positive lymph nodes(No. 12a1, No. 12p1, and No. 12p2). He received chemotherapy with gemcitabine(GEM)plus cisplatin(CDDP)for 9 months, followed by GEM monotherapy for 4 months, and then S-1 monotherapy was started. A right lung nodule was detected 12 months after the initiation of S-1 monotherapy. He received GEM plus S-1 therapy for 28 months, followed by S-1 monotherapy, leading to disappearance of the lung nodule. He remains alive and well without disease 78 months after surgery. Our experience in this case suggests that radical resection followed by chemotherapy may provide a survival benefit in selected patients who have ICC with nodal disease.

[Cancer of the Ascending Colon and Left Breast in an Older Adult Complicated by Thoracic Aortic Aneurysm].

An 87-year-old woman with a gradually enlarging mass in her left breast, diagnosed as having left-sided breast cancer with skin invasion by a local practitioner, was referred to our hospital. Computed tomography revealed ascending colon cancer with abdominal wall invasion and a thoracic aortic aneurysm(Stanford type B), in addition to breast cancer with skin invasion. A thoracic endovascular aortic repair and bypass surgery between the subclavian arteries were both performed for the thoracic aortic aneurysm. After 6 days, a right hemicolectomy and D2 lymphadenectomy were performed for the ascending colon cancer. A postoperative pathological diagnosis of pT3N0M0, pStage Ⅱa, was made. A total left mastectomy with a full-thickness skin graft for left breast cancer was performed after 2 months following the ascending colon cancer surgery. The postoperative pathological diagnosis was pT3N0M0, pStage ⅡB. No evidence of local recurrence or distant metastasis of the ascending colon cancer has been observed at 20 months postoperatively, or of the breast cancer after 18 months following surgery.

[A Case of Appendiceal Carcinoma with BRAF V600E Mutation and Microsatellite Instability-High].

A 75-year-old woman presented to our hospital with abdominal pain and melena. Colonoscopy revealed an ulcer at the appendiceal orifice. Histopathological examination of biopsy specimens revealed adenocarcinoma. Computed tomography showed an appendiceal mass of 11.8×6.7 cm in size involving the cecum and terminal ileum without any distant metastatic findings. Ileocecal resection with regional lymph node dissection to the root of the ileocolonic artery was performed. Histopathological examination of the specimen revealed appendiceal adenocarcinoma. Molecular subtype of the tumor was BRAF V600E mutation and microsatellite instability-high(MSI-H). The pathological stage was pT4bpN1bcM0, pStage ⅢC. She received 8 courses of CapeOX as adjuvant chemotherapy and no recurrence was noted 12 months following the surgery. The establishment of standard treatment strategies including surgery, chemotherapy, and immunotherapy for carcinoma of the appendix with BRAF V600E mutation and/or MSI-H is needed.

[Surgery for Cholangiocarcinoma with Superficial Spread and Lymph Node Metastasis-Report of a Long-Term Survivor Who Had Positive Proximal Ductal Resection Margins with Carcinoma In Situ].

A 66-year-old man was referred to our hospital with fever and abdominal pain. CT showed a mass in the intrapancreatic bile duct but no wall thickness in the perihilar bile ducts. Neither regional lymphadenopathy nor distant metastasis was observed. Biliary cytology showed adenocarcinoma. The diagnosis was distal cholangiocarcinoma, and pancreatoduodenectomy was performed. Intraoperative frozen section examination of the ductal resection margins at the right and left hepatic ducts was positive for carcinoma in situ, and the operation ultimately completed with R1 resection. Histological examination confirmed a diagnosis of cholangiocarcinoma with superficial spread and a single positive lymph node. Adjuvant chemotherapy with S-1 was administered for 1 year. Anastomotic recurrence at the hepaticojejunostomy was found 5 years after resection; biopsy specimens revealed adenocarcinoma. Thereafter, S-1 chemotherapy was resumed, and the patient remains alive and well 9 years and 1 month after resection.

[A Case of Intraductal Papillary Mucinous Adenocarcinoma with Hepatic Dysfunction Due to Tumor Perforation into the Bile Duct].

A 58-year-old woman presented with a complaint of weight loss. Abdominal computed tomography showed dilatation of the biliary and pancreatic ducts and a mural nodule in the pancreatic duct. The diagnosis was intraductal papillary mucinous neoplasm(IPMN). Endoscopic retrograde cholangiopancreatography(ERCP)and cholangioscopy revealed a fistula between the common bile duct and the IPMN. A sudden increase in hepatobiliary enzymes was noted preoperatively. ERCP showed that the common bile duct was obstructed by mucus. A nasobiliary drainage tube was inserted into the bile duct endoscopically and kept open by daily tube washing, and the liver dysfunction improved. Total pancreatectomy, splenectomy, and regional lymph node dissection were performed. Histological examination confirmed that the primary tumor was mixed invasive intraductal papillary mucinous adenocarcinoma. The patient remains alive and well with no evidence of recurrence 18 months after resection.

[Two Operations for Intrahepatic Recurrence of Biliary Cystadenocarcinoma-A Long-Term Survivor].

We report a case of biliary cystadenocarcinoma in which long-term survival was achieved after 2 operations for intrahepatic recurrence. A 72-year-old man with biliary cystadenocarcinoma located mainly in segment 3 of the liver underwent left hepatectomy, extrahepatic bile duct resection, and lymph node dissection. Seven years and 9 months after the initial resection, he underwent partial liver resection(segment 5)for intrahepatic recurrence detected by computed tomography. Fifteen years and 7 months after the initial resection, he underwent repeat partial resection of the liver(segment 5)for intrahepatic recurrence. Histologically, these tumors were confirmed to be recurrence of biliary cystadenocarcinoma. He remains alive and well with no further recurrence 21 years and 6 months after the initial resection. This case and a literature review suggest that hepatic resection is a useful treatment option for intrahepatic recurrence of biliary cystadenocarcinoma.

[A Case of Esophageal Carcinoma with Tracheal Invasion after Preoperative Treatment with Docetaxel, Cisplatin, and 5-Fluorouracil in Which Definitive Chemoradiotherapy and Salvage Esophagectomy Prolonged Survival].

A 57-year-old man was diagnosed as having resectable advanced esophageal carcinoma adjacent to the trachea(Ut, cT3N0M0)and received preoperative docetaxel, cisplatin, and 5-fluorouracil therapy. Due to tracheal tumor invasion and upstaging to cT4bN0M0 after 1 course of chemotherapy, the treatment was converted to definitive chemoradiotherapy (CRT). A remarkable response with no evidence of tracheal invasion was observed on computed tomography following definitive CRT. He underwent successful curative resection with salvage esophagectomy, and the resected tumor was staged as pT1bN0M0. No adjuvant therapy was administered, and the patient was alive with no evidence of disease at the 5-year postoperative follow-up. The response to preoperative treatment should be meticulously assessed and appropriate treatment modalities used to avoid overlooking the potential for cure, even if the response to preoperative treatment with docetaxel, cisplatin, and 5-fluorouracil is poor.

[Resectable Pancreatic Cancer Successfully Treated with Neoadjuvant Chemotherapy Regimen Change to Modified FOLFIRINOX-A Case Report].

A 72-year-old woman presented with obstructive jaundice. Computed tomography revealed a 12-mm low-density mass in the head of the pancreas. She was diagnosed as having pancreatic cancer by endoscopic ultrasound-guided fine-needle aspiration. She received gemcitabine plus nab-paclitaxel as preoperative chemotherapy. After 2 courses, hepatoduodenal lymph node metastasis appeared and was accompanied by increased tumor marker levels. The regimen was changed to modified FOLFIRINOX. After 5 courses, the lymph node metastasis was reduced in size and the tumor marker levels were decreased, so subtotal stomach-preserving pancreaticoduodenectomy was performed. Adjuvant chemotherapy was administered postoperatively. The patient was alive and well without recurrence 2 years and 9 months after the surgery, but died of sepsis. Nevertheless, this case highlights that when preoperative chemotherapy for resectable pancreatic cancer appears to be ineffective, a change in regimen may be useful.

Elucidating the multiple genetic alterations involved in the malignant transformation of a KRAS mutant neurenteric cyst. A case report.

Neurenteric cyst (NC) shows benign histopathology and rarely demonstrate malignant transformation. We herein describe a case of NC that exhibited malignant transformation. A 65-year-old female presented with gait disturbance due to compression by a cystic mass on the dorsal surface of the medulla oblongata. Partial resection was performed twice, leading to improvement of her symptoms. Two years after the second surgery, gadolinium-perfused T1-weighted magnetic resonance imaging revealed an invasive lesion with contrast enhancement at the trigone of the left lateral ventricle for which partial resection followed by radiotherapy was performed. However, mass regrowth was observed, with the patient eventually succumbing to her disease 11 months after her third surgery. Histopathological analyses of the first and second surgical specimens identified pseudostratified cuboidal epithelial cells, with no nuclear or cellular atypia resembling gastrointestinal mucosa, lining the inner surface of the cystic wall. Based on these findings the lesion was diagnosed as NC. The third surgical specimen exhibited apparent malignant features of the epithelial cells with elongated and hyperchromatic nuclei, several mitotic figures, small necrotic foci, and a patternless or sheet-like arrangement. Based on these findings, the lesion was diagnosed as NC with malignant transformation. Next-generation sequencing revealed KRAS p.G12D mutation in all specimens. Additionally, the third surgical specimen harbored the following 12 de novo gene alterations: ARID1A loss, BAP1 p.F170L, CDKN1B loss, CDKN2A loss, CDKN2B loss, FLCN loss, PTCH1 loss, PTEN loss, PTPRD loss, SUFU loss, TP53 loss, and TSC1 loss. The aforementioned results suggest that KRAS mutation is associated with the development of the NC, and that the additional gene alterations contribute to malignant transformation of the NC.

Conversion surgery for stage IV gastric cancer: a multicenter retrospective study.

BACKGROUND: Recent improvements in systemic chemotherapy have provided an opportunity for patients with stage IV gastric cancer (GC) to undergo conversion surgery (CS). The aim of this study was to evaluate the long-term outcomes of patients who underwent CS and to elucidate the prognostic factors for CS in stage IV GC. METHODS: A total of 79 patients who underwent CS with the aim of R0 resection for stage IV GC at six institutions from January 2008 to July 2019 were enrolled. We retrospectively reviewed the clinicopathological data and prognosis. RESULTS: Of the 79 patients, 23 (31.1%) had initially resectable disease (IR) before chemotherapy, defined as positive for cancer on peritoneal cytology (CY1), resectable hepatic metastasis, or para-aortic lymph node No. 16a2/b1 metastasis. Of the 56 remaining patients with primary unresectable disease, 39 had peritoneal dissemination. R0 resection was accomplished in 63 patients (79.7%). The 3-year OS rates for patients with IR and unresectable disease were 78.3% and 44.5%, respectively. Multivariate analysis showed that IR (P = 0.014) and R0 (P = 0.014) were statistically significant independent prognostic factors for favorable OS. Among patients with peritoneal dissemination alone, OS was significantly better for patients with R0 resection than for patients with R1/2 resection, with the 3-year OS rates of 65.5% and 23.1%, respectively (P = 0.011). CONCLUSIONS: CS is a treatment option for selected patients with stage IV GC. Patients with IR and patients who achieve R0 resection may obtain a survival benefit from CS.

[A Case of Unresectable Advanced Gastric Cancer Resected by Conversion Surgery after Trastuzumab Combination Chemotherapy].

A 74-year-old man presented to our hospital with a mass in the left supraclavicular fossa. He was diagnosed with advanced gastric cancer with liver metastasis and left supraclavicular and para-aortic lymph node metastasis, cT3N2M1 (LYM, HEP), cStage Ⅳ(the Union for International Cancer Control, TNM 7th edition). He received a total of 3 courses of S- 1 plus cisplatin therapy. Since he developed adverse reactions such as anorexia, renal dysfunction, and thrombocytopenia and the tumor was HER2-positive, he received 25 courses of capecitabine, cisplatin, and trastuzumab chemotherapy. Three years and 2 months after the first chemotherapy, remarkable tumor reduction was observed. The patient then underwent radical distal gastrectomy with D2 lymphadenectomy, and R0 resection was achieved. The histopathological diagnosis was ypT1aN0M0, ypStage ⅠA. Chemotherapy with trastuzumab may improve the long-term prognosis of HER2-positive Stage Ⅳ gastric cancer if the disease is controlled and radical resection can be achieved.