Metachronous Development Research Articles

Uncommon Metachronicity: Breast and Endometrial Carcinomas in a Young Woman with No Familial Cancer History - A Case Report

Background: Worldwide, breast and endometrial carcinomas are the two most common cancers of women, but their coexistence in a woman <40 years of age is a rare event. The risk of developing a new second primary cancer is higher in cancer survivors compared to those without a history of cancer. The exact pathogenesis of two different primary malignancies is not clear. Still, the coexistence of breast and endometrial carcinoma may be due to germline mutations of p53, BRCA 1, and BRCA 2 genes, environmental, hereditary, and immune-mediated factors. Case Presentation: The present case report briefs the finding of a 37-year-old woman who presented to the Gynecological outpatient department with complaints of abnormal uterine bleeding and a solid irregular lump in the upper outer quadrant of the right breast and the right axilla. She had a history of modified radical mastectomy for left breast ductal carcinoma five years back. She was diagnosed as a case of metachronous endometrial carcinoma (stage IA) with a recurrence of invasive ductal carcinoma in the right breast with metastasis to the right axillary lymph node. Conclusion: The metachronous development of breast and endometrial carcinoma in young women is relatively rare. In young patients <40 years of age with gynecological or breast carcinoma, a thorough work-up, including genetic testing and follow-up, should be done for early diagnosis of metachronous or synchronous primary malignancies of other organs.

Mesothelioma In Situ Mimicking Well-differentiated Papillary Mesothelial Tumor.

We have previously hypothesized that well-differentiated papillary mesothelial tumor (WDPMT) consists of 2 morphologically identical lesions, one of which is true WDPMT, while the other is a form of mesothelioma in situ. Here, we report 8 examples of the latter phenomenon, 3 with pleural disease (2 men/1 woman, ages 66 to 78y); and 5 with peritoneal disease (all women, ages 31 to 81y). At presentation the pleural cases all had effusions but no evidence of pleural tumor on imaging. Four of the 5 peritoneal cases had ascites as the initial finding and all 4 had nodular lesions that by imaging and/or direct inspection were thought to represent a diffuse peritoneal malignancy. The fifth peritoneal case presented with an umbilical mass. Microscopically, the pleural and peritoneal lesions looked like diffuse WDPMT, but all had lost BAP1. Occasional microscopic foci of superficial invasion were present in 3/3 pleural cases, while single nodules of invasive mesothelioma and/or occasional foci of superficial microscopic invasion were found in all of the peritoneal cases. The pleural tumor patients developed what clinically appeared to be invasive mesothelioma at 45, 69, and 94 months. Four/five peritoneal tumor patients underwent cytoreductive surgery and heated intraperitoneal chemotherapy. Three with follow-up data are alive without recurrence at 6, 24, and 36 months; 1 patient refused treatment but is alive at 24 months. We conclude that mesothelioma in situ morphologically mimicking WDPMT is strongly associated with the synchronous or metachronous development of invasive mesothelioma, but that these lesions appear to progress very slowly.

Metachronous development of breast and prostate cancer (case report)

The formation of primary multiple malignant neoplasms, such as breast cancer and prostate cancer, in one patient is a rather rare combination. Treatment and diagnostic strategies in such cases require a multidisciplinary approach. Currently, there are no approved recommendations for the management of patients with a combination of these diseases. This manuscript presents a clinical case of diagnosis and treatment of breast and prostate cancer in one patient.

КЛИНИКО-ЭПИДЕМИОЛОГИЧЕСКИЕ АСПЕКТЫ ОПУХОЛЕЙ ЯИЧНИКОВ В ГРОДНЕНСКОЙ ОБЛАСТИ

Background. When providing specialized medical care and planning preventive measures, analysis of epidemiological data is instrumental in determining what should be done to reduce morbidity and mortality from ovarian malignant neoplasms (OMNs) within the given scenario. Purpose of research. To study the epidemiological situation with OMNs in the Grodno region. Material and methods. The OMN incidence and indicators of the quality of oncological care in the Grodno region were analyzed according to the data obtained from the Belarusian cancer registry. Results. Since 2007, the OMN morbidity and mortality rates have been relatively stable. In most cases, the diagnosis of malignant ovarian pathology has been based on the results of a pathomorphological investigation. The histological variant of the neoplasm significantly affects the prognosis for life. The most common neoplasms are serous ovarian carcinomas (69%). Neoplasms of non-epithelial origin occur in 8% of all cases. About 16% of women have multiple primary neoplasms with ovarian involvement. In most cases of metachronous development of polyneoplasia the ovarian neoplasm occurs last. The analysis of the age-specific morbidity showed that OMN was most often (52%) diagnosed at the age of 46-65 years. During the study period, about 70% of neoplasms were diagnosed at a later stage, 10% of patients were incurable and received only symptomatic therapy. The indicators of the quality of oncological care demonstrate an increase in the number of cases diagnosed at an early stage. In 2019, in the Grodno region, OMNs of stage I-II were diagnosed in 42% of patients. Conclusion. To improve oncological care for the population and reduce morbidity and mortality from OMNs, it is necessary to develop and implement a set of measures aimed primarily at early diagnosis of the disease and prevention of neoplasm development in the case of primary multiple forms.

Direct surgery with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy for patients with colorectal peritoneal metastases

IntroductionNeoadjuvant chemotherapy is widely used in treatment of peritoneal metastases from colorectal cancer, but there is little scientific evidence for this approach. This study aimed to study survival in patients treated with direct surgery with cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (CRS-HIPEC), i.e. without neoadjuvant chemotherapy. Material and methodsPatients with histopathologically confirmed peritoneal metastases from colorectal cancer that underwent first-time CRS-HIPEC with complete cytoreduction (CC0 or 1) at Karolinska University Hospital 2012–2019 were included. Patients with synchronous extraperitoneal metastases were excluded if not treated before end of follow-up. Factors associated with overall survival (OS) and disease-free survival (DFS) were evaluated using the Kaplan-Meier method and Cox regression models. The multivariable models were adjusted for sex, age, synchronous/metachronous peritoneal metastases, peritoneal carcinomatosis index (PCI), extraperitoneal metastases and the pathological tumor (T) and lymph node (N) stage of the primary tumor. ResultsIn all, 131 patients underwent complete CRS-HIPEC for peritoneal metastases without neoadjuvant chemotherapy. The median OS and DFS were 40.3 months and 12.5 months, respectively, in patients treated with direct surgery. In the multivariable model, PCI≥16 was the only variable associated with decreased OS, whereas elevated PCI, metachronous development of peritoneal metastases and synchronous extraperitoneal metastases were associated with decreased DFS. Age was not associated with an impaired prognosis. ConclusionPatients who underwent direct surgery with CRS-HIPEC had a good prognosis, with a median OS of more than 3 years. The results from this study question the need of neoadjuvant chemotherapy in all patients eligible for CRS-HIPEC.

Use of Antibiotics and Probiotics Reduces the Risk of Metachronous Gastric Cancer after Endoscopic Resection.

Simple SummaryHelicobacter pylori is the most important cause of gastric cancer, and its eradication reduces the incidence of gastric cancer after endoscopic resection. However, incidence of metachronous gastric cancer is still high. More studies are needed to identify other chemopreventive drugs that may reduce the incidence of this disease. In this study, we focused on the alteration of the intragastric microbiome and examined the association between the use of antibiotics and probiotic drugs and risk of metachronous gastric cancer. Our findings suggest that the gut microbiome is associated with metachronous gastric cancer development.Metachronous gastric cancer often occurs after endoscopic resection. Appropriate management, including chemoprevention, is required after the procedure. This study was performed to evaluate the association between medication use and the incidence of metachronous gastric cancer after endoscopic resection. This multicenter retrospective cohort study was conducted with data from nine hospital databases on patients who underwent endoscopic resection for gastric cancer between 2014 and 2019. The primary outcome was the incidence of metachronous gastric cancer. We evaluated the associations of metachronous gastric cancer occurrence with medication use and clinical factors. Hazard ratios were adjusted by age and Charlson comorbidity index scores, with and without consideration of sex, smoking status, and receipt of Helicobacter pylori eradication therapy during the study period. During a mean follow-up period of 2.55 years, 10.39% (140/1347) of all patients developed metachronous gastric cancer. The use of antibiotics other than those used for H. pylori eradication was associated with a lower incidence of metachronous gastric cancer than was non-use (adjusted hazard ratio (aHR) 0.56, 95% confidence interval (CI) 0.38–0.85, p = 0.006). Probiotic drug use was also associated with a lower incidence of metachronous gastric cancer compared with non-use (aHR 0.29, 95% CI 0.091–0.91, p = 0.034). In conclusion, the use of antibiotics and probiotic drugs was associated with a decreased risk of metachronous gastric cancer. These findings suggest that the gut microbiome is associated with metachronous gastric cancer development.

Somatic alterations and mutational burden are potential predictive factors for metachronous development of early gastric cancer

The risk of developing metachronous gastric cancer (MGC) following curative endoscopic submucosal dissection (ESD) of early gastric cancer (EGC) remains even after eradicating Helicobacter pylori (HP) successfully. We screened initial EGC and adjacent non-cancerous mucosa ESD-resected specimens for somatic variants of 409 cancer-related genes, assessing their mutational burden (MB) to predict molecular markers for metachronous post-ESD development. We compared variants between ten patients diagnosed with MGC more than 3 years after ESD and ten age-matched patients who did not have MGC developments after successful HP eradication. We found no significant background differences between the two groups. In adjacent non-cancerous mucosa, the MB tended to be higher in the patients with metachronous developments than in the others. Somatic genomic alterations of RECQL4, JAK3, ARID1A, and MAGI1 genes were significantly associated with MGC development. The criteria including both the MB and their variants, which had potential significant values for predicting MGC. In conclusion, combined of assessing specific somatic variants and MB may be useful for predicting MGC development. This study included a limited number of subjects; however, our novel findings may encourage further exploration of the significance of the molecular features of EGC that predict MGC development, thereby promoting focused follow-up strategies and helping elucidate the mechanisms.

Effectiveness of Chemoradiotherapy for Metachronous Esophageal Squamous Cell Carcinoma

Introduction: Multiple Lugol-voiding lesions (LVLs) in the esophagus increase the risk of synchronous and metachronous development of esophageal squamous cell carcinoma (ESCC). Chemoradiotherapy (CRT) following endoscopic submucosal dissection (ESD) may reduce the incidence of metachronous ESCC, but few studies have investigated this. Therefore, we retrospectively examined the effect of CRT on metachronous ESCC and multiple esophageal dysplasias visible as multiple LVLs. Methods: This study reviewed 146 patients who underwent esophageal ESD and were determined pathologically to have noncurative resection. They were divided into 2 groups: those who received additional CRT (CRT group; n = 64) and those without additional treatment (control group; n = 82). Incidence of metachronous ESCC was analyzed using propensity scores to adjust for patient characteristics. The number of multiple LVLs was also examined. Results: The CRT group was significantly younger than the control group (mean 66.6 vs. 70.6 years, p = 0.011), had significantly deeper tumor invasion (p = 0.013), and had a significantly higher rate of lymphovascular invasion (47.8 vs. 12.2%, p < 0.001). The CRT group also had a significantly higher improvement rate of multiple LVLs (58.1 vs. 2.0%, p < 0.001). The LVLs after CRT had a distinctive irregular crack-shaped appearance. Metachronous ESCC was found in 7 patients (10.9%) in the CRT group and in 17 patients (20.7%) in the control group (p = 0.113). In propensity score-adjusted logistic regression analysis, the odds ratio for metachronous ESCC in the CRT group was 0.316 (p = 0.023). The occurrence rate was significantly lower in the CRT group than in the control group. Discussion/Conclusion: CRT may be effective in preventing metachronous ESCC.

Metachronous intraductal papillary mucinous neoplasms disseminate via the pancreatic duct following resection.

Metachronous development of intraductal papillary mucinous neoplasms in the remnant pancreas following resection is a significant clinical burden. Our aim was to characterize the clinicopathological and molecular features of the patients with metachronous tumor development to identify predictive factors and the possible route(s) of dissemination. Seventy-four patients who underwent resection of intraductal papillary mucinous neoplasms with no invasive compartment or associated carcinoma were retrospectively analyzed. In patients with metachronous tumor development, targeted sequencing of 18 genes associated with pancreatic tumorigenesis and immunohistochemical detection of four proteins (p53, SMAD4, p16, and β-catenin) were performed on both primary and metachronous tumors. The distributions of microscopic neoplastic lesions were examined at surgical margins and in apparently normal tissue apart from the primary tumor. During the median follow-up period of 52 months, 9 patients (12%) developed metachronous tumors in the remnant pancreas. Primary tumors located in the body/tail of the pancreas (odds ratio, 15; 95% confidence interval, 1.6-131) and of the pancreatobiliary type (odds ratio, 6.1; 95% confidence interval, 1.1-35.7) were identified as significant risk factors for subsequent metachronous tumor development. Eight of the nine patients shared molecular aberrations between their primary and metachronous tumors, suggesting migrations from the primary tumor to the pancreatic duct as the cause of metachronous tumor development. Our data suggest that these post-resection metachronous tumors develop by skip dissemination of the primary tumor, potentially via the pancreatic duct. The development of strategies to better predict and prevent this form of tumor progression is necessary.

Molecular biomarkers predicting early development of endometrial carcinoma: A pilot study.

Endometrial carcinoma represents the most common gynaecological cancer and the sixth most frequent cancer among women worldwide. The 5-year survival of patients with stage I endometrial carcinoma is 75%-88% versus 50% for stage III or 15% for stage IV disease. Therefore, early detection could improve survival rates. Specifically, in the most prevalent, type 1 endometrial cancer develops from hyperplastic endometrium. The aim of the study was to evaluate the utility of cancer gene mutations from endometrial biopsies towards predicting synchronous or metachronous development of malignant lesions. The aim of the study was to evaluate whether endometrial biopsies could already carry mutations in cancer genes useful for predicting or anticipating subsequent cancer development. Patients with a previous endometrial biopsy negative for cancer, followed by a subsequent biopsy positive for cancer, were included in the study. A fifty cancer genes targeted next-generation sequencing panel were used to investigate mutations in matched non-cancerous and malignant samples. All biopsies from cancer tissues harboured mutations in one or more of the following genes: APC, CTNNB1, FBXW7, HNF1A, KRAS, MTOR, NRAS, PIK3CA, PTEN, RB1 and TP53. Additionally, 50% of the biopsies from matched non-cancerous tissues exhibited mutations in PTEN, KRAS or PIK3CA genes. These results suggest that detecting pathogenic mutations in oncogenes or tumour suppressor genes in an otherwise benign condition is associated with a risk of developing a malignant disease. Given the identification of mutations several months or years before the appearance of a malignancy, our finding suggests that a closer monitoring of patients who present such molecular alterations in non-cancerous uterine mass is warranted.

SPORADIC AND HEREDITARY FORMS OF MULTIPLE PRIMARY MALIGNANT TUMORS IN CHILDREN

The article presents the features of the clinical manifestation of multiple primary sporadic and heritable malignant tumors in 104 children who observed at Pediatric Oncology and Hematology Research Institute of «NN Blokhin's National Medical Research Center of Oncology» from 1998 to 2012. The age of patients at the time of occurrence of the second malignant tumor ranged from 2.8 to 28 years and averaged 15.6 years. The second neoplasia occurred significantly more frequently in the group of primary hemoblastosis, compared with the group of solid tumors - 8.7% versus 3.4%, respectively (p &lt;0.0001). In children with multiple primaries, were found tumors that occur in common the most frequency. Retinoblastoma patients have an increased risk of developing sarcoma. Patients with Hodgkin's lymphoma have an increased risk of developing leukemia. In surviving children after treatment of the first neoplasia the thyroid, bone tissue and breast have a specific risk for the development of metachronous cancer and are target organs for control. Children with new hematopoietic tumors may be candidates for metachronous development of leukemia and bone tissue tumors. The using methods Next Generation Sequencing (NGS) and Multiplex Ligation-dependent Probe Amplification (MLPA) revealed germinal mutations in 12 children with of multiple primary tumors. The mutations in the TP53, RB1, CHEK2, FANCN/PALB2, MLH1, PMS2 genes identified in patients were associated with hereditary syndromes and an increased risk of developing second tumors, among which: sarcomas, brain tumors, hematopoietic tumors were the most frequent. It was shown that the second tumors can appear at the any age. Children who survived the treatment of the first tumor in later life should be monitored annually. Clinical management of children with multiple primary tumors requires a multidisciplinary approach.

Subtype of intraductal papillary mucinous neoplasm of the pancreas is important to the development of metachronous high-risk lesions after pancreatectomy.

Backgrounds/AimsAlthough intraductal papillary mucinous neoplasm (IPMN) has showed a favorable prognosis compared to pancreatic ductal adenocarcinoma, its recurrence patterns have somewhat questionable in detail. After partial pancreatectomy for IPMN, the evaluation for risk of metachronous occurrence of high-risk lesions (HRL) in the residual pancreas is important to establish a postoperative surveillance modality and duration of follow-up. This study aimed to evaluate the factors that may predict the metachronous occurrence of HRL in the remnant pancreas after surgery of the IPMN.MethodsFrom 2005 to 2016, clinicopathologic and surveillance data for 346 consecutive patients who underwent surgical resection for IPMN were reviewed retrospectively. Histologic subtype was classified as gastric, intestinal, pancreato-biliary, or oncocytic type.ResultsAll of IPMN were classified as main duct (n=64, 18.5%), branch duct (n=171, 49.4%), and mixed type (n=111, 32.1%). Forty-eight patients (13.9%) experienced recurrence during follow-up. Among these, 9 patients (2.6%) were identified to metachronous development of HRL in the remnant pancreas. After multivariate analysis, high-grade dysplasia (HGD) or invasive carcinoma (IC) compared to low- or intermediate dysplasia was only independent risk factor for recurrence (HR 3.688, 95% CI 2.124– 12.524, p=0.009). The independent risk factors for metachronous development were HGD/IC (HR 8.414, 95% CI 4.310– 16.426, p=0.001), and intestinal/pancreato-biliary subtype compared to gastric subtype (HR 7.874, 95% CI 3.650– 27.027, p=0.010).ConclusionsPatients with high-grade dysplasia or invasive carcinoma, and with intestinal or pancreatobiliary subtype should undergo close, long-term surveillance of the remnant pancreas after initial resection.

Rearrangements of Immunoglobulin Genes in Tumor Cells of Patients with Primary Mediastinal (Thymic) Large B-Cell Lymphoma

Background. Primary mediastinal (thymic) large B-cell lymphoma (PMBCL) is a malignant tumor with large atypical lymphoid cells expressing post-germinal differentiation markers. Rearrangements of immunoglobulin genes in PMBCL are revealed in 30-65 % of cases. Immunoglobulin molecules, however, are expressed neither on the surface, nor in cytoplasm of tumor cells. Aim. To assess cell clonality rate on the basis of rearrangements of immunoglobulin heavy/light chain genes; to determine rearrangement stability at the time of relapse development; to study the range of rearrangements and clonal relationship with primary tumor in metachronous development of mediastinal gray zone lymphoma. Materials &amp; Methods. The assessment of rearrangements of immunoglobulin heavy/light chain genes was based on molecular analysis of 29 primary tumor biopsies and 4 tissue samples with histologically and immunohistochemically verified relapses or metachronous lymphoma development. Results. In 16 (55.2 %) out of 29 cases a rearrangement of immunoglobulin heavy chain genes was reported, in 7 (24.1 %) cases a rearrangement of light chain genes was identified, in 6 (20.7 %) cases no rearrangements of immunoglobulin heavy/light chain genes were found. On the basis of immunoglobulin gene analysis in 2 patients with early relapse a tumor clone was detected that was identical with the one identified at the onset of the disease. In 2 patients with complete remission a metachronous development of mediastinal gray zone lymphoma was reported, whereas molecular genetic analysis revealed a change/disappearance of initial clonal rearrangements of immunoglobulin genes. Conclusion. Total detection rate of B-cell clonality in PMB-CL was 79.3 %. Molecular genetic analysis confirmed that initial clonal rearrangements of immunoglobulin genes were preserved in early relapses, and invalidated tumor clonal relationship in a metachronous development of mediastinal gray zone lymphoma.

Construction of a risk model for the development of metachronous squamous cell carcinoma after endoscopic resection of esopahageal squamous cell carcinoma.

Previously, we identified that rs1229984 in ADH1B, rs671 in ALDH2, and smoking status were independently associated with the risk of developing metachronous squamous cell carcinoma (SCC) after endoscopic resection (ER) for esophageal SCC (ESCC). However, this analysis included cases with short-term follow-up. In the present study, we investigated the environmental and genetic factors associated with developing metachronous SCC using long-term follow-up observation after ER for ESCC. One hundred and thirty ESCC patients who underwent treatment with ER were followed up using endoscopy for ≥ 30months. We investigated the incidence of, and genetic/environmental factors associated with, metachronous SCC development after ER for ESCC. We also analyzed the potential risk factors for multiple metachronous SCC development using Cox's proportional hazards model. Moreover, we constructed a risk model for the development of metachronous SCC after ER for ESCC. Male, rs1229984, rs671, alcohol consumption (> 20g/day), smoking, and multiple Lugol-voiding lesions (LVLs) significantly affected the incidence of multiple metachronous SCCs. Multiple Cox proportional analysis revealed that rs1229984, rs671, alcohol consumption, smoking, and multiple LVLs were independently associated with the risk of developing metachronous SCC. Patients who had ≤ 2 risk factors did not develop metachronous SCC, and the risk of developing metachronous SCC in patients with ≥ 3 risk factors was significantly higher than in patients with ≤ 2 risk factors. The risk model using these 5 genetic and environmental factors is useful as an indication for multiple metachronous development in ESCC patients.

Evidence of metachronous development of ovarian teratomas: a case report of bilateral mature cystic teratomas of the ovaries and systematic literature review

BackgroundMature cystic teratomas are usually found in the ovaries. They are bilateral in 10 to 15% of cases and multiple cystic teratomas may be present in one ovary. The aim of this study is to clarify if development of mature cystic teratomas of the ovaries in a single host is metachronous or due to autoimplant or recurrence.Case presentationWe report a woman with bilateral mature cystic teratomas of the ovaries. DNA profiles of these teratomas were investigated via short tandem repeat (STR) analysis and methylation statuses were determined via methylation sensitive multiplex ligation-dependent probe amplification methods. The results showed that the cystic teratomas originated from different stages of oogonia or primary oocyte before germinal vesicle stage failure of meiosis I in female gametogenesis.Potentially relevant literature was searched in PubMed database. Cases of bilateral or multiple mature cystic teratomas of the ovaries were analyzed. To date, there has been no reported case of multiple mature cystic teratomas in which clarification of the origin was achieved using molecular genetic methods.ConclusionsThe results of this case study provide evidence of metachronous development of mature cystic teratomas of the ovaries and may serve as a reference in the management of patients following laparoscopic cystectomy.

Long-Term Outcomes of Gastric Endoscopic Submucosal Dissection: Focus on Metachronous and Non-Curative Resection Management

Introduction: Endoscopic submucosal dissection (ESD) is an effective treatment for gastric superficial neoplasms and curative in 80-85% of the patients. The aims of this study were to identify risk factors for non-curative resection and metachronous development, and to evaluate patient management and outcome after non-curative resection. Methods: In this single-centre study, the outcome of consecutive patients submitted to gastric ESD was assessed during a minimum follow-up of 18 months. Univariate analysis and multivariate logistic regression were performed to identify risk factors. Results: ESD was performed in 194 lesions (164 patients) between 2005 and 2014. The median follow-up was 40 months. En bloc and complete resection rates were 95.3 and 93.8%, respectively. Male sex, larger tumor size, longer procedural time, and more advanced histology were associated with a non-curative resection (p < 0.05), but only carcinoma detected in biopsies before resection was identified as a significant risk factor on multivariate analysis. Metachronous lesions occurred in 18.4%, and the incidence rate was 4.7 lesions/100 person-years. Older age at diagnosis was identified as the only predictor of metachronous development in logistic regression. In the non-curative resection group, survival did not differ between patients allocated to surveillance and those submitted to gastrectomy; 75% of gastrectomy specimens showed no residual lesion. Conclusions: The risk factors identified for non-curative resection help to improve patient selection and patient information. Older patients had an increased risk for the development of metachronous lesions. In patients with non-curative resections, individualized patient management and surveillance seems to be an adequate option in selected cases.

Mucinous and Signet Ring Cell Differentiation Affect Patterns of Metastasis in Colorectal Carcinoma and Influence Survival

Peritoneal metastasis in colorectal carcinoma is associated with a dismal prognosis; however, features that correlate with patterns of metastatic spread are not well characterized. We analyzed the clinicopathologic and molecular features of 166 patients with colorectal carcinomas stratified by metastases to the peritoneum or liver. Mucinous and signet ring cell differentiation were more frequently observed in colorectal carcinoma with peritoneal dissemination compared to colorectal carcinoma with liver metastasis (mucinous differentiation: 62% vs 23%, P < .001; signet ring cell differentiation: 21% vs 0%, P < .0001). The significant association of mucinous differentiation with peritoneal dissemination compared with liver metastasis was identified in patients with both synchronous and metachronous development of metastasis ( P < .01). In contrast, colorectal carcinomas with liver metastasis were more frequently low-grade (90% vs 72%, P = .005) and associated with dirty necrosis (81% vs 56%, P = .001) compared with colorectal carcinomas with peritoneal dissemination. No significant differences were identified between colorectal carcinoma with peritoneal metastasis versus liver metastasis with respect to KRAS mutations, BRAF mutation, or high levels of microsatellite instability. Patients with tumors involving the peritoneum had a significantly worse overall survival in comparison to patients with liver metastasis lacking peritoneal involvement ( P = .02). When including only those patients with peritoneal metastasis, the presence of any mucinous or signet ring cell differentiation was associated with a significantly worse overall survival ( P = .006). Our findings indicate that mucinous and signet ring cell differentiation may be histologic features that are associated with an increased risk of peritoneal dissemination and poor overall survival in patients with peritoneal metastasis.

PD-018 Risk factors for metachronous gastric carcinoma development after endoscopic resection of gastric dysplasia

PD-018 Risk factors for metachronous gastric carcinoma development after endoscopic resection of gastric dysplasia

Predictive Factors for the Metachronous Development of High-risk Lesions in the Remnant Pancreas After Partial Pancreatectomy for Intraductal Papillary Mucinous Neoplasm.

To identify factors predicting the development of high-risk lesions in the remnant pancreas after surgery for intraductal papillary mucinous neoplasm (IPMN). IPMN has unique features, including multifocality, adenoma-carcinoma sequence, and the development of distinct pancreatic ductal adenocarcinoma (PDAC) in the same pancreas. Careful attention should, therefore, be paid to the metachronous occurrence of high-risk lesions, including high-grade dysplasia or invasive carcinoma (HGD/INV) of IPMN and concomitant PDAC in the remnant pancreas after partial pancreatectomy for IPMN. Clinicopathologic and surveillance data for 195 patients who underwent partial pancreatectomy for IPMN were reviewed retrospectively. Thirteen patients exhibited metachronous development of high-risk lesions including 6 HGD/INV and 7 concomitant PDACs in the remnant pancreas. The 5- and 10-year cumulative incidences of metachronous high-risk lesions in the remnant pancreas were 7.8% and 11.8%, respectively. Twelve of 13 patients had high-risk lesions at the time of initial surgery, and 10 of the 13 IPMNs were located in the distal pancreas. The IPMN subtypes initially resected were gastric in 6 patients, intestinal in 5, and pancreatobililary in the remaining 2. Univariate and multiple regression analyses identified pathologic results of HGD/INV and IPMN located in the distal pancreas as independent predictive factors for metachronous HGD/INV of IPMN, and the pancreatobiliary subtype of IPMN and presence of concomitant PDAC for metachronous PDAC. Patients undergoing partial pancreatectomy for IPMN are at high risk of developing lesions requiring surgery in the remnant pancreas, and close, long-term surveillance should be considered in these patients.

Mo1348 Effects of Helicobacter pylori Eradication on Progression of Precancerous Lesion to Metachronous Tumor Development After Endoscopic Resection of Early Gastric Cancer

Mo1348 Effects of Helicobacter pylori Eradication on Progression of Precancerous Lesion to Metachronous Tumor Development After Endoscopic Resection of Early Gastric Cancer