Peritoneal Washings Research Articles

OGC SO20 - Audit of the guidelines for staging laparoscopy in gastro-oesophageal cancers

Abstract Background Staging laparoscopy and peritoneal washings form part of surgical work up of oesopheageal and gastric cancers. Peritoneal washings help to identify microscopic disease, the presence of which drastically alters prognosis. This audit looks at the adherence to staging laparoscopy guidelines introduced, and the intraoperative finding. Method Staging laparoscopy and peritoneal washings form part of surgical work up of oesophageal and gastric cancers. Peritoneal washings help to identify microscopic disease, the presence of which drastically alters prognosis. This audit looks at the adherence to staging laparoscopy guidelines introduced, and the intraoperative finding. Results Two hundred and twenty-seven patients were identified. Two patients did not have washings performed due to the extent of their disease, which was appropriate. The remaining patients had washings performed. Twelve patients had washings performed but not in line with policy. In all cases a clinical reason was found. Overall twelve patients had positive cytology from the washings. Of those that had washings, forty-one patient’s had T1/T2 disease and one hundred and eight-four patients had T3/T4 disease. All cytology positive patients had T3/T4 stage disease. Conclusion Two hundred and twenty-seven patients were identified. Two patients did not have washings performed due to the extent of their disease, which was appropriate. The remaining patients had washings performed. Twelve patients had washings performed but not in line with policy. In all cases a clinical reason was found. Overall twelve patients had positive cytology from the washings. Of those that had washings, forty-one patient’s had T1/T2 disease and one hundred and eight-four patients had T3/T4 disease. All cytology positive patients had T3/T4 stage disease

The Advancement Stage of Gastric Cancer and the Levels of CEA and Ca19-9 in Serum and Peritoneal Lavage

Background: This study aimed to analyze the relationship between the levels of tumor markers—specifically, carcinoembryonic antigen (CEA) and Ca19-9 antigen—determined in both serum (sCEA and sCa19-9) and intraoperative peritoneal washings (pCEA and pCa19-9) and the advanced stage of gastric cancer (including the occurrence of cancer cells in cytology from abdominal fluid). Methods: This study included 47 patients with histopathologically confirmed gastric cancer or gastroesophageal junction cancer who underwent surgical treatment. The material for the cytological examination and assessment of CEA and Ca19-9 concentrations in peritoneal fluid was collected intraoperatively. Later, blood was drawn to assess the CEA and Ca19-9 concentrations in blood serum. Results: There was a statistical correlation between a positive cytology result or the presence of peritoneal carcinomatosis and a positive result for the tumor markers obtained from abdominal washings. This correlation was not observed with marker levels obtained from blood serum. The pCEA marker was highly sensitive (93.3%) and specific (93.8%) for detecting cancer cells. The pCa19-9 marker was less effective in detecting cancer but matched pCEA in identifying the absence of cancer. No differences were observed in sCEA and sCA19-9 levels between patients who underwent neoadjuvant chemotherapy and those who did not receive this treatment. However, statistical analysis showed that this relationship did not apply to pCEA and pCa19-9 levels. Conclusions: Intraoperative determinations of tumor marker levels in peritoneal washings may be a predictive factor for a poor prognosis in patients with gastric cancer.

Outcomes of Microscopic Residual Tumor after Curative-Intent Surgery in Adenocarcinoma of Esophagogastric Junction

Objective: Radical surgery is the mainstay treatment for adenocarcinoma of the esophagogastric junction. The presence of microscopic residual tumor tissue after curative-intent surgery is associated with recurrence. This study compared the outcomes of patients with microscopic residual tumor (Residual+ group) and those without microscopic residual tumor (Residual- group). Material and Methods: We retrospectively reviewed the medical records of 71 patients with adenocarcinomas of the esophagogastric junction who underwent curative-intent surgery between January 2005 and August 2018. We evaluated the clinical and pathological characteristics and compared recurrences, rates and patterns, between groups. Five-year overall survival (OS) and 3-year disease-free survival (DFS) were analyzed by Kaplan-Meier analysis. Results: Nineteen (26.8%) patients had microscopic residual tumors, consisting of 8 (11.3%) with positive resection margins, 10 (14.0%) with malignant cells from peritoneal washing fluid cytology, and 1 (1.4%) with both. The median OS in the Residual- group was significantly better than that in the Residual+ group (31.3 vs 11.9 months, P = 0.003). The Residual- group had better 5-year OS (26.2% vs 11.9%, P = 0.015) and 3-year DFS (24.4% vs 9.8%, P = 0.003) than the Residual+ group. During follow-up period, 48% of the patients in the Residual+ group experienced recurrent disease, with a median follow-up time at 7.7 months. Distant metastasis was the most common site of recurrence. Conclusion: Microscopic residual tumor after resection is associated with poorer survival outcomes and higher recurrence rates. Curative surgery should aim to achieve R0 resection in all patients with resectable adenocarcinomas of the esophagogastric junction.

Peritoneal washing analysis in endometrial cancer: Does somatic mutation detection with panel sequencing build upon traditional cytologic analysis?

Peritoneal washing analysis in endometrial cancer: Does somatic mutation detection with panel sequencing build upon traditional cytologic analysis?

The clinicopathologic significance of psammoma bodies in cytology specimens: A series of 78 cases.

Currently the clinicopathologic significance of psammoma bodies in cytology specimens are not completely understood, including types of cytology specimens and pathologic conditions frequently associated with this unique cytologic feature. In this study, we undertook a retrospective approach to review the specimen types, cytology preparations, patient characteristics, organs or tissues involved and differential diagnoses in cytology specimens with the finding of psammoma bodies. Cytology cases with the finding of psammoma bodies from January 2004 to December 2022 were retrieved from our institution's pathology databases, and their clinicopathological features were reviewed. A total of 78 cytology specimens with the finding of psammoma bodies were recorded in our CoPath system. The mean age at diagnosis was 59 years. The patient group showed female gender predominancy (90%). FNA specimens comprised about 38.5% of total cases. Other common specimen types were body cavity fluids (38.5%), including pleural effusion and peritoneal fluid, and about 20.5% of the cases were pelvic washing performed during gynecologic surgeries. Most cytology cases with psammoma bodies had a malignant diagnosis (69%). About 18% of the cases were in the indeterminate diagnostic categories, with 12% suspicious for malignancy and 6% of the cases with atypical cells. About 5% of cases were placed in the neoplastic category, while 8% of cases were negative for malignancy. About 79% of peritoneal cytology with psammoma bodies were neoplastic and mostly gynecologic tumors. Pleural fluids with psammoma bodies were very likely to be malignant and involved by serous carcinoma (15 of 16 cases, 94%). Papillary thyroid carcinoma was the second most common malignancy in our series, present in about 53% of thyroid cytologies with the finding of psammoma bodies. Our study showed that psammoma bodies in cytology preparations were more often associated with malignancies in our study of 78 cytology specimens (69%). The most sampled location in our study was peritoneal cavity, followed by pleural cavity, thyroid, lymph nodes, neck masses, and omentum. The clinicopathologic value of psammoma bodies in predicting malignancy varies depending on locations and specimen types.

The role of pelvic washings in patients with endometrial cancer of high-risk histology in a single institution: A retrospective review

The role of pelvic washings in patients with endometrial cancer of high-risk histology in a single institution: A retrospective review

PERITONEAL KERATIN GRANULOMAS MIMICKING PERITONEAL CARCINOMATOSIS: A POTENTIAL DIAGNOSTIC PITFALL

Abstract Introduction/Objective Keratin granulomas from a primary uterine cancer can present as peritoneal tumor nodules, mimicking peritoneal carcinomatosis. Endometrial adenocarcinomas with viable peritoneal tumor implants and/or involvement of bladder or bowel mucosa are categorized as stage IV disease. We present a rare case of endometrial adenocarcinoma of the uterus with squamous differentiation and multiple peritoneal nodules of keratin granulomas, masquerading as peritoneal carcinomatosis. Methods/Case Report A 68-year-old female with insignificant past medical history presented with complaints of postmenopausal bleeding for the past four months. Physical examination was unremarkable. Transvaginal ultrasound showed a 4.9 cm echogenic mass in the uterus. The endometrial biopsy showed squamous debris with atypical cells suspicious of malignancy. Endometrial curettings revealed endometrial adenocarcinoma, endometrioid type with squamous differentiation, FIGO Grade 1. Subsequently, she underwent hysterectomy with bilateral salpingo- oophorectomy. Intraoperatively, multiple suspicious nodules on the sigmoid colon and in the pelvis were identified, of which excisional biopsies and pelvic peritoneal washing were taken. Microscopic examination of the resection confirmed endometrial adenocarcinoma, FIGO Grade 1, nuclear grade 1, with extensive foreign body giant cell reaction to dead squamous cells (ghost cells). Cytologic examination of the peritoneal washing was unremarkable and excisions of the sigmoid serosal and peritoneal nodules showed pink eosinophilic laminated nodules surrounded by inflammatory cells including plasma cells, lymphocytes and multinucleated giant cells without any viable tumor cells. Results (if a Case Study enter NA) NA Conclusion Keratin granulomas are a foreign body reaction to keratin deposition from the squamous component of endometrioid adenocarcinoma. The pathogenesis of this foreign body response to keratin is considered to be a trans- tubal spread of keratin through retrograde shedding from the fallopian tubes. In the absence of viable tumor cells, it appears to have no negative prognostic significance. Careful microscopic examination of peritoneal keratin granulomas is imperative to avoid erroneous upstaging of the tumor and the subsequent advanced treatment.

A Case Report of Inflammatory Myofibroblastic Tumor Mimicking Leiomyosarcoma of the Uterus

Abstract Introduction/Objective Inflammatory myofibroblastic tumor (IMT) of the uterus is a rare entity that presents significant diagnostic challenges due to its infrequency and has the potential for being misdiagnosed as a leiomyoma, endometrial stromal tumor, or myxoid leiomyosarcoma, resulting in undertreatment or overtreatment. Methods/Case Report We present a case report of a 50-year-old woman with a history of anemia due to heavy menstruation caused by fibroids, who underwent hysterectomy. The concurrent pelvic wash cytology raised suspicious for myxoid leiomyosarcoma. Results (if a Case Study enter NA) Macroscopic examination revealed both well and poorly circumscribed nodules, ranging upto 4.7 cm in maximum dimension. Cut surfaces exhibited a spectrum of appearances, including tan-pink, whorled and rubbery, as well as soft, hemorrhagic, edematous, and mucinous areas with necrosis. Microscopically, the tumor exhibited myxoid spindle cell proliferation, in the background of lymphoplasmacytic inflammatory infiltrates. She was diagnosed with IMT metastasis to left fallopian tube, ovary, and omentum. Immunohistochemical (IHC) analysis further confirmed the diagnosis, showing strong and diffuse cytoplasmic positivity for ALK (anaplastic lymphoma kinase), caldesmon, and smooth muscle actin. This case underscores the critical importance of accurate diagnosis in guiding appropriate treatment strategies. Moreover, given the morphological overlap with other uterine tumors, the identification of ALK rearrangement emerges as a pivotal diagnostic marker, distinguishing IMT from its mimics such as leiomyoma, leiomyosarcoma and smooth muscle tumor of uncertain malignant potential (STUMP). Enhancing our understanding of the histomorphological features and ALK immunostaining of uterine IMT is essential for optimizing patient management and outcomes. Conclusion IMT in the female genital tract can mimic other more common benign and malignant tumors like leiomyoma, leiomyosarcoma, and endometrial stromal sarcoma. Familiarity with clinical and histologic features and the use of ALK immunostaining can be critical for correct diagnosis.

Intraoperative peritoneal cytology for cervical gastric-type adenocarcinoma: Cytopathology and clinical impact.

The objective of this study was to elucidate the frequency and cytologic features of positive peritoneal washing cytology (PWC) in cervical gastric-type adenocarcinoma (GAS) and to clarify the clinical significance of positive PWC. The authors analyzed cases from their institution between 1991 and 2023 in which patients underwent surgery and PWC. The study included 62 patients who had cervical GAS (1991-2023; including seven patients with adenocarcinoma in situ and 26, 15, nine, and five patients with International Federation of Gynecology and Obstetrics 2018 stage I, II, III, and IV disease, respectively) and 100 patients who had usual-type endocervical adenocarcinoma (2007-2023; including 65, 15, and 20 patients with stage I, II, and III disease, respectively). The frequency of positive PWC results and cytologic features was assessed, and correlations between positive PWC results and clinicopathologic factors were examined, including prognosis, in the GAS group. Positive PWC results were significantly more frequent in patients who had GAS at 24% (15 of 62 patients) compared with 7% (seven of 100 patients) in those who had usual-type endocervical adenocarcinoma. The cytologic features of GAS included distinct cellular atypia (enlarged nuclei, nuclear irregularity) and frequent formation of spherical clusters (10 of 15 cases) without the golden-yellowish mucus commonly seen in cervical smears. A positive PWC result in GAS was significantly correlated with larger tumor size, parametrium invasion, lymph node metastasis, and elevated carbohydrate antigen 19-9 levels. In patients with stage I GAS, the PWC-positive group had significantly shorter disease-free survival and overall survival compared with the PWC-negative group. Positive PWC findings are frequent in cervical GAS and are associated with pathologic factors indicative of tumor growth and progression. In patients who have stage I GAS, positive PWC results may indicate a poor prognosis, warranting further investigation.

Is infracolic omentectomy necessary for early-stage (FIGO I–II) borderline ovarian tumors? A protocol for systematic review and meta-analysis

Background: Borderline ovarian tumors (BOTs) are reported to account for 10%–20% of all ovarian tumors. Guidelines for the surgical management of BOTs include hysterectomy with bilateral salpingo-oophorectomy, peritoneal washings, omentectomy, and multiple peritoneal biopsies. However, when omentectomy is recommended, it is unclear whether removal of a normal-appearing omentum has a therapeutic benefit. Methods: We will search the following databases: the Cochrane Central Register of Controlled Trials (CENTRAL), the latest issue in the Cochrane Library, PubMed, EMBASE, LILACS, SCOPUS, Web of Science and Grey literature. Randomized controlled trials (RCTs) and non-randomized studies will be included if the patients are adults (≥18 years) with BOTs in stages I–II according to International Federation of Gynaecology and Obstetrics (FIGO). The methodological assessment will be carried out by two reviewers independently of each other using Cochrane risk-of-bias tool for randomized controlled trials (RoB 2), and the risk of bias in non-randomized studies (ROBINS-I) tool for non-randomized. The search strategy is constructed using the Boolean operators “OR” and “AND,” thorough search, a combination of medical subject heading and free-text terms will be employed. The Review Manager 5.4 will be used for the meta-analysis. For time‐to‐event data, we will use the hazard ratio with a 95% confidence interval (CI). For dichotomous outcomes, we will be used to calculate the risk ratio with a 95% CI. Continuous outcomes will be presented as the weighted mean difference or standardized mean difference with 95% CI. Results: This review will evaluate the effects of non-infracolic omentectomy on overall survival, progression-free survival, quality of life, recurrence index and adverse events in patients with BOTs. Conclusion: Our results will provide clear evidence to determine whether non-infracolic omentectomy is an effective and safe intervention for early stage (FIGO I–II) BOTs, thus benefiting patients, practitioners, and policy makers.

Molecular diagnosis for detecting KRAS mutation in peritoneal washing fluid of pancreatic ductal adenocarcinoma

Positive peritoneal washing cytology is an indicator of poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC); however, its sensitivity is relatively low. This study evaluated the performance of peptide nucleic acid (PNA)-directed PCR clamping as a molecular-based peritoneal washing cytology for sensitive detection of KRAS mutation in PDAC. Intraoperative peritoneal washing fluid (IPWF) obtained from patients with PDAC who underwent surgery was analyzed. PNA-directed PCR clamping was performed on DNA extracted from IPWF. Among 54 patients enrolled, threshold cycle (Ct) was significantly lower in patients with positive peritoneal washing cytology than in those with negative peritoneal washing cytology (P < 0.001) and in patients with peritoneal dissemination than in those without peritoneal dissemination (P < 0.01). The optimal Ct cut-off to predict KRAS mutations in IPWF was 36.42 based on a receiver operating characteristic curve. The sensitivity, specificity, and accuracy for molecular diagnosis were 100%, 80.0%, and 85.2%, respectively. Peritoneal dissemination recurrence was significantly more frequent in patients with a positive molecular diagnosis than in those with a negative diagnosis (38.9 vs. 8.0%, P = 0.013). The genomic approach might be clinically valuable for a more precise tumor cell detection in IPWF.

The Role of Effusion Cytology in the Staging of Primary Digestive Tract Malignancies: An Evaluation of 528 Peritoneal Washing Specimens

The Role of Effusion Cytology in the Staging of Primary Digestive Tract Malignancies: An Evaluation of 528 Peritoneal Washing Specimens

Reclassification of Peritoneal Washings from Gynecologic Oncologic Patients Using The International System For Reporting Serous Fluid Cytopathology

Reclassification of Peritoneal Washings from Gynecologic Oncologic Patients Using The International System For Reporting Serous Fluid Cytopathology

Prognostic analysis of peritoneal washing cytology during interval debulking surgery in advanced ovarian cancer

BackgroundInterval debulking surgery (IDS) following neoadjuvant chemotherapy is a treatment option for advanced ovarian cancer. Optimal surgery is required for better survival; however, while peritoneal washing cytology (PWC) has been identified as a prognostic factor, its comprehensive assessment during IDS remains unexplored. Therefore, we aimed to evaluate PWC efficacy during IDS, alongside other factors including residual disease and the modeled cancer antigen 125 (CA-125) ELIMination rate constant K (KELIM), by retrospectively reviewing the medical records of 25 patients with advanced ovarian cancer underwent neoadjuvant chemotherapy and IDS between January 2017 to June 2023.ResultsTwelve (48.0%) patients were PWC-positive, and the remainder were PWC-negative. PWC was performed at laparotomy during IDS, after which five (41.7%) PWC-positive and four (30.8%) PWC-negative patients received bevacizumab, an anti-vascular endothelial growth factor monoclonal antibody, for maintenance treatment. Four (33.3%) PWC-positive and 10 (76.9%) PWC-negative patients received poly adenosine diphosphate (ADP)-ribose polymerase inhibitors. In patients who received bevacizumab and poly ADP-ribose polymerase inhibitors, overall survival and progression-free survival did not significantly differ between those who were PWC-positive and PWC-negative (p = 0.27 and 0.20, respectively). Progression-free survival significantly differed between those with favorable and unfavorable CA-125 KELIM (p = 0.02). Multivariate analysis indicated that optimal surgery and favorable CA-125 KELIM were associated with better progression-free survival (p < 0.01 and 0.02, respectively), with only optimal surgery associated with better overall survival (p = 0.04).ConclusionsA positive PWC at IDS was not associated with survival in advanced ovarian cancer. Our findings indicate that although PWC status at IDS should be one of the factors determining survival in patients with advanced ovarian cancer, recent improvements in maintenance therapy may make the combination of CA-125 KELIM and PWC status a more useful prognostic factor in selecting treatment after IDS. Further studies are needed to validate these results, highlighting the potential importance of maintenance treatment after IDS and the need for further research to validate the clinical significance of a positive PWC.

68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) for detecting occult peritoneal metastasis in locally advanced gastric cancer: A single-center prospective cohort study.

61 Background: Occult peritoneal metastasis (OPM) is a common finding in patients diagnosed with advanced gastric cancer. Preoperative diagnosis of OPM is crucial for developing treatment strategies and for evaluating the prognosis of patients with locally advanced gastric cancer. To evaluate the accuracy of 68Ga-FAPI-04 PET/CT in diagnosing OPM in locally advanced gastric cancer. Methods: This was a prospective, observational, single-center, single-blind, cohort study. Patients with histologically proven locally advanced gastric or gastroesophageal junction adenocarcinoma on initial staging evaluation were recruited. Laparoscopic staging and cytological analysis of peritoneal washing served as reference standards for the final diagnosis. The primary outcome was the proportion of participants changing treatment strategy from curative to palliative treatment. Results: A total of 49 patients were recruited between November 2022 and July 2023 . Nine of the 49 patients were diagnosed with OPM following 68Ga-FAPI-04 PET/CT examinations. A total of 18.4% (n=9) of patients with locally advanced disease on initial staging evaluation by contrast-enhanced CT were upstaged to stage IV for peritoneal metastasis on 68Ga-FAPI-04 PET/CT. The sensitivity of 68Ga-FAPI-04 PET/CT in detecting OPM was 85.7%, and the specificity was 92.3%. The overall diagnostic accuracy of 68Ga-FAPI-04 PET/CT was 91.8%. Based on ROC curve analysis, the area under the curve (AUC) was 0.893 (95% CI: 0.734–1). Conclusions: The findings of this study suggest a significantly additional value of 68Ga-FAPI-04 PET/CT in detecting OPM. Thus, it would be useful to include 68Ga-FAPI-04 PET/CT in the guidelines for staging locally advanced gastric cancer, instead of laparoscopic staging. Clinical trial information: ChiCTR2300067591 .

Deep learning predicts the 1-year prognosis of pancreatic cancer patients using positive peritoneal washing cytology

Peritoneal washing cytology (CY) in patients with pancreatic cancer is mainly used for staging; however, it may also be used to evaluate the intraperitoneal status to predict a more accurate prognosis. Here, we investigated the potential of deep learning of CY specimen images for predicting the 1-year prognosis of pancreatic cancer in CY-positive patients. CY specimens from 88 patients with prognostic information were retrospectively analyzed. CY specimens scanned by the whole slide imaging device were segmented and subjected to deep learning with a Vision Transformer (ViT) and a Convolutional Neural Network (CNN). The results indicated that ViT and CNN predicted the 1-year prognosis from scanned images with accuracies of 0.8056 and 0.8009 in the area under the curve of the receiver operating characteristic curves, respectively. Patients predicted to survive 1 year or more by ViT showed significantly longer survivals by Kaplan–Meier analyses. The cell nuclei found to have a negative prognostic impact by ViT appeared to be neutrophils. Our results indicate that AI-mediated analysis of CY specimens can successfully predict the 1-year prognosis of patients with pancreatic cancer positive for CY. Intraperitoneal neutrophils may be a novel prognostic marker and therapeutic target for CY-positive patients with pancreatic cancer.

A phase II study evaluating the effect of IMNN-001 on second-look laparoscopy (SLL) when administered in combination with bevacizumab (BEV) and neoadjuvant chemotherapy (NACT) in patients newly diagnosed with advanced epithelial ovarian cancer (EOC).

TPS5633 Background: IMNN-001, an interleukin-12 (IL-12) DNA plasmid formulated with a DNA carrier, polyethyleneglycol-polyethyleneimine cholesterol lipopolymer, has been shown to exhibit a favorable benefit/risk ratio when administered intraperitoneally (IP), in combination with intravenous platinum-taxane chemotherapy, up to doses of 100 mg/m2 in women with advanced EOC in earlier Phase I &amp; II studies. The 201-21-202 study (NCT05739981) is a multi-center, randomized, open-label phase I/II study which hypothesizes the addition of IMNN-001 to neoadjuvant &amp; adjuvant carboplatin-paclitaxel and bevacizumab (chemo + BEV) reduces the risk of histologically documented minimal residual disease (MRD) as determined by SLL by 50%. Methods: Patients with newly diagnosed stage III and IV high grade serous EOC who are candidates for NACT will be enrolled into the trial. Initial safety lead-in will evaluate at least 6 patients randomized to the experimental arm. Upon confirmation of safety by the DSMB, a target of ~50 patients will be randomized 1:1 to receive either chemo + BEV with or without IMNN-001. Patients receive at least 4 cycles of NACT followed by interval cytoreductive surgery (ICS), and 3 additional adjuvant cycles of study treatments will be administered. BEV will be included with each cycle except cycle 1, the last cycle of NACT immediately preceding ICS, and the first cycle of adjuvant chemotherapy. In the experimental arm, IMNN-001 will be administered on C1D15 and continue weekly though the last cycle of adjuvant therapy. Following adjuvant therapy, all patients will undergo SLL with peritoneal washing and multiple biopsies. Pathologic detection of residual tumor in any biopsies or peritoneal cytology constitutes presence of MRD. All patients will receive maintenance therapy with Olaparib + BEV, IMNN-001 + BEV, or BEV alone based on their homologous recombination deficiency status and treatment randomization. Translational:All subjects will undergo biospecimen collection and organoid preparation prior to treatment, at the time of ICS and SLL for comprehensive longitudinal genomic, circulating tumor DNA, immune, and microbiome profiling. Subjects in the experimental arm will also undergo peritoneal lavage and collection of fluid and cells for assessment of the peritoneal tumor environment. Endpoints: The primary endpoint is the rate of MRD at SLL. Secondary endpoints include progression-free survival, overall survival, objective response rate, chemotherapy response score, surgical response, and serologic response. All patients will be evaluated for safety. Status: The study is actively enrolling and is in the safety lead-in portion. We plan to enlist approximately 4 sites in USA. Clinical trial information: NCT05739981 .

68Ga-FAPI-04 positron emission tomography/computed tomography (PET/CT) for detecting occult peritoneal metastasisin locally advanced gastric cancer: A single-center prospective cohort study.

4081 Background: Occult peritoneal metastasis (OPM) is a common finding in patients diagnosed with advanced gastric cancer. Preoperative diagnosis of OPM is crucial for developing treatment strategies and for evaluating the prognosis of patients with locally advanced gastric cancer. To evaluate the accuracy of 68Ga-FAPI-04 PET/CT in diagnosing OPM in locally advanced gastric cancer. Methods: This was a prospective, observational, single-center, single-blind, cohort study. Patients with histologically proven locally advanced gastric or gastroesophageal junction adenocarcinoma on initial staging evaluation were recruited. Laparoscopic staging and cytological analysis of peritoneal washing served as reference standards for the final diagnosis. The primary outcome was the proportion of participants changing treatment strategy from curative to palliative treatment. Results: A total of 49 patients were recruited between November 2022 and July 2023 .Nine of the 49 patients were diagnosed with OPM following 68Ga-FAPI-04 PET/CT examinations. A total of 18.4% (n=9) of patients with locally advanced disease on initial staging evaluation by contrast-enhanced CT were upstaged to stage IV for peritoneal metastasis on 68Ga-FAPI-04 PET/CT. The sensitivity of 68Ga-FAPI-04 PET/CT in detecting OPM was 85.7%, and the specificity was 92.3%. The overall diagnostic accuracy of 68Ga-FAPI-04 PET/CT was 91.8%. Based on ROC curve analysis, the area under the curve (AUC) was 0.893 (95% CI: 0.734–1). Conclusions: The findings of this study suggest a significantly additional value of 68Ga-FAPI-04 PET/CT in detecting OPM. Thus, it would be useful to include 68Ga-FAPI-04 PET/CT in the guidelines for staging locally advanced gastric cancer, instead of laparoscopic staging. Clinical trial information: ChiCTR2300067591.

#578 Calcium-channel blockers chyloperitoneum: an underrated complication in peritoneal dialysis

Abstract Background and Aims Bacterial peritonitis is the most feared complication for peritoneal dialysis (PD) patients. Together with abdominal pain and elevated white cell count in peritoneal effluent, the presence of a cloudy peritoneal effluent represents the main diagnostic criteria. The appearance of this last sign, even in an asymptomatic patient, always represents cause for concern and raises suspicion of an already subclinical peritonitis but can also represent other causes. Among acellular aetiologies for a cloudy peritoneal effluent, there is the presence of triglycerides, usually above 200 mg/dl, called chyloperitoneum, secondary to pancreatitis or concomitant calcium- channel blockers (CCBs) therapy. Most of dialysis patients are affected by hypertension. Considering the frequent necessity of limiting dosage of angiotensin 2 receptors blockers (ARB) and ACE inhibitors (ACE-I) for the risk of hyperkalaemia, CCBs frequently represent one of the most common prescribed antihypertensive drugs. Usually well tolerated and with limited adverse effects, literature demonstrates how they can induce, for not fully understood reasons (research supposed a role for the lipophilicity of these drugs, an impaired lymphatic absorption, an increased lympho-vascular dilatation or lymphatic hydrostatic pression) the presence of triglycerides in peritoneal effluent to levels causing chyloperitoneum. Frequently reported as anecdotical cases, especially in Asian studies, only limited information are available about influence of drug dosage or other concomitant therapies but is evident a higher frequency with lercanidipine assumption. Method We evaluated all patients undergoing peritoneal dialysis in our Centre in 2023. Chyloperitoneum (Fig. 1) diagnosis was obtained in cases of cloudy peritoneal effluent in asymptomatic patients with normal inflammatory indexes, normal white cell count on peritoneal effluent and negative cultural samples on peritoneal effluent associated with complete remission after fast peritoneal washes and reduction or discontinuation of CCBs. Results 16 patients underwent PD in our Centre during 2023: 4 automated (APD) and 12 ambulatory (CAPD). All of them were affected by hypertension and 10 of 16 (2 APD and 8 CAPD) were already in chronic therapy with CCBs (5 with lercanidipine, 4 with lacidipine and 1 with barnidipine), all at maximum accepted dosage. 4 patients presented during 2023 one or more episodes of cloudy peritoneal effluent without any sign or symptom of infection. All these patients were in CAPD and in therapy with lercanidipine and underwent to full remission after fast peritoneal washes; for 2 of them was necessary to discontinue CCBs therapy while for the other 2 dose reduction was fair. In 1 patient was recently associated oral anticoagulant therapy and in another 1 was recently associated dual antiplatelet therapy. None of these patients presented more episodes and all of them are still in PD. Among the other 8 patients in CCBs therapy without episodes of chyloperitoneum, only 1 was already in therapy with single antiplatelet therapy and none of them with double one or with oral anticoagulant. Conclusion cloudy peritoneal effluent is always cause for concern for Nephrologists since that it could represent, event without any other sign or symptom of infection, an already subclinical bacterial peritonitis. Most of dialysis patients are also affected by hypertension. Since usage of ARB and ACE-I is limited by risk of hyperkalaemia, CCBs represents one of the most prescribed antihypertensive drugs. For PD patients, however, the risk of chyloperitoneum must be considered since, even if it can be easily corrected, it could also affect therapy and patient management. Described in literature as only an anecdotical complication, our study shows that the incidence could be much higher and appears to be linked a specific molecule, lercanidipine, taken at higher dosage and to CAPD. Concomitant therapies as dual antiplatelet or oral anticoagulant therapy could represent a stimulating factor but other studies, with more numerous patients, are needed for further considerations.

Asymptomatic endometrial cancer with Lynch syndrome; in a woman with primary infertility-A case report and literature review.

Lynch syndrome, also called hereditary non-polyposis colorectal cancer, is an autosomal dominant disorder characterized by germline pathogenic mutations in DNA mismatch repair genes-resulting in increased susceptibility to colorectal, endometrial, and other tumors. This case report presents an incidental finding of endometrial cancer with Lynch syndrome during investigation for primary infertility. A 34-year-old woman presented to the fertility clinic with unexplained primary infertility. Investigations showed possible endometrial polyp, 13 × 11 mm in size. Hysteroscopic polypectomy and endometrial biopsy revealed complex endometrial hyperplasia amounting to endometroid adenocarcinoma. The case was discussed at the West of Scotland Gynecology-Oncology MDT meeting-management options including fertility-sparing treatment or radical surgery were presented to the patient and she opted for the latter. A total laparoscopic hysterectomy with bilateral salpingo-oophorectomy was performed with pathology results consistent with well-differentiated endometroid adenocarcinoma Stage 1A. Peritoneal washings showed no malignant cells. Genetic testing confirmed a diagnosis of Lynch syndrome. On further questioning, it was revealed that the patient had a strong family history of colon cancer but had not previously met the criteria for genetic testing. She was referred to colorectal surgeons and underwent colonoscopy. This showed no abnormality; she was therefore scheduled for 2-yearly colonoscopic surveillance.