Staging CT Research Articles

Active surveillance follow-up for prostate cancer: from guidelines to real-world clinical practice.

To assess active surveillance (AS) adherence for prostate cancer (PCa) in a "real-world" clinical practice. We utilized our institutional database which was built by interrogating electronic medical records for all men who got diagnosed with PCa from 1995 to 2022. Our cohort included all patients aged < 76 years, with PCa Gleason Grade (GG) 1 or 2, ≤ cT2c, PSA ≤ 20 ng/ml at diagnosis, enrolled on AS, and with at least one biopsy after diagnosis. Patients were separated into two groups based on the monitoring intensity. Patients with at least 1 PSA/year and at least 1 biopsy every 4 years were categorized as adherent to guidelines. Univariable and Multivariable logistic regression analyses were used to examine the impact of covariates on non-adherence to guidelines. Competing risks cumulative incidence was used to depict prostate cancer-specific mortality (PCSM). A total of 546 men met the inclusion criteria. Overall, 63 (11%) patients were adherent to guidelines (Group 1), while 483 (89%) were not (Group 2). Median PSAs/year and median biopsies/year were 2.3 (2.0-2.7) and 0.4 (0.3-0.6) for Group 1, and 1.2 (0.7-1.8) and 0.2 (0.1-0.2) for Group 2, respectively (both p < 0.0001). At multivariable analysis, Black men had a 2.20-fold higher risk of being in Group 2 than White men (p < 0.05). Patients with cT2 (OR:0.24, CI:0.11-0.52) and those with CCI ≥2 (OR:0.40, CCI:0.19-0.82) were less likely to be in Group 2, when compared to cT1 stage and CCI = 0, respectively (both p < 0.05). At 10 years, the cumulative incidence estimate of PCSM for the entire cohort was 2.1%. We found substantial deviations from AS monitoring guidelines, particularly in biopsy frequency, which did not seem to compromise PCSM in patients with stable PSA. Notably, our findings suggest that strict adherence to guidelines, especially in patients with cT2 at diagnosis, remains crucial.

HPB SO24 - Recurrence Pattern of Pancreatic Ductal Adenocarcinoma based on Time-to-Recurrence: A 5-year Single-Centre Retrospective Study

Abstract Background A vast majority of patients with pancreatic ductal adenocarcinoma (PDAC) develop early disease recurrence, even after curative-intent surgical resection. Understanding the pattern of disease recurrence will enable identification of areas for improvement within the preoperative diagnostic and management algorithms for these patients. The aim of the retrospective cohort study was to compare the recurrence pattern of PDAC in patients with early (&amp;lt;12 vs &amp;gt;12 months) and very early (&amp;lt;6 vs &amp;gt;6 months) recurrence following surgical resection. Method A retrospective review of histologically confirmed pancreatic ductal adenocarcinoma patients who underwent pancreaticoduodenectomy (N=151) between 2015-2020 at a tertiary HPB centre was undertaken. All patients underwent CT and PET-CT for initial staging before resection. Initial recurrence after resection was identified through postoperative imaging and/or HPB MDT outcomes. Early recurrence (ER) was defined as recurrence within the first 12 months after surgery (n=78). Additionally, very early recurrence (VEM) was defined as recurrence within the first six months after surgery (n=46). Statistical analysis was performed using GraphPad Prism 8.0. Results In total, 117 (77.5%) of patients experienced recurrence, with a median recurrence-free survival of 11.3 (5.1-19.6) months. Patients with ER had significantly higher pathological T staging (p=0.01), greater margin positivity rate (p=0.01) and higher lymph node ratio (p=0.046), while those in VER had significantly larger maximum tumour diameter and number of involved lymph nodes (p=0.04) compared to their counterparts. Patients with ER (47.4 vs 31.5%, p=0.046) and VER (60.9 vs 30.5%, p&amp;lt;0.001) had significantly greater rates of liver metastasis compared to their counterparts. There were no differences in loco-regional recurrence, peritoneal or pulmonary metastasis between the groups. Conclusion Approximately 20% of patients undergoing surgical resection for PDAC developed liver metastasis within six months of surgery. This raises concerns for the presence of micro-metastatic disease within the liver unidentified on preoperative imaging. Therefore, there is a need to enhance preoperative imaging and treatment algorithms to improve survival of patients with PDAC.

HPB SO38 - Assessing current pancreatic cancer reporting practice against the PACT-UK Synoptic Reporting Template: An initial clinical audit

Abstract Background In the last decade, the incidence of pancreatic cancer has increased by 9% in the UK. The gold standard for initial assessment of pancreatic cancer (or even peri-ampullary cancer) resectability is pancreatic-protocol CT scan. The PACT-UK project introduced a synoptic template for pancreatic cancer to standardise CT reporting practice across UK and enable consistent reporting of pertinent aspects of resectability status such as vascular involvement of the tumour. The aim of this audit is to assess the quality of current CT reports received by a tertiary hepato-pancreato-biliary (HPB) unit against the standards set out by PACT-UK. Method A retrospective analysis of 66 patients who underwent pancreatic resection between September 2023 and May 2024 at a tertiary HPB centre was undertaken. Patients were excluded from the analysis if they underwent resection for benign pancreatic pathology, were diagnosed with pathology other than peri-ampullary cancer or did not have a formal report of their CT scan. Initial CT scans performed at presentation and if available, subsequent up-to-date staging scan prior to surgery were assessed against the PACT-UK reporting template, in accordance with their guidance. The audit was registered with our clinical audit team (no. 11643). Results In total, 42 patients with peri-ampullary cancers were included in this audit. All patients had a reported CT scan on presentation. Additionally, 24 patients had a reported staging CT scan. The compliance (i.e. more than 90% information available) with PACT-UK reporting standards was 0% for initial presentation scans and 4.2% (n=1) for staging scans. The only staging scan with &amp;gt;90% compliance was reported using the PACT-UK template. Majority (more than 80%) of CT scan reports lacked information on aspects such as pancreatic duct size, predicted tumour type and radiological stage, variant vascular anomalies, and arterial/venous involvement. Conclusion This audit highlights the substandard quality of current CT reporting for peri-ampullary cancer. There is an urgent need to adopt a structured and dedicated reporting template to address the issue. Utilising a template such as the one developed by PACT-UK will help ensure that relevant information is formally reported to facilitate optimal decision-making at MDT meetings, and assist surgeons in operative planning and oncologists in assessing treatment response.

EPID-33. EPITHELOID SARCOMA IN A LONG-TERM SURVIVOR OF AN ATYPICAL TERATOID / RHABDOID TUMOR WITH RHABDOID TUMOR PREDISPOSITION SYNDROME

Abstract INTRODUCTION Rhabdoid tumor predisposition syndrome (RTPS) predisposes to a high risk of developing Rhabdoid tumors in Brain, kidney; and is defined by a germline mutation in SMARCB1 (rarely SMARCA4) gene. The most frequent pediatric tumor associated with RTPS is atypical teratoid/rhabdoid tumor (ATRT), commonly diagnosed in children &amp;lt; 3 years of age. Epitheloid Sarcoma (ES) is a rare soft tissue sarcoma, arising in any age group and histologically defined by loss of SMARCB1 in tumor cells. METHODS We describe a long- term survivor of ATRT with RTPS presenting 12 years later with ES. Data was collected from medical chart review. RESULTS Our patient was diagnosed with ATRT and RTPS (SMARCB1) at 6 months of age and treated with chemotherapy as per ACNS0333 at diagnosis; by chemotherapy / focal radiation at first relapse and with alisertib on second relapse. At 10yrs of age she presented with multiple firm, skin-colored dermal nodules in both her hands (palms and fingers). She was diagnosed to have palmar warts and treated with topical cantharidin with a waxing and waning course. Subsequently the hand lesions were diagnosed as granuloma annulare and followed up with no therapy. At 12 years of age, lesion in tip of the right thumb increased in size and a punch biopsy was done which revealed ES with IHC showing loss of SMARCB1 in tumor cells. Staging CT of the chest showed multiple bilateral (b/l) small (&amp;lt;1cm) axillary lymph nodes with a negative PET scan. Bilateral axillary lymph node biopsies were negative for ES. She underwent excision of all the hand lesions with negative margins with no further therapy. CONCLUSION Based on our case and single case report in literature, we hypothesize that ES is likely a primary malignancy of RTPS and should be included in the spectrum of malignancies of RTPS.

Sentinel lymph node biopsy in cT1-2N0 minor salivary gland cancer in oral cavity

ObjectiveTo evaluate the efficacy of sentinel lymph node biopsy (SLNB) in cT1/2N0 minor salivary gland cancer (mSGC) located within the oral cavity.MethodsA retrospective analysis was conducted on patients diagnosed with cT1/2N0 oral mSGC, who were categorized into two groups based on neck management approaches. The impact of SLNB versus observation on regional control and overall survival was assessed using a Cox model.ResultsA total of 177 patients were included in the study, with 53 cases undergoing SLNB. All patients had at least one sentinel lymph node, with the majority having two sentinel lymph nodes. The sentinel lymph nodes were predominantly situated in level I, followed by level II. Four patients had positive sentinel lymph nodes, all of whom had primary tumors in the tongue or the floor of the mouth, and were classified as cT2 stage. This yielded a sensitivity and specificity of 100%, a false negative rate of 0%, and a negative predictive value of 100% for SLNB in predicting occult metastasis. In terms of regional control, SLNB exhibited a reduced hazard ratio of 0.90 (95% confidence interval: 0.64–0.96) compared to observation. However, SLNB did not confer a superior overall survival benefit compared to observation.ConclusionIn patients with cT1/2N0 oral mSGC, SLNB proved to be both technically feasible and oncologically safe. When contrasted with observation, SLNB was associated with enhanced regional control, particularly recommending its use for cases of cT2 mSGC arising from the tongue or the floor of the mouth.

Significant Effect of Carbon-Ion Radiation Therapy Combined With Androgen Deprivation on Biochemical Recurrence Rates in High-Risk Prostate Cancer Patients: A Two-Center Controlled Trial Compare With X-Ray External Beam Radiation Therapy.

To compare the effects of carbon-ion radiation therapy (CIRT) and external beam radiotherapy (EBRT) on the prognosis of patients with prostate cancer. The effects of initial prostate-specific antigen (iPSA), clinical Tumor (cT) stage, radiotherapy method, and other clinical factors on the prognosis of 577 patients with radiotherapy were analyzed. Cox regression analysis showed that CIRT (RR: 0.49, p = 0.0215), cT stage ≥ 3 (RR: 2.72, p = 0.0003), and iPSA ≥ 16 ng/mL (RR: 1.74, p = 0.0347) were independent predictors of biochemical recurrence (BCR). After propensity score matching (PSM), CIRT (RR: 0.42, p = 0.0147), cT stage ≥ 3 (RR: 2.55, p = 0.0092), and iPSA ≥ 16 ng/mL (RR: 2.12, p = 0.0366) were still the predictors of univariate analysis. In multivariate analysis, CIRT (RR: 0.42, p = 0.015) and cT stage≥ 3 (RR:2.21, p = 0.0332) were independent predictors of BCR. Among them, we used iPSA and cT stages to establish a new radiotherapy selection model based on BCR risk. Patients who met more than one factor (score ≥ 1) and underwent CIRT had significantly better BCR progression-free survival (PFS) than those who received EBRT (p ≤ 0.01). This was also confirmed by Kaplan-Meier analysis after PSM. CIRT patients exhibited lower 5-year BCR rates compared to the EBRT group. Patients with a risk score of our model ≥ 1 undergoing CIRT were more likely to experience BCR benefits compared to those receiving EBRT.

Nutritional Supplement with Fermented Soy in Patients Under Active Surveillance for Low-Risk or Intermediate-Risk Prostate Cancer: Results from the PRAEMUNE Trial.

Background/Objectives: To investigate the effect of a fermented soy supplement during 18 months in patients under active surveillance (AS) for low-risk and selected favorable intermediate-risk prostate cancer (PCa), with an emphasis on PSA modulation. Methods: Low-risk patients with ISUP grade 1, clinical stage cT1 or cT2a, PSA < 10 ng/mL and favorable intermediate-risk patients with ISUP grade 2 (<10% pattern 4), clinical stage T2b-c, PSA 10-20 ng/mL. The primary outcome was PSA response defined as maximum PSA rise less than or equal to 0.87 ng/mL after 1 year, based on the weighted average of PSA velocity (PSAV) in previous studies in similar populations. Secondary outcomes were disease progression, adverse histology on repeat biopsy or switch to active therapy. In addition, primary and secondary outcomes with imputed data were also determined as sensitivity analyses, using Mann-Whitney U or Chi-squared tests. Results: Overall, 92 (61.3%) of 150 patients showed a PSA level response. This was more evident in ISUP 1 patients and resulted in fewer follow-up MRIs and fewer control biopsies, as well as a fewer number of positive control biopsies with statistical significance in the imputed dataset. Obtaining a PSA response was numerically associated with less initiated therapy. Conclusions: a fermented soy supplement in patients under AS for low-risk and selected favorable intermediate-risk PCa could be useful in selecting patients who may remain under AS or who may need to switch to active therapy.

The New Era of Total Neoadjuvant FLOT Therapy for Locally Advanced, Resectable Gastric Cancer: A Propensity-Matched Comparison With Standard Perioperative Therapy.

The FLOT 4-AIO trial established the docetaxel-based regimen's superiority over epirubicin-based triplet therapy in terms of survival rates and acceptable toxicity for locally advanced resectable gastric (LARGC). Yet, fewer than half of the patients achieved completion of eight prescribed FLOT cycles. We proposed that administering all FLOT cycles in the form of total neoadjuvant therapy may improve completion rates and downstaging. This study contrasted total neoadjuvant therapy (FLOT x8) with standard neoadjuvant therapy (FLOT 4+4) for patients LARGC adenocarcinoma who underwent curative resection with routine D2 lymphadenectomy, focusing on histopathological outcomes, toxicity, and survival outcomes. We reviewed patients with histologically confirmed advanced clinical stage cT2 or higher, nodal positive stage (cN+), or both, with resectable gastric tumors and no distant metastases (January 2017 to July 2023). We divided patients into two groups, FLOT 4+4 and FLOT x8; FLOT 4+4 patients underwent four preoperative and four postoperative bi-weekly cycles of docetaxel, oxaliplatin, leucovorin, and fluorouracil, while FLOT x8 patients received all eight cycles preoperatively after a gradual practice change starting from January 2020. Propensity score matching adjusted for age, clinical stage, tumor location, and histology. Of the 77 patients in the FLOT x8 group, 37 were propensity-matched to an equal number in the FLOT 4+4 group. Demographics, duration of surgery, and hospital stay showed no significant differences between the groups. The FLOT x8 group exhibited a significantly higher all-cycle completion rate at 89.1% compared to FLOT 4+4's 67.6% (p < 0.01). Both groups demonstrated comparable hematological and non-hematological toxicity rates, Clavien-Dindo ≥ 3 complications, and CAP tumor regression grades. The mean number of harvested lymph nodes was 42.5 and 41.2 in the FLOT 4+4 and FLOT x8 groups, respectively. Similar rates of disease-free survival and overall survival were noted in both groups, despite a trend toward a higher pathological complete response rate, albeit not statistically significant (8.1% vs. 18.9%, p = 0.29), in the FLOT x8 group at a median follow-up of 36 months. Total neoadjuvant therapy with the FLOT x8 protocol corresponds to higher treatment completion rates, a safety profile similar to standard perioperative therapy, and a twofold increase in complete pathological response. Further research on long-term oncological outcomes is needed to confirm the effectiveness of total neoadjuvant therapy.

The time-to-surgery interval and its effect on pathological response after neoadjuvant chemoimmunotherapy in non-small cell lung cancer: a retrospective cohort study.

The time to surgery (TTS) after the completion of the final cycle of neoadjuvant chemoimmunotherapy in patients with non-small cell lung cancer (NSCLC) is inconsistent. Pathological complete response (pCR) and major pathological response (MPR) are associated with enhanced survival in those with NSCLC. The optimal TTS interval remains to be determined, some studies indicated that TTS ≤6 weeks has a vital role in NSCLC prognosis. Therefore, this study aimed to determine whether TTS is correlated with pathological outcomes and to identify the factors associated with TTS. We retrospectively analyzed 82 individuals who had surgery after neoadjuvant chemoimmunotherapy for NSCLC between January 2020 and December 2023. Fifty participants were included in this study after inclusion and exclusion criteria. Participants were categorized into two groups: TTS ≤4 weeks and TTS >4 to 6 weeks. Univariate and multivariate regression analyses were employed to determine the impact of TTS on pathological response and to identify the variables associated with TTS. Variables that showed their P value <0.2 in univariate analyses were included in the multivariate analysis. Kaplan-Meier analysis was used to analyze disease-free survival (DFS). Our study evaluating 50 patients revealed that patients in the TTS ≤4 weeks group achieved pCR or MPR compared to patients in the >4 to 6 weeks group (P=0.01). In univariate analyses, TTS ≤4 weeks was more correlated with achieving pCR or MPR than TTS >4 to 6 weeks [odds ratio (OR) =0.211; 95% confidence interval (CI): 0.062-0.711; P=0.01] The multivariate analysis showed that cT1 stage (compared to cT4), and cN1 stage (compared to cN0) showed statistical correlation with achieving pCR or MPR. cN1 stage was independent predictor of achieving pCR or MPR (OR =27.817; 95% CI: 1.536-503.88; P=0.02). Concerning to the DFS, TTS ≤4 weeks group and TTS >4 to 6 weeks group showed no statistical differences (2-year DFS rate were 70.6% and 72.6%, respectively). Regarding the tendency of being patients' TTS ≤4 weeks, patients with ventilatory impairment (OR =0.203; 95% CI: 0.04-0.98; P=0.047) were more tending to prolong the TTS to >4 to 6 weeks. TTS ≤4 weeks was associated with a significant improvement of pathological response. Therefore, patients with NSCLC should undergo surgery within 4 weeks after the last cycle of neoadjuvant chemoimmunotherapy.

EP.05A.09 The Accuracy of CT, 18FDG-PET/CT, and Mediastinoscopy for Staging in NSCLC - A Systematic Review and Meta-Analysis

EP.05A.09 The Accuracy of CT, 18FDG-PET/CT, and Mediastinoscopy for Staging in NSCLC - A Systematic Review and Meta-Analysis

Survival Benefit from Total Neo-Adjuvant Therapy in Locally Advanced Rectal Cancer Patients

Abstract Background Preoperative chemoradiation in patients with locally advanced rectal cancer has no impact on overall survival (OS) and distant recurrences. The aim of the study was to evaluate local downstaging, toxicity, patient compliance and long-term outcome (2 year OS and DFS) in patients with locally advanced rectal cancer after induction chemotherapy with 12 weeks of 5 fluorouracil based chemotherapy followed by radiotherapy concomitant with capecitabine before total mesorectal excision (TME). Patients and Methods Between January 2018, and December 2019, we enrolled eligible patients with poor-risk rectal cancer defined by high-resolution MRI (Any cT3 and T4 stage, T2 low lying tumor at or below the levators and node positive tumor) and without metastatic disease Patients were planned for 12 weeks of neoadjuvant capecitabine and oxaliplatin (oxaliplatin 130 mg/m² on day 1 with capecitabine 1000 mg/m² twice daily for 14 days every 3 weeks) followed by chemoradiotherapy (50.4 Gy in a conventional fractionation) with capecitabine (825 mg/m² twice daily), then total mesorectal excision (TME) was carried out 6 weeks after the completion of CRT. Results Of 70 consecutively admitted patients starting induction chemotherapy, 55 patients underwent surgery. R0 resection was seen in 92.7% and pathological downstaging in 72.7%. In the intention-to-treat group, Objective response rates after neoadjuvant chemotherapy and chemoradiotherapy were 51.4% and 48.6%, respectively. Pathological complete response was seen in 15.7 %. Two-year disease-free survival (DFS) and OS were 62.5% and 82.6%, respectively. Grade 3/4 toxicity was seen in 20 %, and only one case died within 2 months of therapy. Conclusion Intensification of systemic therapy with neoadjuvant combination chemotherapy before standard treatment is feasible in poor-risk potentially operable rectal cancer, with acceptable safety and promising long-term outcomes. Future development of this multidisciplinary treatment strategy in randomized trials is warranted.

Correlation between MDCT and Postoperative Histopathology in the Staging of Laryngeal Carcinoma

Abstract Background The advantages and disadvantages of CT and MRI in the pre-operative assessment of laryngeal carcinoma still need to be further studied. Multidetector CT is the first line imaging investigation for staging laryngeal carcinoma. Evaluation of laryngeal SCC requires a contrast CT study of the neck. Excellent images of the neck are obtained using a multidectector CT (MDCT) following the injection of an iodinated contrast agent. Aim of the Work To assess the accuracy of preoperative CT staging of laryngeal tumours, and to measure its specificity for cartilage invasion, by comparing imaging with histologic cross-sections of surgical specimens and to clarify impact of these diagnostic modalities on pretherapeutic staging of laryngeal carcinoma. Patients and Methods Our study is a prospective study consisting of 30 patients with laryngeal carcinoma all underwent surgical treatment at Otorhinolaryngology department of Faculty of medicine, Ain Shams University. Results In our study CT showed highest accuracy in preepiglottic space, paraglottic space and Aryepiglottic fold lesions (96.7%), and was least accurate in cartilage invasion (73.4%). In our study the T stage was correctly determined by CT scan in 26 out of 30 cases. The consistency between perceived T stage by CT and histopathological analysis was highest for T3 (63.3%). Conclusion Contrast enhanced CT scan of the neck remains a precise and non-invasive imaging method for the staging of laryngeal carcinoma with high accuracy.

A prospective study to compare the diagnostic accuracy of 99mTc-CNDG SPECT/CT and contrast-enhanced CT in staging of non-small cell lung cancer

ObjectiveTo explore the value of 99mTc-isonitrile deoxyglucosamine (CNDG) SPECT/CT in the staging and resectability diagnosis of non-small cell lung cancer (NSCLC) compared with contrast-enhanced CT (CECT).MethodsThis research was approved by the hospital ethics review committee. Sixty-three patients with NSCLC received 99mTc-CNDG SPECT/CT, CECT and initial TNM staging before treatment. Thirty-three patients who underwent radical surgery underwent postoperative pathological TNM staging as the reference standard. Another thirty patients underwent radiochemotherapy; among them, the reference standard of 7 patients of N staging and 5 patients of M staging was based on biopsy pathology, and the diagnosis of the remaining lesions was confirmed by at least one different image or clinical imaging follow-up for more than 3 months. The McNemar test and receiver operating characteristic (ROC) curve analysis were used to compare the diagnostic accuracy of staging and resectability of 99mTc-CNDG SPECT/CT and CECT in NSCLC, respectively.ResultsFor all patients and surgical patients, the accuracies of 99mTc-CNDG SPECT/CT in diagnosing the T stage and N stage were higher than those of CECT (all patients: 90.5%, 88.9% vs. 79.4%, 60.3%; surgical patients: 81.8%, 78.8% vs. 60.6%, 51.5%), and the differences were statistically significant (all patients: T stage, P = 0.016; N stage, P = 0.000; surgical patients: T stage, P = 0.016; N stage, P = 0.004). For all patients, the accuracy of 99mTc-CNDG SPECT/CT in diagnosing the M stage was higher than that of CECT (96.8% vs. 90.5%), but the difference was not statistically significant (P = 0.289). ROC curve analysis showed that the accuracy of 99mTc-CNDG SPECT/CT in diagnosing the potential resectability of NSCLC was significantly better than that of CECT (P = 0.046).ConclusionThis preliminary clinical study shows that 99mTc-CNDG SPECT/CT is of great value for accurate clinical staging of NSCLC compared with CECT and can significantly improve the accuracy of resectability diagnosis.

Real-world response assessment of immune checkpoint inhibition: comparing iRECIST and RECIST 1.1 in melanoma and non-small cell lung cancer patients.

To compare immune response evaluation criteria in solid tumors (iRECIST) and response evaluation criteria in solid tumors (RECIST) 1.1 for response assessment of immune checkpoint inhibitor (ICI) therapy in a real-world setting in patients with melanoma and non-small cell lung cancer (NSCLC). Two-hundred fifty-two patients with melanoma and NSCLC who received CTLA-4 inhibitor ipilimumab or PD-1 inhibitors nivolumab or pembrolizumab and who underwent staging CT of the chest and abdomen were retrospectively included. Treatment response evaluation according to the RECIST 1.1 and iRECIST guidelines was performed for all patients. Response patterns, as well as overall response rate (ORR), disease control rate (DCR), and time to progression (TTP), were compared between RECIST 1.1 and iRECIST. Out of 143 patients with progressive disease (PD) according to RECIST 1.1, 48 (33.6%) did not attain confirmation of progression (iCPD) as per iRECIST and six patients who were treated beyond RECIST 1.1 progression reached PD at a later point in time in iRECIST, resulting in a significant difference in TTP between iRECIST and RECIST 1.1 (618.3 ± 626.9 days vs. 538.1 ± 617.9 days, respectively (p < 0.05)). The number of non-responders as per RECIST 1.1 was 79, whereas it was 60 when using iRECIST. ORR was 28.5% for RECIST 1.1 and 34.1% for iRECIST, and corresponding DCR of 67.4% for RECIST 1.1 and 74.6% for iRECIST. iRECIST was more suitable than RECIST 1.1 for capturing atypical response patterns to ICI therapy in patients with melanoma and NSCLC, resulting in differences in the assessment of treatment response. Compared to RECIST 1.1, iRECIST may improve patient care and treatment decisions for patients with NSCLC or melanoma who are treated with immune checkpoint inhibitors in clinical routine. RECIST 1.1 may incorrectly assess atypical treatment patterns to immune checkpoint inhibitors. iRECIST better captured atypical response patterns compared to RECIST 1.1. iRECIST was more suitable for assessing response to immune checkpoint inhibitors in non-small cell lung carcinoma and melanoma.

Analysis of Neoadjuvant Chemotherapy Utilization, Pathologic Response, and Overall Survival in Upper Tract Urothelial Carcinoma

IntroductionUpper tract urothelial carcinoma (UTUC) is a rare malignancy with poor prognosis. Radical nephroureterectomy (RNU) remains the standard treatment for high-risk UTUC. Considering the decline in renal function with RNU and results from prospective trials, NAC has emerged as a favored perioperative treatment for chemo-eligible patients with UTUC. However, strong evidence of the efficacy of NAC and predictors for its use are scarce. We aimed to assess trends in NAC utilization and pathologic outcomes and survival with NAC use. MethodsThe National Cancer Database was queried for patients with high-grade cTanyNanyM0 UTUC treated with RNU from 2004 to 2019. Outcomes included overall survival (OS), pathologic response (pR) and pathologic complete response (pCR), defined as ≤pT1pN0/X and pT0pN0/X, respectively. ResultsOf 6,645 patients treated with RNU, 209 received RNU NAC. Greater distance from treatment facility decreased the likelihood of receiving NAC. Higher cT stages (OR 1.72, P = .028), cN+ status (OR 7.40, P < .001) and treatment at an academic facility (OR 2.02, P < .001) predicted NAC treatment. NAC was associated with 34.0% pR and 5.3% pCR. In multivariable analysis, patients with pR and pCR had improved OS (HR = 0.176, P < .014). ConclusionWe report significant response rates with NAC and improved OS in patients who experienced pR or pCR. Over a 15-year study period, NAC was underutilized, especially in nonacademic settings and among patients living farther from care facilities, underscoring the need for improved regionalization and multidisciplinary approaches in UTUC management.

Efficacy of neoadjuvant chemotherapy combined with prophylactic intraperitoneal hyperthermic chemotherapy for patients diagnosed with clinical T4 gastric cancer who underwent laparoscopic radical gastrectomy: a retrospective cohort study based on propensity score matching

BackgroundClinical T4 (cT4) stage gastric cancer presents with frequent postoperative recurrence and poor prognosis. This study is to evaluate the oncological efficacy of laparoscopic radical total gastrectomy combined with postoperative prophylactic hyperthermic intraperitoneal chemotherapy (HIPEC) in patients with cT4N + M0 gastric cancer who received neoadjuvant chemotherapy.MethodsWe reviewed the clinicopathological data of 174 patients with clinical T4 gastric cancer who underwent neoadjuvant chemotherapy followed by laparoscopic radical total gastrectomy between June 2017 and December 2021. Among them, 142 were included in the non-HIPEC group, and 32 in the HIPEC group. Patients in both groups were paired based on propensity score in a 2:1 ratio to assess disparities in tumor recurrence and long-term survival.ResultsAfter matching, there were no significant differences in the clinicopathological data between the two groups. The peritoneum (16.1%) and distant organs (10.9%) were the most frequent locations for recurrence. Prior to matching, the recurrence rates were similar at all sites for both groups. Compared with those in the non-HIPEC cohort, the recurrence rates at all sites, the lung, and the peritoneum were notably lower in the HIPEC cohort. Prior to matching, the 3-year overall survival and disease-free survival rates were similar between the two groups; following matching, the HIPEC group exhibited notably greater survival rates than did the non-HIPEC group. The disparities in survival rates between the groups became even more pronounced after conducting a stratified analysis among patients with stage III disease.ConclusionsNeoadjuvant chemotherapy combined with prophylactic HIPEC after laparoscopic radical gastrectomy can effectively reduce the rate of peritoneal metastasis in patients with cT4N + M0 advanced gastric cancer and significantly improve the prognosis of such patients, which is of great clinical value.

Advanced diffusion-weighted MRI models for preoperative prediction of lymph node metastasis in resectable gastric cancer.

To investigate the potential of six advanced diffusion-weighted imaging (DWI) models for preoperative prediction of lymph node metastasis (LNM) in resectable gastric cancer (GC). Between Nov 2022 and Nov 2023, standard MRI scans were prospectively performed in consecutive patients with endoscopic pathology-confirmed gastric adenocarcinoma who were referred for direct radical gastrectomy. Six DWI models, including fractional order calculus (FROC), continuous-time random walk (CTRW), diffusion kurtosis imaging (DKI), intravoxel incoherent motion (IVIM), the mono-exponential model (MEM) and the stretched exponential model (SEM) were computed. Surgical pathologic diagnosis of LNM was the reference standard, and patients were classified into LNM-positive or LNM-negative groups accordingly. The morphological features and quantitative parameters of the DWI models in different LNM categories were analyzed and compared. Multivariable logistic regression was used to screen significant predictors. Receiver-operating characteristic curves and the area under the curve (AUC) were plotted to evaluate the performances, the Delong test was performed to compare the AUCs. In the LNM-positive group, tumor thickness and kurtosis (DKI_K) were significantly higher, while anomalous diffusion coefficient (CTRW_D), diffusivity (DKI_D), diffusion coefficient (FROC_D), pseudodiffusion coefficient (IVIM_D*), perfusion fraction (IVIM_f), and ADC were lower compared to the LNM-negative group. Clinical tumor staging (cT) and CTRW_D were independent predictors. Their combination demonstrated a superior AUC of 0.930, significantly higher than that of individual parameters. Tumor thickness, DKI_K, CTRW_D, DKI_D, FROC_D, IVIM_D*, IVIM_f and ADC were associated with LNM status. The combination of independent predictors of cT and CTRW_D further enhanced the performance.

EP191 - Laparoscopic right hemicolectomy in a patient with malrotation of bowel and ascending colon tumour

Abstract Aims Ascending colon (AC) tumour in a patient with malrotation of bowel can present diagnostic and surgical challenges. We present such a case managed by laparoscopic resection, and share the difficulties encountered and our preparation to achieve a good outcome Methods A 72-year-old female with iron deficiency anaemia underwent CT colonography after an incomplete optical colonoscopy. The scan revealed malrotation, a pelvic caecum and a midline ascending colon, and a lesion suspicious of cancer in ascending colon with a CT staging of T3N0M0. Patient was scheduled for elective laparoscopic right hemicolectomy. Results Review of vascular anatomy was carried out with radiologist. Several modifications to standard procedure was used – first port-entry site, number of ports, plan of dissection, and site of specimen extraction. Additional challenges were due to the high BMI (40 kg/m2). Patient was discharged on day-7 without major complications. Conclusion Multidisciplinary discussion, optimal pre-operative preparation, and thorough understanding of the vascular profile leads to successful management of these rare presentations by minimally invasive surgery. Pre-operative CT-scan is essential before planning surgical management. Laparoscopic right-hemicolectomy although challenging, can be successfully performed with appropriate expertise.

SP4.10 - Comparison of the Global Leadership Initiative on Malnutrition (GLIM) Phenotypic Criteria in Patients with Oesophagogastric Cancer

Abstract Aim The Global Leadership Initiative on Malnutrition (GLIM) consensus proposed that patients should meet one of three phenotypic criteria for a diagnosis of malnutrition. This study examined the association between these criteria and survival in oesophagogastric cancer. Methods Consecutive patients newly diagnosed with oesophagogastric cancer were identified from a prospectively maintained regional database between 2019-2020. Data were collected regarding the GLIM phenotypical criteria: involuntary weight loss (≥5% in 6 months or ≥10% in &amp;gt;6 months), body mass index (&amp;lt;20kg/m2 (&amp;lt;70 years) or &amp;lt;22kg/m2 (&amp;gt;70 years)) and reduced muscle mass via body composition analysis. Cross-sectional area of skeletal muscle was measured at mid-L3 on staging CT imaging. This was normalised for height to create skeletal muscle index (SMI), with low SMI being defined as per Martin et al. The outcome of interest was overall survival. Results Overall, 465 patients (median 71 years, n=311 males) were identified. Weight loss (p=0.022), BMI (p&amp;lt;0.001) and SMI (p=0.005) cut-offs were all associated with reduced ECOG performance status. BMI and SMI were also associated with increased age. A higher proportion of patients with advanced stage malignancy met the weight loss threshold (p=0.001). Each phenotypical criterion was associated with worsened overall survival (all p&amp;lt;0.001). While all three were prognostic, following adjustment for confounders, low SMI (aHR:1.76 (95%CI:1.39-2.22)) was more strongly associated with poor survival than low BMI (aHR:1.57 (95%CI:1.18-2.08)) or weight loss (aHR:1.46 (95%CI:1.17-1.81)). Conclusion While each of the GLIM phenotypical criteria are adversely prognostic in oesophagogastric cancer, low SMI is most strongly associated with poor survival.

EP496 - Metastatic Invasive Lobular Carcinoma of the Breast mimicking healed Gastric Ulcer: A Case Report

Abstract Introduction Breast cancer metastasizing to the stomach as a new presentation is highly unusual. We report a 77-year-old female with such presentation. Case Presentation A 77-year-old female investigated for significant weight loss. She denied any upper or lower gastrointestinal symptoms. She had bidirectional scopes. Colonoscopy showed only diverticulosis. Two gastroscopies revealed non-specific stellar shaped areas in the anterior antrum wall mimicking a healed gastric ulcer. Biopsies confirmed metastatic lobular carcinoma of the breast, ER+ve, HER2 negative. On further clinical examination she had large mass upper outer quadrant with palpable enlarged nodes. Staging CT scan showed couple of hyper enhancing foci in the right breast which may be potential candidates for primary tumour and enlarged right axillary nodes. Subsequently she had an ultrasound guided biopsy of the breast lesion confirmed invasive lobular cancer. Patient has been referred to the breast MDT for breast and lymph node biopsy. Discussion The incidence of GI metastatic disease from a primary breast cancer is less than 1%. It is more common to diagnose in patients with prior history and treatment for primary breast malignancy. However, occasionally it can be encountered prior to the diagnosis of the primary tumour. Hence, index of high suspicion is required as the endoscopic findings are non-specific.