Esophagogastric Cancer Research Articles

OGC P63 The Influence of PET-CT on the Therapeutic Pathway of Oesophageal and Oesophago-Gastric Junction Cancers. A Clinical Audit in a High Volume UGI Cancer Unit in the UK

Abstract Background Patients with oesophageal and oesophago-gastric Junction (OGJ) cancers require accurate staging to decide on intent of treatment (curative or palliative). The literature reported higher accuracy (82% vs. 64%, P = 0.004) and sensitivity (74% vs. 47%) for PET-CT when compared to CT for detecting distant disease. Consequently, the National Institute for Health and Care Excellence (NICE) recommends PET-CT for all oesophageal and GOJ cancers except T1a tumors. This audit investigated how PET-CT affected the treatment plan of oesophageal and OGJ cancer patients and its impact on MDT decisions and patients’ waiting time before first treatment is started. Methods Retrospective data collection from our institutional electronic database for all oesophageal and OGJ cancer patients that had undergone PET-CT as part of cancer staging in the last 9 months. Data collected was basic demographics, waiting time for PET-CT and discrepancy between CT and PET-CT in finding distant metastasis or other incidental findings. The influence of this on the MDT outcomes was investigated and the delay in cancer treatment secondary to further investigations was recorded. Results A total of 44 oesophageal and OGJ cancer patients had staging PET-CT. Out of 44 patients, 33 (75%) were males. The average age was 67 (45-85) years. Average waiting time for PET-CT was 17(1-57) days. Fourteen (32%) patients had discrepancy between CT and PET-CT. In Group A, 5 (11%) patients, PET-CT reported distant metastasis. In Group B, 9 (20%) patients, PET-CT detected active uptake in colon (n=4), cervical LNs (n=2), thyroid (n=1), tonsils & prostate (n=1) and spine (n=1). Further investigations (endoscopy, ultrasound, biopsy etc.) added a delay with an average of 15 (1-28) days. Conclusions It is proven that PET-CT is essential in staging non metastatic oesophageal and OGJ cancers. It is important for MDTs to be vigilant that PET-CT can delay the start of first treatment for those patients by picking up non UGI cancer related pathology. This initiates a cohort of further investigations, creating some delay. Therefore, timely PET-CT scanning and reporting is recommended e.g during pre-MDT referral triage meetings. Selecting patients for PET-CT may also be helpful based on accurate CT reporting of cancer TNM stage.

EGS P02 Lessons learnt from 450 Endoluminal vacuum therapy (EVT) procedures in the treatment of upper gastrointestinal perforations and leaks

Abstract Background Endoluminal vacuum therapy (EVT[BA1] ) is a novel, yet relatively well established tool in the management of upper gastrointestinal (UGI) leaks and perforations. Despite a growing body of evidence supporting its use, management strategies and techniques used in the context of EVT are yet to be standardised. Furthermore, the uptake of EVT in the UK is limited to a small number of centres. This project aimed to summarise the key lessons learnt from our initial experience of 450 EVT procedures, to inform others about how this technique can be integrated into regular clinical practice. Methods This study draws on experiential reflections and analysis of a prospective database of 450 EVT procedures in 59 patients in our unit from October 2018 – June 2023. This included patients who had undergone oesophago-gastric (OG) cancer resections, bariatric surgery (index procedures both in the UK and abroad) and those presenting with benign disease (oesophageal perforation and iatrogenic injury). The setting was a regional tertiary OG and bariatric centre in the North West of England serving a cancer and benign population of 3.5 million people and a larger undetermined population for bariatric emergencies. Results 51/59 (86%) patients were successfully managed with 446 EVT procedures. Patient, system and technical factors were identified which when addressed, facilitated expeditious healing of leaks, and enabled active management patients unfit for more invasive interventions. Factors included understanding the indications for using and stopping EVT, control of sepsis, and optimisation of nutrition and glycaemic control. Technical factors included sponge placement, managing foreign material (e.g. redundant sutures and drains) and approaches to managing necrosis. System factors included supporting a training programme, the necessity of a comprehensive team approach and the financial and governance challenges with adopting a novel intervention. Conclusions EVT is as an effective technique in the management of complex UGI leaks and perforations. There are multiple patient, financial, logistical, governance and systems factors that present as challenges to the implementation of this technique into routine practice. An integrated team-based approach is key to adoption of EVT by other centres into their routine practice.

OGC P13 CNS and Dietitian led clinical follow-up with support from a survivorship multi-disciplinary team meeting: A model of care for patients after oesophago-gastric (OG) cancer surgery

Abstract Background Major upper gastro-intestinal (UGI) cancer surgery in combination with chemotherapy offers the best chance of cure for patients with oesophageal and gastric cancer. However, these treatments have significant long-term side-effects resulting in a high symptom burden in this patient group. This adversely affects quality of life and places significant demands on healthcare after surgery. There is a large variation in follow-up services nationally, with little guidance on optimal practice. Methods A clinical nurse specialist (CNS) and Dietitian led clinic has been utilised in this patient group for 12 years at St Thomas’ hospital, with UGI surgeon support as required. In 2021, a survivorship multi-disciplinary team meeting (MDM) consisting of CNS, Dietitian, Gastroenterologist, UGI surgeon and psychologist was introduced. This aimed to support the clinic by discussing management of complex cases. Results Since 2011, approximately 3000 patient consults have been undertaken in the survivorship clinic. These patients benefited from specialist follow-up, expertise in symptom management, holistic needs assessments, recurrence surveillance and specialist dietetic advice. These patients were removed from surgical and oncology out-patient clinics, creating greater capacity in these services. Patient feedback has consistently supported this model of follow-up. Complex patients are discussed in the survivorship MDM which supports the clinic. Conclusions CNS and Dietitian led clinics, alongside a survivorship MDM, may provide a better model of follow-up compared to traditional surgical clinics by offering a greater breadth of expertise and consistency of follow-up. Evaluation of patient centred outcomes and economic analysis, in addition to on-going national initiatives to standardise the investigation and management of symptoms following major UGI surgery, would support replicating this model in other centres.

OGC P47 Yield of staging laparoscopy in upper GI cancer; post COVID

Abstract Background Staging laparoscopy is a useful adjunct in preoperative staging process of oesophago-gastric cancer. NICE recommends use of staging laparoscopy in oesophageal cancer cases where it is likely to guide further management. In cases of gastric cancer there is strong evidence to suggest a high specificity of staging laparoscopy in detection of peritoneal metastasis. During COVID very selective use of staging laparoscopy was adopted by our unit. In this study we aimed to evaluate yield of staging laparoscopy in context of gastric and selective oesophageal cancers in our unit during post-COVID period Methods Retrospective analysis of our prospectively kept database in patients undergoing staging laparoscopy between January 2022 to May 2023 in upper GI tertiary cancer centre was performed. Age, sex, tumour grade, nodal status on radiology, histologic type, differentiation, and site of tumour was assessed against positive cytology and presence of peritoneal or occult visceral metastasis. Multivariate logistic regression was applied to identify independent factors associated with findings. Statistical analysis was carried out using EXCEL® and MedCalc® software. Results Among 104 patients, 69 had oesophageal cancer (OC) and 35 had gastric cancer (GC). In OC group cytology was positive in 4 (5.8%), peritoneal metastasis was present in 7 (10.1%) patients. In GC group positive cytology in 8 (22.8%), peritoneal metastasis was found in 8 (22.8%) patients. On multivariate analysis differentiation, T3+ tumour, lower third cancer, male sex was linked with positive findings in OC group. In GC group poor differentiation, T4 disease, mid body tumour, nodal status of N3 were associated positive findings. Yield of laparoscopy was found to be 17.6% and 34.6% in OC and GC groups respectively. Conclusions Despite of recent advances in radiological modalities, staging laparoscopy remains a useful adjunct in diagnosing peritoneal disease. With negligible complication rates and its relatively high yield in lower third and junctional oesophageal cancer it can be utilised to guide further management and reduce unnecessary laparotomies. Mid gastric body site and T4 cancers in our cohort were strong predictors of peritoneal disease further multi centre research on site of tumour is needed to affirm any such association.

OGC P41 Presentation, Management and Outcomes in Young Patients Diagnosed with Oesophageal Cancer

Abstract Background Oesophageal cancer is a devastating malignancy associated with poor prognosis, primarily affecting older individuals with multiple co-morbidities. However, outcomes of younger patients have been perceived as poor due to late diagnosis and more aggressive disease subtype. This subset of patients poses unique clinical challenges and requires a better understanding of their outcomes. This comprehensive retrospective cohort study aimed to evaluate the patient characteristics, treatment modalities, and survival outcomes of young patients diagnosed with oesophageal cancer, to provide further insights into this understudied population. Methods A retrospective analysis was conducted using electronic medical records from a regional oesophago-gastric cancer service serving 3.5 million people across the North West of England, encompassing a 5-year period between January 2018 and December 2022 inclusive. Young patients were defined as being 50 or younger at the time of diagnosis of oesophageal cancer. Clinical and pathological data, including tumour characteristics, treatment approaches, and survival outcomes, were collected. Survival analysis was performed utilising Kaplan-Meier estimates, and survival rates following oesophagectomy were compared to publicly available outcomes. Results 87/2485 (3.5%) of patients studied were aged 50 or below at the time of diagnosis. Mean age at diagnosis was 44.3 (range = 24-50); 71% were male. Adenocarcinoma and SCC accounted for 73% (33% poorly differentiated, 40% moderately differentiated) and 25% of cases respectively. The majority presented with c-stage III (24%), c-stage IVa (17%) and c-stage IVb (46%) disease. Initial treatment intent was curative in 43%. 1-and 3-year overall survival rates were 49% and 21% respectively - similar to the wider population. 1- and 3-year survival rates after oesophagectomy were 80% and 44.5% (versus 82.5% and 59.5% for wider population). Conclusions Our findings underscore the concerns about the proportion of advanced-stage diagnosis in young patients with oesophageal cancer, and poorer longer-term outcomes after curative resection. This highlights the importance of timely detection and appropriate treatment strategies in this patient group. Future research should focus on understanding the underlying mechanisms in this group, exploring novel therapeutic strategies as well as validating these finding in larger and more diverse patient populations.

OGC P42 Presentation, Management and Outcomes in Young Patients Diagnosed with Gastric Cancer

Abstract Background Gastric cancer poses a significant global health challenge, mainly affecting older individuals with well-established risk factors. However, outcomes in young patients have been perceived as poorer due to late diagnosis and more aggressive disease subtype. There are also a small sub-set of younger patients in which gastric cancer is genetically inherited. This comprehensive retrospective cohort study aimed to evaluate the patient characteristics, treatment modalities, and survival outcomes of young patients diagnosed with gastric cancer, to provide valuable insights into optimal therapeutic strategies. Methods A retrospective analysis was conducted using electronic medical records from a regional oesophago-gastric cancer service serving 3.5 million people across the North West of England, encompassing a 5-year period between January 2018 and December 2022 inclusive. Young patients were defined as being 50 or younger (eligible for genetic testing) at the time of diagnosis of gastric cancer. Clinical and pathological data, including tumour characteristics, treatment approaches, and survival outcomes, were collected. Survival analysis was performed utilising Kaplan-Meier estimates, and survival rates following gastrectomy were compared to publicly available outcomes. Results 60/956 (6.3%) patients were aged 50 or below at the time of diagnosis. Mean age was 42.1 (range = 28-50); 48% were male. Stages III and IV of disease were observed in 27% and 57% of patients respectively. Poorly differentiated disease was observed in 53%, with HER-2 positivity in 13%. Distal gastric cancer represented 56% of cases and proximal cancer 27%. Initial treatment intent was curative in 43%. 1-year and 3-year overall survival was 51% and 33. 3-year overall survival was 92% for 20 patients who received gastrectomy versus 60% in all patients reported by NOGCA. Conclusions This study suggests that young patients with gastric cancer present with significantly advanced disease. Despite this, young patients show similar medium- and long-term survival rates. Well selected young patients can be offered treatment with curative intent with good medium- to long-term outcomes. Future research should focus on understanding the underlying mechanisms in this group, exploring novel therapeutic strategies, including the role of genetic testing, as well as validating these finding in larger and more diverse patient populations.

OGC P50 Evaluating the outcomes of routine level one ward care post major oesphago-gastric surgery

Abstract Background Oesophago-gastric cancer resections are complex operations. Many centres routinely manage patients in higher acuity settings such as surgical HDU, ITU or fast track beds. The UK has 2.4 critical care beds per 1000, compared to an average of 5 per 1000 across OECD-EU nations. The COVID-19 pandemic has also had a significant impact on availability of these beds. Patients in our unit are routinely admitted to a standard level one surgical bed with continuous non-invasive cardiac monitoring and nursing care ratio of 1 to 5. This has been in practice for over 10 years with good outcomes. Methods Consecutive major oesophago-gastric resections between April 2020 and March 2023 in a single tertiary unit were included. Patients were split into two groups: Patients who were admitted directly to the surgical ward or had a planned admission to ITU based on pre-operative assessment and routine Integrated Cardiopulmonary Exercise Testing (CPEX) outcomes were considered to have completed a standard pathway. The primary outcome was unplanned ITU admission rate. Secondary outcomes included: total length of stay (TLOS), 30- and 90-day mortality. Results 238 patients (187 M: 51 F) were identified with a median age of 69 (33 – 84 years). The resections performed were Ivor Lewis oesophago-gastrectomy (ILGO) (n=196, 81%), total/extended total (n=30), subtotal (n=10) or distal gastrectomy (n=3). 34 patients were admitted to ITU, of which 23 were unplanned (9.2%) and all had undergone an ILGO. The median TLOS and mortality data are outlined in Table 1, with <1% 30 and 90-day mortality for patients on the standard pathway. The median ITU length of stay was 5 days (1 – 48 days) with reasons for admission listed in Table 2. Conclusions Major oesophago-gastric cancer resections can be managed safely in the early post-operative period, outside of higher acuity care settings with good outcomes.

Modified side-overlap esophagogastric tube reconstruction after laparoscopic proximal gastrectomy for esophagogastric junction cancer (with video)

Modified side-overlap esophagogastric tube reconstruction after laparoscopic proximal gastrectomy for esophagogastric junction cancer (with video)

CRP as an early indicator for anastomotic leakage after esophagectomy for cancer: a single tertiary gastro-esophageal center study

PurposeTo determine the relationship between postoperative C-reactive protein (CRP) as an early indicator of anastomotic leakage (AL) after esophagectomy for esophageal cancer.MethodsWe reviewed patients diagnosed with esophageal or esophagogastric junctional cancer who underwent esophagectomy between 2006 and 2022 at the Karolinska University Hospital, Stockholm, Sweden. Multivariable logistic regression models estimated relative risk for AL by calculating the odds ratio (OR) with a 95% confidence interval (CI). The cut-off values for CRP were based on the maximum Youden’s index using receiver operating characteristic curve analysis.ResultsIn total, 612 patients were included, with 464 (75.8%) in the non-AL (N-AL) group and 148 (24.2%) in the AL group. Preoperative body mass index and the proportion of patients with the American Society of Anesthesiologists physical status classification 3 were significantly higher in the AL group than in the N-AL group. The median day of AL occurrence was the postoperative day (POD) 8. Trends in CRP levels from POD 2 to 3 and POD 3 to 4 were significantly higher in the AL than in the N-AL group. An increase in CRP of ≥ 4.65% on POD 2 to 3 was an independent risk factor for AL with the highest OR of 3.67 (95% CI 1.66–8.38, p = 0.001) in patients with CRP levels on POD 2 above 211 mg/L.ConclusionEarly changes in postoperative CRP levels may help to detect AL early following esophageal cancer surgery.

Continuous glucose monitoring and low-glycaemic index diet in the management of postprandial hypoglycaemia after oesophagogastric cancer surgery.

Continuous glucose monitoring and low-glycaemic index diet in the management of postprandial hypoglycaemia after oesophagogastric cancer surgery.

The Role of Mucin Expression in the Diagnosis of Oesophago-Gastric Cancer: A Systematic Literature Review

Survival in oesophago-gastric cancer (OGC) is poor due to early diagnostic challenges. Non-invasive risk stratification may identify susceptible patients with pre-malignant or benign disease. Following diagnostic confirmation with endoscopic biopsy, early OGC may be treated sooner. Mucins are transmembrane glycoproteins implicated in OGC with potential use as biomarkers of malignant transformation. This systematic review defines the role of mucins in OGC diagnosis. A literature search of MEDLINE, Web of Science, Embase and Cochrane databases was performed following PRISMA protocols for studies published January 1960–December 2022. Demographic data and data on mucin sampling and analysis methods were extracted. The review included 124 studies (n = 11,386 patients). Gastric adenocarcinoma (GAc) was the commonest OG malignancy (n = 101) followed by oesophageal adenocarcinoma (OAc, n = 24) and squamous cell carcinoma (OSqCc, n = 10). Mucins MUC1, MUC2, MUC5AC and MUC6 were the most frequently implicated. High MUC1 expression correlated with poorer prognosis and metastases in OSqCc. MUC2 expression decreases during progression from healthy mucosa to OAc, causing reduced protection from gastric acid. MUC5AC was upregulated, and MUC6 downregulated in GAc. Mucin expression varies in OGC; changes may be epigenetic or mutational. Profiling upper GI mucin expression in OGC, with pre-malignant, benign and healthy controls may identify potential early diagnostic biomarkers.

Psychosocial functioning in individuals with advanced oesophago-gastric cancer: a mixed methods systematic review

BackgroundOesophago-gastric cancer is an aggressive disease with a high rate of recurrence and mortality across the disease trajectory. Reduced psychosocial functioning has been evidenced amongst those with advanced disease, however little is known about the contributing factors. Determining these factors is an important clinical consideration to inform assessment and intervention. This review aimed to synthesise the available evidence on the psychosocial functioning of individuals with advanced oesophago-gastric cancer and their carers.MethodsA JBI mixed-methods systematic review. Four bibliographic databases, MEDLINE, Embase, PsycINFO, and CINAHL, were searched. Quantitative and qualitative studies were screened for inclusion and critically appraised for methodological quality. Both types of data were extracted using JBI tools for mixed-methods systematic reviews. A convergent segregated approach to synthesis and integration was used. The findings of the synthesis have been configured according to JBI methodology.ResultsA total of 12 studies were included in this review, including 6 quantitative studies and 6 qualitative studies. The quantitative results provide preliminary indication of several physical, biological, psychological and macro-level contextual factors associated with psychosocial functioning in this clinical population. The qualitative findings shed light on a range of physical, psychosocial, and existential challenges faced by advanced oesophago-gastric cancer patients. These multiple and often persistent challenges appear to cause considerable distress; however, patients describe the importance of maintaining a sense of normality and control over their illness and its effects. Patients value continuity and structure, however many report shortcomings when accessing care. No findings reporting the experiences from the perspective of carers were found, therefore all findings represent the perspective of the patient.ConclusionsFurther high-quality research is needed to understand how best to support and manage the palliative care needs of individuals living with advanced oesophago-gastric cancer. Implications for practice are discussed, suggesting that psychosocial interventions, complex symptom management and continuity of care could improve the psychosocial functioning of individuals in this setting.Pre-registrationThe systematic review was pre-registered at the International Prospective Register of Systematic Reviews (PROSPERO; CRD42020181273) and the protocol can be viewed on the OSF (http://osf.io/exuzf).

Assessing real-world representativeness of prospective registry cohorts in oncology: insights from patients with esophagogastric cancer

ObjectivesThis study aimed to explore the real-world representativeness of a prospective registry cohort with active accrual in oncology, applying a representativeness metric that is novel to health care. Study Design and SettingWe used data from the Prospective Observational Cohort Study of Esophageal-Gastric Cancer Patients (POCOP) registry and from the population-based Netherlands Cancer Registry (NCR). We used Representativeness-indicators (R-indicators) and overall survival to investigate the degree to which the POCOP cohort and clinically relevant subgroups were a representative sample compared to the NCR database. Calibration using inverse propensity score weighting was applied to correct differences between POCOP and NCR. ResultsThe R-indicator of the entire POCOP registry was 0.72 95% confidence interval [0.71, 0.73]. Representativeness of palliative patients was higher than that of potentially curable patients (R-indicator 0.88 [0.85, 0.90] and 0.70 [0.68, 0.71], respectively). Stratification to clinically relevant subgroups based on treatment resulted in higher R-indicators of the respective subgroups. Both after stratification and calibration weighting survival estimates in the POCOP registry were more similar to that in the NCR population. ConclusionThis study demonstrated the assessment of real-world representativeness of patients who participated in a prospective registry cohort and showed that real-world representativeness improved when the variability in treatment was accounted for.

The Impact of Age on the Post-operative Outcomes in Patients Undergoing Resection for Oesophageal and Gastric Cancer

BackgroundWithin our ageing population, there is an increasing number of elderly patients presenting with oesophagogastric cancer. Resection remains the mainstay of curative treatment however it has substantial morbidity. The aim of this study was to assess whether age was an independent predictor of resection related complications in our unit.MethodsA retrospective cohort study of prospectively collated data from 2002 to 2020 of patients undergoing resection for oesophageal and gastric cancers was analysed. Patients aged over 75 and 75 and under were compared for peri-operative morbidity (via the Clavien-Dindo classification), length of stay (LOS), unplanned readmission, 30- and 90-day mortality, and use of neoadjuvant therapy.ResultsData for 466 consecutive patients undergoing oesophagogastric resection (277 oesophagectomy and 189 gastrectomy) were available for analysis. 22% of patients were aged over 75 (14% (39/277) of the oesophagectomy cohort, 34% (65/189) of the gastrectomy cohort). Oesophagectomy patients over 75 were more likely to develop post-operative complications, particularly cardiac or thromboembolic, (69.2%) than those in the younger cohort (50.4%, p = 0.029). There was no difference in complication rates between the younger and older patients undergoing gastrectomy (29.0% vs. 33.9% p = 0.495). The 30- and 90-day mortality rates were 1.4% (n = 4) and 2.5% (n = 7), respectively, for the oesophagectomy cohort and 1.1% (n = 2) and 1.6% (n = 3) for the gastrectomy cohort, with no difference between age groups.ConclusionIn this series, we found that patients over the age of 75 were able to undergo oesophageal and gastric resection with curative intent with acceptable post-operative morbidity and mortality.

Prior treatment with oxaliplatin-containing regimens and higher total bilirubin levels are risk factors for neutropenia and febrile neutropenia in patients with gastric or esophagogastric junction cancer receiving weekly paclitaxel and ramucirumab therapy: a single center retrospective study

BackgroundWeekly paclitaxel + ramucirumab (wPTX + RAM) therapy is recommended as the standard second-line chemotherapy regimen for unresectable advanced/recurrent gastric cancer (GC) or esophagogastric junction cancer. Recent subgroup analysis of the RAINBOW trial revealed a higher frequency of severe neutropenia due to wPTX + RAM in Japanese compared to Western patients. However, no risk factors for severe neutropenia have been identified.MethodsThis retrospective observational study included patients with advanced/unresectable gastric or esophagogastric junction cancer who received wPTX + RAM after failure to respond to platinum and fluoropyrimidine doublet chemotherapy between June 2015 and April 2020. We conducted multivariable logistic regression analyses to identify the risk factors associated with grade 4 neutropenia and febrile neutropenia (FN). In addition, we investigated the relationship between the number of risk factors and overall survival (OS) and progression-free survival (PFS).ResultsAmong 66 patients who met the inclusion criteria, grade 4 neutropenia and FN occurred in 21 (31.8%) and 12 (18.2%) patients, respectively. Prior treatment with oxaliplatin-containing regimens was identified as an independent risk factor for developing grade 4 neutropenia (odds ratio (OR) 20.034, 95% confidence interval (95% CI) 3.216–124.807, P = 0.001). Total bilirubin of > 1.5 mg/dL (OR 31.316, 95% CI 2.052–477.843, P = 0.013) and prior treatment with oxaliplatin-containing regimen (OR 12.502, 95% CI 1.141–137.022, P = 0.039) were identified as independent risk factors for developing FN. Next, we classified patients with 0, 1, 2 risk factor(s) as RF-0, RF-1, and RF-2 subgroups, respectively, and compared the PFS and OS among the three subgroups. PFS was not significantly different among the three subgroups, whereas OS was significantly shorter in the RF-2 subgroup (median 1.4 month, 95% CI 0.0–5.3 month) than in the RF-0 subgroup (median 10.2 month, 95% CI 6.8–13.5 month, P < 0.01 vs RF-2) and RF-1 subgroup (median 13.3 month, 95% CI 10.9–15.7 month, P < 0.01 vs RF-2).ConclusionsCareful monitoring for grade 4 neutropenia and FN is needed for patients receiving wPTX + RAM therapy who have a history of treatment with oxaliplatin-containing regimens and higher total bilirubin levels.

Audit of 30-day mortality following palliative radiotherapy: are we able to improve patient care at the end of life?

Several measurements defining the expected 30-day mortality (30-DM) to use in audit of radiation oncology departments have been proposed. However, its external validity is limited because of the lack of data from non-English speaking countries. This study assessed 30-DM in patients treated with palliative radiotherapy (PRT) in a Chilean-reference radiotherapy centre and explored if there had been tailored treatment at the end of life. Retrospective data collection was carried out for all patients treated at our institution between 1st January 2018 and 31st December 2021. Individual factors were modelled first to check for univariate association with 30-DM, those variables with a significance level of < 0.05 were considered for the final multivariable model. 3,357 patients were included. The most common primary malignancies were breast (22%) and lung (16.1%). The most common treatment sites were bone (47.7%) and brain (12.2%). Overall, 30-DM was 14.7%, this rate was higher in patients treated for brain metastases (25.7%) and thoracic palliation (22.1%). 30-DM was associated with poor performance status (p < 0.01), lung and esophageal-gastric cancer (p = 0.04 and p = 0.02, respectively), metastases other than bone (p < 0.01), brain metastases (p < 0.01) and private health insurance (p <0.01). In patients treated for brain metastasis and thoracic palliation 30-DM was higher than suggested benchmarks. Moreover, in these groups long courses of PRT were often performed. Audit data should be useful for planning interventions that improve selection of patients and prompting review of policies for indication and fractionation schedules of PRT.

1579P Gender differences and worse metastatic survival outcomes in young adult patients with oesophagogastric cancer: 12-year data from a Czech comprehensive cancer center

1579P Gender differences and worse metastatic survival outcomes in young adult patients with oesophagogastric cancer: 12-year data from a Czech comprehensive cancer center

146P The prognosis value of heat-shock proteins in esophagogastric cancer: A systematic review and meta-analysis

146P The prognosis value of heat-shock proteins in esophagogastric cancer: A systematic review and meta-analysis

The Japanese Nationwide Cohort Data of Particle Beam Therapy for Liver Oligometastasis in Esophagogastric Cancer Patients

A nationwide multicenter cohort study on particle therapy was launched by the Japanese Society for Radiation Oncology (JASTRO) in Japan in May 2016. We analyzed the outcome of proton beam therapy (PBT) for liver oligometastasis of esophagogastric cancers. Cases in which PBT was performed at all PBT facilities in Japan between May 2016 and February 2019 were enrolled. The patients were selected based on the following criteria: controlled primary cancer; liver recurrence without extrahepatic tumors; and no more than three liver lesions. The dose and fraction of PBT were determined using unified treatment policy established by JASTRO. We used the following protocol, 64 gray (relative biological effect) (Gy (RBE))/8 fractions (fr) for the peripheral region, and 72.6 GyE/22fr for the central region. For safety aspect, the hepatocellular carcinoma irradiation protocols of 66 Gy (RBE)/10fr, 72.6-76 Gy (RBE)/20-22fr, and 74-76 Gy (RBE)/37-38fr could be allowed. The overall survival (OS), local control (LC), and adverse events (AEs) were examined. The OS and LC rates were calculated using the Kaplan-Meier method. Factors possibly related to OS, such as tumor size (for multiple lesions, the largest size), number of liver tumors, as well as the presence or absence of prior, concurrent, and post-PBT chemotherapy, were investigated. The cut-off values were estimated using the receiver operating characteristic curve and area under the curve. Univariate analysis was performed using the log-rank test. Statistical significance was P-values < 0.05. Twenty-three males and two females with a median age of 69 (range, 52-80) years and 36 lesions were included. This study included six patients with esophageal and 19 patients with gastric cancer. The median lesion size, fraction size, and biological effective dose (BED)10 were 31 (7-104) mm, 3.8 gray (relative biological effect)/fractions (Gy (RBE)/fr) (2-8 Gy (RBE)/fr), and 96.9 (88.8-115.2) Gy, respectively. The median follow-up period was 18 (4-47) months. The 1-, 2-, and 3-year OS rates were 76.0, 49.5, and 43.3%, respectively, and the median OS was 19 months. The 1-, 2-, and 3-year OS rates of esophageal cancer were 83.3% for all. The 1-, 2-, and 3-year OS rates of gastric cancer were 73.7, 40.2, and 32.2%, respectively, and the median OS was 18 months. The 1-, 2-, and 3-year LC rates were 96.3, 91.5, and 91.5%, respectively. The 1-, 2-, and 3-year LC rates of esophageal cancer were 100% for all. The 1-, 2-, and 3-year LC rates of gastric cancers were 94.7, 88.0, and 88.0%, respectively. Tumor size was the only significant OS-related factor (P < 0.01). No grade 3 or higher adverse events were observed. Owing to the low incidence of adverse events and the high LC rate, PBT is a feasible option for liver oligometastasis of esophagogastric cancers.

Longitudinal Analysis of Circulating Tumor DNA and Detection of Tumor Genomic Alterations Using Liquid Biopsy in Patients with Locally Advanced Esophagogastric Carcinoma

For locally advanced esophageal (E), esophagogastric junction (EGJ), and gastric (G) carcinoma, the standard treatment is neoadjuvant chemoradiotherapy followed by surgery. The curative goal is to control the tumor locally, prevent regional recurrence, and prevent or delay metastatic progression. Up to one-third of patients will achieve complete pathologic response rate (pCR) under this treatment. Yet disease recurrence can occur in one-third of patients after definitive treatment. Our study provides real-world longitudinal data of liquid biopsy to analyze circulating tumor deoxyribonucleotide acid (ctDNA) for minimal residual disease (MRD) as an informative marker for early therapeutic response, detectable disease, and risk for recurrence. Furthermore, the liquid biopsy reveals variable tumor-specific sequence alterations. A total of 8 patients with newly diagnosed locoregional esophagogastric cancers were evaluated with non-invasive plasma sample, collected at baseline, post-neoadjuvant chemoradiation, post-surgery, and serially as disease surveillance. Bespoke mPCR-NGS assay measured the ctDNA-based MRD levels and identified a comprehensive tumor-specific genomic profile. The primary outcome is assay recurrence compared to radiologic disease recurrence, defined as radiologic confirmed disease. Exploratory endpoints are used to examine the profile of tumor. Baseline ctDNA levels were detected in 8 newly diagnosed patients. Longitudinal testing showed a decrease in ctDNA in 4 patients and residual disease in 2 patients after the start of neoadjuvant therapy. 1 patient demonstrated pCR in conjunction with ctDNA clearance. Clearance of ctDNA may correlate to a favorable pCR and indicate a lower risk of relapse, guiding the strategy for adjuvant treatment. Personalized, tumor-informed sequence alterations of the 8 patients revealed a high frequency in TP53 alterations, which occurs early during development in esophagogastric cancer. This prospective study seeks to validate the application of ctDNA surveillance and tumor molecular alterations in a larger cohort after 5 years.