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Department of Surgery, Prince of Wales Hospital, The Chinese University of Hong Kong, Hong Kong SAR

Aim: Sarcopenia is a progressive loss of skeletal muscle mass, strength and function, which is contributed by ageing and pathology like cancer. Sarcopenia has recently been shown to be associated with postoperative risk and prognosis in colorectal cancer patients. Colorectal cancer has the highest incidence among malignancies in Hong Kong with the median age of incidence and mortality around 70s. This study aims to assess whether elderly patients with sarcopenia are at higher risk undergoing curative colorectal cancer surgery.

Methods: Consecutive >70 y.o. patients who underwent curative resection of Colorectal Cancer from January 2017 to January 2020 were identified on a prospectively entered database. Skeletal muscle cross-sectional area was quantified at L3 level in pre-operative CT. Patients were classified into low and high sarcopenia groups according to predetermined cutoffs. Clinical outcomes were analysed and compared between the two groups.

Results: Among 220 patients, High Sarcopenia (HS) group (55.6%) showed significantly higher rate of postoperative complications, longer length of recovery and higher requirement for further postoperative rehabilitation than the Low Sarcopenia (LS) group (44.4%). Among the whole cohort, multivariate logistic regression analysis showed that the independent risk factors for overall complications were low preoperative haemoglobin, HS group and ASM grade ≥3.

Conclusions: Sarcopenia was shown to be associated with higher postoperative complications. More personalised perioperative care and further research could be performed to evaluate the possible benefit with preoperative training program.

Prince of Wales Hospital, Hong Kong SAR

Aim: Use of endoscopic ultrasound (EUS) to acquire portal venous blood (PVA) for CTC enumeration as a prognostic marker for metastasis has only been described for pancreatic cancer. This is a feasibility study on EUS PVA for CTC enumeration and characterisation in CRC.

Methods: Under EUS, left and right PVs were identified. A 19-gauge EUS-FNA needle was advanced trans-hepatically into the portal vein and two sets of 10 ml aliquots of blood were aspirated. Puncture site was monitored for bleeding before needle withdrawal. Paired 10ml peripheral blood were collected. CTCs were sorted based on expression of epithelial cell adhesion molecules.

Results: This prospective, single-centre study was performed in Prince of Wales Hospital between December 2016 and March 2019. Forty six patients with stage 1 to 3 colorectal carcinomas were recruited. Technical success was 100% and none had adverse events. Hepatic cell contamination was suspected in first 28 patients, as CTC yield was inappropriately higher in PVA [207.7(243.2) vs 1.7(7.7), P < .001].More sensitive fluorescence based CTC detection was used in the second half. Subsequently, PVA CTC yield was greater than peripheral blood [4.5(2.9) vs 2.5(2.3), P < .001].In all patients with recurrence, there were no CTCs in peripheral blood, but were detected in PVA in all patients, except one due to cell clumping.There was no correlation between PVA CTC yield and T staging (correlation coefficient -0.68), N staging (-0.86) and overall clinical staging (-0.196).

Conclusions: EUS-guided PVA is a feasible and effective method in CTCs enumeration for CRC. Genetic mutations may have a more significant role than CTC number in correlating to staging. As such, further studies to understand mutations essential in distant metastasis are needed.

Department of Surgery, Queen Mary Hospital, Hong Kong SAR

Aim: Long-term results of high-risk breast cancer surveillance for BRCA mutation carriers are lacking for Asian population. This study aimed to review our 13-year experience of high-risk surveillance and assess the outcome of cancer detection and mortality.

Methods: BRCA mutation carriers under Hong Kong Hereditary Breast Cancer Family Registry from January 2007 to December 2019 were reviewed. Surveillance program included biannual clinical examination, 6-monthly breast imaging with alternating contrast magnetic resonance imaging and a combination of mammogram and ultrasound.

Results: A total of 419 BRCA mutation carriers were managed under the registry; after excluding patients who had bilateral mastectomy before enrolling to the program, 346 patients were followed up in a median period of 39.4 (6–152) months. The uptake of risk-reducing mastectomy was 5%, and particularly low in patients without breast cancer, only 2%. The new breast cancer detection rate was 1.75% (29 cancer diagnosed from 1656 screening imaging). Early cancer detection was achieved with 86.7% diagnosed in stage 0/1 and a node positive rate of 6.7%, with minimal interval cancer occurrence. Overall breast-cancer specific mortality was 3.8%. In initially breast-cancer free patients who later developed breast cancer during surveillance, breast-cancer specific mortality was 0%. Overall survival was largely dependent on ovarian cancer history.

Conclusions: Risk-reducing mastectomy is not popular among Chinese BRCA mutation carriers. High-risk breast cancer surveillance remained the core management and it could achieve early cancer detection with minimal interval cancer occurrence, and a low breast-cancer specific mortality. Further study with cost-effective analysis is warranted.

University of Hong Kong, Hong Kong SAR

Aim: Behavioral changes in seeking medical attention during COVID-19 pandemic and its impact on breast cancer outcomes has never been studied.

Methods: This is a case-control study comparing breast cancer patients treated between Quarter 1 2020 (Case, COVID-19 pandemic) and Quarter 1 2019 (Control).

Clinical and pathological data between the two groups were compared. Patients from the case group were interviewed using a standardized questionnaire.

Results: There were 57 patients in the case group and 101 patients in the control group. Mean ages of diagnosis were 56.1 (Range 34–75) and 57.4 (Range 30–84) years old respectively.

Mean duration of symptom prior to the first specialist consultation in the case group was 6.4 weeks (2–32 weeks) while that in the control group was 3.1 weeks. 12/57 (21.1%) patients had delayed presentation for their breast symptoms during COVID-19 outbreak. The mean score of anxiety on hospital acquired COVID-19 infection was 3.3 out of 5 (Range 1–5)

There were significantly less DCIS in the case group (N = 5 vs 32, 8.8% vs 31.7%) (P = .0009). However, there were more T2 or above cancers in the case group (N = 32 vs 28, 56.1% vs 27.7%) (P = .0008). N stage was not significantly different between the two groups.

Mean surgery waiting time were similar (2.6 and 2.5 weeks respectively). Mastectomy rate was lower in the case group (42% vs 75.4%). There was no difference in reconstruction rate (19.2% vs 16.8%).

Conclusions: Breast cancer patients tends to present late during COVID-19 pandemic.

Prince of Wales Hospital, Hong Kong SAR

Objectives: Post-cardiotomy right ventricular failure (RVF) after triple valve surgery (TVS) is highly fatal. We aim to identifying risk factors and scoring systems predictive of postoperative RVF.

Methods: We performed a retrospective cohort study of 61 consecutive patients who underwent TVS at our institution from November 2005 to June 2016. Demographics, clinical, biochemical and operative data were collected and analysed.

Results: Median follow-up duration was 8.0 years. Mean age at surgery was 58.6 ± 10.9. 86.9% underwent mechanical double valve replacement with tricuspid valve repair. Preoperatively, 85.2% had atrial fibrillation, 90.1% had moderate-to-severe pulmonary hypertension, and 24.6% had class III to IV heart failure symptoms. In-hospital mortality was 8.8%, of which 83.3% were due to RVF. Using the Kaplan-Meier method, 5-year overall survival and MACCE-free survival were 78.6% and 72.1% respectively.

Univariate analysis identified NYHA functional class, creatinine clearance, serum albumin, serum sodium and total bilirubin level as significant predictors of RVF. Multivariate analysis showed that patients with NYHA III to IV status were 13 times more likely to die from RVF.

The predictive value of simplified Model for End-stage Liver Disease score including sodium (MELD-Na) and EuroSCORE for RVF and in-hospital mortality was analysed using ROC curve analyses. For MELD-Na, the area under the ROC curve was 0.992 [95% CI 0.925-1.000]. The Youden Index was 0.982 at a cut-off of 13. For EuroSCORE, the AUC was 0.611 [95% CI 0.477-0.733].

Conclusions: A simplified MELD-Na score above 13 is sensitive and specific for RVF and in-hospital mortality after TVS.

Department of Surgery, United Christian Hospital, Hong Kong SAR

Introduction: Blood supply to the gastric conduit is crucial as in esophagectomy reconstruction while deficiency may lead to serious complications. Intraoperative indocyanine green (ICG) for demonstrating gastric conduit perfusion and deciding on level of transection was proposed to improve the surgical safety. We retrospectively review our data to evaluate the usefulness of ICG use in reducing gastric tube necrosis and anastomotic complications.

Methods: We started our intraoperative ICG application since July 2017. Patient's demographic data, tumour status, surgical approaches, perioperative parameters and gastric conduit and anastomotic complications were compared with the era without the usage of ICG.

Results: From July 2016 to November 2019, total 58 patients underwent minimally invasive esophagectomy anastomosis, in which 30 of them were performed with ICG guidance. No statistical difference was found between two groups in patients demographics including age (67.5 ± 8 vs 65.8 ± 8, P = .419), sex (P = 1.000), smoking status (P = .894), pre-exsiting pulmonary disease (P = 1.000) and ASA grade (P = .803). Tumor TMN staging (P = .411), surgical approach (P = .325), and technique of anastomosis (P = .556) neither showed any statistical difference. ICG group showed significant less anastomotic leakage (3.3% vs 21.4%, P = .048). While the rate of gastric conduit necrosis (0% vs 3.6%. P = .483), conduit ischemia (0% vs 3.6%, P = .483), and anastomotic stricture (6.7% vs 14.3%, P = .415) appeared to be similar.

Conclusions: ICG was effectively demonstrating gastric conduit perfusion in esophagectomy and reduced the rate of anastomotic leakage.

Division of Urology, Department of Surgery, Queen Mary Hospital, Hong Kong SAR. Department of Surgery, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR

Department of Diagnostic Radiology, Queen Mary Hospital, Hong Kong SAR

Aim: To report our early clinical experience with thermal ablation of patients with small renal masses suspicious of renal cell carcinoma (RCC).

Methods: From June 2015, 36 patients underwent thermal ablation for contrast-enhancing renal masses suspicious of RCC. Male to female ratio was 26:10. Mean age was 69 ± 11. Reasons for thermal ablation were patient refusal of partial nephrectomy (64%), partial nephrectomy considered too high risk because of underlying absolute indications of anticoagulation (8%), general anaesthesia risks considered too high (14%), known underlying metastatic malignancy (8%) and solitary functioning kidney (6%). Mean size of renal mass was 2.3 ± 1.0 cm. All patients received CT scan for follow-up. Mean follow-up was 24 ± 18 months.

Results: 75% patients received percutaneous thermal ablation whilst 11% and 14% patients received laparoscopic and open thermal ablation respectively. 81% received radiofrequency ablation whilst 19% received cryo-ablation. One patient developed bleeding in immediate post-ablation period necessitating emergency nephrectomy, one patient developed late ureteral stricture resulting loss of kidney function. Four (11%) patients developed residual disease on follow-up requiring re-ablation. One patient developed rapid disease progression into metastatic state after ablation. The other patients’ renal masses were found to have no residual contrast enhancement on follow-up CT scans.

Conclusions: From our early clinical experience, thermal ablation appears to be a viable option for patients with small renal masses suspicious of RCC when they refuse surgical extirpation or are considered unfit for surgery. Longer follow-up of ablated patients is required to assess long term oncological outcome.

The University of Hong Kong, Hong Kong SAR

Introduction: Genetic testing lies at the heart of personalized oncological treatment, promising the potential for targeted therapies that complement and enhance surgical therapies of tumors with specific mutation profiles. Germline BRCA mutations are commonly targeted by BRCA-pathway inhibitors, but contribute to only approximately 10% of breast cancers in Hong Kong. Somatic tumor mutations can also serve as potential targets for molecular inhibitors. The somatic mutation landscape of breast cancers must hence be properly understood to identify further therapeutic strategies and improve treatment outcomes.

Aim: To identify the somatic mutation profile of non-hereditary breast cancers in Hong Kong

Methods: Multigene sequencing of 93 previously identified predisposition genes were performed on breast cancers without germline mutations or prior chemotherapy exposure. Mutations were classified based on predicted clinical significance according to a four-tier system defined by international guidelines.

Results: Three hundred and sixty nine somatic mutations in 67 predisposition genes among 108 breast cancers were identified. Six tumors were devoid of any somatic mutations. The most frequently mutated pathogenic or likely-pathogenic genes were PIK3CA (28.6%), TP53 (16.9%), MAP3K1 (14.3%), GATA3 (14.3%) and PTEN (5.2%). Only six tumors were found to carry BRCA mutations.

Conclusions: This study identified important somatic mutations among breast cancers in Hong Kong, suggesting the efficacy of already available therapies, such as PIK3 inhibitors and TP53 activators, for a significant cohort of our breast cancer patients. Personalized targeted therapies serve as important adjuvants to surgical treatment of breast malignancies, and hence should be more widely offered to breast cancer patients in Hong Kong.

First Affiliated Hospital of Zhejiang University, China

Aim: Our previous study revealled amplified hazardous effects of macrosteatosis (MaS) on graft failure (GF) in recipients with severe liver damage in short post-operative days, with vague mechanism inside. We aimed to uncover the molecular mechanism of donor MaS on GF, and construct the predictive model to monitor post-transplant prognosis based on “omics” perspective.

Methods: Ultra-performance liquid chromatography coupled to mass spectrometry metabolomic analysis was performed in allograft tissues from 82 patients with initial poor function (IPF) from multi-liver transplant (LT) centers. Pathway analysis was performed by on-line toolkit Metaboanalyst (v 3.0). Predictive model was constructed based on combinative metabonomic and clinical data extracted by stepwised cox proportional analysis.

Results: Principle component analysis (PCA) analysis revealled stratification on metabolic feature in organs classified by MaS status. Differential metabolits both associated with MaS and GF were significantly enriched on pathway of glycerophospholipid metabolism (P < .05). Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) involved in glycerophospholipid metabolism was significantly decreased in cases with MaS donors and GF (P < .05). Better prediction was observed on graft survival by combinative model (area under the curve = 0.91) and confirmed by internal validation.

Conclusions: Metabonomic features of allografts can be clearly distinguished by MaS status in patients with IPF. Dysfunction on glycerophospholipid metabolism was culprit to link donor MaS and final GF. Decrement on PC and PE exerted the fatal effects of MaS on organ failure. Metabonomic data might help for monitoring long-term graft survival after LT.