Laparoscopic liver resection for huge (≥10 cm) hepatocellular carcinoma: A coarsened exact-matched single-surgeon study

Short-term outcomes of laparoscopic extended hepatectomy versus major hepatectomy: a single-center experience

INTRODUCTION

Laparoscopic major hepatectomy (LMH) remains restricted to a few specialized centers and poses a challenge to surgeons performing laparoscopic resections. Laparoscopic extended resections are even more complex and rarely conducted.

METHODS

From a single-institution database, we compared the short-term outcomes of patients who underwent major and extended laparoscopic resections, stratifying the entire retrospective cohort into four groups: right hepatectomy, left hepatectomy, right extended hepatectomy, and left extended hepatectomy. Patient demographics, tumor characteristics, operative variables, and especially postoperative outcomes were evaluated.

RESULTS

250 patients underwent major and extended laparoscopic liver resections, including 160 right, 31 right extended, 36 left, and 23 left extended laparoscopic hepatectomies. The most common indication for resection was colorectal liver metastases (64%). Laparoscopic extended hepatectomy (LEH) showed significantly longer operative time, more blood loss, need for Pringle maneuver, conversion to open surgery, higher rates of liver failure, postoperative ascites, and intra-abdominal hemorrhage, R1 margins and length of stay when compared with the LMH group. Mortality rates were similar between groups. Multivariate analysis revealed intraoperative blood transfusion (OR = 5.1[CI-95%: 1.15-6.79]; p = 0.02) as an independent predictor for major complications.

CONCLUSIONS

LEH showed to be feasible, however with higher blood loss and significantly associated to major complications.

Laparoscopic anatomic vs. nonanatomic liver resection for large hepatocellular carcinoma (≥5 cm) in the right lobe

OBJECTIVE

To determine the impacts and outcomes of laparoscopic anatomic liver resection (LAR) and laparoscopic nonanatomic resection (LNAR) in patients with large hepatocellular carcinoma (HCC) in the right lobe of the liver.

BACKGROUND

There are few comparative studies of LAR and LNAR for large HCC.

METHOD

Three hundred thirty-seven patients underwent liver resection for large HCC (≥5 cm) at Seoul National University Bundang Hospital, Seoul, Korea, between January 2004 and December 2022. After the exclusion of patients treated with open hepatic resection and those who had left-lobe or bilobar tumors, 94 patients were ultimately included. Patients were divided into LAR group (61 patients) and LNAR group (33 patients). After propensity score matching (PSM) with 1:1 matching, 31 patients were included in each group. The outcomes in the two groups were compared.

RESULTS

LAR group had longer operative time than LNAR group (333.7 ± 113.7 vs 210 ± 117.6 min, respectively, P < 0.001), wider safety margin (1.4 ± 1.5 vs 0.7 ± 0.7 cm, respectively, P = 0.015), and lower incidence of recurrence (25.8% vs. 54.8%, respectively, P = 0.021).

CONCLUSION

LAR required longer operative time, achieved wider safety margin, and had lower incidence of recurrence than LNAR.

Short-term and long-term outcomes after robotic versus open hepatectomy in patients with large hepatocellular carcinoma: a multicenter study

BACKGROUND

Robotic hepatectomy (RH) is currently widely accepted and it is associated with some benefits when compared to open hepatectomy (OH). However, whether such benefits can still be achieved for patients with large hepatocellular carcinoma (HCC) remain unclear. This study aimed to evaluate the short-term and long-term outcomes of patients undergoing RH or OH.

METHODS

Perioperative and survival data from patients with large HCC who underwent RH or OH between January 2010 and December 2020 were collected from eight centres. Propensity score matching (PSM) was performed to minimise potential biases.

RESULTS

Using predefined inclusion criteria, 797 patients who underwent OH and 309 patients who underwent RH were enroled in this study. After PSM, 280 patients in the robotic group had shorter operative time (median 181 vs. 201 min, P <0.001), lower estimated blood loss (median 200 vs. 400 ml, P <0.001), and shorter postoperative length of stay (median 6 vs. 9 days, P <0.001) than 465 patients in the open group. There were no significant differences between the two groups in overall survival and recurrence-free survival. Cox analysis showed AFP greater than 400 ng/ml, tumour size greater than 10 cm, and microvascular invasion were independent risk factors for overall survival and recurrence-free survival. After PSM, subgroup analysis showed that patients with a huge HCC (diameter >10 cm) who underwent RH had significantly lower estimated blood loss (median 200.0 vs. 500.0 min, P <0.001), and shorter length of stay (median 7 vs. 10 days, P <0.001) than those who underwent OH.

CONCLUSION

Safety and feasibility of RH and OH for patients with large HCC were comparable. RH resulted in similar long-term survival outcomes as OH.

Impact of Liver Cirrhosis, Severity of Cirrhosis, and Portal Hypertension on the Difficulty and Outcomes of Laparoscopic and Robotic Major Liver Resections for Primary Liver Malignancies

BACKGROUND

Minimally invasive liver resections (MILR) offer potential benefits such as reduced blood loss and morbidity compared with open liver resections. Several studies have suggested that the impact of cirrhosis differs according to the extent and complexity of resection. Our aim was to investigate the impact of cirrhosis on the difficulty and outcomes of MILR, focusing on major hepatectomies.

METHODS

A total of 2534 patients undergoing minimally invasive major hepatectomies (MIMH) for primary malignancies across 58 centers worldwide were retrospectively reviewed. Propensity score (PSM) and coarsened exact matching (CEM) were used to compare patients with and without cirrhosis.

RESULTS

A total of 1353 patients (53%) had no cirrhosis, 1065 (42%) had Child-Pugh A and 116 (4%) had Child-Pugh B cirrhosis. Matched comparison between non-cirrhotics vs Child-Pugh A cirrhosis demonstrated comparable blood loss. However, after PSM, postoperative morbidity and length of hospitalization was significantly greater in Child-Pugh A cirrhosis, but these were not statistically significant with CEM. Comparison between Child-Pugh A and Child-Pugh B cirrhosis demonstrated the latter had significantly higher transfusion rates and longer hospitalization after PSM, but not after CEM. Comparison of patients with cirrhosis of all grades with and without portal hypertension demonstrated no significant difference in all major perioperative outcomes after PSM and CEM.

CONCLUSIONS

The presence and severity of cirrhosis affected the difficulty and impacted the outcomes of MIMH, resulting in higher blood transfusion rates, increased postoperative morbidity, and longer hospitalization in patients with more advanced cirrhosis. As such, future difficulty scoring systems for MIMH should incorporate liver cirrhosis and its severity as variables.

Impact of Tumor Size on the Difficulty of Laparoscopic Major Hepatectomies: An International Multicenter Study

INTRODUCTION

Although tumor size (TS) is known to affect surgical outcomes in laparoscopic liver resection (LLR), its impact on laparoscopic major hepatectomy (L-MH) is not well studied. The objectives of this study were to investigate the impact of TS on the perioperative outcomes of L-MH and to elucidate the optimal TS cutoff for stratifying the difficulty of L-MH.

METHODS

This was a post-hoc analysis of 3008 patients who underwent L-MH at 48 international centers. A total 1396 patients met study criteria and were included. The impact of TS cutoffs was investigated by stratifying TS at each 10-mm interval. The optimal cutoffs were determined taking into consideration the number of endpoints which showed a statistically significant split around the cut-points of interest and the magnitude of relative risk after correction for multiple risk factors.

RESULTS

We identified 2 optimal TS cutoffs, 50 mm and 100 mm, which segregated L-MH into 3 groups. An increasing TS across these 3 groups (≤ 50 mm, 51-100 mm, > 100 mm), was significantly associated with a higher open conversion rate (11.2%, 14.7%, 23.0%, P < 0.001), longer operating time (median, 340 min, 346 min, 365 min, P = 0.025), increased blood loss (median, 300 ml,  ml, 400 ml, P = 0.002) and higher rate of intraoperative blood transfusion (13.1%, 15.9%, 27.6%, P < 0.001). Postoperative outcomes such as overall morbidity, major morbidity, and length of stay were comparable across the three groups.

CONCLUSION

Increasing TS was associated with poorer intraoperative but not postoperative outcomes after L-MH. We determined 2 TS cutoffs (50 mm and 10 mm) which could optimally stratify the surgical difficulty of L-MH.

Sequential transcatheter arterial chemoembolization and portal vein embolization before hepatectomy for the management of patients with hepatocellular carcinoma: a systematic review and meta-analysis

R0 resection is the gold standard for the treatment of hepatocellular carcinoma. However, residual liver deficiency remains a major obstacle to hepatectomy. This article aims to explore the short-term and long-term efficacy of preoperative sequential transcatheter arterial chemoembolization (TACE) and portal vein embolization (PVE) in the treatment of hepatocellular carcinoma. Multiple electronic literature databases up to February 2022 were searched. Furthermore, clinical studies comparing sequential TACE + PVE with portal vein embolization (PVE) were included. The outcomes included hepatectomy rate, overall survival, disease-free survival, overall morbidity, mortality, posthepatectomy liver failure, the percentage increase in FLR. Five studies included 242 patients who received sequential TACE + PVE and 169 patients received PVE. The sequential TACE + PVE group demonstrated more favorable results in terms of hepatectomy rate (OR = 2.37; 95% CI 1.09-5.11; P = 0.03), overall survival (HR 0.55; 95% CI 0.38 to - 0.79; P = 0.001), disease-free survival (HR 0.61; 95% CI 0.44-0.83; P = 0.002), and percentage increase in FLR (MD = 4.16%; 95% CI 1.13-7.19; P = 0.007). The pooled results did not demonstrate significant differences in overall morbidity, mortality, and posthepatectomy liver failure between the sequential TACE + PVE and PVE groups. Preoperative sequential TACE + PVE has been shown to be a safe and feasible treatment for hepatocellular carcinoma to improve resectability, and it has been shown to provide better long-term oncological outcomes than PVE.

Sub-classification of laparoscopic left hepatectomy based on hierarchic interaction of tumor location and size with perioperative outcomes

BACKGROUND

The aim of this multicentric study was to investigate the impact of tumor location and size on the difficulty of Laparoscopic-Left Hepatectomy (L-LH).

METHODS

Patients who underwent L-LH performed across 46 centers from 2004 to 2020 were analyzed. Of 1236 L-LH, 770 patients met the study criteria. Baseline clinical and surgical characteristics with a potential impact on LLR were included in a multi-label conditional interference tree. Tumor size cut-off was algorithmically determined.

RESULTS

Patients were stratified into 3 groups based on tumor location and dimension: 457 in antero-lateral location (Group 1), 144 in postero-superior segment (4a) with tumor size ≤40 mm (Group 2), and 169 in postero-superior segment (4a) with tumor size >40 mm (Group 3). Patients in the Group 3 had higher conversion rate (7.0% vs. 7.6% vs. 13.0%, p-value .048), longer operating time (median, 240 min vs. 285 min vs. 286 min, p-value <.001), greater blood loss (median, 150 mL vs. 200 mL vs. 250 mL, p-value <.001) and higher intraoperative blood transfusion rate (5.7% vs. 5.6% vs. 11.3%, p-value .039). Pringle's maneuver was also utilized more frequently in Group 3 (66.7%), compared to Group 1 (53.2%) and Group 2 (51.8%) (p = .006). There were no significant differences in postoperative stay, major morbidity, and mortality between the three groups.

CONCLUSION

L-LH for tumors that are >40 mm in diameter and located in PS Segment 4a are associated with the highest degree of technical difficulty. However, post-operative outcomes were not different from L-LH of smaller tumors located in PS segments, or tumors located in the antero-lateral segments.

JO, Gastaca M, Fondevila C, Efanov M, Rotellar F, Choi GH, Robles-Campos R, Wang. X, Sutcliffe RP, Pratschke J, Tang CN, Chong CC, D’Hondt M, Yong CC, Ruzzenente A, Herman P, Kingham TP, Scatton O, Liu R, Sandri GBL, Soubrane O, Mejia A, Lopez-Ben S, Monden K, Wakabayashi G, Cherqui D, Troisi RI, Yin M, Giuliante F, Geller D, Sugioka A, Edwin B, Cheung TT, Long TCD, Abu Hilal M, Fuks. D, Chen. KH, Aldrighetti L, Han HS, Goh BKP. Impact of tumor size on the difficulty of laparoscopic left lateral sectionectomies

BACKGROUND

Tumor size (TS) represents a critical parameter in the risk assessment of laparoscopic liver resections (LLR). Moreover, TS has been rarely related to the extent of liver resection. The aim of this study was to study the relationship between tumor size and difficulty of laparoscopic left lateral sectionectomy (L-LLS).

METHODS

The impact of TS cutoffs was investigated by stratifying tumor size at each 10 mm-interval. The optimal cutoffs were chosen taking into consideration the number of endpoints which show a statistically significant split around the cut-points of interest and the magnitude of relative risk after correction for multiple risk factors.

RESULTS

A total of 1910 L-LLS were included. Overall, open conversion and intraoperative blood transfusion were 3.1 and 3.3%, respectively. The major morbidity rate was 2.7% and 90-days mortality 0.6%. Three optimal TS cutoffs were identified: 40-, 70-, and 100-mm. All the selected cutoffs showed a significant discriminative power for the prediction of open conversion, operative time, blood transfusion and need of Pringle maneuver. Moreover, 70- and 100-mm cutoffs were both discriminative for estimated blood loss and major complications. A stepwise increase in rates of open conversion rate (Z = 3.90, P < .001), operative time (Z = 3.84, P < .001), blood loss (Z = 6.50, P < .001), intraoperative blood transfusion rate (Z = 5.15, P < .001), Pringle maneuver use (Z = 6.48, P < .001), major morbidity(Z = 2.17, P = .030) and 30-days readmission (Z = 1.99, P = .047) was registered as the size increased.

CONCLUSION

L-LLS for tumors of increasing size was associated with poorer intraoperative and early postoperative outcomes suggesting increasing difficulty of the procedure. We determined three optimal TS cutoffs (40-, 70- and 100-mm) to accurately stratify surgical difficulty after L-LLS.

Laparoscopic versus open resection of hepatocellular carcinoma in patients with cirrhosis

Hepatocellular carcinoma (HCC) is the sixth commonest malignancy worldwide, and the fourth-leading cause of cancer related death. Partial liver resection (LR) forms the mainstay of therapy for suitable patients with preserved liver function. In recent years, significant advances in surgical technology, refinement of operative techniques and improvements in peri-operative care have facilitated the widespread adoption of laparoscopic liver resection (LLR) with encouraging outcomes. Liver cirrhosis (LC) is present in up to 80% of patients with HCC, and adds a further dimension of complexity to LR. Cirrhotic patients have a propensity for greater intraoperative blood loss as well as increased postoperative complications such as refractory ascites and posthepatectomy liver failure. Tumor localization within the fibrotic parenchyma is challenging, giving rise to concerns about resection margin status. Patients are also at higher risk of developing metachronous lesions, which affects long-term survival. Presently, the exact role of LLR in HCC patients with underlying LC is not well-defined. Current evidence suggests that LLR offers a multitude of benefits in the short-term such as reduced blood loss and blood transfusion requirements and lower morbidity, when compared to open resection. Oncologic adequacy and long-term survival do not appear to be compromised. Special consideration must be given for LLR in patients with advanced cirrhosis, or those who require extensive major hepatectomies. We present here a brief review of the literature surrounding LLR for HCC on a background of LC.

Is Laparoscopic Hepatectomy Safe for Giant Liver Tumors? Proposal from a Single Institution for Totally Laparoscopic Hemihepatectomy Using an Anterior Approach for Giant Liver Tumors Larger Than 10 cm in Diameter

BACKGROUND

The efficacy and safety of laparoscopic liver resections for liver tumors that are larger than 10 cm remain unclear. We developed a safe laparoscopic right hemihepatectomy for giant liver tumors using an anterior approach.

METHODS

Eighty patients who underwent laparoscopic hemihepatectomy between January 2011 and December 2021 were divided into a nongiant tumor group (n = 65) and a giant tumor group (n = 15) for comparison.

RESULTS

The median operating time, amount of blood loss, and length of postoperative hospital stay did not differ significantly between the nongiant and giant tumor groups. The sizes of the tumors and weights of the resected liver were significantly larger in the giant tumor group. A comparison between a nongiant group (n = 23) and a giant group (n = 12) treated with laparoscopic right hemihepatectomy showed similar results.

CONCLUSIONS

Laparoscopic hemihepatectomy, especially that performed on the right side, for giant tumors larger than 10 cm can be performed safely. Surgical techniques for giant liver tumors have been standardized, and their application is expected to spread widely in the future.

Effect of age on the short- and long-term outcomes of patients undergoing curative liver resection for HCC

BACKGROUND

Few studies have evaluated the outcomes of curative liver resection (LR) in octogenarian patients, analysed cancer-specific survival (CSS) with HCC-related death or explored the age-varying effect of HCC-related death in elderly patients undergoing LR. We aim to determine the effect of age on the short and long-term outcomes of LR for HCC.

METHODOLOGY

Between 2000 and 2018, 1,092 patients with primary HCC who underwent LR with curative intent were retrospectively reviewed. The log-rank test and Gray's test were used to assess the equality of survivor functions and competing risk-adjusted cumulative incidence functions between patients in the three age categories respectively. Regression adjustment was used to control for confounding bias via a Principal Component Analysis. Quantile, Firth logistic, Cox, and Fine-Gray competing risk regression were used to analyse continuous, binary, time-to-event, and cause-specific survival respectively. Restricted cubic splines were used to illustrate the dose-effect relationship between age and patient outcomes.

RESULTS

The study comprised of 764 young patients (<70 years), 278 septuagenarians (70-79 years old) and 50 octogenarians (≥80 years). Compared to young patients, octogenarians had significantly lower 5-year OS(62.1% vs 37.7%, p < 0.001). However, there was no significant difference in 1-year RFS(73.1% vs 67.0%, p = 0.774) or 5-year CSS (5.4% vs 15.2%, p = 0.674). Every 10-year increase in age was significantly associated with an increase length of stay (p < 0.001), postoperative complications (p = 0.004) and poorer OS(p = 0.018) but not significantly associated with major complications (p = 0.279), CSS(p = 0.338) or RFS(p = 0.941).

CONCLUSION

Age by itself was associated with OS after LR for HCC but was not a significant risk factor for HCC-related death.

Minimally invasive liver resection for huge (≥10 cm) tumors: an international multicenter matched cohort study with regression discontinuity analyses

Background

The application and feasibility of minimally invasive liver resection (MILR) for huge liver tumours (≥10 cm) has not been well documented.

Methods

Retrospective analysis of data on 6,617 patients who had MILR for liver tumours were gathered from 21 international centers between 2009-2019. Huge tumors and large tumors were defined as tumors with a size ≥10.0 cm and 3.0-9.9 cm based on histology, respectively. 1:1 coarsened exact-matching (CEM) and 1:2 Mahalanobis distance-matching (MDM) was performed according to clinically-selected variables. Regression discontinuity analyses were performed as an additional line of sensitivity analysis to estimate local treatment effects at the 10-cm tumor size cutoff.

Results

Of 2,890 patients with tumours ≥3 cm, there were 205 huge tumors. After 1:1 CEM, 174 huge tumors were matched to 174 large tumors; and after 1:2 MDM, 190 huge tumours were matched to 380 large tumours. There was significantly and consistently increased intraoperative blood loss, frequency in the application of Pringle maneuver, major morbidity and postoperative stay in the huge tumour group compared to the large tumour group after both 1:1 CEM and 1:2 MDM. These findings were reinforced in RD analyses. Intraoperative blood transfusion rate and open conversion rate were significantly higher in the huge tumor group after only 1:2 MDM but not 1:1 CEM.

Conclusions

MILR for huge tumours can be safely performed in expert centers It is an operation with substantial complexity and high technical requirement, with worse perioperative outcomes compared to MILR for large tumors, therefore judicious patient selection is pivotal.

Laparoscopic versus open resection of hepatocellular carcinoma in patients with cirrhosis: a meta-analysis

BACKGROUND

The exact role of laparoscopic liver resection (LLR) in patients with hepatocellular carcinoma (HCC) and underlying liver cirrhosis (LC) is not well defined. In this meta-analysis, both long- and short-term outcomes following LLR versus open liver resection (OLR) were analysed.

METHODS

PubMed, EMBASE, Scopus and Web of Science databases were searched systematically for randomised controlled trials (RCTs) and propensity-score matched (PSM) studies reporting outcomes of LLR versus OLR of HCC in patients with cirrhosis. Primary outcome was overall survival (OS). This was analysed using one-stage (individual participant data meta-analysis) and two-stage (aggregate data meta-analysis) approaches. Secondary outcomes were operation duration, blood loss, blood transfusion, Pringle manoeuvre utilization, overall and major complications, length of hospital stay (LOHS), 90-day mortality and R0 resection rates.

RESULTS

Eleven studies comprising 1618 patients (690 LLR versus 928 OLR) were included for analysis. In the one-stage meta-analysis, an approximately 18.7 per cent lower hazard rate (HR) of death in the LLR group (random effects: HR 0.81, 95 per cent confidence interval [C.I.] 0.68 to 0.96; P = 0.018) was observed. Two-stage meta-analysis resulted in a pooled HR of 0.84 (95 per cent C.I. 0.74 to 0.96; P = 0.01) in the overall LLR cohort. This indicated a 16-26 per cent reduction in the HR of death for patients with HCC and cirrhosis who underwent LLR. For secondary outcomes, LLR was associated with less blood loss (mean difference [MD] -99 ml, 95 per cent C.I. -182 to -16 ml), reduced overall complications (odds ratio 0.49, 95 per cent C.I. 0.37 to 0.66) and major complications (odds ratio 0.45, 95 per cent C.I. 0.26 to 0.79), and shorter LOHS (MD -3.22 days, 95 per cent C.I. -4.38 to -2.06 days).

CONCLUSION

Laparoscopic resection of HCC in patients with cirrhosis is associated with improved survival and perioperative outcomes.

Evolution and trends in the adoption of laparoscopic liver resection in Singapore: Analysis of 300 cases

ABSTRACT Introduction: The introduction of laparoscopic surgery has changed abdominal surgery. We evaluated the evolution and changing trends associated with adoption of laparoscopic liver resection (LLR) and the experience of a surgeon without prior LLR experience. Methods: A retrospective review of 310 patients who underwent LLR performed by a single surgeon from 2011 to 2020 was conducted. Exclusion criteria were patients who underwent laparoscopic liver surgeries such as excision biopsy, local ablation, drainage of abscesses and deroofing of liver cysts. There were 300 cases and the cohort was divided into 5 groups of 60 patients. Results: There were 288 patients who underwent a totally minimally invasive approach, including 28 robotic-assisted procedures. Open conversion occurred for 13 (4.3%) patients; the conversion rate decreased significantly from 10% in the initial period to 3.3% subsequently. There were 83 (27.7%) major resections and 131 (43.7%) resections were performed for tumours in the difficult posterosuperior location. There were 152 (50.7%) patients with previous abdominal surgery, including 52 (17.3%) repeat liver resections for recurrent tumours, and 60 patients had other concomitant operations. According to the Iwate criteria, 135 (44.7%) were graded as high/expert difficulty. Major morbidity (>grade 3a) occurred in 12 (4.0%) patients and there was no 30-day mortality. Comparison across the 5 patient groups demonstrated a significant trend towards older patients, higher American Society of Anesthesiologists (ASA) score, increasing frequency of LLR with previous abdominal surgery, increasing frequency of portal hypertension and huge tumours, decreasing blood loss and decreasing transfusion rate across the study period. Surgeon experience (≤60 cases) and Institut Mutualiste Montsouris (IMM) high grade resections were independent predictors of open conversion. Open conversion was associated with worse perioperative outcomes such as increased blood loss, transfusion rate, morbidity and length of stay. Conclusion: LLR can be safely adopted for resections of all difficulty grades, including major resections and for tumours located in the difficult posterosuperior segments, with a low open conversion rate. Keywords: Laparoscopic hepatectomy, laparoscopic liver resection, robotic hepatectomy, robotic liver resection, Singapore

Impact of tumor size on the difficulty of minimally invasive liver resection

INTRODUCTION

We performed this study in order to investigate the impact of tumour size on the difficulty of MILR, as well as to elucidate the optimal tumour size cut-off/s to distinguish between 'easy' and 'difficult' MILRs.

MATERIALS AND METHODS

This is retrospective review of 603 consecutive patients who underwent MILR between 2006 and 2019 of which 461 met the study inclusion criteria. We first conducted an exploratory analysis to visualize the associations between tumor size and various surrogates of laparoscopic difficulty in order to determine to optimal tumor size cutoff for stratification. Visual inspection of flexible spline-based models as well as quantitative evidence determined that perioperative outcomes differed between patients with tumor size of 30-69 mm and tumours ≥70 mm. These cutoffs were used for further downstream analyses.

RESULTS

The cohort of 461 patients was divided into 3 groups based on tumour diameter size. Patients with larger tumours experienced longer operating times ((P_{Group 2 vs 1}<0.001, P_{Group 3 vs 1}<0.001, P_{Group 3 vs 2}<0.001), higher blood loss (P_{Group 2 vs 1}<0.001, P_{Group 3 vs 1}<0.001, P_{Group 3 vs 2}<0.001), as well as significantly longer hospital stay (P_{Group 2 vs 1}<0.001, P_{Group 3 vs 1}<0.001, P_{Group 3 vs 2}<0.001). There was a monotonic trend towards increasing blood transfusion rates (P = 0.006), overall morbidity (P = 0.029) and 90-day mortality rates (P = 0.047) with increasing tumour size.

CONCLUSION

Although tumour size of 30 mm serves as an optimal cut-off for predicting difficult resections as per the Iwate criteria, a trichotomy (<30 mm, 30-69 mm, ≥70 mm) may provide additional granularity. Further large-scale prospective studies are needed to corroborate these findings.