Extent of lymphadenectomy and perioperative therapies: Two open issues in gastric cancer

A clinicopathologic feature-based nomogram for preoperative estimation of splenic hilar lymph node metastasis in advanced proximal gastric cancer without invasion of the greater curvature

BACKGROUND

The indications for splenic hilar lymph node dissection in advanced proximal gastric cancer without invasion of the greater curvature are controversial. We aimed to develop a preoperative nomogram for individualized prediction of splenic hilar lymph node metastasis in non-greater curvature advanced proximal gastric cancer.

METHODS

From January 2014 to December 2021, 558 patients with non-greater curvature advanced proximal gastric cancer who underwent D2 lymphadenectomy (including splenic hilar lymph node) were retrospectively analyzed and divided into a training cohort (n = 361) and validation cohort (n = 197), depending on the admission time. A preoperative predictive nomogram of splenic hilar lymph node metastasis was established based on independent predictors identified by multivariate analysis, and the performance and prognostic value were confirmed.

RESULTS

In the training and validation cohorts, 48 (13.3%) and 24 patients (12.2%) had pathologically confirmed splenic hilar lymph node metastasis, respectively. Tumor located in the posterior wall, tumor size ≥5 cm, Borrmann type IV, and splenic hilar lymph node lymphadenectasis on computed tomography were preoperative factors independently associated with splenic hilar lymph node metastasis. The nomogram developed based on these four parameters had a high concordance index of 0.850 (95% confidence interval, 0.793-0.907) and 0.825 (95% confidence interval, 0.743-0.908) in the training and validation cohorts, respectively, with well-fitting calibration plots and better net benefits in the decision curve analysis. In addition, disease-free survival and overall survival were significantly shorter in the high-risk group, with hazard ratios of 3.660 (95% confidence interval, 2.228-6.011; log-rank P < .0001) and 3.769 (95% confidence interval, 2.279-6.231; log-rank P < .0001), respectively.

CONCLUSION

The nomogram has good performance in predicting the risk of splenic hilar lymph node metastasis in non-greater curvature advanced proximal gastric cancer preoperatively, which can help surgeons make rational clinical decisions.

Tracers in Gastric Cancer Surgery

The treatment of gastric cancer mainly depends on radical gastrectomy. Determination of appropriate surgical margins and adequate lymph node (LN) resection are two major surgical steps that directly correlate with prognosis in gastric cancer. Due to the expanding use of minimally invasive procedures, it is no longer possible to locate tumors and LNs through touch. As an alternative, tracers have begun to enter the field due to their capacities for intraoperative visualization. Herein, we summarize the application of contemporary tracers in gastric cancer surgery, including isosulfan blue, methylene blue, patent blue, indocyanine green, carbon particles, and radioactive tracers. Their mechanisms, administration methods, detection efficiency, and challenges, as well as perspectives on them, are also outlined.

D2 Lymphadenectomy as an Independent Prognostic Factor in Gastric Cancer

Background: The last decades have been marked by debates based on the importance of lymphadenectomy in gastric cancer, lymphadenectomy being a topic of controversy between the Western Surgical Societies and the Asian side. Lymphadenectomy is currently a globally accepted standard in the treatment of gastric cancer.

Methods: The present study was performed prospectively on a number of 93 patients diagnosed with gastric cancer, who underwent radical gastrectomy with lymphadenectomy in the Surgery Department of the Emergency County Clinical Hospital, Constanta, between January 2012 - December 2016. In 70 cases, an extended D2 or standard D2 lymphadenectomy was performed, and for 23 patients: D1 + lymphadenectomy. The data were statistically analyzed in order to determine the prognostic value of lymphadenectomy in gastric cancer.

Results: The average age was 65.88 ± 8.80 years. The mean number of lymph nodes harvested in D2 lymphadenectomy was 22.8 ± 7.60, with limits between 15 and 43, and the number of positive lymph nodes ranged from a minimum of 0 to a maximum of 37. Histopathological exam of specimens showed that only 17.2% of patients with gastric cancers were without lymph node metastases (pN0), while 45.16% were in the pN3 stage. Analysis of survival curves revealed that 5-year survival was significantly higher in D2 lymphadenectomy compared to D1 + lymphadenectomy (23.8% vs. 8.7%).

Conclusions: The current study validates D2 lymphadenectomy as a standard technique and the superiority of the prognosis in gastric cancer patients through results obtained in terms of 5-year survival.

Lymph Node Mapping in Gastric Cancer Surgery: Current Status and New Horizons

Gastric cancer (GC) remains one of the most important malignant diseases with significant geographical, ethnic, and socioeconomic differences in distribution. Sentinel lymph node (SLN) mapping is an accepted way to assess lymphatic spread in several solid tumors; however, the complexity of gastric lymphatic drainage may discourage use of this procedure, and the estimated accuracy rate is, in general, reasonably good. This study aimed at reviewing the current status of SLN mapping and navigation surgery in GC. SLN mapping should be limited to tumors clinically T1 and less than 4 cm in diameter. Combination SLN mapping with radioactive colloid and blue dye is used as the standard. Despite its notable limitations, SLN mapping and SLN navigation surgery present a novelty individualizing the extent of lymphadenectomy.

Comparison of Treatment Modalities for Locally Advanced Gastric Cancer: A Propensity Score Matching Analysis

Background: A consensus regarding optimum treatment strategies for locally advanced gastric cancer (LAGC) has not yet been reached. We aimed to evaluate the efficacy of various treatment modalities for LAGC and provided clinicians salvage options under real-world situation. Methods: Medical charts of patients with LAGC who underwent radical resection plus adjuvant chemotherapy or chemoradiotherapy from July 2003 to December 2014 were included. Validation cohort were selected from SEER database between 2004 and 2014. Kaplan-Meier and Cox proportional hazardous models were used to evaluate the overall survival (OS), cancer-specific survival (CSS), and disease-free survival (DFS). Propensity score matching (PSM) was used to adjust for potential baseline confounding. Results: A total of 350 patients were included and divided into D1 dissection plus chemotherapy group (D1CT, n = 74), D1 dissection plus adjuvant chemoradiotherapy group (D1CRT, n = 69), D2 dissection plus adjuvant chemotherapy group (D2CT, n = 134), and D2 dissection plus adjuvant chemoradiotherapy group (D2CRT, n = 73). PSM identified 50 patients in each group. After PSM, better DFS (P for D2CRT vs. D1CT, D1CRT, and D2CT was 0.001, 0.006, and 0.001, respectively) and OS (P for D2CRT vs. D1CT, D1CRT, and D2CT was 0.001, 0.011, and 0.022, respectively) were found for the D2CRT group (mean, OS = 110.7months, DFS = 95.2 months) than the other groups. Similar findings were further validated in the Surveillance, Epidemiology, and End Results database (SEER) cohort. In addition, patients in the D1CRT group achieved similar survival outcomes to those in the D2CT group (mean OS, 72.8 vs. 59.1 months, P = 0.86; mean DFS, 54.4 vs. 34.1 months, P = 0.460). Conclusions: The results of the study indicated the better role for D2CRT in treating the LAGC, meanwhile, the patients treated with D1CRT might achieve similar survival as that of D2CT patients.

How Should We Measure the Quality of Lymphadenectomy for Gastric Cancer? Anatomical Versus Numerical Criterion

AIM

To compare anatomical with numerical criterion to measure the quality of lymphadenectomy for gastric cancer.

PATIENTS AND METHODS

We analyzed 447 gastric cancer patients with resectable tumor stage (R0 resection) with at least 16 examined lymph nodes.

RESULTS

Of 447 patients, 82.6% underwent D2 lymphadenectomy for a median of total examined lymph nodes of 28. The 7-year disease-specific survival rate for the whole sample was 71.4%. Survival was significantly different between patients treated with D2 and D1 lymphadenectomy (77.4% versus 44.3%; p < 0.001) and between patients with total examined lymph nodes ≥ 28 and < 28 (74.5% versus 62.3%; p = 0.041). Anatomical criterion significantly differentiated 7-year survival in patients stratified according to a numerical parameter.

CONCLUSION

We should still consider the anatomical criterion as the best item to measure the quality of lymphadenectomy for gastric cancer.

Gastric cancer: factors affecting survival

BACKGROUND AND AIM

The present multicenter, retrospective study aimed at determining the factors affecting survival in patients who were operated on due to gastric cancer (GC).

PATIENTS AND METHODS

The data of 234 patients, who underwent elective surgery due to GC were retrospectively analyzed. The demographic characteristics, tumor localization and diameter, type of resection and lymph node dissection, experience of the operating surgeon (senior or junior), tumor grade, pT stage, number of lymph nodes harvested, number of lymph nodes with and without metastasis, tumor stage and survival data were recorded.

RESULTS

Survival was better a tumor diameter <4 cm, lower localization, experience of the operating surgeon (senior), without metastatic lymph nodes, tumor grade and decreased invasion depth (p < .05). There was no statistically significant difference between D1 LND and D2 LND with respect to survival (p = .793). Mortality was higher and survival was lower in patients with metastatic lymph nodes (p = .001). A number of harvested lymph nodes of 16 or more increased mortality (p = .003). Also, as disease stage increased, there was a decrease in survival and increase in mortality rates (p = .001).

CONCLUSIONS

Survival outcomes in resectable GCs are affected by the experience of the surgeon and patient-related factors at the time of surgery, including tumor size, T stage, and presence of metastatic lymph nodes.

Validation of the American Joint Committee on Cancer (AJCC) 8th edition stage system for gastric cancer patients: a population-based analysis

BACKGROUND

Our aim was to validate the American Joint Committee on Cancer (AJCC) 8th edition stage system for gastric cancer in the Western world and to compare several modifications between the 7th and 8th edition systems.

METHODS

Eligible patients having undergone surgical resection of gastric cancer during 2004-2011 from the Surveillance, Epidemiology, and End Results (SEER) database were included in the current study. Survival differences were assessed by Kaplan-Meier curve and log-rank tests. The discriminative power of the AJCC 8th and 7th editions was compared by Harrell's concordance index (c-index).

RESULTS

Patients with pN3a and pN3b presented distinct survival outcomes, especially for cases in which more than 15 lymph nodes were examined. The overall (OS) and cancer-specific survival (CSS) c-indices for the 8th edition were largely comparable with c-indices for the 7th edition throughout the cohort. Notably, the new edition improved the power of discrimination slightly in OS and CSS (c-indices: 0.717, 0.744) compared with the 7th edition (c-indices: 0.712, 0.739) for patients for whom 15 or more lymph nodes were examined. The analysis of stage migration in the new edition revealed nonhomogeneous survival outcomes in stages IIIB and IIIC.

CONCLUSION

The AJCC 8th stage system for gastric cancer performs as well as the AJCC 7th edition in the United States (USA). Importantly, when more than 15 lymph nodes are examined, the discriminatory performance of the new edition is improved.

Neoadjuvant chemotherapy for gastric cancer. Is it a must or a fake?

AIM

To investigate the neoadjuvant chemotherapy (NAC) effect on the survival of patients with proper stomach cancer submitted to D2 gastrectomy.

METHODS

We proceeded to a review of the literature with PubMed, Embase, ASCO and ESMO meeting abstracts as well as computerized use of the Cochrane Library for randomized controlled trials (RCTs) comparing NAC followed by surgery (NAC + S) with surgery alone (SA) for gastric cancer (GC). The primary outcome was the overall survival rate. Secondary outcomes were the site of the primary tumor, extension of node dissection according to Japanese Gastric Cancer Association (JGCA) performed in both arms, disease-specific (DSS) and disease-free survival (DFS) rates, clinical and pathological response rates and resectability rates after perioperative treatment.

RESULTS

We identified a total of 16 randomized controlled trials comparing NAC + S (n = 1089) with SA (n = 973) published in the period from January 1993 - March 2017. Only 6 of these studies were well-designed, structured trials in which the type of lymph node (LN) dissection performed or at least suggested in the trial protocol was reported. Two out of three of the RCTs with D2 lymphadenectomy performed in almost all cases failed to show survival benefit in the NAC arm. In the third RCT, the survival rate was not even reported, and the primary end points were the clinical outcomes of surgery with and without NAC. In the remaining three RCTs, D2 lymph node dissection was performed in less than 50% of cases or only recommended in the “Study Treatment” protocol without any description in the results of the procedure really perfomed. In one of the two studies, the benefit of NAC was evident only for esophagogastric junction (EGJ) cancers. In the second study, there was no overall survival benefit of NAC. In the last trial, which documented a survival benefit for the NAC arm, the chemotherapy effect was mostly evident for EGJ cancer, and more than one-fourth of patients did not have a proper stomach cancer. Additionally, several patients did not receive resectional surgery. Furthermore, the survival rates of international reference centers that provide adequate surgery for homogeneous stomach cancer patients’ populations are even higher than the survival rates reported after NAC followed by incomplete surgery.

CONCLUSION

NAC for GC has been rapidly introduced in international western guidelines without an evidence-based medicine-related demonstration of its efficacy for a homogeneous population of patients with only stomach tumors submitted to adequate surgery following JGCA guidelines with extended (D2) LN dissection. Additional larger sample-size multicentre RCTs comparing the newer NAC regimens including molecular therapies followed by adequate extended surgery with surgery alone are needed.

Near-infrared fluorescence sentinel lymph node detection in gastric cancer: A pilot study

AIM: To investigate feasibility and accuracy of near-infrared fluorescence imaging using indocyanine green: nanocolloid for sentinel lymph node (SLN) detection in gastric cancer.

METHODS: A prospective, single-institution, phase I feasibility trial was conducted. Patients suffering from gastric cancer and planned for gastrectomy were included. During surgery, a subserosal injection of 1.6 mL ICG:Nanocoll was administered around the tumor. NIR fluorescence imaging of the abdominal cavity was performed using the Mini-FLARE™ NIR fluorescence imaging system. Lymphatic pathways and SLNs were visualized. Of every detected SLN, the corresponding lymph node station, signal-to-background ratio and histopathological diagnosis was determined. Patients underwent standard-of-care gastrectomy. Detected SLNs outside the standard dissection planes were also resected and evaluated.

RESULTS: Twenty-six patients were enrolled. Four patients were excluded because distant metastases were found during surgery or due to technical failure of the injection. In 21 of the remaining 22 patients, at least 1 SLN was detected by NIR Fluorescence imaging (mean 3.1 SLNs; range 1-6). In 8 of the 21 patients, tumor-positive LNs were found. Overall accuracy of the technique was 90% (70%-99%; 95%CI), which decreased by higher pT-stage (100%, 100%, 100%, 90%, 0% for respectively Tx, T1, T2, T3, T4 tumors). All NIR-negative SLNs were completely effaced by tumor. Mean fluorescence signal-to-background ratio of SLNs was 4.4 (range 1.4-19.8). In 8 of the 21 patients, SLNs outside the standard resection plane were identified, that contained malignant cells in 2 patients.

CONCLUSION: This study shows successful use of ICG:Nanocoll as lymphatic tracer for SLN detection in gastric cancer. Moreover, tumor-containing LNs outside the standard dissection planes were identified.

Gastric cancer: Current status of lymph node dissection

D2 procedure has been accepted in Far East as the standard treatment for both early (EGC) and advanced gastric cancer (AGC) for many decades. Recently EGC has been successfully treated with endoscopy by endoscopic mucosal resection or endoscopic submucosal dissection, when restricted or extended Gotoda's criteria can be applied and D1+ surgery is offered only to patients not fitted for less invasive treatment. Furthermore, two randomised controlled trials (RCTs) have been demonstrating the non inferiority of minimally invasive technique as compared to standard open surgery for the treatment of early cases and recently the feasibility of adequate D1+ dissection has been demonstrated also for the robot assisted technique. In case of AGC the debate on the extent of nodal dissection has been open for many decades. While D2 gastrectomy was performed as the standard procedure in eastern countries, mostly based on observational and retrospective studies, in the west the Medical Research Council (MRC), Dutch and Italian RCTs have been conducted to show a survival benefit of D2 over D1 with evidence based medicine. Unfortunately both the MRC and the Dutch trials failed to show a survival benefit after the D2 procedure, mostly due to the significant increase of postoperative morbidity and mortality, which was referred to splenopancreatectomy. Only 15 years after the conclusion of its accrual, the Dutch trial could report a significant decrease of recurrence after D2 procedure. Recently the long term survival analysis of the Italian RCT could demonstrate a benefit for patients with positive nodes treated with D2 gastrectomy without splenopancreatectomy. As nowadays also in western countries D2 procedure can be done safely with pancreas preserving technique and without preventive splenectomy, it has been suggested in several national guidelines as the recommended procedure for patients with AGC.

Surgical interventions for gastric cancer: a review of systematic reviews

AIM

To evaluate methodological quality and the extent of concordance among meta-analysis and/or systematic reviews on surgical interventions for gastric cancer (GC).

METHODS

A comprehensive search of PubMed, Medline, EMBASE, the Cochrane library and the DARE database was conducted to identify the reviews comparing different surgical interventions for GC prior to April 2014. After applying included criteria, available data were summarized and appraised by the Oxman and Guyatt scale.

RESULTS

Fifty six reviews were included. Forty five reviews (80.4%) were well conducted, with scores of adapted Oxman and Guyatt scale ≥ 14. The reviews differed in criteria for avoiding bias and assessing the validity of the primary studies. Many primary studies displayed major methodological flaws, such as randomization, allocation concealment, and dropouts and withdrawals. According to the concordance assessment, laparoscopy-assisted gastrectomy (LAG) was superior to open gastrectomy, and laparoscopy-assisted distal gastrectomy was superior to open distal gastrectomy in short-term outcomes. However, the concordance regarding other surgical interventions, such as D1 vs. D2 lymphadenectomy, and robotic gastrectomy vs. LAG were absent.

CONCLUSION

Systematic reviews on surgical interventions for GC displayed relatively high methodological quality. The improvement of methodological quality and reporting was necessary for primary studies. The superiority of laparoscopic over open surgery was demonstrated. But concordance on other surgical interventions was rare, which needed more well-designed RCTs and systematic reviews.

Extent of lymph node dissection for adenocarcinoma of the stomach

BACKGROUND

The impact of lymphadenectomy extent on the survival of patients with primary resectable gastric carcinoma is debated.

OBJECTIVES

We aimed to systematically review and meta-analyze the evidence on the impact of the three main types of progressively more extended lymph node dissection (that is, D1, D2 and D3 lymphadenectomy) on the clinical outcome of patients with primary resectable carcinoma of the stomach. The primary objective was to assess the impact of lymphadenectomy extent on survival (overall survival [OS], disease specific survival [DSS] and disease free survival [DFS]). The secondary aim was to assess the impact of lymphadenectomy on post-operative mortality.

SEARCH METHODS

We searched CENTRAL, MEDLINE and EMBASE until 2001, including references from relevant articles and conference proceedings. We also contacted known researchers in the field. For the updated review, CENTRAL, MEDLINE and EMBASE were searched from 2001 to February 2015.

SELECTION CRITERIA

We considered randomized controlled trials (RCTs) comparing the three main types of lymph node dissection (i.e., D1, D2 and D3 lymphadenectomy) in patients with primary non-metastatic resectable carcinoma of the stomach.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data from the included studies. Hazard ratios (HR) and relative risks (RR) along with their 95% confidence intervals (CI) were used to measure differences in survival and mortality rates between trial arms, respectively. Potential sources of between-study heterogeneity were investigated by means of subgroup and sensitivity analyses. The same two authors independently assessed the risk of bias of eligible studies according to the standards of the Cochrane Collaboration and the quality of the overall evidence based on the GRADE (Grades of Recommendation, Assessment, Development and Evaluation) criteria.

MAIN RESULTS

Eight RCTs (enrolling 2515 patients) met the inclusion criteria. Three RCTs (all performed in Asian countries) compared D3 with D2 lymphadenectomy: data suggested no significant difference in OS between these two types of lymph node dissection (HR 0.99, 95% CI 0.81 to 1.21), with no significant difference in postoperative mortality (RR 1.67, 95% CI 0.41 to 6.73). Data for DFS were available only from one trial and for no trial were DSS data available. Five RCTs (n = 3 European; n = 2 Asian) compared D2 to D1 lymphadenectomy: OS (n = 5; HR 0.91, 95% CI 0.71 to 1.17) and DFS (n=3; HR 0.95, 95% CI 0.84 to 1.07) findings suggested no significant difference between these two types of lymph node dissection. In contrast, D2 lymphadenectomy was associated with a significantly better DSS compared to D1 lymphadenectomy (HR 0.81, 95% CI 0.71 to 0.92), the quality of the body of evidence being moderate; however, D2 lymphadenectomy was also associated with a higher postoperative mortality rate (RR 2.02, 95% CI 1.34 to 3.04).

AUTHORS' CONCLUSIONS

D2 lymphadenectomy can improve DSS in patients with resectable carcinoma of the stomach, although the increased incidence of postoperative mortality reduces its therapeutic benefit.

Review on the Applications and Molecular Mechanisms of Xihuang Pill in Tumor Treatment

Xihuang pill (XH) is a complementary and alternative medicine that has been used in traditional Chinese medicine (TCM) for the treatment of tumors since the 18th century. XH has clinical effects on non-Hodgkin lymphoma, breast cancer, gastric cancer, liver cancer, and bone metastasis. XH can also inhibit the growth of tumor cells and cancer stem cells, prevent tumor invasion and angiogenesis, and regulate the tumor microenvironment. XH is composed of Ru Xiang (olibanum), Mo Yao (Commiphora myrrha), She Xiang (Moschus), and Niu Huang (Calculus bovis). Some of the compounds found in these ingredients exert multiple antitumor effects and may synergize with the other ingredients. We aimed to summarize the clinical applications and molecular mechanisms of XH and its chemical composition. This review will provide potential new strategies and alternative perspectives for tumor treatments and basic research into complementary and alternative medicine.

Lymphadenectomy extent and survival of patients with gastric carcinoma: a systematic review and meta-analysis of time-to-event data from randomized trials

BACKGROUND

The extent of lymph node dissection in patients with resectable non-metastatic primary carcinoma of the stomach is still a controversial matter of debate, with special regard to its effect on survival.

MATERIALS AND METHODS

We conducted a systematic review and meta-analysis of time-to-event data from randomized controlled trials (RCTs) comparing the three main types of lymphadenectomy (D1, D2, and D3) for gastric cancer. Hazard ratio (HR) was considered the effect measure for both overall (OS), disease-specific (DSS) and disease-free survival (DFS). The quality of the available evidence was assessed using the GRADE system.

RESULTS

Eight RCTs enrolling 2515 patients were eligible. The meta-analysis of four RCTs (n=1599) showed a significant impact of D2 versus D1 lymphadenectomy on DSS (summary HR=0.807, CI: 0.705-0.924, P=0.002), the corresponding number-to-treat being equal to ten. This effect remained clinically valuable even after adjustment for postoperative mortality. However, the quality of evidence was graded as moderate due to inconsistency issues. When OS and DFS were considered, the meta-analysis of respectively five (n=1653) and three RCTs (n=1332) found no significant difference between D2 and D1 lymph node dissection (summary HR=0.911, CI: 0.708-1.172, P=0.471, and summary HR=0.946, CI: 0.840-1.066, P=0.366, respectively). However, at subgroup analysis D2 type resulted superior to D1 type lymphadenectomy in terms of OS considering the two RCTs carried out in Eastern countries (summary HR=0.627, CI: 0.396-0.994, P=0.047). As regards the D3 vs D2 comparison, the meta-analysis of the three available RCTs (n=862) showed no significant impact of more extended lymphadenectomy on OS (summary HR=0.990, CI: 0.814-1.205, P=0.924).

CONCLUSIONS

Our findings support the superiority of D2 versus D1 lymphadenectomy in terms of survival benefit. However, this advantage is mainly limited to DSS, the level of evidence is moderate, and the interaction with other factors affecting patient survival (such as complementary medical therapy) remains to be elucidated.