Incorporating surgical quality into the AJCC 7th edition improves staging accuracy in gastric cancer

Enhancing Lymph Node Yield in Gastric Cancer Resection: Impact of Back Table Dissection on Number of Lymph Node Examined

INTRODUCTION

During gastric cancer resection, back table dissection (BTD) involves examination and separation of lymph node (LN) packets from the surgical specimen based on LN stations, which are sent to pathology as separately labeled specimens. With potential impact on clinical outcomes, we aimed to explore how BTD affects number of LNs examined.

METHODS

A retrospective review of a gastric cancer database was performed, including all cases of gastrectomy with D2 lymphadenectomy from January 2009 to March 2022. Back table dissection and conventional groups were compared using Mann-Whitney U and Fisher's exact tests. Multiple linear regression modeling was used to identify potential predictors of number of LN examined.

RESULTS

A total of 174 patients were identified: 39 (22%) BTD and 135 (78%) conventional. More patients in the BTD group underwent neoadjuvant chemotherapy (62% vs 29%, P < .05). Compared to the conventional group, the BTD group had a greater number of LNs examined (42 [26-59] vs 21[15-33], median [IQR], P < .001), lower LN positivity ratio (.01 vs .07, P = .013), and greater number of LNs in patients with BMI >35 (32.5[27.5-39] vs 22[13-27], P = .041). A multiple linear regression model controlling for age, BMI, preoperative N stage, neoadjuvant chemotherapy, surgeon experience, and operative approach identified BTD as a significant positive predictor of number of LN examined (β = 19.7, P = .001).

CONCLUSION

Back table dissection resulted in improved LN yield during gastric cancer resection. As a simple technical addition, BTD helps enhance pathology examination and improve surgeon awareness, which may ultimately translate to improve oncologic outcomes.

Nomogram-Based Prognostic Evaluation of Gastric Cancer Patients with Low Counts of Examined Lymph Nodes Outperforms the Predictive Ability of the 7th and 8th Editions of the American Joint Committee on Cancer Staging System

BACKGROUND

The American Joint Committee on Cancer (AJCC) staging system has limited accuracy in predicting survival of gastric cancer patients with inadequate counts of evaluated lymph nodes (LNs). We therefore aimed to develop a prognostic nomogram suitable for clinical applications in such cases.

METHODS

A total of 1511 noncardia gastric cancer patients treated between 1990 and 2010 in the academic surgical center were reviewed to compare the 7^th and 8^th editions of the AJCC staging system. A nomogram was developed for the prediction of 5-year survival in patients with less than 16 LNs evaluated (n = 546). External validation was performed using datasets derived from the Polish Gastric Cancer Study Group (n = 668) and the SEER database (n = 11,225).

RESULTS

The 8th edition of AJCC staging showed better overall discriminatory power compared to the previous version, but no improvement was found for patients with < 16 evaluated LNs. The developed nomogram had better concordance index (0.695) than the former (0.682) or latest (0.680) staging editions, including patients subject to neoadjuvant treatment, and calibration curves showed excellent agreement between the nomogram-predicted and actual survival. High discriminatory power was also demonstrated for both validation cohorts. Subsequently, the nomogram showed the best accuracy for the prediction of 5-year survival through the time-dependent ROC curve analysis in the training and validation cohorts.

CONCLUSIONS

A clinically relevant nomogram was built for the prediction of 5-year survival in patients with inadequate numbers of LNs evaluated in surgical specimens. The predictive accuracy of the nomogram was validated in two Western populations.

Superior pancreatic lymphadenectomy with portal vein priority via posterior common hepatic artery approach in laparoscopic radical gastrectomy

BACKGROUND

D2 lymph node dissection for advanced gastric cancer is advocated, and station 8p lymph node should be considered in selected patients, which is, however, technically difficult.

AIM

To introduce a new and easy-to-perform procedure for dissection of the lymph nodes superior to the pancreas.

METHODS

A series of patients who underwent laparoscopic gastrectomy for gastric cancer were retrospectively included with utilization of a new procedure for superior pancreatic lymphadenectomy (LND) with portal vein priority via the posterior common hepatic artery approach (SPLD-PPPH) based on a newly defined portal triangle. The surgical outcome of the patients, as well as the efficacy and safety of SPLD-PPPH are reported.

RESULTS

A total of 51 patients were included with most of them being male (n = 34, 66.7%). According to the 8^th edition of AJCC TNM staging, there were four (7.8%) patients in stage I, 13 (25.5%) in stage II, 33 (64.7%) in stage III and one (2.0%) in stage IV. The average duration for LND was about 1 h (67.7 ± 6.9 min). After surgery, four patients developed morbidities, but all were treated successfully with no perioperative mortality. Among the 51 patients included, the percentage of patients who had lymph node metastasis at station 8p was 9.8%. Of note, with a total of 14 lymph nodes harvested at station 8p, the incidence of nodal metastasis was 14.3%.

CONCLUSION

About one in 10 patients with advanced gastric cancer had nodal metastasis at station 8p. The new approach of SPLD-PPPH is safe and effective for D2+ LND during laparoscopic radical gastrectomy.

Comparison of the sixth, seventh, and eighth editions of the American Joint Committee on Cancer Tumor-Node-Metastasis staging system for gastric cancer: A single institution experience

In 2018, the eighth edition of the American Joint Committee on Cancer Tumor-Node-Metastasis classification and staging system was implemented. Few reports were made comparing the performance of different editions of the American Joint Committee on Cancer (AJCC) system. Therefore, this study aimed to examine the prognostic predictability from the sixth to the eighth editions of the AJCC staging system for gastric cancer.A total of 414 patients with gastric cancer who underwent surgery at Changhua Christian Hospital from January 2007 to December 2017 were enrolled in the study. To identify the prognostic factors for gastric cancer death, univariate and multivariate analyses were performed. The homogeneity and discrimination abilities of the sixth to eighth editions of the staging system were compared using the likelihood ratio chi-square test, linear trend chi-square test, and Akaike information criterion.The sixth edition of the staging system had the lowest Akaike information criterion value, suggesting a better prognostic stratification than other editions. From the result of the likelihood ratio chi-square test, the T and N staging systems of the seventh and eighth editions had better homogeneity and discriminatory ability than the sixth edition. The eighth edition had better prognostic performance in patients at stage III compared with the seventh edition.The AJCC seventh and eighth editions had improved prognostic predictability of the T and N factors compared with the sixth edition. However, the overall staging performance of the eighth edition is not superior compared to the sixth edition. Further studies with larger sample size should be conducted to compare the performance of different editions of the AJCC staging system for different ethnic populations.

Impact of Lymph Node Ratio on Survival Outcome in Esophageal Squamous Cell Carcinoma After Minimally Invasive Esophagectomy

BACKGROUND

Esophageal squamous cell cancer (ESCC) is one of the deadliest cancers in the world. Esophagectomy remains the principal treatment, and minimally invasive esophagectomy (MIE) has been performed worldwide. This study aimed to clarify whether the lymph node ratio (LNR), defined as the ratio of metastatic lymph nodes (LNs) to examined, is a prognostic factor for ESCC after MIE.

METHODS

This study included 327 MIEs with the patient in the prone position at two institutions from 2010 to 2015. Cox proportional hazards regression analyses using clinicopathologic characteristics and the LNR were performed for the pN1 patients and the whole cohort.

RESULTS

In the multivariate analysis for all stages, independent prognostic factors were depth of tumor invasion (P < 0.0001), LNR (P = 0.014), operative time (P = 0.003), and pneumonia (P = 0.012). In the analysis of the pN1 subgroup, the optimum LNR cutoff level for overall survival (OS) was 9 based on receiver operation characteristic analysis. The LNR was significantly associated with depth of tumor invasion (P = 0.004) and number of metastatic LNs (P < 0.0001). The OS curve for the group with an LNR of 9 or higher was significantly worse than for the group with an LNR lower than 9 (P < 0.001). Multivariate analyses demonstrated that the LNR is a unique independent prognostic factor for the pN1 subgroup (hazard ratio, 6.811; 95% confidence interval, 2.009-23.087; P = 0.002).

CONCLUSIONS

The LNR is an independent prognostic factor in ESCC after MIE. Especially for patients with pN1 status, the LNR is more useful than the number of metastatic LNs for predicting survival outcome.

Lymph Node Yield Following Packet Submission After Isolation By Surgeon During Gastrectomy

Purpose

To compare the lymph node yields of lymph node packet submission (PS), packet submission after isolation by surgeons (PSI), and en bloc lymph node submission (EBS) after gastrectomy.

Methods

We conducted a prospective study including 118 gastric cancer patients who underwent gastrectomy between June 2016 and August 2016. We also retrospectively reviewed 607 patients who underwent gastrectomy from May 2015 to May 2016. Following gastrectomy, lymph node specimens were either submitted en bloc (EBS group), divided into packets with accompanying adipose tissue according to the lymph node stations (PS group), or isolated individually based on the surgeon’s visualization and palpation before submission to the Pathology Department (PSI group).

Results

The average lymph node yield was significantly higher in the PSI compared with the PS group in the prospective study (46.5±19.4 vs 31.8±11.1), and significantly higher in the PS compared with the EBS group in the retrospective study (31.5±12.6 vs 23.9±8.9) (both P<0.001). There was no significant difference in positive lymph node yields in either of these comparisons (prospective study, P=0.581; retrospective study, P=0.489). The survival curve indicated no significant difference between the PS and PSI groups (log rank P=0.957); however, these three groups share different lymph node ratio (LNR).

Conclusion

PSI could yield more lymph nodes than PS or EBS with a lower LNR at pathological examination. However, the difference in lymph nodes harvested had no impact on survival, which may need further investigation.

Evaluating Dissemination of Adequate Lymphadenectomy for Gastric Cancer in the USA

BACKGROUND

Adequate lymphadenectomy (AL) of 15+ lymph nodes comprises an important component of gastric cancer surgical therapy. Despite endorsement by the National Comprehensive Cancer Network and the Committee on Cancer, initial adoption of this paradigm has been relatively slow. The current analysis sought to perform an adjusted time-trend evaluation of the factors associated with AL and its dissemination.

METHODS

Utilizing the 2004-2015 National Cancer Database, 28,985 patients were identified who underwent gastrectomy for adenocarcinoma. An adjusted time-trend analysis was performed to estimate the adoption of AL overall. Multivariable logistic regression was utilized to assess factors associated with these observed trends. Interactions and stratified models determined disparate effects in vulnerable populations (older adults, ethnic minorities, low socioeconomic status).

RESULTS

The adjusted time-trend analysis demonstrated an overall 30% increase (28.8 to 58.7%) in receipt of AL (OR 1.10 increase/year; 95%CI 1.09-1.10) from 2004 to 2015. This trend persisted even after stratifying the models by age, race/ethnicity, and income (OR 1.07-1.12; p < 0.05). Slowest rates of adoption were seen amongst hospitals in the Midwest census region (OR 1.08, CI 1.06-1.90) and comprehensive community hospitals (OR 1.08, CI 1.06-1.91) and with African-American patients (OR 1.09, CI 1.06-1.11) (all p < 0.05).

CONCLUSION

This multi-center evaluation demonstrates increased adoption of AL during gastric cancer surgery in the USA overall and amongst vulnerable populations, although regional and racial disparities were observed. Future studies are needed to investigate reasons underlying racial and regional differences in receipt of AL.

Relationship between celiac artery variation and number of lymph nodes dissection in gastric cancer surgery

BACKGROUND

Radical D2 lymphadenectomy for advanced gastric cancer as a standard procedure has gained global consensus. Mounting studies have shown that the number of lymph nodes dissection directly affects the prognosis and recurrence of gastric cancer. Our previous study showed that there was no obvious lymph node around the abnormal hepatic artery derived from the superior mesenteric artery.

AIM

To investigate the relationship between celiac artery variation and the number of lymph nodes dissection in gastric cancer surgery.

METHODS

The clinicopathological data of 421 patients treated with radical D2 lymphadenectomy were analyzed retrospectively. The difference of the number of lymph nodes dissection between the celiac artery variation group and the normal vessels group and the relationship with prognosis were analyzed.

RESULTS

Celiac artery variation was found in 110 patients, with a variation rate of 26.13%. Celiac artery variation, tumor staging, and Borrmann typing were factors that affected lymph node clearance in gastric cancer, and the number of lymph nodes dissection in patients with celiac artery variation was significantly less than that of non-variant groups (P < 0.05). Univariate analysis showed that there was no significant difference in survival time between the two groups (P > 0.05). Univariate and multiple Cox regression analysis showed that celiac artery variation was not a prognostic factor for gastric cancer (P > 0.05). Tumor staging, intraoperative bleeding, and positive lymph node ratio were prognostic factors for gastric cancer patients (all P < 0.05).

CONCLUSION

The number of lymph nodes dissection in patients with celiac artery variation was reduced, but there was no obvious effect on prognosis. Therefore, lymph nodes around the abnormal hepatic artery may not need to be dissected in radical D2 lymphadenectomy.

Survival Analysis with Extended Lymphadenectomy for Gastric Cancer: Removing Stage Migration from the Equation

The survival benefit of an extended versus standard lymphadenectomy for gastric cancer (GC) is often attributed to upstaging when more lymph nodes (LNs) are removed, i.e., stage migration. An extended lymphadenectomy is defined as 30 or more LNs examined, a surrogate for a D2 dissection. The aim of this study is to examine whether the survival benefit of extended lymphadenectomy persists when stage migration is not possible. The National Cancer Data Base was queried to identify patients with pathologic N3 (pN3, ≥7 positive LNs) gastric adenocarcinoma. Overall survival (OS) was compared by extent of lymphadenectomy (7–14, 15–29, and ≥30 LN) and stratified by Tstage. Of 2101 pN3 patients, 419 (19.9%) had 7 to 14 LNs examined, 1164 (55.4%) had 15 to 29 LNs examined, and 518 (24.7%) had ≥30 LNs examined. Unadjusted three-year OS in the entire cohort was 24.6, 27.3, 30.5 per cent for 7 to 14 LNs, 15 to 29 LNs, and ≥30 LNs, respectively (P = 0.003). On adjusted survival analysis by stage for patients with pT1-T2N3 disease, removing ≥30 LNs significantly improved OS compared with removing 7 to 14 LNs (hazard ratio [HR] 2.45, 95% confidence interval = 1.25–4.82, P = 0.009). Extended lymphadenectomy may confer a survival benefit in select patients with pT1N3 and pT2N3 GC, highlighting the importance of the number of LNs examined rather than stage migration on survival. For the majority of the N3 population, pT3-pT4, the extent of lymphadenectomy did not significantly improve the OS.

Predicting the survival of patients with small bowel neuroendocrine tumours: comparison of 3 systems

Neuroendocrine tumours (NET) are clinically challenging due to their unpredictable behaviour. Nomograms, grading and staging systems are predictive tools with multiple roles in clinical practice, including patient prognostication. The NET nomogram allocates scores for various clinicopathological parameters, calculating percentage estimates for 5- and 10-year disease-specific survival of patients with small bowel (SB) NET. We evaluated the clinical utility of three prognostic systems in 70 SB NET patients: the NET nomogram, the World Health Organisation (WHO)/European Neuroendocrine Tumour Society (ENETS) grading system and the American Joint Commission on Cancer (AJCC)/Union Internationale Contre le Cancer (UICC) TNM staging method. Using Kaplan-Meier methodology, neither the WHO/ENETS grade (P = 0.6) nor the AJCC/UICC stage (P = 0.276) systems demonstrated significant differences in patient survival in the cohort. The NET nomogram was well calibrated to our data set, displaying favourable prediction accuracy. Harrel's C-index for the nomogram (a measure of predictive power) was 0.65, suggesting good prediction ability. On Kaplan-Meier analyses, there were significant differences in patient survival when stratified into nomogram score-based risk groups: low-, medium- and high-risk tumours were associated with median estimated survivals of 156, 129 and 112 months, respectively (P = 0.031). Our data suggest that a multivariable analysis-based NET nomogram may be clinically useful for patient survival prediction. This study identifies the limitations of the NET nomogram and the imperfections of other currently used single or binary parameter methodologies for assessing neuroendocrine disease prognosis. The future addition of other variables to the NET nomogram will likely amplify the accuracy of this personalised tool.

Equipping the 8th Edition American Joint Committee on Cancer Staging for Gastric Cancer with the 15-Node Minimum: a Population-Based Study Using Recursive Partitioning Analysis

BAKCGROUND

The recently proposed 8th American Joint Committee on Cancer (AJCC) staging for gastric cancer (GC) did not include the evaluated lymph node (ELN) count as a prognostic indicator. In this study, we performed recursive partitioning analysis (RPA) to objectively combine the 15-ELN threshold and 8th AJCC stage to refine the staging for GC.

METHODS

We analyzed 19,018 patients with non-metastatic GC from the Surveillance, Epidemiology, and End Results database. The dataset was randomly divided into training and validation sets.

RESULTS

For each 8th AJCC stage, survival was significantly better for patients with ≥15 ELNs versus those with <15 ELNs (P < 0.001 for all). RPA divided non-metastatic GC into seven stages: RPA-IA (8th AJCC IA with ≥15 ELNs), RPA-IB (IA with <15 ELNs and IB/IIA with ≥15 ELNs), RPA-IIA (IB with <15 ELNs and IIB with ≥15 ELNs), RPA-IIB (IIA with <15 ELNs and IIIA with ≥15 ELNs), RPA-IIIA (IIB with <15 ELNs), RPA-IIIB (IIIA with <15 ELNs and IIIB ≥15 ELNs), and RPA-IIIC (IIIB with <15 ELNs and IIIC). The corresponding 5-year survival rates were 84.1, 70.3, 52.8, 41.4, 32.9, 21.7, and 10.2%, respectively (P < 0.001 for all pairwise comparisons). The RPA staging outperformed the 8th AJCC staging in terms of discrimination and homogeneity among the SEER training and validation sets, as well as an independent Chinese cohort.

CONCLUSION

By equipping the 8th AJCC stage with the 15-ELN threshold, the proposed RPA staging is superior to the 8th AJCC staging without overcomplicating.

Influence of Total Lymph Node Count on Staging and Survival After Gastrectomy for Gastric Cancer: An Analysis From a Two-Institution Database in China

BACKGROUND

Although current guidelines suggest that 16 or more lymph nodes (LNs) are required for the appropriate staging of gastric cancer, the effect that the minimum number of examined LNs (eLNs) in the different types of gastrectomy has on survival remains unclear.

METHODS

This study retrospectively analyzed 2662 patients who underwent curative gastrectomy with D2 lymphadenectomy for gastric cancer at Fujian Medical University Union Hospital from January 2000 to December 2010 and randomly divided them into development (70 %, n = 1863) and validation (30 %, n = 799) data sets. An additional external validation was performed using the data set (n = 285) collected during the same period from the Sun Yat-sen University Cancer Center in Guangzhou, China. A hypothetical tumor-node-metastasis (TNM) classification (hTNM) was proposed based on eLNs and survival.

RESULTS

The mean numbers of nodes removed during radical distal and total gastrectomy were respectively 26 ± 9.6 and 29 ± 10.7 (p < 0.01). The optimal LN-count thresholds were determined to be 16 for patients who underwent curative distal gastrectomy and 21 for patients who underwent total gastrectomy. The hTNM staging system had higher linear trend and likelihood ratio χ ² scores and lower Akaike information criterion (AIC) values than the seventh American Joint Committee on Cancer (AJCC) TNM classification. Thus, the hTNM staging system exhibited superior prognostic stratification. Similar results were found in the two validation data sets.

CONCLUSION

A harvest of at least 21 LNs may represent a superior threshold for radical total gastrectomy (RTG) and could yield a better prognosis. For patients undergoing RTG, the hTNM staging system may predict survival more accurately and discriminatively. However, a validation from a Western institution is warranted.

Lymph node ratio as a novel and simple prognostic factor in advanced gastric cancer

TNM staging is no doubt the most critical prognostic factors, representing tumor (T)/lymph node metastasis (N)/distant metastasis (M) in gastric cancer. Lymph node ratio-based N system (Nr) has been repeatedly reported to be of prognostic relevance in advanced gastric cancer independent of stage in the multivariate analysis world-wide, and proposed as more sophisticated than N with regard to predicting accurate prognosis. As a result, proposed TNrM system may predict survival more accurately than the present TNM staging system for patients undergoing limited lymph node analysis. It could adjust stage migration when the lymph node number was used as staging factor. Although correlation of the number of metastatic lymph nodes and lymph node ratio is obvious, biological characteristics other than that could also have been reflected on. It may indicate how successful the operation of lymph node dissection was, or it may be revealing the potential of the patient's lymph node immune-reaction. Recently, high lymph node ratio is closely associated with EGFR expression in advanced gastric cancer. When efficiency of applying lymph node ratio as a biomarker is verified and confirmed in an expansive research, and when cancer causing molecules are identified, as well as the competence as a treatment target is studied, the new biomarker, namely, lymph node ratio, could find itself in a limelight in gastric cancer treatment in the future.

Overall Survival Is Impacted by Birthplace and Not Extent of Surgery in Asian Americans with Resectable Gastric Cancer

Survival from gastric cancer in the USA still lags behind Asia. Genetic, environmental, and tumor biology differences, along with extent of surgery have been implicated. Our aim was to evaluate survival outcomes in Asian-American gastric cancer patients undergoing surgical resection by comparing place of birth and clinicopathologic characteristics (including evaluation of 15 lymph nodes).The Surveillance, Epidemiology, and End Results database was queried to identify patients treated surgically for gastric cancer with curative intent in the USA (2000-2010). US-born versus foreign-born Asian-American patients were analyzed for survival. Secondary comparison was made to non-Asian patients. Stage IV and non-surgical patients were excluded. Of 10,089 patients identified, 1467 patients were Asian: 271 were born in the USA, and 1196 were born outside the USA. Median survival was 32 months for non-Asians and 29 months for US-born Asians versus 61 months for Asian immigrants (p < 0.001). On multivariable analysis of overall survival in Asian patients, only US birthplace, older age, and higher stage yielded a significantly poorer outcome. Asian-American patients have a worse prognosis if born in the USA. Anatomic and surgical differences do not explain this disparity; environmental factors may be responsible.

Techniques that accurately identify the sentinel lymph node in cancer

Sentinel lymph node (SLN) biopsy has become the gold standard for patients with melanoma and breast cancer but it’s clinical application in other solid tumor types such as cancers of the esophagus, stomach, colon and rectum, head and neck, penis, uterine cervix and endometrium has been somewhat limited. Commonly used mapping techniques utilizing the combination of radiocolloid and blue dye may result in reduced SLN detection and increased false negative rates when applied to cancers with more complex lymphatic drainage patterns. Novel localization techniques including near infrared fluorescence, high resolution imaging and molecular targeted agents have been developed to address the limitations of conventional SLN detection practices in many solid tumor types. This article reviews the indications, techniques and detection rates for SLN biopsy in several different solid tumor types as well as the promising novel techniques created to address the contemporary limitations of this procedure.