Predicting lymph node metastases in early gastric cancer: radical resection or organ-sparing therapy?

Machine learning for lymph node metastasis prediction of in patients with gastric cancer: A systematic review and meta-analysis

Objective

To evaluate the diagnostic performance of machine learning (ML) in predicting lymph node metastasis (LNM) in patients with gastric cancer (GC) and to identify predictors applicable to the models.

Methods

PubMed, EMBASE, Web of Science, and Cochrane Library were searched from inception to March 16, 2022. The pooled c-index and accuracy were used to assess the diagnostic accuracy. Subgroup analysis was performed based on ML types. Meta-analyses were performed using random-effect models. Risk of bias assessment was conducted using PROBAST tool.

Results

A total of 41 studies (56182 patients) were included, and 33 of the studies divided the participants into a training set and a test set, while the rest of the studies only had a training set. The c-index of ML for LNM prediction in training set and test set was 0.837 [95%CI (0.814, 0.859)] and 0.811 [95%CI (0.785-0.838)], respectively. The pooled accuracy was 0.781 [(95%CI (0.756-0.805)] in training set and 0.753 [95%CI (0.721-0.783)] in test set. Subgroup analysis for different ML algorithms and staging of GC showed no significant difference. In contrast, in the subgroup analysis for predictors, in the training set, the model that included radiomics had better accuracy than the model with only clinical predictors (F = 3.546, p = 0.037). Additionally, cancer size, depth of cancer invasion and histological differentiation were the three most commonly used features in models built for prediction.

Conclusion

ML has shown to be of excellent diagnostic performance in predicting the LNM of GC. One of the models covering radiomics and its ML algorithms showed good accuracy for the risk of LNM in GC. However, the results revealed some methodological limitations in the development process. Future studies should focus on refining and improving existing models to improve the accuracy of LNM prediction.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/, identifier CRD42022320752

Establishment of Decision Rules and Risk Assessment Model for Preoperative Prediction of Lymph Node Metastasis in Gastric Cancer

Background: Preoperative accurate prediction of lymph node status is especially important for the formulation of treatment plans for patients with gastric cancer (GC). The purpose of this study was to establish decision rules and a risk assessment model for lymph node metastasis (LNM) in GC using preoperative indicators. Methods: The clinical data of 554 patients who underwent gastrectomy with D2 lymphadenectomy were collected. A 1:1 propensity score matching (PSM) system was used, and the clinical data of the matched 466 patients were further analyzed. The important risk factors for LNM were extracted by the random forest algorithm, and decision rules and nomogram models for LNM were constructed with a classification tree and the "rms" package of R software, respectively. Results: Tumor size (OR: 2.058; P = 0.000), computed tomography (CT) findings (OR: 1.969; P = 0.001), grade (OR: 0.479; P = 0.000), hemoglobin (Hb) (OR: 1.211; P = 0.005), CEA (OR: 1.111; P = 0.017), and CA19-9 (OR: 1.040; P = 0.033) were independent risk factors for LNM in GC. Tumor size did rank first in the ranking of important factors for LNM in GC and was the first-level segmentation of the two initial branches of the classification tree. The accuracy, sensitivity, specificity, and positive predictive value of the decision rules in diagnosing preoperative LNM in GC were 75.6, 85.7, 73.9, 73.5, and 79.3%, respectively. The accuracy, sensitivity, and specificity of the risk assessment model in predicting preoperative LNM in GC were 79.3, 80.3, and 79.4%, respectively. Conclusion: Tumor size was the most important factor for evaluating LNM in GC. This decision rules and nomogram model constructed to take into account tumor size, CT findings, grade, hemoglobin, CEA, and CA19-9 effectively predicted the incidence of LNM in preoperative GC.

Sex-specific differences in risk factors of lymph node metastasis in patients with early gastric cancer

Accurate prediction of lymph node status is of crucial importance in the appropriate treatment planning for patients with early gastric cancer (EGC). Some studies have examined factors predicting lymph node metastasis (LNM) in EGC; however, these studies did not consider sex-specific differences. This study aimed to investigate sex-specific differences in predictive risk factors of LNM in EGC based on surgical specimens. Patients who underwent surgical treatment for EGC between January 2003 and February 2016 were retrospectively evaluated. Patients who underwent previous gastric surgery or treatment for gastric neoplasms were excluded. Finally, 1076 patients treated for EGC were included in the analysis. We analyzed risk factors of LNM by dividing patients into male and female groups. Of 1076 patients (mean age 59.6 years), 69% were men. The overall LNM rate was 9.4%. The LNM rate was lower in men (7.8%) than in women (12.9%). Multivariate analysis showed that elevated type (odds ratio [OR], 2.084; 95% confidence interval [CI]: 1.053–4.125; P = 0.035), submucosal invasion (OR, 2.162; 95% CI: 1.018–4.595; P = 0.045), undifferentiated type (OR, 2.044; 95% CI: 1.107–3.772; P = 0.022), and lymphovascular invasion (LVI) (OR, 7.210; 95% CI: 3.835–13.554; P<0.001) were independent predictive risk factors of LNM in EGC in men. However, only submucosal invasion (OR, 8.772; 95% CI: 2.823–27.259; P<0.001) and LVI (OR, 8.877; 95% CI: 3.861–20.410; P<0.001) were independent predictive risk factors of LNM in EGC in women. Submucosal invasion and LVI were risk factors of LNM in both men and women. However, elevated and undifferentiated types were risk factors in men but not in women. Clinicians should consider these sex-specific differences with regard to individualized management.

Increased circulating levels of vascular endothelial growth factor C can predict outcome in resectable gastric cancer patients

Background

Neoangiogenesis has proven to be a relevant pathogenetic mechanism in gastric cancer (GC) and lymphatic spread represents an important well-known prognostic factor. Vascular endothelial growth factor C (VEGF-C) plays a key role in lymphangiogenesis and its blood levels in GC patients are easily measurable. This analysis aimed to investigate the prognostic role of preoperative VEGF-C blood levels.

Methods

VEGF-C serum levels were determined by enzyme-linked immunoadsorbent assay (ELISA) in 186 patients observed at our institution from January 2004 until December 2009 and 82 healthy subjects. Statistical analyses were performed using SPSS 21.0.

Results

VEGF-C levels were significantly higher in GC patients (median: 287.4 pg/mL; range, 76.2-865.2 pg/mL) than in the control group (median VEGF-C: 31 pg/mL; range, 12-97 pg/mL). A significant correlation between VEGF-C levels, T, N and tumor stage has been described. The median overall survival (OS) was statistically significantly higher in pts with low serum VEGF-C levels [median: not reached (NR) vs. 26 months; P<0.0001]. Higher preoperative VEGF-C levels correlated also with earlier disease relapse and poor disease-free survival (DFS) (median NR in each subgroup, P=0.005). Furthermore, high VEGF-C levels [hazard ratio (HR) =2.7; P=0.018] and tumor grading (HR =0.44; P=0.007) were independent prognostic factors for OS at multivariate analysis.

Conclusions

Our study showed that increased VEGF-C levels are significantly associated with advanced regional lymph node involvement and poor OS and DFS in pts with resected GC paving the way to a possible application as prognostic factor in the clinical practice.

Lymph node metastasis in differentiated-type early gastric cancer: a single-center retrospective analysis of surgically resected cases

BACKGROUND

Lymph node metastasis (LNM) from early gastric cancer (EGC) is rare, especially for differentiated-type EGC. However, LNM has been reported in a few cases after endoscopic curative resection of differentiated-type EGC. This study aimed to evaluate LNM risk factors to identify those that should be considered during the preoperative evaluation of differentiated-type EGC.

PATIENTS AND METHODS

A total of 976 EGC patients who underwent radical gastrectomy were reviewed in this study. Univariate and multivariate analyses were used to analyze the predictive factors for LNM based on the histology of the differentiated-type EGC cases.

RESULTS

Differentiated-type EGC was observed in 59% of the cases. The rate of LNM was 6.6% (38/576 patients) in the differentiated-type EGC cases. Macroscopic shape, ulcers, tumor size, deeper invasion and lymphovascular invasion were shown to be related to LNM in differentiated-type EGC. Multivariate analysis revealed that size, depth, ulceration and lymphovascular invasion were independent predictors of LNM in differentiated-type EGC. When lymphovascular invasion was absent, the presence of one or more of the risk factors of ulcer lesions, tumor size >30 mm and submucosal invasion increased the rate of LNM. Thirteen patients who underwent radical gastrectomy were shown to have differentiated-type EGC with LNM that met the standard and expanded criteria of endoscopic submucosal dissection.

CONCLUSIONS

As endoscopic resection is widely used, it is important to clarify the clinical significance of LNM in differentiated-type EGC and to screen for LNM with this incidence in mind and to follow the clinical courses of such cases, especially in China.

HER2 Status in Premalignant, Early, and Advanced Neoplastic Lesions of the Stomach

Objectives. HER2 expression in gastric cancer (GC) has received attention as a potential target for therapy with Trastuzumab. We reviewed the current knowledge on HER2 status in premalignant gastric lesions and in early (EGC) and advanced (AGC) GC to discuss the possible pathogenetic and prognostic roles of HER2 overexpression in GC. Results. HER2 overexpression was documented in gastric low-grade (LG) and high-grade intraepithelial neoplasia (HG-IEN), with higher frequency in gastric type dysplasia. HER2 overexpression was significantly associated with disease recurrence and poor prognosis in EGC representing an independent risk factor for lymph node metastases. HER2 overexpression was more frequent in AGC characterized by high grade, advanced stage, and high Ki-67 labeling index. The discordance in HER2 status was evidenced between primitive GC and synchronous or metachronous metastases. Conclusions. HER2 overexpression in premalignant gastric lesions suggests its potential involvement in the early steps of gastric carcinogenesis. The assessment of HER2 status in EGC may be helpful for the identification of patients who are at low risk for developing nodal metastases. Finally, the possible discordance in HER2 status between primary GC and its synchronous metastases support routine assessment of HER2 both in the primary GC and in its metastatic lesions.

Lymph node metastasis in early gastric cancer

OBJECTIVE: to evaluate the incidence of lymph node metastasis in early gastric cancer, identifying risk factors for its development. METHODS: we conducted a prospective study of patients with gastric cancer admitted to the Section of the Esophago-Gastric Surgery of the Surgery of Service HUCFF-UFRJ, from January 2006 to May 2012. RESULTS: the rate of early gastric cancer was 16.3%. The incidence of nodal metastases was 30.8% and occurred more frequently in patients with tumors with involvement of the submucosa (42.9%), in those poorly differentiated (36.4%), in tumors larger than 2 cm (33.3%) and in type III ulcerated lesions (43.8%). CONCLUSION: the incidence of lymph node metastases in patients was very high and suggests that one should keep the radicality of resection in early gastric cancer, particularly in relation to D2 lymphadenectomy, recommended for advanced gastric cancer. Conservative resections, with lymphadenectomies smaller than D2, should be performed only in selected cases, well-studied as for the risk factors of lymph node metastasis. Despite the small number of cases did not permit to relate the rate of lymph node metastasis to the risk factors considered, we noted a strong tendency for the occurrence of these metastases in the poorly differentiated, type III, larger than 2 cm tumors, and in the Lauren diffuse types.

Minor gastric resections with modified lymphadenectomy in early gastric cancer with negative sentinel node

OBJECTIVE

To study the sentinel lymph node in early gastric cancer as a diagnostic method of unsuspected lymph node metastasis, which may allow the performance, in those with negative lymph nodes, of smaller gastric resections with limited lymphadenectomy.

METHODS

We studied seven patients with early gastric cancer treated at the Hospital Universitário Clementino Fraga Filho, Federal University of Rio de Janeiro, from September 2008 to May 2011, who underwent sentinel lymph node exams, performed by intraoperative peritumoral endoscopic injection of patent blue dye.

RESULTS

We found an average of three sentinel nodes per patient. The frozen biopsy of lymph nodes was negative for metastases, which allowed the realization of atypical gastric resection in three cases and antrectomy with BI reconstruction in four. The performed lymphadenectomy was modified D1. There was no operative mortality. The duration of postoperative follow-up ranged from five to 37 months, without evidence of recurrence. One patient developed a second early tumor 13 months after the initial surgery and underwent total gastrectomy.

CONCLUSION

The sentinel lymph node in early gastric cancer proved to be an effective method for the evaluation of nodal metastases in seven patients and allowed for smaller gastric resections and limited lymphadenectomies. These minor procedures reduce the risk of postoperative complications, maintaining, on the other hand, the oncological radicality that is required in the treatment of gastric cancer.

Lymphatic invasion in small differentiated-type mucosal gastric cancer

Endoscopic resection for early gastric cancer is indicated for patients who are at negligible risk of lymph node metastasis. A 71-year-old female underwent endoscopic resection for a 15-mm differentiated-type mucosal gastric tumor, as recommended in the Japanese treatment guidelines. A histological examination revealed lymphatic invasion. Therefore, we performed laparoscopy-assisted distal gastrectomy and D1+ lymph node dissection. A histological examination detected no.3 lymph node metastasis, but no residual cancer cells were observed at the site of the endoscopic resection. This case is rare as lymphatic invasion and lymph node metastasis are highly unusual in small differentiated-type mucosal gastric cancer. Having experienced this case, we consider that en-bloc endoscopic resection of such lesions is extremely important, as it allows precise histological examinations to be performed, which can determine the necessity of additional treatment.

Clinical significance of the pattern of lymph node metastasis depending on the location of gastric cancer

Purpose

When performing a laparoscopic assisted gastrectomy, a function-preserving gastrectomy is performed depending on the location of the primary gastric cancer. This study examined the incidence of lymph node metastasis by the lymph node station number by tumor location to determine the optimal extent of the lymph node dissection.

Materials and Methods

The subjects consisted of 1,510 patients diagnosed with gastric cancer who underwent a gastrectomy between 1996 and 2005. The patients were divided into three groups: upper, middle and lower third, depending on the location of the primary tumor. The lymph node metastasis patterns were analyzed in the total and early gastric cancer patients.

Results

In all patients, lymph node station numbers 1, 2, 3, 7, 10 and 11 metastases were dominant in the cancer originating in the upper third, whereas station numbers 4, 5, 6 and 8 were dominant in the lower third. In early gastric cancer patients, the station number of lymph nodes with a metastasis did not show a significant difference in stage pT1a disease. On the other hand, a metastasis in lymph node station number 6 was dominant in stage pT1b disease that originated in the lower third of the stomach.

Conclusions

When performing a laparoscopic-assisted gastrectomy for early gastric cancer, a limited lymphadenectomy is considered adequate during a function-preserving gastrectomy in mucosal (T1a) cancer. On the other hand, for submucosal (T1b) cancer, a number 6 node dissection should be performed when performing a pylorus preserving gastrectomy.

Treatment strategy for early gastric cancer

Gastric cancer ranks the second leading cause of cancer-specific mortality worldwide. With a poor prognosis, 5-year survival rate of gastric cancer is less than 20%-25% in the USA, Europe, and China [1]. However, early gastric cancer(EGC) offers an excellent (over 90%) chance of cure based on surgical resection [2]. As the increasing detection of EGC, more treatment options have been developed both curatively and minimally invasively to maintain a good quality of life(QOL). One of the advanced therapeutic techniques is endoscopic dissection. Improvements in surgical treatment include minimizing lymph node dissection, reconstruction methods, laparoscopy-assisted surgery, and sentinel node navigation surgery(SNNS) [3]. With technological advances, even Natural Orifice Transluminal Endoscopy Surgery (NOTES) and robotic surgery are expected to represent the next revolution [4]. However, there still remains much dispute among these treatments, which arouses further clinical trials to verify. Update of the treatments, controversial indications, prognosis and current strategies for EGC are discussed in this review.