Background
The relation between gastric cancer characteristics and lymph node (LN) metastatic patterns is not fully clear, especially following neoadjuvant chemotherapy (NAC). This study analyzed ...nodal metastatic patterns.
Methods
Individual LN stations were analyzed for all patients from the LOGICA-trial, a Dutch multicenter randomized trial comparing laparoscopic versus open D2-gastrectomy for gastric cancer. The pattern of metastases per LN station was related to tumor location, cT-stage, Lauren classification and NAC.
Results
Between 2015–2018, 212 patients underwent D2-gastrectomy, of whom 158 (75%) received NAC. LN metastases were present in 120 patients (57%). Proximal tumors metastasized predominantly to proximal LN stations (no. 1, 2, 7 and 9;
p
< 0.05), and distal tumors to distal LN stations (no. 5, 6 and 8; OR > 1,
p
> 0.05). However, distal tumors also metastasized to proximal LN stations, and vice versa. Despite NAC, each LN station (no. 1–9, 11 and 12a) showed metastases, regardless of tumor location, cT-stage, histological subtype and NAC treatment, including station 12a for cT1N0-tumors. LN metastases were present more frequently in diffuse versus intestinal tumors (66% versus 52%;
p
= 0,048), but not for cT3–4- versus cT1–2-stage (59% versus 51%;
p
= 0.259). However, the pattern of LN metastases was similar for these subgroups.
Conclusions
The extent of lymphadenectomy cannot be reduced after NAC for gastric cancer. Although the pattern of LN metastases is related to tumor location, all LN stations contained metastases regardless of tumor location, cT-stage (including cT1N0-tumors), histological subtype, or NAC treatment. Therefore, D2-lymphadenectomy should be routinely performed during gastrectomy in Western patients.
To improve identification of peritoneal and distant metastases in locally advanced gastric cancer using
FFDG-PET radiomics.
FFDG-PET scans of 206 patients acquired in 16 different Dutch hospitals ...in the prospective multicentre PLASTIC-study were analysed. Tumours were delineated and 105 radiomic features were extracted. Three classification models were developed to identify peritoneal and distant metastases (incidence: 21%): a model with clinical variables, a model with radiomic features, and a clinicoradiomic model, combining clinical variables and radiomic features. A least absolute shrinkage and selection operator (LASSO) regression classifier was trained and evaluated in a 100-times repeated random split, stratified for the presence of peritoneal and distant metastases. To exclude features with high mutual correlations, redundancy filtering of the Pearson correlation matrix was performed (r = 0.9). Model performances were expressed by the area under the receiver operating characteristic curve (AUC). In addition, subgroup analyses based on Lauren classification were performed.
None of the models could identify metastases with low AUCs of 0.59, 0.51, and 0.56, for the clinical, radiomic, and clinicoradiomic model, respectively. Subgroup analysis of intestinal and mixed-type tumours resulted in low AUCs of 0.67 and 0.60 for the clinical and radiomic models, and a moderate AUC of 0.71 in the clinicoradiomic model. Subgroup analysis of diffuse-type tumours did not improve the classification performance.
Overall,
FFDG-PET-based radiomics did not contribute to the preoperative identification of peritoneal and distant metastases in patients with locally advanced gastric carcinoma. In intestinal and mixed-type tumours, the classification performance of the clinical model slightly improved with the addition of radiomic features, but this slight improvement does not outweigh the laborious radiomic analysis.
Quality of gastric cancer surgery is crucial for favorable prognosis. Generally, prospective trials lack quality control measures. This study assessed surgical quality and a novel D2-lymphadenectomy ...photo-scoring in the LOGICA-trial.
The multicenter LOGICA-trial randomized laparoscopic versus open total/distal D2-gastrectomy for resectable gastric cancer (cT1-4aN0-3M0) in 10 Dutch hospitals. During the trial, two reviewers prospectively analyzed intraoperative photographs of dissected nodal stations for quality control, and provided centers weekly feedback on their D2-lymphadenectomy, as continuous quality-enhancing incentive. After the trial, these photographs were reanalyzed to develop a photo-scoring for future trials, rating the D2-lymphadenectomy dissection quality (optimal-good-suboptimal-unevaluable). Interobserver variability was calculated (weighted kappa). Regression analyses related the photo-scoring to nodal yield, recurrence and 5-years survival.
Between 2015 and 2018, 212 patients underwent total/distal D2-gastrectomy (n = 122/n = 90), and 158 (75%) received neoadjuvant chemotherapy. R0-resection rate was 95%. Rate of ≥15 retrieved lymph nodes was 95%. Moderate agreement was obtained in stations 8 + 9 (κ = 0.522), 11p/11d (κ = 0.446) and 12a (κ = 0.441). Consensus was reached for discordant cases (30%). Stations 8 + 9, 11p/11d and 12a were rated ‘optimal’ in 76%, 63% and 68%. Laparoscopic photographs could be rated better than open (2% versus 12% ‘unevaluable’; 73% versus 50% ‘optimal’; p = 0.042). The photo-scoring did not show associations with nodal yield (p = 0.214), recurrence (p = 0.406) and survival (p = 0.988).
High radicality and nodal yield demonstrated good quality of D2-gastrectomy. The prospective quality control probably contributed to this. The photo-scoring did not show good performance, but can be refined. Laparoscopic D2-gastrectomy was better suited for standardized surgical photo-evaluation than open surgery.
Complications can be classified using the most-severe Clavien-Dindo-Classification (CDC) per patient or the total complication burden per patient expressed in the Comprehensive Complication Index ...(CCI). This study determined the additional value of CCI to CDC in examining the impact of complications after gastric cancer surgery.
The CCI and CDC were determined in the multicenter randomized LOGICA-trial comparing laparoscopic versus open D2-gastrectomy for cancer (cT1-4aN0-3M0). Differences in median CCI between laparoscopic and open gastrectomy were compared for overall postoperative complications and cardiovascular, gastrointestinal, infectious, pulmonary, and other complications. CCI and CDC were correlated to hospitalization, ICU-stay and reoperations using Spearman's rho-test and compared with standard Fisher's z-transformation.
Between 2015 and 2018, 211 patients underwent laparoscopic (n = 106) or open (n = 105) D2-gastrectomy, and 157 (74%) received neoadjuvant chemotherapy. Median CCI was comparable between laparoscopic versus open gastrectomy regarding overall complications (CCI 0 IQR 0-23.5 versus 0 IQR 0-22.6; p = 0.755) and subgroups of complications (p > 0.05). Both CCI and CDC showed moderate positive correlations for hospitalization (r
= 0.646 versus r
= 0.628; p = 0.001, difference clinically irrelevant), and reoperations (r
= 0.590 versus r
= 0.599; p = 0.070), and weak correlations for ICU-stay (r
= 0.446 versus r
= 0.440; p = 0.189).
The CCI is a composite scoring system based on the CDC and reflects a subjective interpretation of complication burden from the perspectives of both physicians and patients, following abdominal surgery other than gastrectomy. Implementing CCI showed no clinically relevant benefit and caused additional workload compared to CDC for assessing complication burden. Therefore, using the CCI alongside the CDC after gastric cancer surgery is not recommended.
Staging laparoscopy is a common diagnostic tool in gastric cancer, but its performance varies widely. The aim of this study was to gain Dutch nationwide consensus regarding the indications for and ...execution of staging laparoscopy in patients with gastric cancer.
All surgeons in the Netherlands specialized in gastric cancer surgery (n = 52) were asked to participate in a Delphi consensus study. The study involved an initial questionnaire with a 3-point Likert scale, an online consensus meeting, and a second questionnaire using a 2-point Likert scale (agree/disagree). Consensus was defined as 70% or more agreement among participants.
In total, 45 experts completed both questionnaires (87% response rate). Consensus was reached on the indication to perform staging laparoscopy in cT3-4 or cN + or diffuse-type gastric cancer, including Siewert type III oesophagogastric junctional cancer. The experts agreed that if preoperative scans suggest infiltration of surrounding organs (cT4), the tumour's resectability should explicitly be investigated. Consensus was also reached for a systematic peritoneal cavity inspection according to Sugarbaker's Peritoneal Cancer Index (PCI) score. All regions should be inspected routinely, although the omental bursa may be inspected on indication. Aspiration of ascites or peritoneal washing should be performed for cytology. The experts agreed that restaging laparoscopy should be performed before resection in case of progressive disease on preoperative imaging. Without progression, global inspection was considered sufficient.
The results of this Dutch nationwide Delphi consensus study exposed the variability of performing staging laparoscopy in patients with gastric cancer and provided the concept for a standardized protocol.
Patients with locally advanced gastric cancer have a five-year survival rate of 36-45% after curatively intended D2-gastrectomy combined with perioperative chemotherapy. This relatively poor survival ...is mainly due to recurrence of the disease. The aim of this study was to improve detection of peritoneal and distant metastases on sup.18FFDG-PET images in patients with advanced gastric cancer using radiomics. Radiomics consists of the extraction of large amounts of quantitative features from medical imaging and the subsequent mining of this dataset for potential information to monitor disease characteristics in clinical practice. Three classification models were developed to determine the added value of radiomics: a model with clinical variables only, a model with radiomic features only, and a clinicoradiomic model, combining clinical variables and radiomic features. sup.18FFDG-PET-based radiomics showed no additional value in predicting peritoneal and distant metastases in locally advanced gastric cancer patients. Aim: To improve identification of peritoneal and distant metastases in locally advanced gastric cancer using sup.18FFDG-PET radiomics. Methods: sup.18FFDG-PET scans of 206 patients acquired in 16 different Dutch hospitals in the prospective multicentre PLASTIC-study were analysed. Tumours were delineated and 105 radiomic features were extracted. Three classification models were developed to identify peritoneal and distant metastases (incidence: 21%): a model with clinical variables, a model with radiomic features, and a clinicoradiomic model, combining clinical variables and radiomic features. A least absolute shrinkage and selection operator (LASSO) regression classifier was trained and evaluated in a 100-times repeated random split, stratified for the presence of peritoneal and distant metastases. To exclude features with high mutual correlations, redundancy filtering of the Pearson correlation matrix was performed (r = 0.9). Model performances were expressed by the area under the receiver operating characteristic curve (AUC). In addition, subgroup analyses based on Lauren classification were performed. Results: None of the models could identify metastases with low AUCs of 0.59, 0.51, and 0.56, for the clinical, radiomic, and clinicoradiomic model, respectively. Subgroup analysis of intestinal and mixed-type tumours resulted in low AUCs of 0.67 and 0.60 for the clinical and radiomic models, and a moderate AUC of 0.71 in the clinicoradiomic model. Subgroup analysis of diffuse-type tumours did not improve the classification performance. Conclusion: Overall, sup.18FFDG-PET-based radiomics did not contribute to the preoperative identification of peritoneal and distant metastases in patients with locally advanced gastric carcinoma. In intestinal and mixed-type tumours, the classification performance of the clinical model slightly improved with the addition of radiomic features, but this slight improvement does not outweigh the laborious radiomic analysis.
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