International consensus on the management of metastatic gastric cancer: step by step in the foggy landscape : Bertinoro Workshop, November 2022

BACKGROUND

Many gastric cancer patients in Western countries are diagnosed as metastatic with a median overall survival of less than twelve months using standard chemotherapy. Innovative treatments, like targeted therapy or immunotherapy, have recently proved to ameliorate prognosis, but a general agreement on managing oligometastatic disease has yet to be achieved. An international multi-disciplinary workshop was held in Bertinoro, Italy, in November 2022 to verify whether achieving a consensus on at least some topics was possible.

METHODS

A two-round Delphi process was carried out, where participants were asked to answer 32 multiple-choice questions about CT, laparoscopic staging and biomarkers, systemic treatment for different localization, role and indication of palliative care. Consensus was established with at least a 67% agreement.

RESULTS

The assembly agreed to define oligometastases as a "dynamic" disease which either regresses or remains stable in response to systemic treatment. In addition, the definition of oligometastases was restricted to the following sites: para-aortic nodal stations, liver, lung, and peritoneum, excluding bones. In detail, the following conditions should be considered as oligometastases: involvement of para-aortic stations, in particular 16a2 or 16b1; up to three technically resectable liver metastases; three unilateral or two bilateral lung metastases; peritoneal carcinomatosis with PCI ≤ 6. No consensus was achieved on how to classify positive cytology, which was considered as oligometastatic by 55% of participants only if converted to negative after chemotherapy.

CONCLUSION

As assessed at the time of diagnosis, surgical treatment of oligometastases should aim at R0 curativity on the entire disease volume, including both the primary tumor and its metastases. Conversion surgery was defined as surgery on the residual volume of disease, which was initially not resectable for technical and/or oncological reasons but nevertheless responded to first-line treatment.

Omentectomy as part of radical surgery for gastric cancer: 5-year follow-up results of a multicenter prospective cohort study

INTRODUCTION

Curative therapy for gastric cancer usually consists of perioperative chemotherapy combined with a radical (R0) gastrectomy. In addition to a modified D2-lymphadenectony, a complete omentectomy is recommended. However, there is little evidence for a survival benefit of omentectomy. This study presents the follow-up data of the OMEGA-study.

METHODS

This multicenter prospective cohort study included 100 consecutive patients with gastric cancer undergoing (sub)total gastrectomy with complete en bloc omentectomy and modified D2 lymphadenectomy. Primary outcome of the current study was five-year overall survival. Patients with or without omental metastases were compared. Pathological factors associated with locoregional recurrence and/or metastases were tested with multivariable regression analysis.

RESULTS

Of 100 included patients, five had metastases in the greater omentum. Five-year overall survival was 0.0% in patients with omental metastases and 44.2% in patients without omental metastases (p=0.001). Median overall survival time for patients with or without omental metastases was seven months and 53 months. A (y)pT3-4 stage tumor and vasoinvasive growth were associated with locoregional recurrence and/or metastases in patients without omental metastases.

CONCLUSION

The presence of omental metastases in gastric cancer patients who underwent potentially curative surgery was associated with impaired overall survival. Omentectomy as part of radical gastrectomy for gastric cancer might not contribute to a survival benefit in case of undetected omental metastases.

The impact of paratracheal lymphadenectomy on lymph node yield and short-term outcomes in esophagectomy for cancer: a nation-wide propensity score matched analysis

INTRODUCTION

The balance between potential oncological merits and surgical risks is unclear for the additional step of performing paratracheal lymphadenectomy during esophagectomy for cancer. This study aimed to investigate the impact of paratracheal lymphadenectomy on lymph node yield and short-term outcomes in patients who underwent this procedure in The Netherlands.

METHODS

Patients who underwent neoadjuvant chemoradiotherapy followed by transthoracic esophagectomy were included from the Dutch Upper Gastrointestinal Cancer Audit (DUCA). After propensity score matching Ivor Lewis and McKeown approaches separately, lymph node yield and short-term outcomes were compared between patients who underwent paratracheal lymphadenectomy versus patients who did not.

RESULTS

Between 2011-2017, 2128 patients were included. Some 770 patients (n=385 vs. n=385) and 516 patients (n=258 vs. n=258) were matched for the Ivor Lewis and McKeown approaches, respectively. Paratracheal lymphadenectomy was associated with a higher lymph node yield in Ivor Lewis (23 vs. 19 nodes, P<0.001) and McKeown (21 vs. 19 nodes, P=0.015) esophagectomy. There were no significant differences in complications or mortality. After Ivor Lewis esophagectomy, paratracheal lymphadenectomy was associated with longer length of stay (12 vs. 11 days, P<0.048). After McKeown esophagectomy, paratracheal lymphadenectomy was associated more re-interventions (30% vs. 18%, P=0.002).

CONCLUSIONS

Paratracheal lymphadenectomy resulted in a higher lymph node yield, but also in longer length of stay after Ivor-Lewis and more re-interventions following McKeown esophagectomy.

Blood-borne assessment of stromal activation in esophageal adenocarcinoma to guide tocilizumab therapy: A randomized phase II proof-of-concept study (NCT04554771)

TPS4166

Background: The tumor stroma is increasingly acknowledged to harbor tumor-promoting properties. Recently, we found that stroma activity measured by serum ADAM12 predicts response to chemoradiation in esophageal adenocarcinoma (Veenstra et al., Oncogenesis, 2018). Preclinically, the esophageal adenocarcinoma stroma was found to produce interleukin 6, which causes epithelial-to-mesenchymal transition of tumor cells. These mesenchymal tumor cells have a poor response to chemoradiation (Ebbing et al., PNAS, 2019). Therefore, stroma-derived interleukin 6 provides a potential new target to improve the treatment of esophageal adenocarcinoma. Tocilizumab is an interleukin 6 receptor inhibitor clinically used in rheumatoid arthritis and cytokine-release syndrome. In this phase II proof-of-concept clinical trial, we aim to demonstrate that stroma-targeting by tocilizumab in esophageal adenocarcinoma patients with highly activated stroma increases efficacy of chemoradiation measured by pathological response according to the Mandard criteria. Methods: BASALT is a multi-center, randomized, open-label phase II proof-of-concept clinical trial in patients with surgically resectable adenocarcinoma of the esophagus or gastroesophageal junction (NCT04554771). To assess efficacy of tocilizumab in addition to chemoradiation, 48 patients will be grouped for serum ADAM12 level with a cutoff of 203 pg/mL. Patients are then randomized in a 1:1:1:1 ratio to receive three cycles of tocilizumab every two weeks in addition to paclitaxel, carboplatin and radiation (Table). The sample size is based on the rule-of thumb estimate of 12 patients per arm. Tocilizumab will be given intravenously at a dose of 8 mg/kg with a maximum of 800 mg per dose. Efficacy will be assessed by pathological response to chemoradiation according to the Mandard criteria. Secondary endpoints are overall and progression free survival, safety and toxicity, feasibility and efficacy of interleukin 6 inhibition with serum interleukin 6 levels, immunohistochemistry and RNA-sequencing. Currently, 28 out of the 48 planned patients have been enrolled. Clinical trial information: NCT04554771. [Table: see text]

Circulating tumor DNA (ctDNA) analysis by low-coverage whole genome sequencing (lcWGS) of resectable esophageal adenocarcinoma (rEAC) patients

4033

Background: ctDNA is becoming an established marker to assess tumor burden, relapse after surgery, and to identify responders in immunotherapy studies. In the phase II PERFECT trial rEAC patients were treated with neoadjuvant chemoradiotherapy (nCRT) and a PD-L1 inhibitor (van den Ende et al. CCR. 2021). Here we evaluated the potential of cell-free DNA (cfDNA) to predict pathological complete response (pCR) and recurrence. Methods: The cohort consisted of 40 patients and 145 plasma samples. EDTA blood samples were drawn at baseline (B, N = 40), in week 5 of nCRT (W5, N = 40), before surgery (OR, N = 33) and 3 months after surgery (FU, N = 32). cfDNA was isolated by affinity columns (CNAkit, QIAgen) quantified by spectrofluorometer (BioAnalyzer, Agilent), sequencing libraries were prepared for lcWGS ( < 5-fold coverage, Tag-seq, Takara) and sequenced on a NovaSeq (S4, PE150). Sequencing data were processed with an in-house pipeline. Copy number aberrations (CNA) and the tumor fraction were estimated using the ichorCNA tool. Insert sizes were recovered and we determined a Tumor Enriched Fragment Fraction (TEFF), calculated by doing the ratio of fragments between 90-150 bp and 250-320 bp (enriched in tumor signal) and fragments between 150-250 bp and 320-360 bp (poor in tumor signal). ichorCNA and TEFF were used to quantify the ctDNA fraction in plasma samples. pCR was defined as ypT0N0. Residual tumor, progression or death before surgery were considered non-pCR. Relapse-free survival (RFS) was defined as the time after surgery until recurrence. Results: The pCR rate was 25% (10/40). The median fold change TEFF between B and W5 was -0.15 (range -0.67 to 0.44) in the pCR group and 0.16 (range -1.40 to 0.76) in the non-pCR group (Mann–Whitney U; p = 0.047). Of the 17 patients in whom ctDNA was detected (TEFF≥0.3 and/or ichorCNA≥0.03) in the FU sample, 13 (76%) showed a recurrence. Of the 15 patients with no ctDNA detected 5 (33%) showed a recurrence. Patients with ctDNA detected at FU had worse RFS, HR = 2.72 (95%CI 0.96-7.71; p = 0.050). Recurrences were detected earlier by FU ctDNA than by imaging due to physical complaints with a median of 312 days (163-798 days). Conclusions: lcWGS appears to be a useful tool to predict pCR and recurrence in resectable esophageal cancer. These lcWGS results will be further combined with fragmentomics analysis and targeted mutational data (Ion Torrent next-generation sequencing) in order to assess response to immunotherapy. Clinical trial information: NCT03087864.

Treatment patterns and overall survival for recurrent esophageal or gastroesophageal junctional cancer: A nationwide European population-based study

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Background: Esophageal cancer has a high risk for recurrence after treatment with curative intent. This study describes the characteristics of patients with esophageal or gastroesophageal junctional cancer at the time of recurrence, treatment patterns and overall survival (OS) after recurrence. Methods: Patients selected from the nationwide Netherlands cancer registry had received a primary diagnosis of non-metastatic squamous cell carcinoma or adenocarcinoma of esophagus or gastroesophageal junction in 2015 or 2016 and experienced recurrence after primary treatment with curative intent. Curative intent was defined as receiving resection (with or without [neo]adjuvant therapy) or definitive chemoradiotherapy (dCRT) without surgery. Recurrence within or after six months was calculated from resection date or end of dCRT. OS was calculated from recurrence and analysed using Kaplan-Meier curves with Log-Rank test. Results: We identified 856 patients who presented with disease recurrence after potentially curative treatment with resection (75%) or dCRT (25%). At recurrence, the majority of patients were male (78%),the median age was 68 years and 77% of patients had adenocarcinoma. Twenty-six percent of patients had disease recurrence within six months after curative treatment. Eighteen percent of patients had locoregional recurrence only, 48% distant recurrence only and 33% both locoregional and distant recurrence. Among patients with a distant recurrence, 37% had metastases in non-regional lymph nodes, 31% in the liver and 30% in the lung. After disease recurrence, 29% of patients received systemic therapy (chemo- or targeted therapy), 5% chemoradiotherapy, 1% surgery and 66% best supportive care only. The most common systemic treatment regimen was CapOx/FOLFOX (54%) and13% of patients received a targeted agent: trastuzumab containing regimen (n = 26) or paclitaxel and ramucirumab (n = 5). Among all patients, the median OS from date of recurrence was 4.4 months. Patients with recurrence within six months had a poorer median survival (2.1 months) compared to patients with recurrence after six months (5.7 months; p < 0.001). Median OS in patients with locoregional recurrence only was 7.4 months, distant recurrence only was 4.0 months, and both locoregional and distant recurrence was 3.4 months (p < 0.001). Patients with prior primary treatment with resection had median OS of 4.2 months and patients with prior dCRT of 5.1 months (p = 0.605). Conclusions: The majority of patients had distant metastases at disease recurrence and a small proportion received systemic therapy after recurrence. Overall prognosis was poor, and survival outcomes were poorest among patients with recurrence within six months of initial curative treatment suggesting a worse biological tumor behaviour.

Disease-free and overall survival in nonmetastatic esophageal or gastroesophageal junctional cancer after treatment with curative intent: A nationwide population-based study

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Background: Among patients with potentially curable esophageal cancer (EC) or gastroesophageal junctional cancer (GEJC) treated with curative intent, survival remains poor and around half of these patients have disease recurrence within a few years. This study addresses the need for real-world data on disease-free survival (DFS) and overall survival (OS) in patients with EC or GEJC who underwent potentially curative treatment. Methods: Patients selected from the nationwide Netherlands cancer registry (NCR) had received a primary diagnosis of non-metastatic EC or GEJC (excluding patients with T4b tumors) in 2015 or 2016 and received treatment with curative intent. Curative intent was defined as receiving resection (with or without [neo]adjuvant therapy) or definitive chemoradiotherapy (dCRT) without surgery. DFS and OS were analysed using Kaplan-Meier curves with Log-Rank test from resection date or end of dCRT. A sub-analysis was performed for NCR patients selected to align with the population of the CheckMate-577 phase 3 study of adjuvant nivolumab, i.e. patients with non-cervical stage II/III disease, R0 resection and residual pathological disease after neoadjuvant CRT (nCRT) and surgery. Results: We identified 1916 patients of median age of 67 years and predominantly male (76%). The majority (79%) received surgery and 21% of patients received dCRT. In resected patients, 83% received nCRT, 10% neoadjuvant chemotherapy (with or without adjuvant CRT) and 7% received no (neo)adjuvant treatment. Compared to the resected group, the population receiving dCRT had significantly fewer males (65% vs 78%), a higher median age (72 vs 65 years) and worse performance status. Patients receiving dCRT significantly shorter median DFS (14.2 months) and OS (20.9 months) compared to resected patients (DFS: 26.4 months, p < 0.001; OS: 40.5 months, p < 0.001). The 1- and 3-year DFS probabilities were 68% and 44%, respectively, in resected patients, and 56% and 24%, respectively, in patients receiving dCRT. In patients receiving nCRT followed by surgery, the median DFS and OS were 25.2 and 38.0 months, respectively, and 1- and 3-year DFS probabilities were 67% and 43%, respectively. In the sub-analysis (n = 725) the median DFS and OS were 19.2 and 29.4 months, respectively, and the 1- and 3-year DFS rates were 62% and 36%, respectively. Conclusions: Although patients are treated with curative intent, a considerable amount of patients with non-metastatic EC or GEJC experienced recurrence within two years. Resected patients had a higher DFS and OS compared to patients receiving dCRT.

Transthoracic Versus Transhiatal Esophagectomy for Esophageal Cancer: A Nationwide Propensity Score-Matched Cohort Analysis

Background

Chemoradiation followed by resection has been the standard therapy for resectable (cT1-4aN0-3M0) esophageal carcinoma in the Netherlands since 2010. The optimal surgical approach remains a matter of debate. Therefore, the purpose of this study was to compare the transhiatal and the transthoracic approach concerning morbidity, mortality and oncological quality.

Methods

Data was acquired from the Dutch Upper GI Cancer Audit. Patients who underwent esophagectomy with curative intent and gastric tube reconstruction for mid/distal esophageal or esophagogastric junction carcinoma (cT1-4aN0-3M0) from 2011 to 2016 were included. Patients who underwent a transthoracic and transhiatal esophagectomy were compared after propensity score matching.

Results

After propensity score matching, 1532 of 4143 patients were included for analysis. The transthoracic approach yielded more lymph nodes (transthoracic median 19, transhiatal median 14; p < 0.001). There was no difference in the number of positive lymph nodes, however, the median (y)pN-stage was higher in the transthoracic group (p = 0.044). The transthoracic group experienced more chyle leakage (9.7% vs. 2.7%, p < 0.001), more pulmonary complications (35.5% vs. 26.1%, p < 0.001), and more cardiac complications (15.4% vs. 10.3%, p = 0.003). The transthoracic group required a longer hospital stay (median 14 vs. 11 days, p < 0.001), ICU stay (median 3 vs. 1 day, p < 0.001), and had a higher 30-day/in-hospital mortality rate (4.0% vs. 1.7%, p = 0.009).

Conclusions

In a propensity score-matched cohort, the transthoracic esophagectomy provided a more extensive lymph node dissection, which resulted in a higher lymph node yield, at the cost of increased morbidity and short-term mortality.