External validity of clinical trials with diverse trastuzumab-based chemotherapy regimens in advanced gastroesophageal adenocarcinoma: data from the AGAMENON-SEOM registry.

BACKGROUND: Trastuzumab combined with cisplatin and fluoropyrimidines, either capecitabine or 5-fluorouracile (XP/FP), is the standard first-line treatment for advanced, HER2-positive, gastric cancer patients based on the ToGA trial. Despite the lack of phase III trials, many clinicians administer trastuzumab with alternative regimens. One meta-analysis suggests that substituting cisplatin for oxaliplatin might lead to greater efficacy and less toxicity. METHODS: 594 patients with HER2-positive gastroesophageal adenocarcinoma were recruited from the AGAMENON-SEOM registry. The objective was to evaluate the external validity of clinical trials with chemotherapy and trastuzumab. RESULTS: The regimens used in at least 5% of the patients were XP (27%), oxaliplatin and capecitabine (CAPOX) (26%), oxaliplatin and 5-fluorouracil (FOLFOX) (14%), FP (14%), triplet with anthracycline/docetaxel (7%), and carboplatin-FU (5%). Median exposure to trastuzumab was longer with FOLFOX (11.4 months, 95% CI, 9.1-21.0) versus ToGA regimens (7.5, 6.4-8.5), p < 0.001. Patients with HER2-IHC 3+ cancers had higher response rates than those with IHC 2+/FISH+, odds-ratio 1.97 (95% CI, 1.25-3.09). The results achieved with CAPOX-trastuzumab were comparable to those attained with ToGA regimens. FOLFOX-trastuzumab was superior to ToGA schemes in terms of overall survival (OS), with a greater magnitude of effect in IHC 2+/FISH+ tumors (HR 0.47, 0.24-0.92) compared with IHC 3+ (HR 0.69, 0.49-0.96), and in diffuse (HR 0.37, 0.20-0.69) versus intestinal-type tumors (HR 0.76, 0.54-1.06). CONCLUSION: We have updated the external validity of clinical trials with trastuzumab in first-line treatment of gastric cancer. Our data confirm the comparable outcomes of ToGA regimens and CAPOX-trastuzumab in clinical practice and point toward a possible benefit of FOLFOX-trastuzumab, contingent on the subtypes typically less sensitive to trastuzumab, to be confirmed in clinical trials.

Is advanced esophageal adenocarcinoma a distinct entity from intestinal subtype gastric cancer? Data from the AGAMENON-SEOM Registry.

BACKGROUND: Advanced esophageal adenocarcinoma (EAC) is generally treated similarly to advanced gastroesophageal junction (GEJ-AC) and gastric (GAC) adenocarcinomas, although GAC clinical trials rarely include EAC. This work sought to compare clinical characteristics and treatment outcomes of advanced EAC with those of GEJ-AC and GAC and examine prognostic factors. PATIENTS AND METHODS: Participants comprised patients with advanced EAC, intestinal GEJ-AC, and GAC treated with platin and fluoropyrimidine (plus trastuzumab when HER2 status was positive). Overall and progression-free survival were estimated using the Kaplan-Meier method. Cox proportional hazards regression gauged the prognostic value of the AGAMENON model. RESULTS: Between 2008 and 2019, 971 participants from the AGAMENON-SEOM registry were recruited at 35 centers. The sample included 67.3% GAC, 13.3% GEJ-AC, and 19.4% EAC. Pulmonary metastases were most common in EAC and peritoneal metastases in GAC. Median PFS and OS were 7.7 (95% CI 7.3-8.0) and 13.9 months (12.9-14.7). There was no difference in PFS or OS between HER2- and HER2+ tumors from the three locations (p > 0.05). Five covariates were found to be prognostic for the entire sample: ECOG-PS, histological grade, number of metastatic sites, NLR, and HER2+ tumors treated with trastuzumab. In EAC, the same variables were prognostic except for grade. The favorable prognosis for HER2+ cancers treated with trastuzumab was homogenous for all three subgroups (p = 0.351) and, after adjusting for the remaining covariates, no evidence supported primary tumor localization as a prognostic factor (p = 0.331). CONCLUSION: Our study supports the hypothesis that EAC exhibits clinicopathological characteristics, prognostic factors, and treatment outcomes comparable to intestinal GEJ-AC and GAC.

External validity of docetaxel triplet trials in advanced gastric cancer: are there patients who still benefit?

BACKGROUND: The purpose of our study was to develop an online calculator to estimate the effect of docetaxel triplets (DPF) in first line of advanced gastric cancer (AGC), and to assess the external validity of docetaxel trials in individual patients. METHODS: The study includes patients with HER2(-) AGC treated with platin and fluoropyrimidine (PF) or with DPF in first line. Treatment effect and interactions were assessed using Bayesian accelerated failure time models. RESULT: The series comprises 1376 patients; 238 treated with DPF and 1138 with PF between 2008 and 2019. DPF was associated with increased progression-free survival (PFS) and overall survival (OS) with time ratio (TR) 1.27 (95% credible interval [CrI], 1.15-1.40), and TR 1.19 (95% CrI, 1.09-1.27), respectively. Serious adverse events were more common with DPF, particularly hematological effects (32% vs 22%). Younger participants received greater DPF dose density without achieving greater disease control, while severe toxicity was likewise higher. DPF yielded superior OS in Lauren intestinal (TR 1.27, 95% CrI, 1.08-1.11) vs diffuse subtype (TR 1.17, 95% CrI, 1.09-1.24) and the probability of increasing OS > 15% was 90% vs 67% in each subtype, respectively. The effect dwindles over time, which can be attributed to pathological changes and clinical practice changes. CONCLUSION: Our study confirms the effect of DPF is highly dependent on several clinical-pathological variables, with discreet and gradually declining benefit over platinum doublets in later years, at the expense of increased toxicity. These results may help to underpin the idea that external validity of AGC trials should be revised regularly.

Second-line treatment in advanced gastric cancer: Data from the Spanish AGAMENON registry.

BACKGROUND: Second-line treatments boost overall survival in advanced gastric cancer (AGC). However, there is a paucity of information as to patterns of use and the results achieved in actual clinical practice. MATERIALS AND METHODS: The study population comprised patients with AGC in the AGAMENON registry who had received second-line. The objective was to describe the pattern of second-line therapies administered, progression-free survival following second-line (PFS-2), and post-progression survival since first-line (PPS). RESULTS: 2311 cases with 2066 progression events since first-line (89.3%) were recorded; 245 (10.6%) patients died during first-line treatment and 1326/2066 (64.1%) received a second-line. Median PFS-2 and PPS were 3.1 (95% CI, 2.9-3.3) and 5.8 months (5.5-6.3), respectively. The most widely used strategies were monoCT (56.9%), polyCT (15.0%), ramucirumab+CT (12.6%), platinum-reintroduction (8.3%), trastuzumab+CT (6.1%), and ramucirumab (1.1%). PFS-2/PPS medians gradually increased in monoCT, 2.6/5.1 months; polyCT 3.4/6.3 months; ramucirumab+CT, 4.1/6.5 months; platinum-reintroduction, 4.2/6.7 months, and for the HER2+ subgroup in particular, trastuzumab+CT, 5.2/11.7 months. Correlation between PFS since first-line and OS was moderate in the series as a whole (Kendall's τ = 0.613), lower in those subjects who received second-line (Kendall's τ = 0.539), especially with ramucirumab+CT (Kendall's τ = 0.413). CONCLUSION: This analysis reveals the diversity in second-line treatment for AGC, highlighting the effectiveness of paclitaxel-ramucirumab and, for a selected subgroup of patients, platinum reintroduction; both strategies endorsed by recent clinical guidelines.

Multistate Models: Accurate and Dynamic Methods to Improve Predictions of Thrombotic Risk in Patients with Cancer.

Research into cancer-associated thrombosis (CAT) entails managing dynamic data that pose an analytical challenge. Thus, methods that assume proportional hazards to investigate prognosis entail a risk of misinterpreting or overlooking key traits or time-varying effects. We examined the AGAMENON registry, which collects data from 2,129 patients with advanced gastric cancer. An accelerated failure time (AFT) multistate model and flexible competing risks regression were used to scrutinize the time-varying effect of CAT, as well as to estimate how covariates dynamically predict cumulative incidence. The AFT model revealed that thrombosis shortened progression-free survival and overall survival with adjusted time ratios of 0.72 and 0.56, respectively. Nevertheless, its prognostic effect was nonproportional and disappeared over time if the subject managed to survive long enough. CAT that occurred later had a more pronounced prognostic effect. In the flexible competing risks model, multiple covariates were seen to have significant time-varying effects on the cumulative incidence of CAT (Khorana score, secondary thromboprophylaxis, high tumor burden, and cisplatin-containing regimen), whereas other predictors exerted a constant effect (signet ring cells and primary thromboprophylaxis). The model that assumes proportional hazards was incapable of capturing the effect of these covariates and predicted the cumulative incidence in a biased way. This study evinces that flexible and multistate models are a useful and innovative method to describe the dynamic effect of variables associated with CAT and should be more widely used.

Surgery for metastases for esophageal-gastric cancer in the real world: Data from the AGAMENON national registry.

INTRODUCTION: The effect of surgery for metastases in patients with esophagogastric cancer is unknown, given the lack of randomized clinical trials; likewise, the criteria for selecting eligible patients remain to be determined. METHODS: This registry evaluates the results of patients with advanced adenocarcinoma of the stomach, distal esophagus, or gastro-esophageal junction from 32 centers. To assess selection criteria and prognostic factors, a state arrival extended Markov proportional hazards (PH) model was used. RESULTS: 1792 subjects were analyzed, 5% of whom (n = 92) underwent surgery for metastasis. The most common surgeries were peritoneal (29%), hepatic (24%), and distant lymph nodes (11%). Subjects chosen for metastasectomy had higher survival rates, HR 0.34 (95% CI, 0.06-0.80, p = 0.021). Patients who underwent surgery had a mOS since metastasectomy of 16.7 months (95% CI, 12.5-22.4). The 1- and 3-year relapse rates following R0 resection were 58% and 65%, respectively. Median time since R0 metastasectomy until relapse was 8.4 months (95% CI, 7.6-23.7). The 3-year OS after surgery was 30.6% (95% CI, 19.3-40.4). Duration of chemotherapy prior to surgery (months) increased mortality (HR 1.04 [95% CI, 1.01-1.07]), p = 0.009. The only significant interaction involved the use of anti-HER2 therapy. CONCLUSION: The AGAMENON registry suggests that subjects with limited metastatic disease, selected on a clinical basis, can benefit from early surgeries. Prospective trials are needed to confirm these data.