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.

Lauren subtypes of advanced gastric cancer influence survival and response to chemotherapy: real-world data from the AGAMENON National Cancer Registry.

BACKGROUND: The choice of chemotherapy in HER2-negative gastric cancer is based on centre's preferences and adverse effects profile. No schedule is currently accepted as standard, nor are there any factors to predict response, other than HER2 status. We seek to evaluate whether Lauren type influences the efficacy of various chemotherapies and on patient overall survival (OS). METHODS: We have conducted a multicenter study in 31 hospitals. The eligibility criteria include diagnosis of stomach or gastroesophageal junction adenocarcinoma, HER2 negativity, and chemotherapy containing 2-3 drugs. Cox proportional hazards regression adjusted for confounding factors, with tests of 'treatment-by-histology' interaction, was used to estimate treatment effect. RESULTS: Our registry contains 1303 tumours analysable for OS end points and 730 evaluable for overall response rate (ORR). A decrease in ORR was detected in the presence of a diffuse component: odds ratio 0.719 (95% confidence interval (CI), 0.525-0.987), P=0.039. Anthracycline- or docetaxel-containing schedules increased ORR only in the intestinal type. The diffuse type displayed increased mortality with hazard ratio (HR) of 1.201 (95% CI, 1.054-1.368), P=0.0056. Patients receiving chemotherapy with docetaxel exhibited increased OS limited to the intestinal type: HR 0.65 (95% CI, 0.49-0.87), P=0.024, with no increment in OS for the subset having a diffuse component. With respect to progression-free survival (PFS), a significant interaction was seen in the effect of docetaxel-containing schedules, with better PFS limited to the intestinal type subgroup, in the comparison against any other schedule: HR 0.65 (95% CI, 0.50-0.85), P=0.015, and against anthracycline-based regimens: HR 0.64 (95% CI, 0.46-0.88), P=0.046. CONCLUSIONS: As a conclusion, in this registry, Lauren classification tumour subtypes predicted survival and responded differently to chemotherapy. Future clinical trials should stratify effect estimations based on histology.

Prognostic significance of performing universal HER2 testing in cases of advanced gastric cancer.

BACKGROUND: Trastuzumab significantly improves overall survival (OS) when added to cisplatin and fluoropyrimidine as a treatment for HER2-positive advanced gastric cancers (AGC). The aim of this study was to evaluate the impact of the gradual implementation of HER2 testing on patient prognosis in a national registry of AGC. METHODS: This Spanish National Cancer Registry includes cases who were consecutively recruited at 28 centers from January 2008 to January 2016. The effect of missing HER2 status was assessed using stratified Cox proportional hazards (PH) regression. RESULTS: The rate of HER2 testing increased steadily over time, from 58.3 % in 2008 to 92.9 % in 2016. HER2 was positive in 194 tumors (21.3 %). In the stratified Cox PH regression, each 1 % increase in patients who were not tested for HER2 at the institutions was associated with an approximately 0.3 % increase in the risk of death: hazard ratio, 1.0035 (CI 95 %, 1.001-1.005), P = 0.0019. Median OS was significantly lower at institutions with the highest proportions of patients who were not tested for HER2. CONCLUSION: Patients treated at centers that took longer to implement HER2 testing exhibited worse clinical outcomes. The speed of implementation behaves as a quality-of-care indicator. Reviewed guidelines on HER2 testing should be used to achieve this goal in a timely manner.

On the Effect of Triplet or Doublet Chemotherapy in Advanced Gastric Cancer: Results From a National Cancer Registry.

BACKGROUND: There is currently no consensus regarding first-line chemotherapy for patients with advanced gastric cancer (AGC) who are ineligible to receive trastuzumab. The objective of this study was to evaluate the efficacy and tolerance of triplets versus doublets by analyzing a national gastric cancer registry. PATIENTS AND METHOD: Patients with AGC treated with polychemotherapy without associating trastuzumab were included from 2008 through 2016. The effect of triplets versus doublets was compared using 3 methods: Cox proportional hazards regression, propensity score matching (PSM), and coarsened exact matching (CEM). RESULTS: A total of 970 patients were recruited (doublets: n=569; triplets: n=401). In the multivariate Cox model, the use of triplets was associated with better overall survival (OS), with a hazard ratio (HR) of 0.84 (95% CI, 0.72-0.98; P=.035). After PSM, the sample contained 340 pairs. A significant increase in OS, 11.14 months (95% CI, 9.60-12.68) versus 9.60 months (95% CI, 8.44-10.75), was seen in favor of triplets (HR, 0.77; 95% CI, 0.65-0.92; stratified log-rank test, P=.004). The effect appeared to be comparable for anthracycline-based (HR, 0.78; 95% CI, 0.64-0.94) or docetaxel-based triplets (HR, 0.78; 95% CI, 0.60-1.009). The trend was similar after applying the CEM algorithm, with an HR of 0.78 (95% CI, 0.63-0.97; P=.03). Triplet therapy was viable and relative dose intensities exceeded 85%, except for cisplatin in DCX (docetaxel, cisplatin, capecitabine). Triplets had more severe toxicity overall, especially hematologic, hepatic, and mucosal adverse events. CONCLUSIONS: With the limitations of a retrospective study that examines a heterogeneous set of chemotherapy regimens, we found that triplets are feasible in daily practice and are associated with a discreet benefit in efficacy at the expense of a moderate increase in toxicity.

The AGAMENON-SEOM model for prediction of survival in patients with advanced HER2-positive oesophagogastric adenocarcinoma receiving first-line trastuzumab-based therapy.

Background: Trastuzumab and chemotherapy is the standard first-line treatment in human epidermal growth factor receptor 2 (HER2)-positive advanced gastro-oesophageal cancer. The objective was to develop a predictive model for overall survival (OS) and progression-free survival (PFS) in patients treated with trastuzumab. Methods: Patients with HER2-positive advanced gastro-oesophageal adenocarcinoma (AGA) from the Spanish Society of Medical Oncology (SEOM)-AGAMENON registry and treated first line with trastuzumab and chemotherapy between 2008 and 2021 were included. The model was externally validated in an independent series (The Christie NHS Foundation Trust, Manchester, UK). Results: In all, 737 patients were recruited (AGAMENON-SEOM, n = 654; Manchester, n = 83). Median PFS and OS in the training cohort were 7.76 [95% confidence interval (CI), 7.13-8.25] and 14.0 months (95% CI, 13.0-14.9), respectively. Six covariates were significantly associated with OS: neutrophil-to-lymphocyte ratio, Eastern Cooperative Oncology Group performance status, Lauren subtype, HER2 expression, histological grade and tumour burden. The AGAMENON-HER2 model demonstrated adequate calibration and fair discriminatory ability with a c-index for corrected PFS/OS of 0.606 (95% CI, 0.578-0.636) and 0.623 (95% CI, 0.594-0.655), respectively. In the validation cohort, the model is well calibrated, with a c-index of 0.650 and 0.683 for PFS and OS, respectively. Conclusion: The AGAMENON-HER2 prognostic tool stratifies HER2-positive AGA patients receiving trastuzumab and chemotherapy according to their estimated survival endpoints.

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.

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.