Estimating survival scenarios in advanced or metastatic gastric and oesophageal adenocarcinoma: a systematic review of randomized-controlled trials.

Background: We aimed to summarize survival data from RCTs in patients with GO adenocarcinoma; estimate and explain worst-, typical-, and best-case-scenarios of survival time; and determine if simple multiples of median overall survival (mOS) could estimate these percentiles.

Methods: We systematically searched RCTs of systemic therapies for GO adenocarcinoma published 2000-2022. The following key percentiles were extracted from overall survival curves: 90th (worst-case), 75th (lower-typical), 25th (upper-typical), and 10th (best-case). We tested if these percentiles could be estimated by simple multiples of mOS: 0.25 of the median for the 90^th percentile, 0.5 for the 75^th, 2 for the 25^th, and 3 for the 10^th.

Results: We identified 44 trials (22,447 participants). For first line chemotherapy and immunotherapy combined (CI) trials (n = 3) worst-to-best case survival time ranged from 4 months to not reached, compared to 3-30 months for other trials (n = 27) and 1-23 months for subsequent lines (n = 14). Simple multiples of mOS accurately estimated the following survival percentiles: 90^th (n = 3/3 trials), 75^th (n = 3/3), and 25^th (n = 2/3) in first line CI trials. In other first line trials, the mOS accurately estimated the 90^th survival percentile in n = 22/27 trials, 75^th percentile in n = 26/27, 25^th percentile in 27/27 trials, and 10^th percentile in 22/27 trials. Simple multiples of the mOS accurately predicted the 90^th, 75^th, 25^th, and 10^th survival percentiles in the majority of trials of second and subsequent lines apart from chemotherapy and immunotherapy only trials.

Conclusion: We provide realistic, evidence-based prognostic information as scenarios for survival time which can inform clinical decision-making. Simple multiples of the mOS accurately estimated the percentiles for most groups.