Neoadjuvant therapy for gastrointestinal stromal tumors: A propensity score?weighted analysis

Retrospective and single-arm prospective studies have reported clinical benefit with neoadjuvant imatinib for GISTs. In the absence of randomized Phase III data, impact systemic therapy (NAT) on survival compared to upfront resection (UR) remains unknown. We identified N = 16 308 patients within National Cancer Database (2004-2016) who underwent localized GIST stomach, esophagus, small bowel colorectum, or without ?3 months NAT. Inverse probability treatment weighting adjusted covariable imbalance among groups. estimated effect NAT overall a weighted time-dependent Cox proportional hazards model, 90-day postoperative mortality R0 logistic regressions. Eight hundred sixty-five (5.3%) received 15 443 (94.7%) UR. Median duration was 6.3 months. 53.7% were male vs 48.6% UR patients, 67.3% 65.1% had primary gastric 72.8% 49.7% at high risk. larger tumors higher mitotic index. >3 associated significant (weighted HR 0.85 [0.80-0.91]). rate 4/865 (0.5%) 346/15443 (2.2%). lower odds mortality. not significantly different between conclusion, despite risk features this analysis suggests that is modest mortality, no difference in likelihood achieving an resection.