Treatment and Prognoses in Patients With Primary Gastrointestinal Stromal Tumors ≥10 cm: A Single-Institution Experience in China

Data on treatments and specific outcomes of primary gastrointestinal stromal tumors (GISTs) ≥10 cm are limited. We here report the treatments and survival outcomes concerning a subgroup of primary giant GISTs. Data of 83 consecutive patients with primary GISTs ≥10 cm in a single institution were retrospectively collected. Fifty-eight patients underwent surgery before imatinib mesylate (IM) treatment (Group A), 10 underwent surgical resection following IM therapy (Group B), whereas 15 patients took IM as drug therapy alone (Group C). The baseline clinical characteristics were similar among the 3 groups. However, a lower proportion in Group A had metastatic disease at the time of diagnosis or surgery compared with Groups B and C (8.6% vs 40.0% vs 40.0%, P < 0.05). The median follow-up duration was 21.5 months. No statistically significant differences were observed on progression-free survival (PFS) among the groups. However, patients in Group B showed significantly better overall survival (OS) compared with those in Group C (P = 0.044). Multivariate analysis showed that patients treated with adjuvant IM were associated with better PFS (hazard ratio [HR] 3.01; 95% confidence interval [CI] 1.13–7.97; P = 0.027) and OS (HR 29.11; 95% CI 3.32–125.36; P = 0.004). The subgroup with mitotic count >10/50 high-power fields (HPF) showed worse PFS (HR 3.50; 95% CI 1.19–10.25; P = 0.022) and OS (HR 20.04; 95% CI 1.67–143.79; P = 0.018) than that of mitotic count ≤5/50 HPF. Clinical treatment patterns for primary giant GISTs are different, and the outcomes of different interventions vary. The optimal treatments for these subgroup of patients still require further long-term investigation. Moreover, mitotic count and adjuvant IM are closely associated with PFS and OS in giant GISTs.