Prognostic Analysis Of Duodenal GIST And Evaluation Of Efficacy And Safety Of Sunitinib For Advanced GIST

Background and objective: Gastrointestinal stromal tumor(GIST)is regarded as the most common mesenchymal tumor in gastrointestinal tract.Our study aims on duodenal GIST and advanced GIST.We focus on the manifestations and prognostic factors of duodenal GIST,and we evaluate the efficacy and safety of sunitinib,a second-line treatment for advanced GIST after imatinib failure.Methods: Retrospective analysis was conducted for clinical and pathological data of patients with primary duodenal GIST diagnosed and operated at Ruijin Hospital from September 2003 to April 2015,and followup was performed for these patients to determine survival outcomes and prognostic factors.On the other hand,we followed up patients diagnosed with advanced GIST at Ruijin Hospital from March 2008 to December 2017 treated with sunitinib after imatinib failure to evaluate the efficacy and safety of sunitinib as a second-line treatment.Results: 62 duodenal GIST patients were identified and follow-up for55 of them were completed,the follow-up rate was 88.7%,and the median time to tumor recurrence was 24 months(4-121months).Kaplan-meier survival analysis revealed that tumor size,mitotic activity,Ki-67 index and pathological risk were prognostic factors for duodenal GIST patients and Ki-67 was an independent prognostic factor affecting recurrence free survival and overall survival(P = 0.007 and 0.028,resp.).In addition,the prophylactic effect of post-surgical imatinib in patients with high pathological risk in RFS or OS was not comfirmed(P>0.05).75 sunitinibtreated patients with advanced GIST were successfully followed-up among81 objects,the follow-up rate was 92.6%.The clinical benefit rate was 67%,the median progression free survival was 32 weeks(95%CI: 26.90-37.10weeks),the overall survival was 64 weeks(95%CI:54.31-73.69 weeks).Survival analysis showed that primary non-gastric GIST,exon 11 mutation,long-term imatinib treatment,tumor progression despite imatinib escalation to 600-800mg/d,continuing imatinib in stead of switching to sunitinib when tumor demonstrated imatinib resistance were risk factors for prognosis.Sunitinib was well tolerated and effective for GIST patients,with manageable adverse events significantly alleviated and reduced by active adjustment of dose and support medical care.Conclusion:1.Tumor size,mitotic activity,Ki-67 index and pathological risk were prognostic factors for duodenal GIST patients after R0 tumor resection and high-level Ki-67 was an independent risk prognostic factor.2.Primary non-gastric GIST,exon 11 mutation,long-term use of firstline imatinib at escalated dose without quick switch to second-line sunitinib after tumor progression were risk factors for prognosis of advanced GIST patients treated by second-line sunitinib.3.Sunitinib demonstrated efficacy as a second-line treatment in improving the prognosis for patients with advanced GIST with imatinib resistance with safety and manageable adverse events.