A REVISIT TO MANAGEMENT OF GASTROINTESTINAL STROMAL TUMOUR (GIST) Joint Hospital Surgical Grand Round 17 Jan 2015 Grace Liu Pamela Youde Nethersole Eastern Hospital

INTRODUCTION Surgical management is indicated whenever possible because it is the only potentially curative option High risk GISTs  36 months adjuvant target therapy (imatinib)

HOW TO DEAL WITH SMALL GISTS? When we saw a small submucosal mass, what should we do?

Small GIST <2cm, asymptomatic High Risk EUS features? Irregular border, cystic spaces, ulceration, echogenic foci, heterogenity yes no Endoscopic surveillence at months intervals Resection Follow-up CT every 3-6 months for 3-5 years, then yearly NCCN guideline 2014 only a few small tumors (3 of 23; 13.0%) without high-risk EUS features progressed during long-term follow-up Lok KH et al J Gastrointestin Liver Dis 2009;18:177–180.

WHICH APPROACH FOR RESECTION?

LOCALIZED GISTS Principle of surgery: Complete macroscopic resection Negative microscopic margins (R0 resection) Avoid tumour rupture Lymph node dissection not necessary

Surgical approaches: Endoscopy (risk of positive margins) Laparoscopy (risk of technical challenges with large tumors) GISTs <5cm; anterior wall of stomach,jejunum,ileum Laparoendoscopy (evidence limited to case reports) Laparotomy (more invasive)

LAPAROSCOPIC RESECTION for small tumours <5cm, favourable anatomical locations (anterior wall of the stomach, jejunum, and ileum) High success rates >90% Studies have shown laparoscopic resections of tumours up to 6cm with low recurrence rates and margin negativity Koh, Y.X. et al. Annals of Surgical Oncology, 20,

Overall survivalDisease free survival Size >5-10cm DA Bischof et al

High risk GIST after resection should receive adjuvant imatinib for 36 months

A TUMOUR TOO LARGE…

NEOADJUVANT THERAPY Aim: reduce tumor size to facilitate R0 resection and increase the likelihood of organ preservation may decrease the risk of bleeding, postoperative complications, or tumour rupture unresectable or borderline resectable primary tumour potentially resectable tumour that requires extensive surgery local recurrence of locally advanced disease NCCN Clinical Practice Guideline in Oncology. ESMO Clinical Practice

Imatinib is given 2-6 months before surgery Interval assessment of response by PET scan Before SUV= weeks after SUV=5.8

P Rutkowski et al Retrospective analysis of 10 EORTC centres, 161 patients with locally advanced, non-metastatic GIST Only 2 patients have disease progression during pre- operative phase R0 resection 83%, 5 yr DSS 95%

CONCLUSION Surgery for resectable GISTs, laparoscopic resection for tumours <5cm Endoscopic surveillence for small asymptomatic GIST Neoadjuvant therapy may facilitate resection and decrease morbidity of surgery

Thank you