Downsizing treatment with tyrosine kinase inhibitors in patients with advanced gastrointestinal stromal tumors improved resectability.
BACKGROUND
Gastrointestinal stromal tumors (GISTs) express the receptor tyrosine kinase KIT. Most GISTs have mutations in the KIT or PDGFRA gene, causing activation of tyrosine kinase. Imatinib, a tyrosine kinase inhibitor (TKI), is the first-line palliative treatment for advanced GISTs. Sunitinib was introduced for patients with mutations not responsive to imatinib. The aim was to compare the survival of patients with high-risk resected GISTs treated with TKI prior to surgery with historical controls and to determine if organ-preserving surgery was facilitated.


METHODS
Ten high-risk GIST-patients had downsizing/adjuvant TKI treatment: nine with imatinib and one with sunitinib. The patients were matched with historical controls (n = 89) treated with surgery alone, from our population-based series (n = 259). Mutational analysis of KIT and PDGFRA was performed in all cases. The progression-free survival was calculated.


RESULTS
The primary tumors decreased in mean diameter from 20.4 cm to 10.5 cm on downsizing imatinib. Four patients with R0 resection and a period of adjuvant imatinib had no recurrences versus 67% in the historical control group. Four patients with residual liver metastases have stable disease on continuous imatinib treatment after surgery. One patient has undergone reoperation with liver resection. The downsizing treatment led to organ-preserving surgery in nine patients and improved preoperative nutritional status in one patient.


CONCLUSIONS
Downsizing TKI is recommended for patients with bulky tumors with invasion of adjacent organs. Sunitinib can be used for patients in case of imatinib resistance (e.g., wild-type GISTs), underlining the importance of mutational analysis for optimal surgical planning.
Sjölund
Katarina
K
Department of Surgery, Sahlgrenska Academy at the University of Gothenburg, Sahlgrenska University Hospital, 413 45 Gothenburg, Sweden.
Andersson
Anna
A
Nilsson
Erik
E
Nilsson
Ola
O
Ahlman
Håkan
H
Nilsson
Bengt
B
D000368:Aged; D001549:Benzamides; D017024:Chemotherapy, Adjuvant; D004252:DNA Mutational Analysis; D018450:Disease Progression; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000000981:diagnostic imaging / Q000235:genetics / Q000401:mortality / Q000601:surgery*; D006801:Humans; D000068877:Imatinib Mesylate; D007211:Indoles / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D020125:Mutation, Missense; D010879:Piperazines / Q000627:therapeutic use*; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors*; D011743:Pyrimidines / Q000627:therapeutic use*; D011758:Pyrroles / Q000627:therapeutic use; D017384:Sequence Deletion; D000077210:Sunitinib; D016019:Survival Analysis; D014057:Tomography, X-Ray Computed
D001549:Benzamides; D007211:Indoles; D010879:Piperazines; D011743:Pyrimidines; D011758:Pyrroles; D000068877:Imatinib Mesylate; D011505:Protein-Tyrosine Kinases; D000077210:Sunitinib