Neoadjuvant imatinib in locally advanced gastrointestinal stromal tumors.
OBJECTIVE
To study the role of neoadjuvant imatinib mesylate in downsizing tumors in patients with locally advanced nonmetastatic gastrointestinal stromal tumors (GISTs), thus improving the possibility of complete resection.


METHODS
We used neoadjuvant imatinib in six patients with locally advanced GISTs, at a dose of 400 mg daily, given orally in all patients for a median period of 3.5 months (range 1-20 months). All patients had a computerized tomography scan (CT scan) once before starting the treatment and a repeat CT scan 1 month after starting imatinib. Some patients had another CT scan done at 3 months. The tumor volume was calculated using the formula V=4/3 pir3.


RESULTS
Following imatinib therapy, the median reduction in the tumor volume was 40% (range 20-50%). Four of the six patients underwent successful complete resection of the tumor following neoadjuvant imatinib for a median period of 2 months, and are disease free after a median follow-up of 10.5 months (range 3-20 months). Two patients in whom the tumors were deemed to be operable after downsizing refused surgery and are continuing imatinib. Imatinib did not produce serious toxicity in any patient.


CONCLUSIONS
Neoadjuvant imatinib can be used successfully in patients with locally advanced nonmetastatic GISTs to improve the rates of complete resection and reduce the chance of tumor spill. The optimal duration of neoadjuvant treatment needs to be tailored based on response assessment at frequent intervals to identify the ideal window period for surgery.
Seshadri
Ramakrishnan A
RA
Department of Surgical Oncology, Cancer Institute (WIA), Annexe Campus, Guindy, Chennai, India.
Rajendranath
Rejiv
R
D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001549:Benzamides; D003131:Combined Modality Therapy; D005260:Female; D046152:Gastrointestinal Stromal Tumors / Q000188:drug therapy* / Q000601:surgery; D006801:Humans; D000068877:Imatinib Mesylate; D008297:Male; D008875:Middle Aged; D020360:Neoadjuvant Therapy / Q000379:methods*; D010879:Piperazines / Q000627:therapeutic use*; D011743:Pyrimidines / Q000627:therapeutic use*; D016896:Treatment Outcome
D000970:Antineoplastic Agents; D001549:Benzamides; D010879:Piperazines; D011743:Pyrimidines; D000068877:Imatinib Mesylate