The effect of surgery and grade on outcome of gastrointestinal stromal tumors

Prognostic factors influencing surgical management and outcome of gastrointestinal stromal tumours

BACKGROUND

The purpose of this study was to review surgical experience with gastrointestinal stromal tumours (GISTs) at a single tertiary university hospital, and to identify morphological and genetic prognostic markers of tumour progression.

METHODS

Forty-eight GISTs from 39 patients were reviewed retrospectively. The prognostic significance of DNA copy number changes, measured by comparative genomic hybridization (CGH), and morphological markers in low-risk and high-risk tumours were investigated.

RESULTS

Significantly more patients died from disease after incomplete tumour resection than after complete primary resection (P = 0.020). Tumour size of 5 cm or greater, mitotic count of 2 or more, and proliferative activity greater than 10 per cent were significantly associated with a shorter recurrence-free survival (P = 0.020, P = 0.001 and P = 0.002 respectively). Patients with low-risk tumours had a significantly better outcome than those with high-risk GISTs, both in terms of overall and recurrence-free survival (P < or = 0.001). CGH performed on 16 tumours revealed fewer DNA sequence copy number changes in low-risk than in high-risk GISTs. Non-progressive GISTs contained significantly fewer genetic alterations than recurrent or metastatic tumours (P < 0.001). Only tumours with more than five changes showed disease progression.

CONCLUSION

Complete surgical resection is the most important means of cure for GISTs. DNA copy number changes are related to the behaviour of these tumours and may serve as additional prognostic markers.

A phase II and pharmacokinetic study of ecteinascidin 743 in patients with gastrointestinal stromal tumors

PURPOSE

To assess the efficacy, tolerability, and pharmacokinetics of ecteinascidin 743 (ET-743) in patients with advanced gastrointestinal stromal tumors (GISTs).

PATIENTS AND METHODS

The study was confined to adult patients with radiographically measurable GISTs. ET-743 was administered as a 24-hour continuous i.v. infusion at a dose of 1.5 mg/m(2) repeated every 3 weeks. Pharmacokinetic blood sampling was performed during the first cycle of therapy. Tumors were restaged after every second cycle of therapy.

RESULTS

A total of 20 patients was enrolled in the study, 19 of whom were treated with 47 cycles of ET-743 (median 2, range 1-10). Severe toxicities were limited to reversible grade 3 transaminitis in 10 patients and grade 3 fatigue in one patient. There were no objective responses, and disease stabilization occurred in two patients lasting for periods of 4 and 10 months. The 1-year survival rate was 71.1%. Mean +/- standard deviation values of the maximum plasma concentration and total plasma clearance were 1.1 +/- 0.4 ng/ml and 44 +/- 16 l/h/m(2), respectively, for 19 of the 20 patients.

CONCLUSION

This study is the first report of a prospective phase II trial to evaluate a cytotoxic agent in patients with GISTs. This study underscores the primary resistance of GISTS to chemotherapy and stands in stark contrast to the encouraging results recently achieved with STI571. The lack of response may be associated with a therapeutically ineffective exposure to the drug based upon the lower incidence of severe toxicities and greater clearance than described in phase I and II trials of ET-743.

Gastrointestinal stromal tumors: chemotherapy and imatinib

Gastrointestinal stromal tumors (GISTs), previously thought to arise from the smooth muscles of the gastrointestinal tract, have recently been identified as a separate clinicopathologic entity. This new entity was revealed when investigations using more refined techniques suggested that GISTs had neural rather than smooth muscle differentiation and expressed the cell surface receptor Kit (CD117). Ensuing research led to development of a new molecularly targeted therapy, imatinib mesylate, which showed significant response among GIST patients in initial clinical trials. This review describes treatment of GIST before and after imatinib and the significance of this accomplishment.

[Current findings on gastrointestinal stromal tumors: seven observations of malignant tumors]

PURPOSE

Gastrointestinal stromal tumors (GIST) are rare neoplasms, 1-3% of malignant gastrointestinal tumors. They are immature proliferations of spindled and/or epithelioid cells, developed in the muscular layer of the digestive tract, showing uncompleted or partial muscular, nervous or mixed differentiation. Immunohistologic knowledge about these tumors has recently progressed because of the discovery of specific markers (coexpression vimentin-CD117, oncogenes): GIST can now be distinguished from the other mesenchymal tumors.

METHODS

Retrospective study of seven patients with GIST who received the same treatment.

RESULTS

For our seven patients the mean age was 49 years with a male predominance (sex-ratio 4/3). The tumoral localisations are principally the small bowel (four cases), the rectum (two cases) and the stomach (one case). The treatment consisted of a first surgery, adapted to the tumoral localisation and extension, associated to chemotherapy in case of metastasis or local recurrence. The study of the histological grading for the seven patients showed tumors with poor prognoses. Six patients developed recurrence in a 2-year period; for the survey we are too close for a proper view.

CONCLUSIONS

A review of the literature on stromal tumors finds older patients (59 years) with an equal sex ratio. Against the results of our series, the most frequent location is the stomach (50%). But the main problem is the better understanding of the particular evolution of these tumors. The bad short-date prognosis imposes carrying out larger studies, in order to confirm the principal hypothesis of histogenesis and to improve the survey by an optimal treatment.