Gastrointestinal Stromal Tumor

Three-Year Survival Up for Gleevec Patients

Novartis announced data showing a significant improvement in both recurrence-free survival and overall survival for patients taking Gleevec (imatinib mesylate) tablets for three years after surgery to remove KIT (CD117)-positive gastrointestinal stromal tumors (KIT+ GIST) compared to one year of treatment.

Gastrointestinal stromal tumors are a rare, life-threatening cancer of the gastrointestinal tract. The major cause of GIST is an abnormal form of the protein KIT, which causes cells to grow uncontrollably and become cancerous. Patients with GIST are at risk of recurrence following complete resection of primary GIST.

The results show that 66% of patients taking Gleevec for three years remained free of cancer recurrence compared to 48% who had received Gleevec for only one year. Moreover, 92% of patients taking Gleevec for three years were alive compared to 82% who had received Gleevec for only one year. Median patient follow-up was 54 months.

The 400-patient Phase III trial, conducted by the Scandinavian Sarcoma Group (SSG) and the Sarcoma Group of the Arbeitsgemeinschaft Internistische Onkologie (AIO), is the first prospective multicenter clinical trial to demonstrate a survival benefit of adjuvant Gleevec therapy for KIT+ GIST with extended three years of therapy relative to one year of therapy. The side effect profile in the clinical trial was consistent with that reported in previous studies with Gleevec.

"This study confirms the hypothesis that extending the duration of Gleevec treatment for patients following surgery improves recurrence-free survival. For the first time, an effect on overall survival was found," said Heikki Joensuu, MD, PhD, professor of oncology, University of Helsinki. "Results from this trial may positively impact clinical practice by helping physicians create the optimal treatment plan for patients with operable KIT+ GIST.

Giant Gastrointestinal Stromal Tumor Presenting as a Palpable ...

Abstract

Gastrointestinal stromal tumors (GIST-) account for the majority of mesenchymal tumors arising within the gastrointestinal tract. GIST presenting as a palpable abdominal mass is extremely rare. We report four additional cases of a GIST presenting as an abdominal mass along with a pertinent review of the literature. Twenty five cases of GISTs presenting with an abdominal mass, including 4 cases discussed here, have been reported in the world literature since 2001. The mean duration of symptoms was 152.7 days. Twenty one of 25 (84%) patients received surgical resection. The mean tumor size was 17.2 cm, with an average mitotic index of 7.6 per 50 high power fields. Thirteen of 14 (92.9%) patients had a high-risk tumor. Five patients were disease-free at a mean followup of 11 months, 2 patients had stable disease and 2 patients had progressive disease, and one patient had a partial response. In conclusion, symptomatic patents have an increased incidence of high-risk tumors and metastases at presentation. Adjuvant therapy with imatinib improves disease-free survival in patients with large abdominal GIST tumors, but no change in overall survival was noted. Finally, GISTs should be considered in the differential diagnosis of an abdominal mass in an elderly patient.

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the gastrointestinal tract. Terminology used to describe gastrointestinal mesenchymal tumors has been variable. Traditionally, these tumors have been called leiomyomas, cellular leiomyomas, or leiomyosarcomas, depending on the degree of cellularity, mitotic activity, and evidence of dissemination, or leiomyoblastomas, when showing epithelioid morphology. Although the term gastrointestinal stromal tumor is now preferred, phenotypic overlap between leiomyomas and GISTs exists, especially in that many GISTs show α -smooth muscle actin expression and some show desmin expression [ 1 ]. The incidence of GISTs has been historically underestimated prior to the introduction of CD117 staining. The annual worldwide incidence of GISTs since introduction of CD117 staining increased from 1.1 per 100,000 people to 2.1 per 100,000 people. Commensurate with an increased overall incidence has been a 25-fold increase in the age-adjusted incidence of GISTs (from 0.028 per 100,000 in 1992 to 0.688 per 100,000 in 2002), with a current annual incidence of 14.5/100,000 population [ 2 ]. Most patients with GISTs are asymptomatic although patients with advanced disease may present with symptoms of a mass lesion, abdominal pain, or bleeding. At least 10 to 30% of GISTs are discovered incidentally during laparotomy, endoscopy, or other imaging studies, with 15% to 50% of GISTs presenting with metastatic disease [ 3 ]. GISTs initially presenting as an abdominal mass are exceedingly rare, and only 21 such cases have been reported in the world literature (Table 1 ). In this paper, we discuss four additional cases of GISTs presenting as an abdominal mass admitted at a tertiary care teaching hospital in New Delhi, India and provide a pertinent review of literature.

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Gastrointestinal stromal tumor (GIST), from pathology to molecular target therapy

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