Recurrent gastrointestinal stromal sarcomas

Mitoxantrone suppresses vascular smooth muscle cell (VSMC) proliferation and balloon injury-induced neointima formation: An in vitro and in vivo study

Neointima formation, which occurs after vascular injury due to vascular disease or interventions such as angioplasty and stent placement, is a complex process that involves multiple molecular and cellular mechanisms. The inhibition of neointima formation is vital to prevent restenosis of blood vessels. In the present study, we investigated whether the systemic administration of mitoxantrone can inhibit neointima formation, and evaluated the underlying mechanisms under in vitro and in vivo experimental conditions. In vitro, rat and human vascular smooth muscle cells (RVSMCs and HVSMCs) were stimulated with platelet-derived growth factor-BB (PDGF-BB) and treated with mitoxantrone or DMSO as a control. In vivo, 54 male Sprague-Dawley rats were subjected to carotid artery balloon injury and then intravenously administered with mitoxantrone. Cell proliferation was determined using the CCK-8 assay. Cell cycle analysis was performed using flow cytometry, and protein expression was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis. We used monoclonal mouse anti-bromodeoxyuridine (BrdU) antibody for the detection of BrdU and anti-Topoisomerase II antibody for staining Type II topoisomerase (Topo II), one week after the ballon injury. In both RVSMCs and HVSMCs, mitoxantrone treatment induced Topo II degradation, as well as suppressed DNA replication, cell cycle progression, and VSMC proliferation. A reduction in intimal hyperplasia, intimal-to-medial area ratio, and Topo II level was observed in mitoxantrone-treated rats, as compared to the control (saline) group. Overall, our results indicate that systemic administration of mitoxantrone can reduce neointimal hyperplasia and, thus, represents a suitable option for restenosis treatment.

Cyto-reductive Surgery combined with Hyperthermic Intra-peritoneal Chemotherapy for Peritoneal Surface Malignancies: current treatment and results

Cyto-reductive Surgery (CS) combined with Hyperthermic Intra-peritoneal Chemotherapy (HIPEC) as loco-regional treatment of Peritoneal Surface Malignancies (PSM) has increasingly gained acceptance in clinical practice. This review summarizes the more relevant studies on this topic. Indications, pre-operative work-up, technical aspects, outcome and future directions of this combined approach in the treatment of Peritoneal Surface Malignancies are discussed here and proposed in an informative and didactic manner.

Toxicity and Outcomes Associated with Surgical Cytoreduction and Hyperthermic Intraperitoneal Chemotherapy (HIPEC) for Patients with Sarcomatosis

BACKGROUND

Treatment of peritoneal recurrence following surgical resection of intra-abdominal sarcomas presents a significant challenge to clinicians. Historically, treatment with systemic chemotherapy has been ineffective and surgical resection alone has not been durable. We prospectively evaluated the feasibility of cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC) with cisplatin (CDDP) alone or in combination with mitoxantrone (MITOX) for the treatment of sarcomatosis.

METHODS

Two phase I trials of HIPEC were conducted (1998-2003). Eligible patients with evidence of sarcomatosis underwent cytoreductive surgery followed by HIPEC. In the first trial, CDDP dosing was established as 90 mg/m2 with a perfusate time of 90 minutes and temperature of 41 degrees C. In the second trial, MITOX (20 mg/m2) was instilled following perfusion with CDDP. Toxicity, efficacy, and quality of life (QOL) were evaluated.

RESULTS

A total of 28 patients were enrolled in the two trials. We noted a higher overall toxicity score and complication rate with combination CDDP/MITOX versus CDDP alone and shorter overall survival duration (5.5 months vs 16.9 months, respectively). In addition, local recurrence rates were similar in both groups (CDDP 79% vs CDDP/MITOX 68%). As expected, QOL scores at 6-8 weeks following HIPEC were 15-25% lower than the baseline scores; however, they returned to baseline at 3-6 months.

CONCLUSIONS

Although the HIPEC technique is feasible for patients with sarcomatosis, it is associated with significant toxicity and limited clinical benefit. Combination CDDP/MITOX failed to demonstrate any benefit over CDDP alone; moreover, there was an increase in toxicity.

Synchronous colorectal adenocarcinoma and gastrointestinal stromal tumor (GIST)

BACKGROUND

Little is known about the synchronous occurrence of gastrointestinal stromal tumors (GISTs) and other gastrointestinal tumors. We present two cases of an invasive colon cancer with a synchronous small-bowel GIST; immunohistochemistry studies were performed to evaluate possible genetic similarities.

METHODS

This paper reports two cases of synchronous GISTs and colorectal cancer (CRC) with immunohistochemistry analysis of c-Kit expression. This paper is also a review of the existing literature on the association of GISTs and CRC and the role of c-Kit in CRC.

RESULTS

In the last 2 years, we observed two patients with synchronous CRCs and GISTs of the small bowel. The GISTs were incidentally discovered during the work-up for CRCs and excised at the time of the colon resection. Immunohistochemistry study did not reveal an expression of c-Kit in CRCs. Clinical implications of the association between these two neoplasms are described in this paper.

CONCLUSIONS

Synchronous CRC and GIST has been more frequently reported. Because of the limited number of cases, we cannot exclude an incidental relationship. The genetic pathways of tumorigenesis appear different for the two neoplasms. Further studies are needed to clarify a possible role of c-Kit in the development of colonic adenocarcinomas.

Interstitial cells of Cajal in health and disease. Part II: ICC and gastrointestinal stromal tumours

Mesenchymal tumours in the gastrointestinal tract have long been problematic in terms of diagnosis, prognosis and therapy, but recent advances in immunohistochemistry and related therapies have allowed more specific diagnosis. In particular, the recognition that both the interstitial cells of Cajal (ICC) and many gastrointestinal stromal tumours (GISTs) are positive for c-kit and CD34 and have other features similar to those of ICC has led to the use of imatinib, a novel small molecule therapy that blocks the CD117/c-kit tyrosine kinase receptor, which shows remarkable efficacy in treatment of malignant and metastatic GISTs as well as other malignancies.

Molecularly targeted agents: Their promise as cancer chemopreventive interventions

Molecular medicine has fully entered in to the oncology arena. The development of targeted therapies is one of the major ongoing efforts in cancer treatment. Targeted therapy refers to treatment strategies directed against molecular targets considered to be involved in neoplastic transformation. Such molecularly targeted agents (MTA) are currently under study in all treatment settings including that of chemoprevention, defined as the use of natural or synthetic agents to interrupt the carcinogenic process, to nip tumours in the bud. This review article aims to provide a general overview of the potential use of some of these MTA in the chemoprevention setting.

The role of surgery in the management of gastrointestinal stromal tumors (GISTs) in the era of imatinib mesylate effectiveness

Surgical resection is the treatment of choice for the gastrointestinal stromal tumors (GISTs). In the literature, the 5-year patient survival after surgical resection, ranged from 48 to 80%, before the era of imatinib mesylate and the exploration of the prognostication criteria. Imatinib mesylate targets an intracellular signaling molecule of the natural history and malignant development of GISTs, and increased the 5-year survival rate, after the resection of primary low-risk GISTs, to similar values to the normal population. For high-risk GISTs, current knowledge which is still under expansion, show major improvement at the 1-year survival rate of more than 90% versus less than 50% before imatinib era. After surgical resection, for both low and high malignant potential GISTs, a closed control directed to the early identification of confined resectable recurrences, is required. This paper assesses the current knowledge of GIST management, motivated by a case of patient with intermediate risk GIST.

Preliminary investigation of mitoxantrone coating on stent-grafts to inhibit neointimal proliferation

PURPOSE

To investigate the inhibition of neointimal proliferation induced by a stent-graft loaded with mitoxantrone.

METHODS

Stent-grafts with and without mitoxantrone loading (150 microg per device) were inserted into the carotid artery of 7 and 6 rabbits, respectively. After an observation period of 28 days, the animals were sacrificed, and a detailed morphological and morphometric workup of the stented vessels was performed.

RESULTS

Uncoated stent-grafts induced a thick neointima (median diameter 97+/-99 microm), whereas no neointima formed in mitoxantrone-loaded stent-grafts. However, the loaded devices were not fully covered by an endothelial layer. The underlying media was significantly thinner (31.8+/-5.6 versus 48.6+/-3.3 microm, p=0.002) and showed a widespread loss of smooth muscle cells.

CONCLUSIONS

Mitoxantrone loading of a stent-graft inhibited the formation of a neointima. However, important regenerative processes were prevented as well, indicating a local overdose. More experiments using lower doses are warranted.

Prognostic factors after surgery of primary resectable gastrointestinal stromal tumours

AIMS

To analyse the prognostic factors of gastrointestinal stromal tumours (GIST) after a complete resection of the primary tumour.

PATIENTS AND METHODS

Fifty-nine patients who underwent a complete initial resection of a GIST were studied. Peritumoral resections (PTR) were compared to segmental organ resections (SOR). Overall survival (OS) and the disease-free survival (DFS) were calculated using the Kaplan-Meier method.

RESULTS

Primary sites were: stomach (25), small intestine (22), rectum (7), duodenum (5). Two patients had nodal involvement. The median follow-up was 45 months. Local DFS was significantly better after SOR compared to PTR (median 63 vs. 11 months, respectively, p<0.001). Univariate analysis for OS identified the grade (p=0.005) and size (p=0.02) as prognostic factors. Only a high histologic grade was an independent factor (p=0.02) in the multivariate analysis. Out of 49 patients who relapsed, the first recurrence was local only in 12, local and distant in 10 and distant only in 27; only one had a lymph node failure. Recurrences were accessible to curative surgery in 22 cases. OS of patients submitted to complete resection of their recurrence was significantly better than patients whose recurrence could not be resected (median 52 vs. 12 months, respectively, p<0.001).

CONCLUSION

Complete surgery without rupture remains the mainstay of treatment in patients with localized, resectable disease. A peri-tumoral resection confers a high risk of local recurrence and should be avoided. Lymphadenectomy is not systematic. Grade is the main prognostic factor for OS and can be a decision marker for adjuvant treatment with Gleevec.

Surgery and imatinib in the management of GIST: emerging approaches to adjuvant and neoadjuvant therapy

Gastrointestinal stromal tumor (GIST) is a neoplasm of the gastrointestinal tract, mesentery, or omentum that expresses the protein-tyrosine kinase KIT (CD117) and is the most common mesenchymal tumor arising at these sites. Surgical resection is the first-line intervention for operable GISTs, particularly localized primary tumors, and it was historically the only effective treatment. However, more than half of all GIST patients present with locally advanced, recurrent, or metastatic disease. The 5-year survival rate ranges from 50% to 65% after complete resection of a localized primary GIST and decreases to approximately 35% for patients with advanced disease who undergo complete surgical resection. A total of 40% to 90% of all GIST surgical patients subsequently have postoperative recurrence or metastasis. Imatinib is a potent, specific inhibitor of KIT that has demonstrated significant activity and tolerability in the treatment of malignant unresectable or metastatic GIST, inducing tumor shrinkage of 50% or more or stabilizing disease in most patients. A key strategy for prolonging the survival of patients with GIST is to improve the outcome of surgery. It is possible that the adjuvant and neoadjuvant use of imatinib (e.g., rendering initially inoperable tumors resectable) in the overall management approach to advanced GIST may contribute to surgeons' success in attaining this objective.

Gastrointestinal stromal tumors respond to tyrosine kinase-targeted therapy

Gastrointestinal stromal tumors (GISTs) are rare tumors of the wall of the stomach and small bowel, and also occasionally arise in the mesentery, omentum, or retroperitoneum. The incidence of GIST in the United States is approximately 500 to 750 patients per 100,000 people. GISTs often present late in their clinical course unless they are the cause of gastrointestinal bleeding or perforation. Surgical resection is the standard of care for primary GIST. However, there is a high risk of recurrence in the peritoneum and liver. For metastatic GIST, imatinib mesylate is the standard of care. Two phase III studies presented in 2003 in abstract form show slightly different results. In the US study, 400 mg/d was found to be equivalent to 800 mg/d with respect to response, progression-free survival, and overall survival at 12 months. In the European/Australasian study, the response rate was the same with either dosage, but progression-free survival was better with 800 mg/d compared with 400 mg/d. Overall survival data for the latter study were too immature for analysis as of May 2003. Adjuvant or neoadjuvant therapy with imatinib is the topic of at least three studies through the American College of Surgeons Oncology Group and Radiation Therapy Oncology Group and the American College of Radiology Imaging Network. Every effort to enroll eligible patients on these studies should be made. New treatments for metastatic disease under investigation include a tyrosine kinase inhibitor with an expanded panel of targets compared with imatinib (SU011248), and the addition of a mammalian target of rapamycin (mTOR) inhibitor and the rapamycin derivative RAD001 to imatinib. Given the finding of a specific molecular defect to exploit, GISTs have gone from an orphan disease to a proving ground for tyrosine kinase-targeted therapy.

Gastrointestinal stromal tumors: from a surgical to a molecular approach

Gastrointestinal stromal tumors (GISTs) are the most common mesenchymal tumors of the digestive tract. These tumors span a wide clinical spectrum from benign to malignant and have long been recognized for their nearly absolute resistance to chemotherapy and radiation treatment. We reviewed the worldwide experience on GIST diagnosis, prognosis and treatment and describe our own series. PubMed was searched for references using the terms gastrointestinal stromal tumor, GIST and gastrointestinal sarcoma. Recent reports were given emphasis because GIST is a novel clinical entity and older published work on gastrointestinal sarcomas might be contaminated with other histologic tumor types. At present, surgery is the standard treatment for primary resectable GIST. To increase the activity of conventional chemotherapeutic agents, locoregional therapies are being implemented in the clinical setting. A major breakthrough is the development of a new class of anticancer agents targeting tumor-specific molecular abnormalities. Preliminary results on administration of imatinib mesylate, a signal transduction inhibitor, are particularly encouraging, showing potent activity of this drug against metastatic GIST. Molecular targeting of the critical pathogenetic mechanism underlying GIST might not only revolutionize the strategy to treat locally advanced and metastatic GIST but also improve disease control after macroscopically radical surgery.

The GIST of targeted cancer therapy: a tumor (gastrointestinal stromal tumor), a mutated gene (c-kit), and a molecular inhibitor (STI571)

Although gastrointestinal stromal tumor (GIST) is the most frequent mesenchymal neoplasm of the gastrointestinal tract, until recently it has been an obscure disease. Now, there is widespread scientific and clinical interest in GIST because its principal pathogenetic defect has been identified and a specific molecular inhibitor of GIST has been developed. Most GISTs contain a gain-of-function mutation in the c-kit proto-oncogene. Mutation results in constitutive activation of the Kit receptor tyrosine kinase, which induces cellular proliferation. STI571 is an oral agent that selectively inhibits Kit. It is a landmark development in cancer treatment and marks a new era of targeted molecular therapy. Its efficacy proves that a specific inhibitor can counteract the effects of a genetic defect responsible for neoplasia. Although STI571 was first applied to GIST only 2 years ago, it has already revolutionized the treatment of patients with metastatic disease and is also currently being tested as an adjuvant therapy after the resection of primary GIST.

Clinical management of gastrointestinal stromal tumors: before and after STI-571

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. Until recently, surgery has been the only effective therapy for GIST. However, even after complete resection of tumor, many patients still eventually die of disease recurrence. Conventional chemotherapy and radiation therapy have been of limited value. Within the last few years, it was discovered that most GISTs have a gain-of-function mutation in the c-kit proto-oncogene. This results in ligand-independent activation of the KIT receptor tyrosine kinase and an unopposed stimulus for cell growth. STI-571 is a small molecule that selectively inhibits the enzymatic activity of the ABL, platelet-derived growth factor receptor, and KIT tyrosine kinases and the BCR-ABL fusion protein and is a landmark development in cancer therapy. Its clinical development marks a new era of rational and targeted molecular inhibition of cancer that emanates from direct collaborations between scientists and clinicians. It provides proof of the principle that a specific molecular inhibitor can drastically and selectively alter the survival of a neoplastic cell with a particular genetic aberration. The advent of STI-571 has markedly altered the clinical approach to GIST. It has proven to be effective in metastatic GIST and is also under investigation as a neoadjuvant and adjuvant therapy.

Inhibition of KIT tyrosine kinase activity: a novel molecular approach to the treatment of KIT-positive malignancies

PURPOSE

Activation of the KIT tyrosine kinase by somatic mutation has been documented in a number of human malignancies, including gastrointestinal stromal tumor (GIST), seminoma, acute myelogenous leukemia (AML), and mastocytosis. In addition, paracrine or autocrine activation of this kinase has been postulated in numerous other malignancies, including small-cell lung cancer and ovarian cancer. In this review, we discuss the rationale for and development of KIT tyrosine kinase inhibitors for the treatment of human malignancies.

MATERIALS AND METHODS

Studies were identified through a MEDLINE search, review of bibliographies of relevant articles, and review of abstracts from national meetings.

RESULTS

Four tyrosine kinase inhibitors that have activity against KIT are currently being used in clinical trials, and one, STI571, has recently been approved by the United States Food and Drug Administration for treating patients with chronic myelogenous leukemia. The role of KIT inhibitors in treating KIT-positive malignancies is reviewed.

CONCLUSION

Targeted therapy to inhibit the kinase activity of KIT is a rational approach to the treatment of KIT-positive malignancies. Two key factors are the potency of a given inhibitor and the relative contribution of KIT activation to the growth of the tumor. Given our current understanding of KIT activity in human malignancy, the best candidate diseases for treatment with KIT inhibitors are GIST, mastocytosis, seminoma and possibly some cases of AML. Additionally, KIT inhibitors may play an adjunctive role in diseases such as small-cell lung cancer, in which KIT activation is secondary to ligand binding rather than an acquired mutation.