Israel Medical Association Journal

Background: High dose interleukin-2 therapy, adminis­tered in bolus, is considered to be a reasonable treatment option in a selected group of patients with metastatic malignant melanoma.

Objectives: To present our experience using this mode of therapy in 21 patients with metastatic melanoma.

Materials and Methods: The 21 patients in our study group comprised 13 men and 8 women with a mean age of 46 years (range 29-63). Their metastatic disease was present in all extracranial sites, dermal and sub-dermal metastases being the most common (15 patients had at least one site, in addition to other locations of metastases). Patients with intracranial disease were excluded due to the poor effectivity of IL-2 at this site. Treatment comprised a course of 2 weeks of therapy with a 1 week rest interval between. Radiological and physical evaluation was performed 6-8 weeks after the first course. If a response was achieved a second course of therapy was given. Patients received up to 14 planned doses of IL-2 in each week, 720,000 lU/kg of IL-2 per dose iv. in 15 minutes. All treatments were given in the surgical ward, and only one patient was hospitalized in the intensive care unit.

Results: Of the 21 patients, one had a complete response that has lasted for 17 months and 5 patients had a partial response (range 3 months to 3 years). One patient died during treatment, and one patient who refused further treatment because of no response died a few days after completion of treatment. Prior to therapy three of the responders had received autologous vaccines with good immunological response (P=0.115). Toxic side effects were significant, but they were treated successfully with no residual damage.

Conclusions: High dose IL-2 can be administered safely in a surgical department. The response rates achieved in this series justify the use of high dose IL-2 in a selected group of patients. To improve response rates, a combination of auto­logous vaccines prior to high dose IL-2 may be recommended.

Background: The transfer of therapeutic genes into malignant brain tumors has been the subject of intense pre­clinical and clinical research in recent years. Most approaches have used direct intratumoral placement of a variety of vectors and genes, such as retroviruses or adenoviruses carrying drug-susceptibility genes, modified replication-competent herpes virus, and several vectors carrying tumor suppressor genes such as the p53 gene. However, clinical results have so far been disappointing, mainly due to the limited ability to effectively distribute the genetic material into the target cell population. Accordingly, alternative delivery approaches into the central nervous system, e.g., intravascular, are under investigation. Genetic vectors administered intravascularly are unlikely to penetrate the blood-brain barrier and transfer a gene into brain or tumor parenchyma. However, intravascular delivery of vectors may target endothelial cells lining the blood vessels of the brain. Since endothetial cells participate in a variety of physiological and pathological processes in the brain, their modulation by gene transfer may be used for a variety of therapeutic purposes. Angiogenically stimulated endothelial cells within tumors replicate rapidly and hence may become targets for retroviral-mediated gene transfer.

Objective: To assess the anti-tumor effect of transferring a drug-susceptibility gene into endothelial cells of the tumor vasculature.

Methods: As a model for this approach we delivered concentrated retroviral vectors carrying a drug-susceptibility gene via the internal carotid artery of rats with malignant brain tumors. The safety and efficacy of this approach, without and with subsequent treatment with a pro-drug (ganciclovir). was evaluated.

Results: No acute or long-term toxicity was observed after intraarterial infusion of the vector. Treatment with ganciclovir resulted in variable hemorrhagic necrosis of tumors, indicating preferential transduction of the angiogenically stimulated tumor vasculature. This was accompanied by severe toxicity caused by subarachnoid hemorrhage and intracerebral hemorrhage in vascular territories shared by the tumor and adjacent brain.

Conclusion: The data indicate that endothelial cells can be targeted by intraarterial delivery of retroviral vectors and can be used for devising new gene therapy strategies for the treatment of brain tumors.

Objectives: To analyze the incidence of mesothelioma in Israel during the years 1960-96, and to project its trend for the following years.

Methods: We conducted a population-based study of the incidence of mesothelioma reported to the Israel Cancer Registry during 1960-96. Time trends were analyzed from data on the annual import of asbestos to Israel, which may indicate the magnitude of past exposure. Based on these findings, trends in the incidence of mesothelioma in Israel were projected for the subsequent years.

Results: A total of 327 cases of mesothelioma were reported to the Israel Cancer Registry during the study period. The incidence in Jews was higher than in Arabs (age-standardized incidence rate 2.64 vs. 1.35 per million/year, respectively). Among the Jewish population, Israeli-born males and males born in Europe and America showed the highest incidence (ASR 4.23 and 4.15 per million/year, respectively). Israeli-born males were 20 years younger than Jewish males born elsewhere. The incidence was twice as high among males than females and increased sevenfold from its nadir (1.17 per million/year) in 1978--80 to its peak (8.5 per million/year) in 1993-96. During a similar period the incidence among females increased from 0.33 to 2.56 per million/year. The incidence in both sexes does not appear to level off. The large wave of immigration from the former Soviet Union that began in 1989 only partly accounts for the increased incidence in 1993-96. The time trend in the incidence of mesothelioma in both sexes parallels the use of asbestos in Israel, which peaked in the years 1976-78.

Conclusions: The incidence of mesothelioma in Israel has increased sharply in recent years, unrelated to a wave of immigration from East Europe, and is predicted to continue to rise for another 10-15 years.

Objectives: To assess the risk factors for malignant melanoma among kibbutz members compared to matched healthy controls.

Methods: We conducted a case-control study of 168 malignant melanoma patients and 325 healthy controls, matched by age and gender. Data were collected on three categories of risk: demographic, personal (e.g., skin, eye and hair color), and environmental/behavioral (e.g., sun exposure, use of sunscreens).

Results: There were no differences between the groups regarding sociodemographic data. Significantly more patients than controls had fair, vulnerable skin (P<0.001), light eyes (P<0.05), and fair hair (P<0.001). There was no difference in family history of malignant melanoma or other cancers. Patients with malignant melanoma had significantly more additional skin lesions (e.g., keratoses) (P<0.001). More patients than controls recalled having been exposed to the sun for long periods when they were 6–13 years of age. A conditional logistic regression analysis showed that fair hair, fair vulnerable skin, and additional skin lesions were independently associated with malignant melanoma (P<0.01).

Conclusions: The main target population for interventions to reduce the incidence of malignant melanoma among kibbutz members should be individuals with these risk factors. A history of increased exposure to the sun from age 6 to 13 should also be taken into account as an independent risk factor.