Meta-analysis of radiation therapy with and without adjuvant chemotherapy for malignant gliomas in adults

The contribution of cytotoxic chemotherapy to 5-year survival in adult malignancies

AIMS

The debate on the funding and availability of cytotoxic drugs raises questions about the contribution of curative or adjuvant cytotoxic chemotherapy to survival in adult cancer patients.

MATERIALS AND METHODS

We undertook a literature search for randomised clinical trials reporting a 5-year survival benefit attributable solely to cytotoxic chemotherapy in adult malignancies. The total number of newly diagnosed cancer patients for 22 major adult malignancies was determined from cancer registry data in Australia and from the Surveillance Epidemiology and End Results data in the USA for 1998. For each malignancy, the absolute number to benefit was the product of (a) the total number of persons with that malignancy; (b) the proportion or subgroup(s) of that malignancy showing a benefit; and (c) the percentage increase in 5-year survival due solely to cytotoxic chemotherapy. The overall contribution was the sum total of the absolute numbers showing a 5-year survival benefit expressed as a percentage of the total number for the 22 malignancies.

RESULTS

The overall contribution of curative and adjuvant cytotoxic chemotherapy to 5-year survival in adults was estimated to be 2.3% in Australia and 2.1% in the USA.

CONCLUSION

As the 5-year relative survival rate for cancer in Australia is now over 60%, it is clear that cytotoxic chemotherapy only makes a minor contribution to cancer survival. To justify the continued funding and availability of drugs used in cytotoxic chemotherapy, a rigorous evaluation of the cost-effectiveness and impact on quality of life is urgently required.

Altered therapy schedules in postoperative treatment of patients with malignant gliomas. Twenty year experience of the Maria Skłodowska-Curie Memorial Center in Kraków, 1973-1993

Results of altered therapy schedules obtained in postoperative treatment of 294 patients with malignant gliomas over last 20 years are presented. During this period 135 patients received Conventional Irradiation and Chemotherapy (CICH), 61 patients received Conventional Irradiation (CI), 59 patients received Split Course High Fractional Dose Irradiation (SCHFDI), and 39 patients received Twice a Day Accelerated Irradiation (TDAI). Actuarial survival rates at 2, 3 and 5 years were 19%, 7%, 0% respectively for patients treated with CICH, and they were 21%, 10%, 0% for CI group, 24%, 12%, 0% for SCHFDI option and 15%, 8%, 0% for TDAI schedule. According to the Cox proportional hazard model, only age was significant factor in prognosis.

Radiotherapy of primary malignant brain tumors

Radiotherapy is usually recommended for patients with a primary malignant brain tumor. The foundation for its use is grounded on the results of randomized trials for malignant gliomas which have demonstrated a relationship between survival and external beam radiation dose. Although similar trials have not been performed for most other primary intracranial tumors, radiation oncologists treat them in a similar fashion, delivering the highest possible dose consistent with acceptable levels of normal tissue damage. In most cases, focal therapy is required, using modern three-dimensional treatment planning and delivery--with whole brain or craniospinal therapy used only for infrequently encountered clinical presentations. With modern planning, the volume of normal tissue subjected to possible radiation damage can be minimized. Radiation effects in normal tissues typically occur months to years after treatment.