Combined modalities aid brain cancer survival
December 1, 2001
Combined modalities aid brain cancer survival
Whole brain radiotherapy, radiosurgery effective
A review of studies from 10 separate facilities indicates that patients with brain metastases who receive radiotherapy — small doses of radiation given over the course of 10 to 15 days — and stereotactic radiosurgery (RS) — a one-time shot of high-dose radiation — show an extensive improvement in survival.1
For the past 20 years, the authors note, the median survival of patients with brain metastases has remained level at six months. However, they point out, two recent trials that compared whole brain radiotherapy (WBRT) with surgical resection plus WBRT for patients with single brain metastases have shown statistically significant improved survival. In addition, retrospective studies suggested that RS improved control of intracranial metastases and yielded survival advantage.
"The retrospective studies, and studies where surgery had been used for solitary lesions, showed good results," notes Seema Sanghavi, MD, attending, radiation oncology, at Saint Vincents Comprehensive Cancer Center in New York City, and lead author of the article. "The surgical studies are prospective and also showed there could be benefit. We took multi-institution results, factored out possible biases, and still found a survival benefit."
Sanghavi and her co-authors accomplished this using a method called Recursive Partitioning Analysis, which allows the researcher to identify the most important prognostic factors and then put them into classes, and, by comparing treatment among similar classes, controlling for biases. "If everyone has the same main characteristics influencing their survival, then in the same group they would not be a factor," she explains. "The only influence would be treatment."
In explaining her rationale for the study, Sanghavi notes that whole-brain radiotherapy already is considered the standard of care. The goal of the study was to examine the addition of stereotactic radiosurgery and "determine whether that would have any additional benefit."
The data for the study were drawn from results at 10 facilities: nine in the United States and one in Brazil. A total of 502 patients were studied. They were divided as follows:
• Class I, a Karnofsky Performance Status (KPS) of >70, age < 65 years, controlled primary tumor site and no extracranial metastases;
• Class III, KPS < 70;
• Class II, all others.
The overall medial survival was 10.7 months. The addition of RS boosted results in median survival (16.1, 10.3, and 8.7 months for classes I, II, and III, respectively) compared with the median survival (7.1, 4.2, and 2.3 months) in patients treated with WBRT alone.
While noting possible limitations on their findings, the authors cited "a significantly better survival rate for patients with newly diagnosed brain metastases who received RS in addition to WBRT . . . We do not wish this report to be regarded as uncritical acceptance of RS in the treatment of brain metastases patients, but expect it to serve as an impetus for further randomized evaluation of this modality."1
"The results are very promising, but you can’t control for everything; it’s not a prospective study," Sanghavi concedes. "However, there is a randomized trial that has not yet been published." Nevertheless, she says, the advantage of combining modalities is that "potentially you can treat the whole brain with an external beam and positively impact survival. Even if the patient has disease elsewhere, you can at least prolong survival by getting better intracranial control."
Hospital quality managers should be aware that "Basically, irrespective of your parameters, there’s a suggestion that combined modality can improve survival," she continues, "Especially if the cancer can be controlled at the primary site. If the patient has a good performance status, the benefit appears to be quite promising."
Is this approach replicable at many different facilities? "Wherever you have radio-surgery you can do this," says Sanghavi, "And it’s starting to become a lot more common."
References
1. Sanghavi SN, Miranpuri SS, Chappell R, et al. Radiosurgery for patients with brain metastases: A multi-institutional analysis stratified by the RTOG recursive partitioning analysis method. Int J Radiat Oncol Biol Phys 2001; 51:426-434. n
Need more information?
For more information, contact: Seema Sanghavi, MD, Attending, Radiation Oncology, Saint Vincents Comprehensive Cancer Center, Section of Radiation Oncology, 325 W. 15th St., New York, NY 10021. Telephone: (212) 604-6085.
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