Radiosurgery Now: a patient-centered approach to managing brain metastases
Dr. Dheerendra Prasad, Director at the Gamma Knife Center at Roswell Park Comprehensive Cancer Center, USA recently presented a webinar featured on Physics World discussing the urgency of overhaul required in the modern management of brain metastases.
While the technology of stereotactic radiosurgery (SRS) has evolved over time to handle larger and complex tumors, its incorporation into novel treatment regimens over the past decade has been slow, and not reflective of the urgent need for improved therapy. One of the key reasons behind this is the continued adherence to the premise of prevention of brain failure when treating brain metastases patients, which has led to a continued use of whole brain radiation therapy as the most common choice of treatment. During the course of the webinar, Dr. Prasad dispels this and many other commonly held misconceptions.
Volume matters, not numbers
It is a widely held and somewhat historical belief that treating larger numbers of multiple tumors is a risky undertaking. For instance, although current NCCN treatment guidelines have increased the number of brain metastases recommended for treatment with radiosurgery from 4 to up to 10, many physicians are still reluctant to begin therapy for patients with multiple metastatic lesions. In Dr. Prasad’s opinion, physicians should not base their patient selection criteria for radiosurgery solely on numbers included in guidelines but should also take into account a growing body of modern data demonstrating that the total volume of the metastatic disease in the patient’s brain has a greater impact on patient survival than the actual number of tumors present.
Recently published data in the past few years clearly show that if the total volume of the brain treated by radiation is restricted to just the affected portions, this leads to a greater cognitive payback. Data from a study by Chang et al show that patients treated with whole brain radiation therapy (WBRT) plus stereotactic radiosurgery (SRS) experienced significantly higher neuro-cognitive decline compared to those treated with SRS alone. With cutting-edge SRS technologies such as Leksell Gamma Knife, less than ~2% of the brain is exposed to radiation, even if you treat a large number of metastases and the patient undergoes repetitive Gamma Knife surgery.
Managing brain metastases like a chronic disease
With survival rates of brain metastases patient counting in years instead of the earlier median rate of 6-7 months, we now have the opportunity to treat brain metastases as a chronic disease – similar to how a diabetologist would manage diabetes for their patients. Brain metastases should be treated, as and when they appear. In an established and standard clinical setting, this can often be done as a same-day procedure. Dr. Prasad shares that he has treated a patient with up to 44 brain metastases with minimal dose wash to the brain. If this same person were treated with WBRT or linacs, the dose wash would have been much higher.
Radiosurgery Now –Treat more, treat sooner
With hospitals coming under intense pressure due to the rapidly increasing burden of brain metastases worldwide, it has become imperative to treat efficiently and quickly. The Gamma Knife Icon is well suited for this purpose due to quick treatment planning and the choice of multiple workflows it offers – a clear reason why the Gamma Knife Center at Roswell Park treats about 600 patients a year, of which about 70% are brain metastases patients.
High throughput also translates into quicker initiation of SRS therapy. This is absolutely critical for patients with aggressive brain metastases, such as those associated with non-small cell lung cancer and melanoma where the target volume can grow by as much as 30% within a week.
With Gamma Knife and the high throughput it offers, rapid treatment planning and delivery is a certainty. With other treatment modalities, planning and treatment can take up to several weeks during which the metastatic lesions can grow to very large volumes, resulting in obsolete plans and lesions too large to treat effectively with radiosurgery.
Irrespective of the number, size, location or recurrence of their brain metastases, patients deserve the best possible treatment that technology today has to offer. We owe it to our patients and their families.
You can view the full webinar here