Whole brain radiotherapy (WBRT) has notoriously been associated with a cognitive decline in cancer patients. Apparently sun is setting for WBRT as a viable treatment option as yet another research, this time a large-scale, federally-funded, multi-institutional study from the US, reaffirms that while WBRT arrests tumor growth in cancer patients with 1-3 spots in brain, it causes severe memory and thought problems.
Cancer patients with brain metastases are better off with tumor-focused radiosurgery called stereotactic radiosurgery (SRS) because it causes less memory damage. Right from the outset, the use of WBRT in patients with brain metastases has been controversial. Its adverse-effects outweigh its benefits. For instance, it causes more thought and memory problems than simple radiosurgery. Even though it does arrest cancerous growth, it neither lengthens patients’ lives nor offers any treatment benefit. It may however reduce symptoms caused by the disease per se. Nonetheless, over the years, its use has diminished at cancer institutes.
“We used to offer whole brain radiation early on, but now we know that the side effects of this therapy are worse for the patient than cancer growth or recurrences in the brain,” said senior study author Jan C Buckner, MD, a professor of oncology at Mayo Clinic in Rochester, MN. “We expect that practice will shift to reserve the use of whole brain radiation therapy for later treatment and palliative care.”
The study in question was Mayo Clinic led and conducted at 34 different institutes of the country. It was recently published in various renowned journals, one of which is BMJ. Led by a radiation oncologist at Mayo Clinic, Paul Brown, the study enrolled 213 patients between 2012 and 2013. All patients had cancer that had spread to the brain. Patients were randomized into two groups: the SRS group (111 patients) and SRS followed by WBRT group (102). All patients were followed up at three months. At the end of the follow-up, researchers noticed less cognitive decline in patients in SRS group compared to the SRS + WBRT group i.e., 63.5% vs 91.7% respectively. Also, quality of life and median survival rate was far better in the former group than in the latter group i.e., 10.4 months vs 7.4 months.
While definitely not the first of its kind, this is the first large-scale clinical study to evaluate the effects of WBRT on patients with 1-3 brain metastases. Over the years, extensive research has been done on the effects of WBRT. The technique has sparked much interest among oncologist owing to its potential of halting tumor growth and improving symptoms in patients. Despite its potential though, WBRT continues failing the researchers in years. One similar study performed last year by Dr Jan Buckner had findings mirroring those of the current study. Dr Buckner wanted to see whether WBRT conferred any additional benefits in patients with brain mets but the results were anything but hopeful. Compared to the patients who received conventional treatment with radiosurgery, those who received WBRT following radiosurgery exhibited a worse outcome in terms of cognitive function, although admittedly WBRT showed far more superiority in controlling the tumor growth in patients.
So what is it about WBRT that makes it sound like such a horrifying thing? But before we explain what WBRT does, let us find out what it is and why do patients need it.
WBRT is a type of external radiation therapy that is given to patients in whom cancer has spread to the brain. Cancer takes a heavy toll on your mental and physical health, it is by far the most debilitating disease where survival is perpetually at stake. One of the scariest things about cancer is that it spreads (a phenomenon called metastasis) and recurs. Some cancers, such as lung skin and breast cancer, have the propensity to spread to the brain requiring specialized medical attention including surgery and radiation. About 400,000 cancer patients i.e., 20-40%, in the US develop brain metastases each year. Brain mets can also develop in patients with the cancers of colon, bladder and kidney.
Resultantly, oncology researchers are on a constant lookout to invent curative and supportive therapy to ease a patient’s pain and help him beat the demon with an unending appetite. All cancer patients need supportive therapy and care, the very need led to the use of WBRT. A few studies, such as one by Chao et al in 1954, found that the use of external radiation therapy could alleviate symptoms in as many as 63% of the patients undergoing therapy. This and other similar studies provided the foundation for WBRT. While deemed fit initially, WBRT can cause a number of side effects, both over short- and long-term, some of which include severe fatigue, somnolence, brain’s white matter disease (leukoencephalopathy), radiation necrosis, and most importantly an irreversible decline in memory that can begin as soon as three to four months or as late as 30 or more years following the treatment.
These adverse effects have rendered WBRT a less viable option in patients. In fact, doctors all across the world recommend in unison that WBRT should not constitute the initial treatment of brain metastases because it dramatically hikes the risk of cognitive decline without improving survival outcomes. The clinical studies and trials, emerging every few years, keep vouching for the recommendation.