With the success of recent research in the area of genetics, doctors have been looking forward to bringing personalized treatment to their mesothelioma patients. By identifying specific genetic mutations, or biomarkers, within tumors doctors can target treatment according to the patient’s unique characteristics. For example, crizotinib has been found to be an effective drug for treating non-small cell lung cancer patients with tumors that express the abnormal anaplastic lymphoma kinase (ALK) gene. However, according to researchers in Great Britain, treatment based on genetic markers could fail due to genetic diversity within each tumor.
Personalized care has been touted as offering treatment options that might not otherwise have been considered. Personalized care also optimizes the potential for success of the treatment. Mesothelioma, an asbestos-caused cancer, currently has limited treatment options, but genetic science has promised to allow physicians to tailor treatment to individual patients based on their genetic makeup.
According to an article published in the New England Journal of Medicine (NEJM), though, genetic tests can be misleading. Depending on where on a tumor a biopsy is conducted, or whether it is from the primary or secondary tumor, the results could lead a physician down an incorrect path.
The researchers from the London Research Institute report that most often only one biopsy sample is taken to drive the course of treatment. But after they mapped the “genetic changes or faults in different regions of the same tumor” they believe physicians could miss the gene they had hoped to find to guide the patient’s treatment with just a single test.
The researchers analyzed kidney cancer tumors with samples taken from different regions of the primary tumor as well as biopsies from organs where the cancer had metastasized. They found that nearly 70% of the biomarkers differed across samples. This led them to conclude that these differences “may present major challenges to personalized-medicine and biomarker development.”
“We’ve known for some time that tumors are a patchwork of faults, but this is the first time we’ve been able to use cutting-edge genome sequencing technology to map out the genetic landscape of a tumor in such exquisite detail,” said Charles Swanton of University College London’s cancer institute who led the study.
In an editorial responding to the article, Dan Longo, MD, Deputy Editor of the NEJM, suggested the findings are a stark difference to the “overoptimism” in the field. He added that the drive toward personalized medicine may be more difficult than previously thought.
The researchers do not want the study to dampen enthusiasm for using genetically targeted therapies, however, they point out the focused treatment could become more costly. Mesothelioma advocates, although disappointed in the fact that personalized medicine may be more challenging, are encouraged that the findings now suggest physicians conduct multiple tests prior to subscribing to a particular treatment.