Traditional cancer biopsies involve cutting a piece of the patient's tumor but this may change soon as researchers now tests a so called liquid biopsy, a blood test that shows potentials in finding hints of cancer DNA in a person's blood.

The simple blood draw is less dangerous compared with the traditional biopsies and CT scan. The technique will also allow oncologists to easily figure out if a particular treatment is working and to continue tracking the treatment in case the cancer cells already developed resistance.

The researchers said that the method could change how doctors follow up patients' response to treatments as well as track the emergence of resistance. It means that failing treatments could be abandoned earlier and this will spare the patient from the treatment's side effects as well as allow doctors to try other alternative methods of treating the disease.

"This could change forever the way we follow up not only response to treatments but also the emergence of resistance, and down the line could even be used for really early diagnosis," said Memorial Sloan Kettering Cancer Center chief medical officer José Baselga.

Current standard methods for detecting cancer and determining whether or not a treatment is effective are vague as they depend on the improvement of a patient's symptoms, which can be challenging given that symptoms vary with each individual. Doctors may even be fooled into believing that a tumor is still present when it is already gone.

Small studies of the new biopsy method involving colon, lung and blood cancers have already been conducted and early results appear to be encouraging. A study conducted by the National Cancer Institute published in the Lancet Oncology on April 1 found that in patients with the most prevalent form of lymphoma, the blood test could predict recurrences as early as more than three months before they were detected on CT scans. The liquid biopsy was also able to identify the patients who were not likely to respond to therapy.

"Surveillance circulating tumour DNA identifies patients at risk of recurrence before clinical evidence of disease in most patients and results in a reduced disease burden at relapse," study researcher Wyndham Wilson, from the National Cancer Institute, and colleagues reported in their study. "Interim circulating tumour DNA is a promising biomarker to identify patients at high risk of treatment failure."

Photo: Alden Chadwick | Flickr