Precision medicine approach to cancer improves on older methods: study

Precision medicine, or the practice of targeting biological markers on a patient's tumors, proved significantly more effective at shrinking tumors and stalling the progression of cancer in the first large-scale analysis of such treatments.

Researchers from the University of California-San Diego School of Medicine pooled the results of 346 early-stage clinical trials involving more than 13,000 patients that were published between 2011 and 2013. Their findings were released on Wednesday and will be presented in full at the American Society of Clinical Oncology meeting in Chicago next month.

The precision medicine approach is part of a transition away from treating cancer based on specific organs. Instead, it focuses on the defective genes driving the disease, and uses that information to determine which drugs, or combinations of drugs, could best attack specific biological targets on tumors.

Although there has been ample anecdotal evidence that precision medicine can have dramatic effects in some patients, there has been scant evidence looking at the approach on a larger scale. The new study found that patients whose treatment was selected based on the molecular characteristics of their tumor had significantly better outcomes.

"Our study suggests that, with a precision medicine approach, we can use a patient's individual tumor biomarkers to determine whether they are likely to benefit from a particular therapy, even when that therapy is at the earliest stage of clinical development," said lead study author Maria Schwaederle of UCSD's the Center for Personalized Cancer Therapy.

The researchers found that tumors in patients who received targeted treatments had shrinkage rates of 30.6 percent, compared with 4.9 percent in those who did not. Patients treated with a precision medicine approach also had a longer time before the disease worsened, with median progression-free survival of 5.7 months compared with 2.95 months for those who were not.

"This strategy often results in good outcomes for patients, and I hope it will encourage and reassure doctors and patients considering enrollment in precision medicine-based (early-stage) trials," Schwaederle said in a statement.