Tailoring cancer treatment to genetic profile extends lives, study finds

Cancer patients with diseases that are difficult to treat may live longer if doctors engage in genetic sequencing and then match treatment to their illness, a long-term “precision medicine” study has found.

The study represents part of a push in cancer treatment to personalize medicine for specific patients, matching known tumor mutations to treatments in an effort to extend patients’ lives. It is the first long-term study to compare tailored methods to traditional, more generic treatment.

“All patients should have access to next generation sequencing and I believe in the next few years we are going to see this approach dramatically improving outcomes,” said Apostolia Maria Tsimberidou, a professor at the University of Texas MD Anderson Cancer Center, who led the research.

“We need to know what is really causing these diseases so we can treat them properly.”

The study was presented at the annual meeting of the American Society of Clinical Oncology (Asco) in Chicago, the world’s largest gathering of cancer specialists.

The study looked at more than 3,700 people with cancer that had proved difficult to treat and who had already undergone other types of treatments. Their ages ranged from 16 to 86, with a median of 57.

Included in the study were gastrointestinal (24.2%), gynecological (19.4%), breast (13.5%), skin (11.9%) and lung (8.7%) cancers.

Of those patients, 1,307 had a known mutation, and 711 received treatment based on that genetic profile. Those patients were twice as likely to live three years (15%) versus those who did not receive tailored treatments (7%). Patients were also six times more likely to live 10 years if they received tailored treatment, at 6% of the sample compared with just 1% for those who received general treatment.

Another, more comprehensive trial is due to take place at the MD Anderson Cancer Center, which will address an admitted shortcoming in the previous study, by using randomized trials.

Tsimberidou said her own clinic had witnessed the potential of personalized cancer medicines. One patient has been kept alive despite being diagnosed in 2011 with an aggressive form of brain cancer called glioblastoma. The same cancer killed the former US vice-president Joe Biden’s son, Beau, who died in 2015, and former British cabinet minister Tessa Jowell, last month.

Cancer research is increasingly pushing for patients to have tumors sequenced for personalized treatment after analyzing key details within the DNA.

Some types of genetic testing are already on the market. Another major study presented at the conference found that many women with the most common form of early breast cancer do not benefit from chemotherapy. That test looked only at 21 genes.

Researchers believe more detailed genetic testing is on the horizon.

Dr Catherine Diefenbach, an Asco expert, said scientists had barely “scratched the surface” of the potential of precision medicine.

“Now with faster and more robust genetic tests, we can help even more patients by treating the cancer based on its genetic makeup rather than solely on its location in the body,” she said.