A blood test could replace lung cancer biopsies

A study published in JAMA Oncology has shown that a blood test may be sufficient to identify the presence of specific mutations in lung tumors. This would prevent or significantly reduce the number of biopsies.

The study was led by Rafael Rosell, a specialist in lung cancer at ICO Badalona, and has been attended, among others, of Felip Cardenal, ICO Hospitalet, Ruth Porta, ICO Girona, and Enric Carcereny, Teresa Moran, Cristina Queralt, Itziar Aguirre and Jose Luis Ramirez, ICO Badalona. The work was carried out with the support of the three involved research institutes: Bellvitge Biomedical Research Institute (IDIBELL) at ICO L'Hospitalet, the Institute Germans Trias (GIBT) in Badalona, and the Institute of Biomedical Research of Girona (IdIBGi) in Girona.

Liquid biopsy

In recent years there has been much progress in personalized cancer treatment, ie provide a therapy based on the particularities of their tumor. In the case of lung cancer, for example, it is known that patients with certain mutations in the EGFR gene respond well to inhibitors of this gene, such as erlotinib, which has become the treatment of choice in these cases.

However, to determine if the tumor has or not the gene mutated it should be done one or more biopsies to extract sufficient tumor sample to be genetically analyzed.

The study published in JAMA Oncology,led by Rafael Rosell, analyzed the peripheral blood of 97 patients with mutations the EGFR gene, to see if, using a specific test, which is called liquid biopsy, one could detect the presence of these mutations.

The result was positive in 78% of patients. In these cases, then, there wouldn't have to do conventional biopsy because the blood test would be enough to establish the desirability of treating the patient with erlotinib.

These blood tests not only serve to establish the initial mutations that have the patient's tumor, but to see how it evolves throughout the treatment and if patient acquires or not resistance to drugs.

Different mutations, different prognosis

The study also served to confirm that not all mutations in the EGFR gene offered the same prognosis. Thus, it has been found that a punctual alteration in a region of the gene (exon 21) has a worse prognosis than the deletion of exon 19. This indicates the need for better treatment of this mutation carriers.