Targeted therapies of solid cancers: new options, new challenges

The landscape of medical oncology is filled with approvals of new anticancer agents, the majority of which are targeted agents. This shift in therapies raises multiple challenges including the appearance of new toxicities, the need for biomarkers, the emergence of genomics and the evolution of cancer molecular imaging.

Biopsy of metastatic lesions is slowly becoming a standard of care before the initiation of any therapy. These invasive procedures have been found to be generally well tolerated and are being put to use with the emergence of genomics. Gene sequencing and new imaging techniques are serving the understanding of tumor biology and the search for 'biomarkers' predicting response and resistance to treatment. New clinical trial designs incorporating the 'presumed' biomarkers are guiding patients to specific treatments and have shown outcome improvements.

Many questions remain however unanswered and new challenges appear. Intratumor heterogeneity emerges as a brake to personalized cancer care. Relevant targets remain undruggable and costs may hinder progress. Furthermore, technical issues continue to arise. The ultimate goal remains to achieve cure by blocking the multiple pathways of cancer development and proliferation, while sparing the patients the burden of therapy.