Joseph Siu Kie Au

Precision Oncology: Myth or Reality?


Precision oncology is defined as the molecular profiling (often restricted to comprehensive genomic profiling by some authors) of cancers to identify targetable alterations, based on which tailored treatments are given. Undoubtedly, it has undergone rapid advancements in recent years, and is now a part of mainstream clinical practice. In the NCI-MATCH precision medicine Genomic study of 6000 NCI-MATCH cancer patients, the use of tumor gene testing makes major contributions to select treatment for patients. Forty percent of patients had tumor gene abnormalities that matched to targeted drugs studied in the trial. The rate may increase as more drugs become available, especially ones that target common gene defects.

However, this concept of ‘personalized cancer medicine’ often gets oversold, and many patients start believing that tailor-made ‘magic pills’ can provide miracle cures for their cancers.

The accelerated approval of gefitinib for advanced non-small cell lung cancer by FDA in 2003 can be considered as a milestone of development in targeted therapy for a common solid cancer. As compared with chemotherapy, there was marked improvement in objective response (50-75%), progression-free survival (about 10 months) and possibly overall survival (about 28 months) in those with sensitising EGFR mutations. There have been rapid developments of various targeted drugs for various cancers in the subsequent developments over these 18 years. It appears that we have reached a ceiling beyond which further improvement in clinical outcomes is difficult. Cure is still very uncommon. Moreover, financial toxicities and inequality of health care are becoming more severe.

Holistic personalized management of cancer is still most important for the quality of life of our patients.  A personalized cancer therapy based on molecular or genetic information is just part of a broader multidisciplinary treatment plan. The promise of precision oncology should be communicated to patients realistically, discarding blind hope and making informed consent.