A Brave New World of Personalized Cancer Care
Scientists and cancer specialists are striving to create a future in which cancer prevention, diagnosis, and treatment can be personalized, tailored to the biology of individual patients and their cancers. The future of personalized cancer therapy dictates one size does not fit all.
There are more than 200 types of cancer. Understanding the molecular basis of each type is a critical step toward personalizing cancer care. Molecular research is the key to developing approaches for predicting how individuals may respond to a treatment.
A complete catalog of the human cancer genome will one day allow categorization of all the mutations found in different tumors, providing insights into the causes of cancer and leading to many new drug treatment targets. Genomic technology already has been used to distinguish different types of cancer. Accurate diagnosis based on the molecular characteristics of the disease enables selection of the best treatment.
Understanding the molecular characteristics of a patient's cancer increases the likelihood of selecting the treatment most likely to help. There may be a "targeted therapy" option – a drug designed to precisely target cancer cells while sparing healthy tissue. Cancer specialists are using genetic and molecular information from tumors to match patients with the most appropriate drugs.
Targeted cancer therapies block the growth and spread of cancer by interfering with specific molecules. Scientists often call these molecules “molecular targets.” Targeted cancer therapies are sometimes called “molecularly-targeted drugs,” “molecularly-targeted therapies,” or other similar names.
By focusing on molecular and cellular changes specific to cancer, targeted cancer therapies may be more effective than other types of treatment and less harmful to normal cells. Targeted cancer therapies interfere with cancer cell division and spread in different ways. Many therapies focus on proteins that are involved in cell signaling pathways, a complex communication system which governs basic cellular functions and activities. Those activities include cell division, cell movement, how a cell responds to specific external stimuli, and cell death.
Twenty - nine targeted therapies are available today for cancer patients.
- Some targeted therapies block specific enzymes and growth factor receptors involved in cancer cell growth (Tarceva).
- Other targeted therapies modify the function of proteins that regulate gene expression (Targretin).
- Some targeted therapies (Velcade) induce cancer cells to undergo cell death (called apoptosis).
Tumor growth beyond one millimeter in size requires a blood supply to get oxygen and nutrients. There are targeted therapies which block the growth of blood vessels to tumors (called angiogenesis), thereby blocking growth.
- A treatment that interferes with angiogenesis (Avastin) may block tumor growth.
- Some targeted therapies (Rituxan) act by helping the immune system destroy cancer cells.
- Another class of targeted therapies (Zevalin) includes monoclonal antibodies which are used to deliver toxic molecules or radioisotopes to cancer cells.
Cancer vaccines and gene therapy are considered targeted therapies because they interfere with the growth of specific cancer cells. Targeted cancer therapies are being used alone, in combination with other targeted therapies, and in combination with chemotherapy.
Evidence-based results of a few targeted drugs/treatments
- Herceptin was one of the first targeted drugs found effective against a type of breast cancer that makes too much of a protein called HER-2.
- Patients whose colorectal cancers have a mutant form of the KRAS gene do not benefit from treatments involving Erbitux, and therefore can be spared that drug's side effects and cost.
- The treatment of chronic myelogenous leukemia has been revolutionized using Gleevec, a drug that targets a specific genetic mutation, the BCR-ABL fusion gene.
- A 70-gene Mammaprint analysis and a 21-gene Oncotype DX analysis are being used to predict which patients with lymph node negative breast cancer are most likely to benefit from chemotherapy.
These are a few examples heralding the dawn of personalized cancer care and future direction of cancer research, providing the right treatment recipe for the right patient.
Dr. Gagliano has more than 30 years experience in treating cancer patients. He has participated in many clinical trials and studies.