20.21: Combination Therapies and Personalized Medicine
Combining two or more treatment methods increases the life span of cancer patients while reducing damage to vital organs or tissue from the overuse of a single treatment. Combination therapy also targets different cancer-inducing pathways, thus reducing the chances of developing resistance to treatment.
The combination of the drug acetazolamide and sulforaphane is a good example of combination therapy to treat cancer. The cells in the interior of a large tumor often die due to the hypoxic and acidic microenvironment. In order to overcome this, cancer cells overexpress the enzyme carbonic anhydrase that catalyzes the reversible conversion of carbon dioxide to bicarbonate and neutralizes the acidic tumor microenvironment.
Acetazolamide is a carbonic anhydrase inhibitor that inhibits the enzyme carbonic anhydrase accelerating the death of cancer cells. Another drug, sulforaphane, activates certain anti-cancer responses and suppresses tumor progression. Combined administration of acetazolamide and sulforaphane results in the enhanced killing of cancer cells and reduced tumor progression.
Personalized medicine or precision medicine
Precision medicine or personalized medicine is an advanced technique that allows treatments based on the genetic background of the disease. The treatment is designed based on specific abnormal genes or proteins in the tumor cells of each individual. The details about cancer genetics are usually obtained from a tumor biopsy. The morphology of the tumor cells followed by genome sequencing reveals mutations or changes in the specific biochemical pathways. Based on this information, drugs and treatment regimens are decided.
Personalized medicine has four significant attributes. First, it is personalized. It integrates the genetic profile of patients to strengthen and target the therapy and reduce drug toxicity. Second, it is preventive. Females with mutations in BRCA1 or BRCA2 genes have a higher disposition of developing breast cancer. Such genetic data allow disease management through early intervention. The third attribute is predictive. Gene expression profiles are used to assess the risk of metastasis in patients with early-stage cancer. Based on the expression profiles, doctors can decide whether to use hormone therapy or more aggressive chemotherapy. Fourth is participation. The personalized treatments are less toxic and more effective. Hence, patients are more likely to comply with their treatments.