Sunday, September 13, 2015


All types of cancer involve Uncontrolled Cellular Division.  Cancer fighting drugs can vary in their mechanism of action and side affects.

Most chemotherapeutic drugs fall into three categories:
(1) Cytotoxic
(2) Targeted Therapy
(3) Immunotherapy

Cytotoxic drugs can not distinguish normal cells from cancer cells, and thus, these drugs kill or damage all types of cells, even healthy cells. Mechanisms of action may relate to preventing the cells from replicating (Alkylating agents); interference with RNA or DNA replication (Anti-metabolites & anti-tumor antibiotics); disrupting the activities of enzymes that aid in the separation of DNA strands during DNA replication (Topoisomerase inhibitors); and drugs that stop mitosis - a process where a single cell splits into two cells (Mitotic Inhibitors).  These drugs typically have significant side effects to include hair loss, nausea and vomiting, fatigue and nerve damage.

Targeted therapy is more selective.  These drugs disrupt the activity of specific molecules that promote the growth of cancer cells. Mechanisms of action may relate to blocking enzymes that signal cancer cells to divide (Signal transduction inhibitors); controlled and targeted cell death in cancer cells (Apoptosis inducers); blocking formation of new blood vessels to tumors, thus "starving" the tumors from oxygen and nutrition which results in cancer cell death (Angiogenesis Inhibitors); blocking hormone production that may stimulate the growth of certain cancers (Hormone Therapies);
a molecular cytotoxic drug or radioactive agent is linked to a monoclonal antibody that targets and kills cancer cells (Antibody-drug conjugates). Targeted therapy drugs tend to have less serious side effects, but can result in diarrhea, fever, blood clotting issues, wound healing problems and skin problems, hypertension and liver problems.

Immunotherapy drugs stimulate the body's natural immune system to fight cancer. Interferons boost the ability of the body's immune cells to fight cancer or infections.  Interleukins help immune cells to grow and replicate more quickly, thus allowing the body to fight the cancer more efficiently. Some immunotherapies may cause flu-like symptoms, rashes or hypotension.

Many times, combining the different categories of chemotherapeutic drugs to treat certain cancers add benefit and reduces the chance of resistance to chemotherapy.

For some cancers, surgery is the first line treatment.  For other types of cancer, radiation is the preferred treatment.  Some cancers are treated by chemotherapy alone.  Other cancers are better treated with a  combination of surgery, radiation and chemotherapy.