Cancer Vaccines and Immunotherapy
Cancer immunotherapies, including cancer vaccines, are novel investigational cancer therapies. In contrast to chemotherapy and radiotherapy regimens that are often associated with severe side effects, cancer immunotherapy stimulates the body’s immune system and natural resistance to cancer, thus offering a gentler means of cancer treatment that is less damaging to the rest of the body. Surgery is generally (but not always) performed, prior to immunotherapy, to remove most of the tumor (Hanna MG, Jr. et al 2001; Jocham D et al 2004). Vaccination or immunotherapy prompts the immune system to kill residual cancer cells that persist after surgery and could result in the cancer recurring.
The status of the patient’s immune system is the key physiological factor affecting the outcome of cancer immunotherapy. However, each individual’s immune status is in turn affected by several factors (including age, tumor-induced and surgery-associated immunosuppression, and nutritional status) that need to be assessed, and some require continuous monitoring for the successful application of immunotherapeutic regimens. Immune cells play a central role in mediating the effects of immunotherapy, and specific nutritional supplements that enhance immune cell function can be effective in preparing patients for immunotherapy or vaccination (Malmberg KJ et al 2002).
Therapeutic cancer vaccines developed for melanoma, renal cell carcinoma, and colorectal cancer have shown benefits in phase III trials by extending the disease-free survival period (before relapse) and overall survival. In addition, several immunotherapy clinical trials have been performed for metastatic breast cancer and non-Hodgkin’s lymphoma.