WHAT IS CANCER? Part III

17. What is adjuvant therapy?

Adjuvant means "assisting or aiding," but we use this term to mean assisting after surgical or radiotherapeutic control of the primary tumor. Adjuvant chemotherapy is of documented benefit in the treatment of breast cancer, colorectal cancer, stomach cancer, pancreatic cancer, and ovarian and testicular tumors. Adjuvant radiation therapy is effective in reducing the risk of tumor recurrence around the surgical site. It is often used in treating patients with rectal, breast, head and neck, and stomach cancers as well as sarcomas. Conceptually, both surgery and radiation are local/regional therapies. Although chemotherapy is obviously a systemic treatment, it may help sensitize tumors to radiation. The term "neoadjuvant" doesn't really mean anything, but it is often used to describe preoperative chemotherapy or radiotherapy (which might more accurately be described as "induction" treatment).

18. What cancer treatments are available in addition to surgery, radiation therapy, and cytotoxic chemotherapy?

Hormonal manipulation has been used for decades to slow the growth of some tumors. Stimulation of the patient's immune system to combat cancer is potentially promising. This approach may involve vaccines, training of T cells, or enhancement of the immune response. New types of anticancer agents include drugs that interfere with tumor angiogenesis, antibodies and other drugs that interfere with growth factor receptors, other sorts of drugs that alter intracellular signaling, and drugs that restore cell cycle control. The limitation of all of these approaches resides in our inability to specify a target unique to cancer cells. Hence, treatments damage the rest of the patient, with potentially fatal toxicity.

19. Does the body fight cancer on its own?

Certainly. Some scientists believe that early cancers are regularly extirpated by the immune system (as we "catch" cancer every day) and that clinical cancers reflect a breakdown in immune surveillance. Immunocompromised patients with transplants or AIDS develop cancers with frightening frequency. Thus, rejection and sepsis are no longer the most common causes of death among kidney transplant patients-it's cancer. "Spontaneous remissions" of melanoma and renal cell carcinoma do occur and must be immunologically mediated. Indeed, these are the tumors that initially seemed to respond well to "adoptive immunotherapy" and interleukin-2.

20. What is a tumor-infiltrating lymphocyte (TIL)?

TILs are lymphoid cells that infiltrate solid tumors and appear reactive to autologous tumor antigens. Compared with circulating lymphocytes, TILs more aggressively target cancer.

21. What are palliative treatments?

Palliative means "affording relief but not curing."

22. Give some examples of palliative procedures.

Resection of the primary tumor in the face of distant metastases may be performed to treat bleeding or obstruction. Procedures to bypass intestinal or biliary obstruction in patients with unresectable cancer are common. Tracheotomies are created for patients who are unable to breathe because of upper airway obstruction, and feeding tubes may permit enteral nutrition in patients who cannot eat. Removal of isolated brain metastases often improves the patient's quality of life. Many patients with functioning endocrine tumors benefit from reduction in tumor mass.

23. What is cytoreductive surgery?

Cytoreductive ("debulking") procedures are designed to decrease tumor burden. Simply reducing tumor bulk is seldom sufficient to prolong survival. For cytoreductive surgery to be beneficial, the nonsurgical (adjunctive) therapy must be highly effective-such as radiation for glioblastoma or chemotherapy for ovarian cancer.