Cancer presents difficult treatment challenges. Unlike normal healthy cells, cancer cells have the ability to migrate, or metastasize, to organs distant from the original tumor site. Because it is impossible to be certain no cancer cells remain after primary therapy, oncologists often follow surgery or radiation therapy with a course of medications to kill any lingering cancer cells. This secondary treatment is called adjuvant chemotherapy.
What is Adjuvant Chemotherapy
Adjuvant chemotherapy helps prevent cancer recurrence. It consists of a series of cancer-fighting medications administered following primary therapy, either surgical removal of the tumor or radiation therapy (eChemotherapy.com). Even after a tumor is surgically or radiologically removed, individual cancer cells may remain. Additionally, cancer cells may have already metastasized to distant organs through the bloodstream or lymphatic system regardless of how early the cancer is discovered.
The remaining cancer cells are too small to be detected by scans or other tests, and they cause no symptoms until the tumor has grown and cancer has recurred (American Cancer Society). Adjuvant chemotherapy is an attempt to kill these remaining cells before the cancer grows and symptoms develop. Neoadjuvant chemotherapy, on the other hand, is given prior to surgery to shrink the tumor to make it easier to remove.
How Does Adjuvant Chemotherapy Fight Cancer
The medications used for adjuvant chemotherapy are either injected or taken orally. The drugs are systemic; that is, they travel throughout the body and are not limited to a specific organ (Chemocare.com). The therapy works by targeting some of the characteristics that differentiate a cancer cell from a normal healthy cell. In addition to the ability to metastasize, other defining characteristics include a tendency to multiply too quickly and a failure of the mechanism that initiates natural cell death. Chemotherapy drugs target rapidly dividing cells and damage the ability of those cells to replicate, leading to cell death (Chemocare.com).
Types of Chemotherapy Agents
Each type of drug used for chemotherapy works differently and targets different phases of the cell cycle. For example, alkylating agents are most effective against cells in a resting phase whereas antitumor antibiotics are active against cells in multiple phases (Chemocare.com). Antimetabolites and topoisomerase inhibitors enter the cancer cell and interfere with the ability of the cell to divide. Targeted therapies, such as monoclonal antibodies, target specific proteins or enzymes on cancer but not normal cells. Chemotherapy is administered as a series of treatments, alternating between different types of drugs for maximum effect.
Side Effects
Chemotherapy is associated with a number of side effects, some of which may be severe. Although the medications target rapidly dividing cells, they cannot distinguish between cancerous and healthy cells that naturally divide quickly, such as cells in the mouth, hair follicles, stomach, intestines and blood. This leads to side effects such as nausea and vomiting, hair loss, low blood cell counts, diarrhea and constipation (Chemocare.com).
When is Adjuvant Chemotherapy Used
Adjuvant chemotherapy is used primarily for cancers with the highest rates of recurrence. These include breast, ovarian, testicular and colorectal cancers (ChemotherapyFacts.com).
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