Chemotherapy uses drugs that target and kill cancer cells. After surgery, most women with ovarian cancer get as a first-line chemotherapy a combined treatment with a platinum-based drug and a taxane.
• Platinum-based drugs, such as cisplatin, (trade name Platinol) and carboplatin (trade name Paraplatin) have the chemical element platinum as part of their molecular structure. These drugs form highly reactive platinum complexes that bind and crosslink DNA, a double-stranded molecule inside the nucleus of the cell that controls cellular activity. The chemical crosslinking within the DNA prevents cancer cells from growing and causes them to die.
• Taxanes, include paclitaxel, (trade name Taxol) or docetaxel, (trade name Taxotere), are a type of drug originally extracted from the Pacific yew tree, but now are chemically synthesized. Taxanes target microtubules, structures akin to internal highways inside cells. Taxanes prevent the microtubules from reorganizing themselves so cancer cells are no longer able to divide and grow.
Chemotherapy is delivered in cycles, with each treatment period followed by a rest period. How the chemotherapy is delivered depends on the stage of the disease and how much of the tumor was removed:
• Intraperitoneal chemotherapy is done through a surgically implanted catheter in the peritoneum, or abdominal cavity, to destroy cancer located in the abdomen or pelvis. The catheter inside the abdominal cavity is connected to a port, which the surgeon situates between a rib and abdominal muscle. The port has a chamber outside of the skin for delivery of drugs, which then enter the catheter to wash over internal organs. Some of the drug also diffuses into the bloodstream.
• Systemic chemotherapy is done by mouth or intravenously, through the vein to destroy or control cancer throughout the body.
In January 2006, the National Cancer Institute announced that it was now recommending both systemic intravenous and intraperitoneal chemotherapy for certain women with advanced ovarian cancer, particularly women with stage III cancer whose tumor was debulked to less than one centimeter in size or had no visible sign of the disease. Approximately 60 percent of women diagnosed with ovarian cancer have stage III disease. The combined approach, with intraperitoneal treatment after intravenous drug therapy, is more toxic, with more side effects, but extends overall survival for women with advanced ovarian cancer by about a year compared to intravenous delivery alone.
Although many women have trouble completing all the chemotherapy rounds with the combined intravenous and intraperitoneal treatments, whatever they can withstand is still thought to be effective. Doctors believe that intraperitoneal therapy works by bringing the toxic drugs in a more concentrated form closer to the site of the disease and are therefore more effective at killing the cancer cells. Intravenous therapy, being more systemic, aims to kill cancer cells wherever they might be located in the body.
Women with earlier stage disease and women with cancers that cannot be reduced to less than one centimeter in size usually get intravenous chemotherapy with a platinum-based drug and a taxane.