Platinum-based chemotherapy is a mainstay of treatment for many types of cancer, and works by directly binding to DNA and forming cross links between the strands. This, in turn, inhibits DNA synthesis and results in cell death. Cisplatin was the earliest agent developed in this group, and to date (December 2009) is the most extensively used cancer medication due to its effectiveness in many types of malignancies. Newer agents include carboplatin and oxaliplatin, which have similar efficacy to cisplatin, but with a lower side effect profile. All chemotherapeutics have toxic side effects which can be tolerated; however, occasionally dose-limiting toxicities can occur, at which point treatment must not be augmented, and in some cases even must be ceased.
Cisplatin
Cisplatin is used for many types of cancer, including testicular, breast, lung, ovarian, gastric and esophageal cancers. It has a highly emetogenic potential, which is why common toxicities are nausea and vomiting. Other side effects include renal toxicity, ototoxicity (high frequency hearing impairment) and peripheral neuropathy. The renal toxicity can be reduced via extensive hydration and dieresis (usually osmotically with mannitol), and the toxicity is usually cumulative when it occurs. The peripheral neuropathy is primarily reported in those receiving high cumulative doses of the drug.
Carboplatin
Carboplatin is often used as an alternative to cisplatin, as it does not share many of cisplatin's dose-limiting toxicities. It does have the emetogenic properties, but they are much less severe than cisplatin's and can be controlled by antiemetic agents. In addition, it also causes bone marrow suppression; most notably resulting in thrombocytopenia, or extremely low platelet counts.
Oxaliplatin
This chemotherapeutic is currently used in colorectal cancer treatment, and investigations are underway regarding its efficacy in other solid tumors. Common toxicities include nausea and vomiting, but stomatitis and diarrhea also frequently occur. Serious toxicities include risks of neutropenia and peripheral neuropathy. A March 2008 article in "Gastroenterology Clinics" showed that in systemic therapy for colon cancer, changing to a regimen that incorporated oxaliplatin showed better mortality results with much higher toxicities involving parasthesias.
Cisplatin vs. Carboplatin
A 2002 study in the "Annals of Oncology" comparing cisplatin and carboplatin has shown that cisplatin seems to have a higher survival benefit; however, the toxicities incurred seemed to be worse. This is why consultation with health care specialists is of paramount importance, as they are trained to weigh the risks and benefits, and present all the options to the patient in a manner that is easily understood. The complex nature of cancer, especially late and end stage disease, also has palliative and ethical considerations that must be weighed as well before embarking on any chemotherapeutic course of action.
References
- "The Lancet Oncology;" Cisplatin as a cornerstone of modern chemotherapy; Mir O., Ropert S., Goldwasser F.; March 2009
- "Gastroenterology Clinics;" Systemic Therapy for Colon Cancer; Asmis T., Saltz L.; March 2008
- "Annals of Oncology;" Phase III randomised trial comparing paclitaxel/carboplatin with paclitaxel/cisplatin in patients with advanced non--small-cell lung cancer: a cooperative multinational trial; Rosell R., Gatzemeier U., Betticher D.C.; 2002
