Frequent Taxane use Increases the Need for Erythropoietin, and Frequent Doses of Docetaxel Found to have Unacceptable Levels of Skin Toxicity

Paclitaxel is a type of chemotherapy drug that is sometimes used in the treatment of breast cancer. Other studies have found that the more frequently you give paclitaxel, the better the outcome and the higher the rate of survival. Docetaxel is a drug that is sometimes used instead of paclitaxel. One study has looked at whether this can be used in the same way as paclitaxel, by giving it more frequently and seeing if it also led to better results. The study showed that using either drug more frequently leads to a higher need for erythropoietin (a drug used to help with anaemia), but lowers the amount of patients that had a low white cell count. The study also showed however, that docetaxel, when used frequently in the same way as paclitaxel, leads to very bad skin and nail damage. This damage was very bad, and very common to the point where most patients treated with it had to stop. Due to this, the authors cannot recommend the use of very frequently administered docetaxel for the treatment of breast cancer.

One standard regimen of treatment for breast cancer is two drugs, doxorubicin and cyclophosphamide, with the addition of a ‘taxane’ agent (usually paclitaxel). Taxanes work by stopping cells from dividing as effectively, slowing the cancer’s growth. It has been shown that giving paclitaxel more frequently leads to better long-term survival for patients and so it is now often given in what is called a ‘dose-dense’ way. Dose-dense simply means that doses are given more frequently, with less time in between the dosages. This treatment is now often used for therapy in breast cancer.Sometimes in the normal treatment of breast cancer, doctors will replace paclitaxel with another chemotherapy agent, docetaxel because they consider it better at fighting the cancer. One study recently looked at whether or not you can use docetaxel in this same ‘dose-dense’ way as you can paclitaxel, and whether it would have better or worse outcomes. They also looked at other side-effects, such as how many people got anaemia (low levels of red cells in the blood), neutropaenia (low levels of white cells in the blood) and how many people got serious side effects like major damage to the skin and nails.Erythropoietin is a hormone released by the body that tells the bone marrow to create more red blood cells that carry oxygen. Using it in cancer treatment can overcome some of the damage that chemotherapy agents can cause to the normal production of blood cells and hopefully prevent anaemia. In this study, the researchers found that giving paclitaxel more frequently meant that doctors had to use erythropoietin more often. This might be because dose-dense paclitaxel causes more damage, but might also just mean that doctors were more afraid with the dose-dense method of treatment and so were more likely to try and prevent anaemia before it happened.Colony-stimulating factors are another type of chemical released by the body that tells it to produce more white cells. White cells are part of the immune system and fight infection. Colony stimulating factors are used in dose-dense treatment for cancer because the chemotherapy agents are more damaging to the white cells. Without help, the level of white cells can fall dangerously low. This study found that in the dose-dense therapy, the rate of neutropaenia was actually lower than normal (meaning white cell counts were better), which they put down to an increased use of these colony-stimulating factors.The unfortunate finding of the study though, was that when you replaced paclitaxel with docetaxel in this dose-dense treatment regimen, the side-effects were so bad that therapy had to be stopped. For some unknown reason, this type of dose-dense docetaxel therapy led to very bad skin and nail toxicity where the skin as well as finger and toenails started to break down. The only way they could help these people was by giving them skin moisturiser. While this could happen in the paclitaxel group, the rate was so much higher in the docetaxel group that there must be a reason behind it. Due to this, the authors of the study say that they cannot recommend the use of docetaxel instead of paclitaxel in dose-dense therapy until someone finds a way to reduce the toxicity.On the bright side, their study did confirm that more frequent (dose-dense) administration of paclitaxel did lead to better outcomes and survival for the patients, confirming what other studies have shown.