Researchers have found that a specific type of chemotherapy used to treat some breast cancer patients may increase the risk of the disease spreading. The work has been published in the journal Science Translational Medicine.
Either taken in drug or intravenous form, chemotherapy is cytotoxic, meaning that it kills cells, both healthy and cancerous. When it comes to treating breast cancer, there are a number of different routes that can be taken, depending on how advanced it is, whether or not the patient is to undergo surgery, and how they may respond to specific drugs.
This latest research focused exclusively on neoadjuvant chemotherapy, which is given to patients before they are to undergo surgery to remove the tumor. The purpose of it is to shrink the cancer in order to make the procedure easier and less evasive, as well as to lower the chances of the cancer coming back. Patients are usually given a combination of two or three drugs, but which ones depend on different factors, such as the risk it will return, or previous medical conditions.
The study specifically looked at neoadjuvant chemotherapy using the drug paclitaxel after a dose of doxorubicin in combination with cyclophosphamide. The research was carried out in mice, tissue in the lab, as well as patient-derived tissue grafted into the animal models. They found that the specific chemo used did decrease the size of the tumor, but that there were also some undesirable side effects.
It turns out the therapy seemed to increase what is known as “intravasation”. This is where the membranes surrounding the blood and lymphatic vessels effectively become leaky, and let things through, including cancerous cells. This is one of several ways in which cancer can metastasize, or spread around the body and infect other tissues.
This is clearly a worrying development, particularly when so many people are diagnosed with breast cancer every year, but it is also important to maintain a sense of proportion. The work is clearly significant, but it is relating only to one type of chemo given to patients suffering from one type of cancer, taking a specific combination of drugs, and was carried out in mice. What’s more, the researchers also found a way in which to prevent this process from occurring.
The researchers suggest that there are ways to minimize the risk while more investigations are carried out. “One approach would be to obtain a small amount of tumor tissue after a few doses of preoperative chemotherapy,” Dr George Karagiannis told the Telegraph. “If we observe that the markers scores are increased we would recommend discontinuing chemo and having surgery first, followed by post-operative chemo. We are currently planning more extensive trials to address the issue.”