化疗不会降低乳腺癌扩散的风险

Once again, chemotherapy causes harm to breast cancer patients

Often, breast cancer patients like many other cancer patients would think that metastatic cancer kills patients because there is no medicine they can use to treat the disease once it spreads to another organ.  It is not 100% accurate.  In a sense, the treatments per se can contribute to the death of the patient.

This is obvious.  Cancer patients often do not feel anything abnormal when they are diagnosed with cancer.  But soon after they get treated, they start to experience terrible sickness and adverse effects from the treatments.  And the cancer condition can even get worse after surgery, radiation therapy and chemotherapy.  It does not need a rocket scientist to prove the harm from these treatments.

A study published in Science Translational Medicine found several  chemotherapy drugs commonly used to treat breast cancer can actually increase the number of microscopic structures in breast cancer tumors.

This is a condition called the tumor microenvironment of metastasis (MTEM).  This can eventually help invasive cancer cells to break out of the tumor envelope and escape into the blood which carries the cancer cells to remote organs and tissues, causing metastatic cancer. Metastatic cancer is lethal.

Cancer patients are often treated with chemotherapy before surgery.  The rationale is to shrink primary tumors and make it easy for doctors to remove the tumors and hopefully it can also reduce the risk for metastasis.  In fact, the study found pre-surgery chemotherapy can increase the risk of metastasis.

First, the study demonstrated use of chemotherapy drug paclitaxel increased the number of TMEM two to three times as those who were not treated with the drug.  Additionally, use of the drug also increased the TMEM activity.  Specifically, under the influence of the drug, the density of macrophages increased, the permeability of tumor blood vessels increased and expression of Mena protein forms in invasive cancer cells also increased.

And not just in tumors, this drug has a harmful effect.   This drug also doubled the number of tumor cells in the blood stream, and increased micro-metastasis in the subject’s lungs.  The study identified three drugs that cause breast cancer to spread.

The other two chemotherapy drugs are cyclophosphamide and doxorubicin.  Both do harm as Paclitaxel does, increasing the TMEM activity, TMEM sites and the number of circulating tumor cells in mice.

These harmful effects are not just observed in mice.  They increased risk of metastatic breast cancer also in human breast cancer patients.

In this study, researchers compared biopsy specimens taken from 20 breast cancer patients before and after treatment with doxorubicin, cyclophosphamide, and paclitaxel.  They found the majority of patients had a noted increase in TMEM sites after the chemotherapy.  Five patients had a five-time increase in the number of TMEM while none of others showed any decrease.  This means that these chemotherapy drugs can either increase risk or not decrease the risk of breast cancer metastasis.

The Pharma Death Clock estimates that since Jan 1, 2000, nearly 18 million people have died from chemotherapy.

One of the worst side effects of chemotherapy drugs is the brain damage in breast cancer patients.  Stanford University studied this side effect and found women receiving chemotherapy for breast cancer had reduced their cognitive abilities, which are important for planning, memory and cognitive control.

This is not the first study that found that use of chemotherapy can increase the risk of metastatic breast cancer.   At least two major studies have demonstrated that chemotherapy treatments increase the risk of metastasis by opening the door of the tumors for cancer cells to escape into the blood stream.

化疗药物紫杉醇帮助乳腺癌扩散到肺部

An Australian study revealed that on average 64 % cancer patients survived from cancer for five years or longer.   2.2% out of this 64% can be attributed to chemotherapy.  Not a whole lot while the adverse effects can be huge.

具有细胞毒性的化疗药物帮助癌症患者生存？