In 2012 I wrote about a study which found that chemotherapy can backfire causing damage to healthy cells and triggering them to secrete a protein called WNT16B, which causes cancer cells to grow, invade new tissue, and resist further treatment.
In 2016 we learned that chemo causes long-term immune system damage in breast cancer patients, reducing key immune cells for at least 9 months after treatment.
In July 2017 a study found that, while shrinking tumors, chemotherapy opens a gateway for breast cancer cells to spread into the blood and other parts of the body.
Today, on January 3rd, 2019 (Happy New Year!), we have a new study to talk about, which found that two commonly used breast cancer drugs can promote lung metastasis in a previously undiscovered way.
Some breast cancer patients are given ‘neoadjuvant’ chemotherapy before surgery, to reduce the size of a tumor. In some cases, pre-surgery chemo can reduce or eliminate the tumor completely.
However, if the tumor does not respond to neoadjuvant chemo, there can be a higher risk of metastasis to other organs, bones or the lungs.
Researchers found that two chemotherapy drugs frequently used for patients, Taxol (paclitaxel) and Adriamycin (doxorubicin), induce breast cancer tumors to release tiny fluid filled sacs called exosomes, which contain a unique protein called annexin-A6 (ANXA6).
After being released from a chemotherapy-treated tumor, the exosomes circulate in the blood. When they reach the lungs, the exosomes release their content, including annexin-A6, which stimulates lung cells to release another protein, CCL2, which attracts immune cells called monocytes.
This immune reaction can be dangerous, as previous studies have shown that monocytes can actually help cancerous cells grow and survive in the lungs.
“In short, our study has identified a new link between chemotherapy and breast cancer metastasis,” says author Michele De Palma.
Corroborating their laboratory data, the researchers found increased levels of annexin-A6 also in the exosomes of breast cancer patients undergoing neoadjuvant chemotherapy. However, De Palma cautions against jumping to conclusions: “While this observation supports the significance of our findings, at the moment we don’t know if annexin-A6 has any pro-metastatic activity in human breast cancer”.
The researchers also found that neutralizing annexin-A6 or blocking monocytes with additional drugs during chemotherapy prevents the experimental mammary tumors from metastasizing to the lung.
“Various monocyte inhibitors have been developed for clinical use, so they may be tested in combination with neoadjuvant chemotherapy to potentially limit unwanted side effects mediated by exosomes,” says De Palma.
In light of their findings, the study authors still recommend breast cancer patients undergo neoadjuvant chemotherapy if recommend by their doctor.
In some cases chemotherapy can be helpful, depending on the type and stage of cancer, but it can also do more harm than good by causing profound immune system damage, while making cancer stem cells more aggressive and helping them spread. And some chemotherapy drugs can even cause new cancers in the body.
It’s important that patients fully understand the risks and benefits before agreeing to treatment. Please download my free guide 20 Questions for Your Oncologist, which will arm you with information that will help you and your loved ones make the best decision.
How chemotherapy can backfire and boost cancer growth
Chemo may spread breast cancer and trigger more aggressive tumors
Chemo causes long-term immune system damage in breast cancer patients
Study finds half of breast cancer patients don’t need chemo
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