The looming threat of a relapse is something that hovers over many cancer survivors. Breast cancer in particular is known to enter extremely long dormant periods, and a new study led by researchers from Imperial College London is suggesting the drugs used to initially treat the cancer may be responsible, triggering some cancer cells to enter a sleeper state.
Around 70 percent of breast cancers are classified as oestrogen-receptor positive. This means the cancer utilizes oestrogen to grow, and following an initial surgery hormone drug therapy is usually administered. However, the relapse rate for patients undergoing this kind of hormone therapy is about 30 percent, and the cancer can unexpectedly recur as late as 20 years after initial treatment.
“For a long time scientists have debated whether hormone therapies – which are a very effective treatment and save millions of lives – work by killing breast cancer cells or whether the drugs flip them into a dormant ‘sleeper’ state,” says Luca Mangani, lead author on the new study.
Investigating thousands of breast cancer cells in the lab, the new study discovered current hormone treatments can in fact trigger some cancer cells to enter a dormant phase. Not only that, but the researchers also suspect this dormant phase to be part of the process the cancer cells move through before ultimately becoming resistant to the hormone therapy.
“These sleeper cells seem to be an intermediate stage to the cells becoming resistant to the cancer drugs,” explains Iros Barozzi, co-author on the new study. “The findings also suggest the drugs actually trigger the cancer cells to enter this sleeper state.”
This new study in no way suggests women be hesitant in undergoing hormone therapy to treat breast cancer but instead it directs researchers to new understandings into how cancer cells enter dormant phases and why they reawaken years later. Answering these questions could help prevent long-term breast cancer relapses.
“If we can unlock the secrets of these dormant cells, we may be able to find a way of preventing cancer coming back, either by holding the cells in permanent sleep mode, or be waking them up and killing them,” says Mangani.
The new study was published in the journal Nature Communications.
Source: Imperial College London