Dormant Cancer Cells Linger in the Body: The Hidden Driver of Breast-Cancer Recurrence
After initial treatment, breast cancer tumors recur in about 30 percent of patients, contributing to roughly 685,000 cancer deaths worldwide each year. Dormant tumor cells (DTCs) can linger in the bone marrow and elsewhere, quietly capable of reigniting disease. This hidden reservoir is a key reason why post-treatment surveillance has not prevented relapse. As oncologist Angela DeMichele notes, “Right now, we just don’t know when or if someone’s cancer will come back – that’s the problem we set out to solve.”
In This Article:
A New Strategy: Targeting Dormant Cells Instead of Waiting for Recurrence
Rather than waiting and watching for relapse, researchers tested a strategy to attack the root causes of recurrence by targeting dormant cells themselves. Dormant tumor cells have only recently been confirmed as treatable targets. In this study, researchers used drugs to reach these sleeper cells, including the autoimmune drug hydroxychloroquine and the anti-cancer drug everolimus, or both.
Drugs That Target Sleepers: Hydroxychloroquine and Everolimus Show Dramatic Results
In a study of 51 patients with prior breast cancer and confirmed DTCs, the drugs cleared up to 80 percent of dormant cells when used alone and 87 percent when combined. In the group receiving both drugs, every participant remained cancer-free for three years. Those who took only one drug still showed strong results, with 92–93 percent cancer-free after three years.
The Biology Is Different: Dormant Cells Respond Differently from Active Cancer
Cancer biologist Lewis Chodosh notes that dormant tumor cells behave differently from actively growing cancers. Some drugs that work on fast-growing tumors don’t affect sleepers, while others can target these sleeper cells. This biology helps explain why a “sleeper” cancer may be more susceptible to treatment even when the active tumor is resistant.
Next Steps and Cautious Optimism
Not all survivors harbor DTCs, but for those who do, the early signs are encouraging. The next steps include larger trials, testing different drug combinations and doses. While breast cancer recurrence remains a major challenge, this line of research could shift the landscape from waiting for relapse to actively preventing it. The findings were published in Nature Medicine, and DeMichele hopes they ignite more research in this area.
