Recently, on World Health Day, filmmaker and writer Tahira Kashyap revealed that her breast cancer had returned — seven years after her first diagnosis in 2018. In a social media post, she said, “Seven-year itch or the power of regular screening — it’s a perspective,” urging people to go for regular mammograms. “Round 2 for me … I have got this,” the post added.
Cancer recurrence happens when cancer returns after a period of remission. It can occur in the same place as the original tumour (local recurrence), nearby (regional recurrence), or in a different part of the body (distant recurrence or metastasis). Recurrence, however, does not mean the treatment failed — it means some cancer cells remained in the body after treatment and later started growing again. Regular follow-ups and screenings play a crucial role in catching recurrences early, which can improve treatment options and outcomes.
Dr CN Patil, HOD, medical oncology and haemato-oncology at Aster RV Hospital, highlighted that emerging research suggests that lifestyle factors after treatment may influence the risk of cancer recurrence in ways not fully understood. “For instance, disruptions to the body’s circadian rhythm — such as irregular sleep patterns or exposure to light at night — have been linked to changes in cell behaviour and immune function,” Dr Patil said, adding that these subtle biological shifts can create conditions where previously eliminated cancer pathways may quietly reactivate.
It’s not just about diet or exercise, but how daily habits interact with the body’s internal clock, potentially influencing cancer’s return. Additionally, the microbiome — the trillions of bacteria living in our gut — is gaining attention as a hidden player in cancer recurrence, he added. “A disturbed or imbalanced microbiome can interfere with how the body processes drugs, metabolises nutrients, and regulates inflammation. Some studies have shown that patients with a more ‘diverse gut microbiota’ respond better to treatment and have lower recurrence rates. This opens up a new frontier where managing gut health might one day become a key part of preventing cancer from coming back,” Dr Patil explained.
Dr Rahul S Kanaka, surgical oncology consultant at Manipal Hospitals, emphasised that while most people think cancer recurrence is just a return of the disease in the same area after treatment, what’s less known is that some recurrences happen because tiny clusters of cancer cells, too small to be detected during scans, remain hidden in the body. These “sleeper” cells can stay inactive for years, surviving treatment by entering a dormant state, he said.
When the environment inside the body changes — due to stress, inflammation, or hormonal shifts — these cells can “wake up” and start growing again, leading to a recurrence.
Another lesser-known factor is the role of the immune system. After initial treatment, a person’s immune response might weaken due to aging or other illnesses. This reduced immune surveillance means that previously controlled cancer cells can slip past unnoticed and begin multiplying. In some cases, the very treatment used to kill cancer cells — such as chemotherapy or radiation — might cause changes in healthy cells that make them more vulnerable to becoming cancerous in the future, contributing to a second round of the disease, Dr Kanaka explained.
Apart from tests, changes in how a person feels can also signal early warning signs — though these can sometimes be vague. Experts highlight that unexplained fatigue, weight loss, persistent pain in a specific area, or unusual symptoms similar to those experienced before the first diagnosis should be checked out. Regular follow-ups and honest conversations with doctors about new symptoms or concerns are crucial. Doctors also use tumour markers, imaging scans, and personalised risk profiles based on the cancer’s type, grade, and genetics to keep an eye on any possible return, they said.