By LabMedica International staff writers

One of the methods for treating bladder cancer involves the use of chemotherapy and/or radiation therapy, followed by a radical cystectomy only for patients who do not achieve a complete response. Those who do achieve a complete response are closely monitored following chemotherapy and/or radiation and undergo radical cystectomy if cancer reoccurs. However, radical cystectomy is a significant operation that necessitates urinary diversion, leading to life-altering consequences. Now, a new blood test may enable bladder cancer patients to avoid a precautionary cystectomy after immunotherapy treatment.

Scientists at the Netherlands Cancer Institute (NKI, Amsterdam, Netherlands) in collaboration with Inivata (Cambridge, UK) have demonstrated that a novel technique can improve the prediction of tumor recurrence. In the study, the scientists examined the blood of bladder cancer patients who had undergone immunotherapy. These patients were part of a high-risk group with an increased likelihood of disease recurrence, placing them on a waiting list for bladder removal surgery as a preventive measure. The scientists analyzed the freely circulating DNA in the patients' blood: small DNA fragments that travel through the bloodstream, which can sometimes contain mutated DNA from a tumor. The researchers investigated whether they could detect tumor DNA in these patients and use these findings to predict the likelihood of tumor recurrence.

The study's results were encouraging. In most cases, the researchers were able to accurately predict patients' recovery after immunotherapy based on the blood test findings. Small mutated DNA fragments from the tumor were often present in patients who did not respond well to the therapy. In contrast, no tumor DNA was detected in the blood of patients who responded positively to the immunotherapy. This latter group also experienced significantly fewer tumor recurrences. This breakthrough is crucial because cystectomies are highly invasive. There are instances where no tumor cells are detected during surgery, suggesting that the procedure might not have been necessary.

"We seem to be able to predict the course of bladder cancer with great precision using this technique," said principal investigator Michiel van der Heijden.. "That might help prevent radical surgery for a number of patients. Patients whose blood no longer contains tumor DNA may no longer need surgery at all.”