Residual Cancer Predicts Poorer Patient Outcomes

Radiotherapy, particularly stereotactic ablative radiotherapy (SABR), is widely used for treating cancers in the lung, liver, prostate, and other organs. While this high-precision, high-dose radiation therapy often yields promising scan results, new research suggests that hidden cancer cells may persist, leading to worse long-term outcomes (1^✔ ✔Trusted Source
No disease left behind

Go to source). In a newly published editorial in the Oncotarget journal, Dr. Muzamil Arshad from the University of Chicago Medical Center and colleagues have raised concerns over the limitations of imaging in assessing treatment success. They argue that relying solely on scans may not provide a complete picture of a patient's cancer status.

What is Residual Cancer

Residual cancer refers to cancer cells that remain in the body after initial treatment, even if scans appear clear. These lingering cells can lead to recurrence and worse outcomes if not detected early. Symptoms vary depending on the cancer type but may include persistent fatigue, unexplained pain, lumps, or abnormal weight loss.

Diagnosis typically involves imaging tests like MRI, CT scans, or PET scans, along with biopsies and blood tests to detect remaining cancer cells. Treatment options may include additional surgery, radiation therapy, chemotherapy, targeted therapy, or immunotherapy to eliminate residual cancer and reduce the risk of recurrence. Regular follow-ups and monitoring are crucial for early detection and better prognosis.

While post-treatment scans may suggest a tumor has been eradicated, microscopic cancer cells can remain undetected. Follow-up biopsies conducted months or years later often reveal lingering cancer that was missed by imaging tests.

“Residual cancer is identified on histology in 40% of lung, 57–69% of renal cell, 7.7–47.6% of prostate, and up to 86.7% of hepatocellular carcinoma cases,” the researchers noted. This discrepancy between imaging and actual tissue analysis poses serious consequences for patient survival and recurrence rates.

Studies across multiple cancer types—including rectal, cervical, prostate, and liver cancers—indicate that even a small amount of residual cancer can significantly increase the risk of recurrence and shorten survival.

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In some cases, undetected cancer cells can eventually spread to distant organs, making future treatment more challenging. The researchers emphasize that a "complete response" seen in scans does not necessarily mean the tumor has been fully eliminated.

The study underscores the need for improved post-radiotherapy monitoring, including biopsies and advanced molecular testing, to ensure no cancer remains. The researchers urge the cancer care community to rethink how treatment success is measured and adopt more comprehensive follow-up strategies.

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With these findings, experts hope to raise awareness about the hidden risks of residual cancer and encourage clinicians to explore new methods of post-treatment surveillance. By doing so, the medical community can enhance survival rates and provide patients with more accurate assessments of their cancer status.

Reference:

1. No disease left behind - (https://www.oncotarget.com/article/28700/pdf/)

Source-Medindia