Bone Lesions with Metastatic Cancer Pose Biopsy Dilemma

A new bone lesion in a patient with metastatic cancer is most likely the result of the primary tumor spreading, rather than a benign growth or a secondary malignant tumor, says a study recently published in the American Journal of Roentgenology. However, radiologists should still evaluate each case to determine whether a biopsy is needed.

In the study, researchers looked at 54 bone biopsies performed over five years in patients with a history of primary malignant tumors— most often from breast cancer, lung cancer, or non-Hodgkin’s lymphoma. All the biopsies, usually of the lumbar spine and ilium, were performed using CT localization, and samples were analyzed by cytopathology or core-biopsy.

Results showed that 42 out of 43 positive biopsy findings (98 percent) had spread from the primary malignant tumor. The remaining positive finding was a new malignancy, which was found in a man with chronic myelectic leukemia. That leaves a low probability (2 percent) that a biopsy will show a new bone lesion to be something other than metastasis from the primary tumor.

The research demonstrates how radiologists are often faced with the question of whether a biopsy is actually needed to determine a diagnosis, said Rahul Pawar, MD, in a review of the study. Yet despite the study’s findings, radiologists shouldn’t assume that every new bone growth signals metastasis. “Statistics and probability should not transform into unwavering bias toward a particular diagnosis,” Pawar wrote.

Related seminar: Neuroradiology Review