Is it necessary to biopsy the obvious?

The radiologist and oncologist are often confident that biopsy will confirm their suspicion of recurrent disease, but a biopsy is performed to confirm the histologic diagnosis before beginning or altering therapy. We have examined data to determine how often the biopsied lesion represents recurrent disease from the primary tumor or is an instance of new cancer, and whether recurrent disease can be predicted.

We reviewed the medical and imaging records of 253 patients who underwent CT-guided biopsy of an abdominal or pelvic lesion between 1993 and 1996. Sixty-nine of the 253 patients had a previously diagnosed primary tumor and were being examined for possible tumor recurrence or metastasis. The images of these 69 patients were analyzed to determine if the pattern of disease was typical of recurrence or metastasis.

In 55 of the 69 patients, the pattern was judged to be typical of metastatic or recurrent disease. Biopsy confirmed this suspicion in all 55 patients. In 14 of the 69 patients, the pattern of spread was judged not to be typical of recurrence or metastasis. These 14 patients were found to have a new primary tumor (n = 4), benign processes (n = 2), and recurrences (n = 8).

Of the patients for whom radiographic findings suggested recurrence, we found no patients in whom a new primary tumor would have been missed if biopsy had been avoided. Data should now be acquired prospectively to determine whether it may be prudent to make treatment decisions on the basis of imaging findings alone, without histologic confirmation.