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Tumor recurrence criteria for postoperative contrast-enhanced computed tomography after surgical treatment of oral cancer and flap repair.

OBJECTIVE
To characterize the computed tomography (CT) findings that distinguish cancer recurrence from postoperative changes that mimic such recurrence.


STUDY DESIGN
We evaluated a total of 72 CT scans from 32 patients who had undergone surgery with either pectoralis major myocutaneous flap or forearm flap. The observers evaluated the presence and pattern of enhancement, the presence of low density areas, and changes in the adipose tissue of the flap.


RESULTS
A persistent zone of high attenuation over 6 months suggested the high possibility of recurrence. However, an enhancement within 6 months occurred both with the recurrent tumor and with postoperative tissue. In the patients with recurrence (n = 12), the enhanced areas were focal (n = 8) or diffuse (n = 4). Focal-type recurrence often occurred at the posterior margin. The presence of low-density areas and changes in the adipose tissue in the flap are also helpful for detecting recurrence.


CONCLUSIONS
The combination of several features seen on CT images can be useful in differentiating tumor recurrence from postoperative tissue changes.