What factors indicate a high risk of recurrence in GIST patients?

In gastrointestinal stromal tumors (GISTs), the risk of recurrence is primarily assessed based on tumor size and mitotic rate, which are critical factors in determining the tumor's aggressiveness. A size greater than 5 cm combined with a mitotic rate of more than 5 mitoses per 50 high power fields is particularly indicative of a high risk of recurrence.

Tumors that exceed 5 cm in size typically demonstrate a greater potential for invasive behavior and metastasis. Additionally, a higher mitotic rate signifies a more aggressive tumor that is characteristically more likely to recur. This combination reflects a significant departure from benign behavior, categorizing the tumor as high risk.

Other size thresholds and mitotic rates highlighted in alternative options do not convey the same level of risk. For example, a size greater than 7 cm with a low mitotic rate may suggest less aggressive behavior. Similarly, a tumor smaller than 5 cm, regardless of its mitotic activity, generally reflects lower risk. Therefore, the parameters described in the correct answer effectively identify a tumor profile that correlates with poor prognostic outcomes in GISTs.