Treatment of PEComas

There are no standard treatment options. Treatment may include surgery or observation followed by surgery when the tumor is large.[145]

In tumors with evidence of mTORC1 activation and TSC1 or TSC2 loss, including lymphangioleiomyomatosis and angiomyolipoma,[141] clinical activity using mTOR inhibitors, such as sirolimus, has been well documented. In a small case series, three adult patients with PEComas responded to sirolimus.[146]

In a phase II trial, 34 patients with metastatic or locally advanced malignant PEComas were treated with sirolimus protein-bound particles for injectable suspension (albumin-bound) (nab-sirolimus). Of the 31 patients eligible for efficacy analysis, 12 (39%) had a response (1 complete response and 11 partial responses), 16 (52%) had stable disease, and 3 (10%) had progressive disease. Responses were rapid and durable. The median duration of response was not reached after a median follow-up of 2.5 years. Treatment was ongoing for 7 of 12 patients who responded to treatment (range, 5.6 months to longer than 47.2 months). Tumor variant profiling was completed for 25 specimens. Eight of nine patients with TSC2 variants responded to treatment, while only 2 of 16 patients without TSC2 variants responded. In addition, responses were noted in 10 of 17 patients with phospho-S6 (pS6) expression. No response was noted in eight patients without pS6 expression. The absence of pS6 expression reflects the lack of mTORC1 activation.[147][Level of evidence C1] In 2021, the FDA approved nab-sirolimus for adult patients with PEComas.