Long-term control for > 9 years with megestrol acetate-letrozole: metastatic endometrioid carcinoma case report

TL;DR

A patient with advanced endometrial cancer had long-term disease stability using megestrol acetate and letrozole, suggesting a promising treatment approach.

Contribution

This is the first case report showing durable antitumor activity with full-dose megestrol acetate plus letrozole in HR-high metastatic endometrial cancer.

Findings

The patient achieved stable disease for over 9 years with megestrol acetate and letrozole.

Disease progression occurred when the treatment was reduced, but resumed therapy restored stability.

The treatment was well-tolerated with minimal toxicity over the long term.

Abstract

Hormone receptor–positive (HR+) endometrial carcinoma (EC) responds to endocrine therapy, but clinical benefit duration is often limited, especially in patients with widely metastatic or recurrent disease.

A 54-year-old woman with HR-high (ER/PR 90%) metastatic EC (FIGO IIIC2) discontinued adjuvant chemotherapy due to severe toxicity. She initiated megestrol acetate and letrozole in March 2017, achieving stable disease (SD) for 38 months. Self-discontinuation (January–July 2020) led to disease progression (new retroperitoneal lymph nodes), but resuming full-dose therapy restored SD for 49 months. After dose reduction (July 2023), the disease progressed again at 12 months; re-escalation to full dose induced regression. At last follow-up (OS: 108 months), she maintained SD with minimal toxicity.

This is the first case demonstrating that full-dose megestrol acetate plus letrozole may induce durable antitumor activity in HR-high expression metastatic EC, warranting prospective validation.

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