Mirena (Levonorgestrel) Use in Patients with Uterine Cancer
Mirena (levonorgestrel-releasing intrauterine device) is contraindicated in patients with current uterine cancer but may be used as a therapeutic option in specific cases of early endometrial cancer when surgery is not feasible.
Current Guidelines on Mirena and Uterine Cancer
The U.S. Medical Eligibility Criteria for Contraceptive Use classifies endometrial cancer as a contraindication for IUD insertion, with both initiation and continuation rated as category 4 (contraindicated) 1. This means that Mirena should not be inserted in patients with diagnosed uterine cancer as a contraceptive method.
However, clinical guidelines recognize specific therapeutic uses of levonorgestrel-releasing IUDs in certain uterine cancer scenarios:
Therapeutic Use in Select Cases
Non-surgical candidates: For patients with early endometrial cancer who are poor surgical candidates due to medical comorbidities, the NCCN guidelines indicate that progestin-based therapy, including levonorgestrel-releasing IUDs, may be considered 1.
Fertility preservation: For young patients with grade 1, stage IA endometrioid adenocarcinoma who wish to preserve fertility, progestin-loaded IUDs are mentioned as a treatment option, though not as first-line therapy 1.
Clinical Decision Algorithm
When Mirena is Contraindicated:
- Active/current uterine cancer requiring standard treatment
- High-grade endometrial carcinomas
- Non-endometrioid histologies (serous, clear cell, carcinosarcoma)
- Advanced stage disease
- Patients who can undergo standard surgical treatment
When Mirena May Be Considered (with oncology consultation):
- Grade 1 endometrioid endometrial cancer with:
- Patient medically unfit for surgery (ASA class IV)
- Patient desiring fertility preservation (strictly selected cases)
- No myometrial invasion on MRI
- Positive hormone receptor status
- Patient acceptance of close follow-up
Efficacy and Outcomes
The efficacy of Mirena as a treatment for early endometrial cancer is limited:
- Complete response rates range from 25-79% 2, 3
- Recurrence rates of 16-22% have been reported 3
- Treatment failure occurs in approximately 10-12% of cases 4
Research suggests that Mirena may actually have a protective effect against developing endometrial cancer, with a 33% lower risk observed in a large Swedish cohort study 5. However, this protective effect does not extend to treating established cancer outside of specific circumstances.
Monitoring Requirements
If Mirena is used as therapy for early endometrial cancer:
- Endometrial sampling every 3-6 months is mandatory 1
- Pelvic MRI should be performed if cancer persists after 6 months of therapy 1
- Definitive surgical treatment should be pursued if:
- Disease progression occurs
- Cancer persists after 6-12 months of therapy
- After childbearing is complete (in fertility-sparing cases)
Important Caveats
- The use of Mirena for treatment of endometrial cancer is not FDA-approved
- This approach should only be considered in specialized centers with expertise in gynecologic oncology
- Patients must be informed that this is not standard of care treatment
- Close surveillance is essential to detect treatment failure or disease progression
Conclusion
For most patients with uterine cancer, Mirena is contraindicated and standard surgical treatment remains the gold standard. However, in carefully selected cases of early endometrial cancer where surgery is not feasible or fertility preservation is desired, Mirena may be considered as part of a progestin-based treatment plan under close oncologic supervision.