Risk of Malignancy Index (RMI) for Ovarian Cancer
Combines ultrasound score (U), menopausal status (M), and serum CA-125 to calculate RMI. RMI >200 = high risk of ovarian malignancy; refer to specialist cancer centre. Validated in UK NHS setting (RCOG guideline).
Score interpretation
RMI <25 — low risk of ovarian malignancy
→ Conservative management; repeat ultrasound and CA-125 in 4–6 months; if cyst resolves, discharge; if persists or changes, reassess
RMI 25–200 — intermediate risk; borderline indeterminate
→ Gynaecology review; MDT discussion; consider MRI pelvis; serial monitoring; surgical assessment if indicated; apply IOTA Simple Rules or ADNEX model
RMI ≥200 — high risk of ovarian malignancy
→ Urgent referral to specialist gynaecology oncology centre (RCOG/NICE guideline); staging CT chest/abdomen/pelvis; MDT planning; laparotomy/staging procedure by specialist team; full staging surgery
Interpretation bands for the RMI. Apply clinical judgement and local guidance.
References
- Jacobs I et al. A risk of malignancy index incorporating CA 125, ultrasound and menopausal status for the accurate preoperative diagnosis of ovarian cancer. Br J Obstet Gynaecol. 1990;97(10):922–929.
Related
Curated clinical cross-links plus same-class fallbacks.
Decision support only — verify against a current formulary, NICE, or your local guideline before clinical use.