Uterine Artery Pulsatility Index (UAPI) Improves Prediction of Methotrexate Resistance (MTX-R) Risk in Patients with Gestational Trophoblastic Neoplasia (GTN) and FIGO score 5-6


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Ailsa Sita-Lumsden1,2, Hanine Medani1, Victoria Harding1, Rosemary Fisher1,2, Dee Short1, Neil Sebire1,2, Richard Harvey1, Philip Savage1, Adrian Lim1, Michael Seckl1, Roshan Agarwal1
1Imperial NHS Trust, London, UK, 2Imperial College London, London, UK

Background

UAPI is a Doppler ultrasound based measure of tumour vascularity. It has been suggested that a UAPI=1 and a FIGO score 5-6, may identify a subgroup of GTN patients with a >75% predicted risk of MTX-R and might benefit from upfront multi-agent instead of single agent methotrexate. This group of patients is most in need of further predicitive markers for treatment, but only constituted a small percentage of the cohort (2008-11), in our previous report. This study therefore focused on patients with FIGO 5-6 GTN, treated over a 12 year period, to obtain a larger cohort of patients, to validate and more precisely the predictive value of UAPI in this group of patients.

Method

92 patients with GTN and FIGO scores 5 or 6, were treated with single agent methotrexate between January 1999 and June 2011 at Charing Cross Hospital, London. Patients had a pelvic Doppler ultrasound (USS) to assess the UAPI prior to chemotherapy, as part of their baseline staging USS. The lowest of the left and right UAPIs was used, and resistance to first line methotrexate (MTX-R) was recorded.

Results

73 of the patients were assessable for both UAPI (median 0.74, range 0.1-2.9) and MTX-R (58% of patients). UAPI predicted MTX-R independent of the FIGO score (HR 2.9, p=0.036), by logistic regression. MTX-R rates were 67% versus 42% in patients with a UAPI =1 and UAPI>1 (p=0.036), respectively. After stratification by FIGO score, MTX-R rates ranged from 43% with FIGO 5 UAPI>1, to 75% in patients with FIGO 6 UAPI=1.

Conclusion

This study validates UAPI as a clinically useful predictor of first-line MTX-R, in patients with FIGO 5-6 GTN, a subgroup where use of UAPI will have maximum impact in addition to the FIGO score for MTX-R risk stratification, and treatment selection.