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Two-year surveillance unnecessary in gestational trophoblastic neoplasia

Obstetrics and gynaecology

Obstetrics and gynaecology

Trophoblastic disease complicates around 1,500 pregnancies in the UK each year. Most cases settle spontaneously, but a minority persist and develop into persistent gestational trophoblastic neoplasia (pGTN). This is more common following a complete, rather than partial, hydatidiform mole (pGTN rate 15% and 0.5% respectively).

When identified early and treated promptly, the cure rate is almost 100%. A national surveillance programme has been in place for many years. All new cases of trophoblastic disease are monitored by one of three regional centres and treated if necessary.

Until recently, women diagnosed with a molar pregnancy where hCG levels took longer than 56 days to return to normal were kept under surveillance for two years. A study has suggested that this protocol may be overzealous.

Two surveillance regimens were compared using a retrospective analysis of data collected over a 10-year period at the Charing Cross Regional Trophoblastic Disease Centre. The old protocol required two years' surveillance in all women whose hCG had not returned to normal within 56 days. The new protocol requires hCG surveillance for just six months after levels return to normal (see box 1,attached).

During the study period 6,701 women were registered, of whom just 422 (6%) required chemotherapy for pGTN. Of these, 419 were diagnosed within 12 months of the initial diagnostic evacuation.

Under the old protocol, two of the three remaining women were not picked up by the surveillance programme. One had a normal hCG level at 56 days and re-presented at 13 months. The other re-presented 42 months after the original molar pregnancy.

Had the new protocol been used, only one further case would have been missed: a woman whose hCG returned to normal after day 56 and she re-presented at 23 months.

The new Charing Cross protocol is less expensive to run and less stressful for most of the women concerned. Of the 6,701 women registered, just three cases would have been missed using the new protocol over a ten-year period, compared with two cases under the old protocol.

The Charing Cross team consider this acceptable, bearing in mind the financial and emotional implication of prolonged surveillance.

Sebire NJ, Foskett M, Short D et al. Shortened duration of human chorionic gonadotrophin surveillance following complete or partial hydatidiform mole: evidence for revised protocol of a UK regional trophoblastic disease unit. BJOG 2007;114:760-762

Box 1: hCG surveillance protocols for women after a diagnosis of hydatidiform mole Reviewer

Dr Chris Barclay
GP, Sheffield

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