The chances of surviving placental-site trophoblastic tumours (PSTTs)— malignant tumours usually presenting months to years after pregnancy—depends on how long ago the related pregnancy took place. The management of this rare condition is discussed in an Article published Online First and in an upcoming edition of The Lancet, written by Dr Peter Schmid and Professor Michael J Seckl, Imperial College NHS Healthcare Trust, London, UK, and colleagues. This landmark paper is the first study presenting an entire national experience of the disease over 30 years and represents the world's largest series.
PSTTs are slow-growing tumours that present months or possibly years after a normal pregnancy, abortion, miscarriage, or hydatidiform mole*. They are the rarest form of gestational trophoblastic** disease (GTD) accounting for only 0.2% of all GTDs. PTTs were diagnosed in 1 per 20,000 women in the UK from 2003-2007. In this study, the authors looked at 35550 women with GTD in the UK from 1976-2006, of whom 62 were diagnosed with PSTT. Patients were treated with surgery, chemotherapy, or both. The authors then estimated the probabilities of overall survival and survival without recurrence of disease 5 and 10 years after the date of first treatment, and the association of these endpoints with various prognostic factors.
The researchers found that probability of overall and recurrence-free survival 10-years after first treatment were 70% and 73% respectively. Patients with stage I disease had a 10-year probability of overall survival of 90%, and did not benefit from post-operative chemotherapy. Patients with stage II, III or IV disease needed both surgery and chemotherapy, or both. Overall survival at 10 years was 52% for patients with stage II disease and 49% for those with stage III or IV disease. Patients with recurrent disease or disease resistant to treatment had poor survival, with only 4 (22%) of patients surviving beyond 5 years. The only significant independent predictor of overall survival was time since the preceding pregnancy, which predicted survival extremely accurately—if more than four years had elapsed from the preceding pregnancy to PSTT presentation, 100% (13 of 13 women) died within 5 years despite therapy), but if presentation was within four years, 98% (48 of 49 women) were cured.
The authors conclude: "Future studies could address the hypothesis that additional genetic changes in patients presenting at 48 months or later, compared with those presenting within 48 months, could account for the altered biology of the tumours. Consideration of time since antecedent pregnancy in the diagnosis of placental-site trophoblastic tumours could help to direct development of effective treatment strategies."
In an accompanying Comment, Dr Ernest I Kohorn, Yale University School of Medicine, New Haven, CT, USA, says that this study shows more convincingly than was previously evident that the greater the interval between the index pregnancy and appearance of the tumour, the more aggressive is the disease. He concludes: "Gratifyingly, today's report advocates adjuvant chemotherapy even for stage I disease."
Dr Miahel J Seckl, and Dr Peter Schmid, Imperial College NHS Healthcare Trust, London, UK T) +44 (0) 20 8846 1418 E) p.schmid@imperial.ac.uk / m.seckl@imperial.ac.uk
Dr Ernest I Kohorn, Yale University School of Medicine, New Haven, CT, USA T) +1 203-795-3151 E) ernest.kohorn@yale.edu
For full Article and Comment see: http://press.thelancet.com/trophoblastic.pdf
Notes to editors:
*Molar pregnancy is an abnormal form of pregnancy, characterized by the presence of a hydatidiform mole (or hydatid mole, mola hytadidosa). Molar pregnancy comprises two distinct entities, partial and complete moles. Complete moles have no identifiable embryonic or fetal tissues and arise when an empty egg with no nucleus is fertilised by a normal sperm. In contrast, a partial mole occurs when a normal egg is fertilised by two spermatozoa.
**Trophoblasts are cells which provide nutrients to the embryo and develop into a large part of the placenta. They are formed during the first stage of pregnancy and are the first cells to differentiate from the fertilised egg
Journal
The Lancet