Source: DGNews  |  Posted 2 years ago

LONDON -- June 22, 2009 -- 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 and in an upcoming edition of The Lancet. This 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. PSTTs were diagnosed in 1 per 20,000 women in the United Kingdom from 2003-2007. In this study, the authors looked at 35,550 women with GTD in the United Kingdom 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 survival 10 years after first treatment was 70% and the probability of recurrence-free survival after 10 years was 73%. Patients with stage I disease had a 10-year probability of overall survival of 90%, and did not benefit from postoperative 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 4 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 4 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, Connecticut, 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.”

SOURCE: The Lancet