Introduction

Gestational trophoblast tumours (GTT) form a spectrum of rare diagnoses from the usually benign partial and complete molar pregnancies through to the aggressive malignancies of choriocarcinoma and placental site trophoblast tumour. The majority of care for the patients with molar pregnancies takes place in their local hospitals, with less than 10% of patients needing chemotherapy treatment. The cure rate for postmolar pregnancy GTT is 100% and most patients only need single-agent chemotherapy treatment. For the patients with rarer diagnoses of choriocarcinoma or placental site trophoblast tumour (PSTT), nearly all will be cured, even those presenting unwell with advanced metastatic cancer.

To provide an effective service in the UK for these rare conditions the Department of Health directly funds a national trophoblast service that cares for all patients with GTT. The trophoblast service has two specialist treatment centres, one at Weston Park Hospital in Sheffield and the other at Charing Cross Hospital in London. These centres, in addition to providing expert clinical care, also run the national human chorionic gonadotrophin (hCG) surveillance and follow-up programmes in conjunction with the Scottish follow-up centre in Dundee.

Although the main clinical care for GTT patients is centralised in the UK, it remains important for all oncologists to have a working knowledge of GTT because choriocarcinoma and PSTT can present as malignancies of unknown primary. In these patients, early involvement from the local oncology team in achieving the correct diagnosis and expediting treatment can be life-saving.

The pattern of GTT management in other countries varies; some countries have established centralised care, whereas in many other countries, patients are treated locally by doctors who are likely to only see a case every few years.

This chapter outlines the pathology, natural history and management of GTT based on the experience of the UK GTT service at Charing Cross Hospital in London.

Types of gestational trophoblast tumour

Gestational trophoblast tumours are divided into the premalignant partial and complete molar pregnancies and the malignant forms of invasive mole, choriocarcinoma and PSTT, as shown in Table 30.1. All forms of GTT constitutively produce hCG, although abnormalities of the molecule from some tumour cells can lead to false-negative results occasionally in some types of hCG assays (Cole et al., 2001).