NECT trial: more than a small victory over sleeping sickness.

www.thelancet.com Vol 374 July 4, 2009 7 trophoblastic tumour. These advances have become possible because of the ability to measure tumour load with hCG, diagnose hydatidiform mole in early pregnancy by ultrasound, and the ability to determine whether or not metastases are present on CT and MRI, together with greater understanding of the pathology and molecular physiology of trophoblastic neoplasia. Schmid and colleagues focus on a rare entity of trophoblastic neoplasia, which is placental-site trophoblastic tumour. The condition was fi rst described in 1976 and named trophoblastic pseudotumour, and was thought to be benign. It was not until 1981 that Twiggs and colleagues encountered a patient who had metastases, and in 1982 Eckstein and colleagues reported four further cases from Charing Cross Hospital. Most reports since then have been case reports or the small number of patients that are cited in today’s report. It is now accepted that placental-site trophoblastic tumours diff er from other trophoblastic neoplasms in that the tumour load is not accurately correlated with the concentration of hCG, and that the tumour might be less sensitive to chemotherapy that is eff ective in the other types of trophoblastic neoplasia. Placentalsite trophoblastic tumours might follow any type of pregnancy event, not infrequently becoming clinically apparent even years later, and there is great variability in its malignant aggressiveness. The neoplasm arises from intermediate trophoblast, unlike chorio carcinoma, which arises from villous trophoblast. There can be diffi culty with the diagnosis if access to biopsy is not easy, and there is diffi culty in histological diff erentiation of placental-site trophoblastic tumours from the other trophoblastic neoplasms. Unlike with postmolar trophoblastic neoplasia, precise histological diagnosis is essential. Immunohistological staining for human placental lactogen and hCG is especially helpful. Raised free β-hCG concentration in serum can also point to the diagnosis when germ-cell tumours of the ovary and other cancer entities can be excluded by clinical examination and imaging. What Schmid and colleagues show more convincingly than was previously evident is that the greater the interval between the index pregnancy and appearance of overt neoplasia, the more likely the disease will be aggressive. It is gratifying to fi nd that the investigators advocate adjuvant chemotherapy even for stage I disease.