OBJECTIVE To describe 34 cases of placental site trophoblastic tumor (PSTT) treated at Charing Cross Hospital over 25 years. METHODS Between 1975 and 2001, 1,685 patients with gestational trophoblastic disease (GTD) were treated; 34 of them had PSTT (2%). The computer database clinical notes and the pathology reports were accessed to obtain data on this patient group. The data were subsequently analyzed using Excel computer software. RESULTS The mean age of the group was 33 years (95% CI 25-41). The antecedent pregnancy was a full-term, normal one in 18 cases (53%), a molar pregnancy in 7 (21%) and a missed abortion in 5 (15%). The mean interval from the last pregnancy to diagnosis was 3.4 years (95% CI 1.9-4.9). The range of serum hCG concentrations at diagnosis was 0-58,000, 79% with levels < 1,000 and 58% < 500. hCG was raised in all with active disease. The most frequent presenting complaint was vaginal bleeding, in 27 cases (79%). At diagnosis, the disease was localized to the uterus in 15 (44%); there was pelvic involvement in 8 (24%) and lung secondaries in 10 (29%). All seven deaths were disease related (21%); all had lung secondaries and presented more than four years since the last pregnancy. Excluding the seven deaths, the primary treatment was surgery alone in 10 cases (37%) (8 hysterectomies and 2 dilatation and curettages); 4 had surgery followed by adjuvant chemotherapy; 5 had neoadjuvant chemotherapy followed by surgery; 1 had chemotherapy alone, and the disease recurred and was successfully rechallenged; and 5 had surgery between chemotherapy cycles. The most common regimens consisted of EMA/CO and EP/EMA. CONCLUSIONS Risk factors for death include lung metastatic involvement (50%) and an antecedent pregnancy interval of four years or more (100%). In contrast, those with no extrapelvic disease or a pregnancy interval of less than four years had 100% survival. In two-thirds of patients with disease limited to the uterus, surgery alone was curative. The WHO scoring system for GTD did not correlate with this outcome. Patients with PSTT should be managed separately from those with other types of GTD, as the disease behavior is different.