Chemotherapy for patients with two favourable subsets of unknown primary carcinoma: active, but how effective?

Carcinoma of unknown primary (CUP) is characterized by dismal patient survival. The outcome of patients with two favourable risk CUP subsets was studied. Eighty patients diagnosed with either midline lymph node metastases (n=33) or peritoneal carcinomatosis (n=47) were analysed retrospectively. The majority had poorly differentiated adenocarcinoma or undifferentiated carcinoma, treated with platinum-taxane based chemotherapy from 1996 till 2002. Females with peritoneal carcinomatosis also underwent surgical debulking. Objective tumour regression was present in 44% of patients (nodal group 30% versus peritoneal group 53%, p=0.066). Complete responses were seen more often in peritoneal carcinomatosis patients (nodal group 9%, peritoneal group 36%, p=0.008). At a median follow up of 60 months, median progression-free and overall survival were 5 and 10 months respectively in the nodal group, 7 and 15 months in the peritoneal group. Five-year survival was 7% (nodal group 0% vs. peritoneal group 10%, p=0.05). Complete responders fared better than non-CR patients. Fewer than four metastatic sites, elevated CA 125, and normal CA 19-9 levels were favourable prognostic factors for survival. Modern combination chemotherapy has satisfactory activity, with a minority of CUP patients enjoying long-term responses. Research efforts towards complete remission consolidation and molecular profiling are imperative.