Treatment for patients with unknown primary cancer and favorable prognostic factors.

Patients with carcinoma of unknown primary site are heterogeneous with respect to clinical and pathologic features. Within this diverse group, specific clinical and/or pathologic features can be used to define several subsets with favorable prognoses. Specific subsets include women with peritoneal carcinomatosis, women with isolated axillary lymph node metastases, adenocarcinoma presenting as a single metastatic lesion, young men with features of extragonadal germ cell tumor, squamous carcinoma involving cervical or inguinal lymph nodes, and neuroendocrine carcinoma. Prospective identification of patients in these favorable subgroups allows the most effective treatment to be selected. This review summarizes current recommendations for the evaluation and treatment of patients in each of these favorable prognostic subsets.