The overwhelming majority of patients presenting with carcinoma of unknown primary (CUP) have disseminated disease that is relatively chemoresistant. Potentially curative treatment can be delivered, however, in a few situations.
Clinical validity refers to the predictive value of a test for a given clinical outcome (e.g., the likelihood that cancer will develop in someone with a positive test). It is primarily determined by the sensitivity and specificity with which a test identifies people with a defined clinical condition within a given population. Sensitivity of a test refers to the proportion of people who test positive for a clinical condition among those who actually have the clinical condition; specificity refers...
All patients should undergo a careful head, neck, and lung evaluation including coronal computed tomography and/or magnetic resonance imaging of the head and neck and directed biopsies of the nasopharynx and tongue base. In those patients with squamous cell or undifferentiated carcinoma, tonsillectomies have been recommended and should be considered if the tonsils have not been previously removed. Fluorodeoxyglucose F 18-positron emission tomography scan may identify an occult primary site in the head and neck area.[2,3] If no primary site can be determined, the following approaches should be considered:
Radical radiation therapy with curative intent to the cervical lymph nodes and possible sites of origin. Intensity-modulated radiation therapy (IMRT) may have less short- and long-term toxicity than conventional radiation therapy in terms of xerostomia, acute dysphagia, and skin fibrosis.
Preoperative radiation therapy followed by radical neck dissection.
Radical neck dissection.
Radical neck dissection followed by postoperative radiation therapy to possible sites of origin.
(Refer to the PDQ summary on Metastatic Squamous Neck Cancer with Occult Primary Cancer Treatment for more information.)
Poorly Differentiated Carcinomas
Patients who have poorly differentiated carcinomas with or without serologic or histologic evidence of beta human chorionic gonadotropins or alpha-fetoprotein should be treated with intensive chemotherapy as used in the treatment of disseminated germ cell tumors.
In a series, more than 220 patients with excellent performance status were treated with aggressive combination chemotherapy. This chemotherapy generally consisted of vinblastine, bleomycin, and cisplatin; however, some patients received a doxorubicin-containing modification of this regimen and some received etoposide instead of vinblastine. The response rate was 63%, with a complete response rate of 26%, and a long-term disease-free survival of 16%. Carboplatin-containing regimens were found to have equal activity. A paclitaxel-based combination yielded a 48% response rate in 71 patients with various histologic types of carcinoma of unknown origin.
Poorly Differentiated Neuroendocrine Carcinomas
In a series of 29 patients with poorly differentiated neuroendocrine carcinomas, 19 were treated with intensive cisplatin-based combination chemotherapy, and six additional patients received doxorubicin combinations. Six patients achieved complete response and four of these patients were alive 19 to 100 months after diagnosis.
Women with peritoneal carcinomatosis of an adenocarcinoma serous histologic type have a favorable response to chemotherapy and improved prognosis. Response and survival rates in these patients approach those seen in ovarian cancer patients, and therapy appropriate for ovarian cancer should be used.[11,12] (Refer to the PDQ summary on Ovarian Epithelial Cancer Treatment for more information.)