METASTASIS OF UNKNOWN ORIGIN: AN ENIGMA IN CLINICAL ONCOLOGY

Abstract

Anil Kumar Dhull1, Rajeev Atri2, Vivek Kaushal3, Narayan P. Patel4, N. Balasubramanian5, Rakesh Dhankhar6, Ashok K. Chauhan7, Kamal Nain Rattan8

INTRODUCTION
Metastasis of unknown origin (MUO) represents a heterogeneous group of malignancies presenting with lymph nodes or distant metastases, for which diagnostic workup fails to identify the site of origin. Management of MUO with undetermined primary remains unclear because of the heterogeneous pathological condition and the treatment for such cases is still controversial. Various therapeutic regimens are present, but no clear-cut consensus has evolved. MUO on the whole carries a very poor prognosis. To assess the outcome of patients in a real-world situation, we retrospectively reviewed the database in our department to determine patterns of presentation and to analyse the response of various treatment modalities.
MATERIAL AND METHODS
The patients of metastasis of unknown origin who presented in the Department of Radiotherapy, PGIMS Rohtak from Jan 1st, 2008 to December 31st, 2010 were retrospectively analysed to determine patterns of presentation and to elucidate the outcome of various treatment modalities like radiation, surgery and chemotherapy.
RESULTS
Total 349 patients of metastasis of unknown origin were identified in the Department of Radiotherapy, PGIMS Rohtak, which constituted 4.9% of the total cancer patients. The median age at presentation was 56 years. Most of the patients presented in advanced stage (stage III-93% & stage IV-7%). In this retrospective analysis, the presenting site was lymph nodal in 68% and visceral in 32%. Out of total 349 patients of metastasis of unknown origin, 77 patients (22%) did not report for treatment after initial investigations. Out of the remaining 272 patients who took treatment, 185(68%) patients underwent radiotherapy and 137 patients (50%) received different chemotherapy protocols. 20% were given radical treatment and 58% were treated with palliative intent. Primary site was found in 13(5%) patients and were treated accordingly.
CONCLUSION
The overall prognosis in patients with MUO is generally very poor with a mean survival of 5-10 months. The most common site of presentation observed was cervical lymphadenopathy. Most of the patients presented in advanced stage and accordingly were treated with palliative intent. Evaluation of patients with metastasis of unknown origin should be structured to quickly identify treatable tumours or the need for palliation. Radiation therapy, chemotherapy and surgery were used alone or in combination to treat these patients to prolong survival and improve the quality of life.

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