Efficacy of PET CT scan in detecting occult primary with cervical lymph node metastasis

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Efficacy of PET CT scan in detecting occult primary with cervical lymph node metastasis

Journal Title: Medpulse International Journal of ENT - Year 2017, Vol 1, Issue 2

Abstract

Background: There are several causes of the low rate of detection of the primary. It is hypothesised that in patients who present with CUPS, the primary tumour either remains microscopic and escapes clinical detection or disappears after seeding the metastasis because its angiogenetic incompetence leads to marked apoptosis and cell turnover. Furthermore the sensitivity of conventional diagnostic procedures may not be satisfactory. Objectives: To study the efficacy of PET CT scan in detecting occult primary with cervical lymph node metastasis. Materials and method: The present study was conducted in the Army Hospital (Research and Referral), Delhi Cantt. The patients attending Head and Neck Oncology clinic with metastatic cervical lymph node (s) without evidence of primary by clinical evaluation were enrolled in the present study. Total 27 patients were selected and were analysed. All the selected patients underwent review of their medical history and thorough medical examination. The patients in whom a primary tumour was not detected were accrued into the study and classified as patients with Carcinoma of Unknown Primary Site (CUPS), and they formed the cohort of our study. All the study patients were subjected to ultrasonography of the abdomen, CT scan of the neck and chest and panendoscopy under general anaesthesia, to look for any evidence of a primary tumour. All the patients were subjected to whole body PET-CT scan. The outcome of tests have been tabulated and analysed to ascertain the sensitivity, specificity, positive and negative predictive values of whole body PET-CT scan in detecting the primary in CUPS with cervical lymph node metastasis. Results: It was observed that age profile of the patients varied from 48 to 86 yrs with mean age as 62. Eleven of these patients had squamous cell carcinoma, seven had adenocarcinoma, six had poorly differentiated carcinoma, and remaining three had undifferentiated carcinoma metastases. FDG-PET-CT was negative in 14 (51.85%) patients and was positive in 13 (48.15%) patients. Out of these thirteen patients, nine had primary tumour, while four patients had evidence of distant metastasis. The Sensitivity and specificity of FDG-PET-CT in our study was 87.5 and 89.5% respectively while Positive and Negative predictive values were 77.8 and 94.4% respectively. Conclusion: The PET-CT has sensitivity and specificity of 87.5 and 89.5% respectively. Thus it can be used as valuable diagnostic tool in patients with CUPS as it was able to detect the unknown primary tumour, not detected by the other conventional investigative modalities. Additionally it has detected the presence of distant metastases, thereby assisting in both guiding biopsies for histological evaluation (for primary) and selecting the appropriate treatment protocols in these patients.

Authors and Affiliations

S Hari Kumar, Rajesh Kumar Singh, P S Sukthankar, S S Anand

Keywords

PET CT scan cervical lymph node metastasis Carcinoma of unknown primary site

EP ID EP261453
DOI -
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