[201Thalium SPECT in the detection of recurrent laryngeal carcinoma]

To evaluate the diagnostic yield of (201)Thallium SPECT in the detection of local and/or regional lymph node dissemination of pharyngolaryngeal carcinoma.

29 patients who had been diagnosed with pharyngolaryngeal carcinoma were studied (mean age: 60.9 years). These patients had been treated by surgery, chemotherapy and radiotherapy. At between 3 to 6 month after finishing the treatment, all of them underwent a planar and SPECT study at one hour after the administration of 148 MBq of (201)Thallium. Uptake was scored on four grades: from 0 (no uptake) to 3 (very intense uptake). The presence or non-presence of lymph nodes with uptake was also evaluated. All the results on the scintigraphy were correlated with long term clinical and radiological follow-up (mean: 2.5 years). The studies were classified as positive for recurrence when the uptake was 2-3 and/or with presence of lymph nodes with uptake.

We obtained 9 true positive, 14 true negative, 3 false positive and 3 false negative results. Sensitivity was 75%, specificity was 82.4%, positive predictive value was 75% and negative predictive value was 82.4%. Two out of three false positives corresponded to the surgical bed uptake and one was attributed to the laterocervical lymph nodes. The three false negatives had grade 1 uptakes, two of them corresponding to pulmonary metastasis without evidence of local recurrence.

The use of (201)Thallium SPECT in the prognostic evaluation in patients with a treated laryngeal carcinoma shows very acceptable results in the detection of local recurrence and/or regional lymph node dissemination.