Carotid body tumors: radioguided surgical approach

Aim. Aim of this article was to define the role of color-coded imaging (CCI) and Indium In-111 pentetreotide scintigraphy-SPECT (In-111SRS-SPECT) for preoperative and intraoperative detection of carotid body tumor (CBT) site, nature and multicentricity, and for follow-up within a multidisciplinary treatment. Methods. From January 1997 to June 2008, 12 patients suffering from 15 CBT (4 bilateral) and 1 vagus nerve neurinoma were submitted to CCI and In-111SRS-SPECT preoperatively and during follow-up. Intraoperative radiocaptation by Octreoscan was also carried out on all lesions. Results. Preoperatively In-111SRS-SPECT detected all chemodectomas (sensitivity 100%) and no radioisotopic uptake was detected in vagus nerve neurinoma. CCI and In-111SRS-SPECT also provided data to group CBTs showing a good agreement with Shamblin classification: 5 in class 1,5 in class II and the remaining 5 in class III. Preoperative embolization was carried out for 7 larger tumors as evaluated by CCI and In-111SRS-SPECT. When CCI and radioisotopic scans demonstrated a very high tumor site above the angle of the mandible, a multidisciplinary treatment involving vascular and maxillo-facial teams was planned. Intraoperatively Octreoscan demonstrated microscopic tumor leftovers promptly removed in 1 case and an unresectable remnant at base skull in 1. During follow-up CCI and radioisotopic scans showed no recurrence in all cases and a slightly enlargement of that intracranial residual detected during surgery. Conclusion. Computed tomography (CT) and magnetic resonance (MR) imaging are reliable techniques for CBTs detection but do not provide any information concerning metastatic repetitions or multicentricity. An early and far less invasive localization of those tumors at neck can be achieved by ultrasounds. Radioisotopic scans seem to provide useful data for diagnosis of all types of paragangliomas and of malignant, recurrent or multicenter tumors; nuclear and ultrasound studies confirmed by CT or MR examination provide data for a multidisciplinary approach involving vascular, maxillofacial surgeons and radiologist. During surgery, radiolocalization is helpful in detecting tumor leftovers, which would entail a recurrence and allows a more radical radioguided excision. ECD and In-111SRS-SPECT may reliably be used for follow-up minimizing the need of postoperative CT or MR controls.

Background: Carotid body tumours (CBTs) are very rare lesions which should be treated as soon as possible even when benign since small tumour size permits easier removal and lower incidence of perioperative complications and recurrence. Malignant forms are rare and they can be identified by lymph node invasion and metastases in distant locations. The need of reliable and effective diagnostic modalities for both primary CBTs and its metastases or recurrence is evident. The present study reviews our experience and attempt to define the role of colour coded ultrasound (CCU) and Somatostatin receptor scintigraphy (SRS) with Indium-III-DTP-Apentetretide (Octreoscan (R)) using both planar and single photon emission tomography (SPECT) technique in the diagnosis and follow-up of these uncommon lesions within a multidisciplinary approach. Methods: From 1997 to 2008, 12 patients suffering from 16 CBTs (4 bilateral) were investigated by CCU and SRS-SPECT before and after surgery. All tumours were grouped according to Shamblin's classification in order to assess the technical difficulties and morbidity of surgical resection on the ground of their size and relationship with the carotid arteries. Intraoperative radiocaptation by Octreoscan (R)) was also carried out in all cases to evaluate the radicality of surgery. All perioperative scans were evaluated by the same nuclear medicine physician. Results: Preoperatively CCU showed CBTs (four were not palpable) with a sensitivity of 100%. Radioisotope imaging identified the CBTs as chemodectomas in 15 cases while no radioisotopic uptake was detected in 1 vagus nerve neurinoma. No evidence of metastasis or multicentricity were seen by total body radioisotopic scans. Combined data from CCU and SRS-SPECT allowed to determine tumour size in order to select 7 larger tumours which were submitted to selective preoperative embolization. Intraoperatively Octreoscan demonstrated microscopic tumour leftovers promptly removed in 1 case and an unresectable remnant at the base of the skull in another case. During follow-up CCI and radioisotope scans showed no recurrence in 14 cases and a slightly enlargement of the intracranial residual as detected during surgery in 1 patient. Conclusion: CCU may allow an early and noninvasive detection of CBTs and hence safer operations. The combined use of CCU and SRS-SPECT provide useful data to identify those tumours and to evaluate their extent and carotid arteries infiltration. Radioisotope imaging is a sensitive modality to detect metastases and lymph node involvement that are markers of CBT malignancy. After surgery CCU and SRS-SPECT can be accurate modalities for surveillance for an early detection of CBTs recurrence.