A multi-institutional feasibility lead-in trial of lymphatic mapping with SPECT-CT for evaluating contralateral disease in lateralized oropharynx cancer using 99m-technetium sulfur colloid.

BACKGROUND: Lymphatic mapping with SPECT-CT has been demonstrated to accurately define lymphatic drainage patterns in oropharyngeal cancer but there has yet to be a study demonstrating its feasibility across multiple institutions. METHODS: Twelve adult patients with lateralized oropharyngeal carcinoma (T1-T3) who were planned for definitive or adjuvant radiotherapy without contralateral nodal disease underwent injection of 99-m technetium sulfur colloid followed by static planar lymphoscintigraphy to verify tracer migration, and SPECT-CT acquired at 30 ± 15 min (optional) and 3 h (±1 h) (mandatory time-point). RESULTS: All 12 patients completed the study with 7/12 patients having the injections performed under local anesthetic and 5 patients requiring general anesthetic. There were no tracer migration failures and there were no serious adverse events or complications encountered. Four out of 12 patients (33%) showed contralateral drainage patterns. CONCLUSIONS: Lymphatic mapping with SPECT-CT of lateralized oropharyngeal squamous cell carcinoma can be performed safely across multiple institutions.

SDH deficiency is very common in carotid body paragangliomas: Genetic counseling and testing should be offered to all patients.

BACKGROUND: Collectively, germline pathogenic variants in succinate dehydrogenase (SDH) genes are the most common cause of hereditary paragangliomas. Loss of immunohistochemical expression of SDHB protein (termed SDH deficiency) occurs whenever there is biallelic inactivation of any SDH gene. We sought to estimate the prevalence of SDH deficiency in patients with carotid body paragangliomas. METHODS: We identified all carotid body paragangliomas that had undergone surgical excision at our institution over the last 30 years. If SDHB immunohistochemistry was not performed at the time of excision, it was performed on archived material. RESULTS: There were 64 carotid body paragangliomas identified in the 62 patients. Two-thirds of the patients were female, and 43 (67%) were SDH-deficient. CONCLUSION: Up to two-thirds of all carotid body paragangliomas are associated with SDH deficiency. Therefore, genetic testing and counseling should be offered to all patients with carotid body paragangliomas, regardless of age or family history.