Incidentally detected 18 F-FDG PET-CT-avid thyroid nodules in patients with advanced malignancy: long-term oncological outcomes from a single-centre retrospective cohort.

OBJECTIVES: In this retrospective study, we assessed the clinical outcomes of patients with a primary malignancy who had incidentally detected thyroid avidity on their staging 18 F-fluorodeoxyglucose PET-computed tomography ( 18 F-FDG PET-CT) examinations. METHODS: A focused retrospective search was made using a Radiology Information System to identify only patients with positive thyroid nodules on their 18 F-FDG PET-CT imaging between January 2012 and December 2017. Patient demographics, principal oncological diagnosis, and stage were recorded. The sonographic appearances of thyroid nodules, number of fine needle aspiration (FNA) attempts, final cytology, management plan, and clinical outcome were recorded. Follow-up records were available for between 2 and 7 years. RESULTS: Following exclusions, 136 patients were found to have incidental thyroid avidity on their 18 F-FDG PET-CT. A total of 50 of these patients proceeded to thyroid ultrasound assessment. Of these, 37 patients underwent FNA (average 1.3 FNA attempts) with 17 having atypical cytology and 6 diagnosed with an incidental thyroid cancer either by FNA or thyroidectomy. Four patients who underwent surgery had benign pathology. All thyroid cancers identified were indolent papillary cancers without any impact on the treatment plan or survival. CONCLUSION: The clinical outcomes of patients with an established primary malignancy are determined by their primary cancer and not by incidentally detected thyroid cancer. It may therefore be reasonable not to formally investigate a proportion of incidental 18 F-FDG PET-CT positive thyroid nodules where added benefit is unlikely. In such cases, a 'watch-and-wait' approach to the thyroid might be considered more appropriate.

Small cell rectal cancer: a therapeutic challenge.

A generally well 71-year-old man presented to his general practitioner with altered bowel habit and haematochezia. Colonoscopy revealed a malignant-appearing rectal mass, with histological features of extrapulmonary small cell carcinoma (EPSCC) of the rectum. Imaging demonstrated limited stage disease with a threatened circumferential resection margin. He was treated with a modified platinum chemoradiotherapy regimen for small cell lung cancer with an excellent response. Unfortunately, his cardiac function precluded surgery at the time and the patient subsequently developed hepatic metastases with local disease recurrence, and died 15 months following his initial diagnosis. Rectal EPSCC is a rare diagnosis, and this case represented a challenge for the multidisciplinary team given the limited evidence base. Medical therapy reflects extrapolation of small cell lung cancer treatment and the role of surgery is less clearly defined given aggressive and refractory disease is common. Immunotherapy, however, represents an exciting development for metastatic disease.