The aim of this study is to search for relationships between histology, radioiodine (¹³¹I) uptake, fluorodeoxyglucose (FDG) uptake, and disease outcome in patients with metastatic thyroid cancer. Eighty patients with metastatic thyroid cancer (34 males, 46 females, mean age at the time of the diagnosis of metastases: 55 years) were retrospectively studied. All patients were treated with radioactive iodine and evaluated by FDG-positron emission tomography (PET). Primary tumor tissue sample was available in all cases. Forty-five patients (56%) had a papillary, 12 (15%) a follicular, and 23 (29%) a poorly differentiated thyroid cancer. Cellular atypias, necrosis, mitoses, thyroid capsule infiltration, and vascular invasion were frequently detected (70, 44, 52, 60, and 71% respectively). Metastases disclosed FDG uptake in 58 patients (72%) and ¹³¹I uptake in 37 patients (45%). FDG uptake was the only significant prognostic factor for survival (P=0.02). The maximum standardized uptake value and the number of FDG avid lesions were also related to prognosis (P=0.03 and 0.009). Age at the time of the diagnosis of metastases (P=0.001) and the presence of necrosis (P=0.002) were independent predictive factors of FDG uptake. Radioiodine uptake was prognostic for stable disease (P=0.001) and necrosis for progressive disease at 1 year (P=0.001). Histological subtype was not correlated with in vivo tumor metabolism and prognosis. In conclusion, FDG uptake in metastatic thyroid cancer is highly prognostic for survival. Histological subtype alone does not correlate with ¹³¹I/FDG uptake pattern and patient outcome. Well-differentiated thyroid cancer presenting histological features such as necrosis and FDG uptake on PET scan should be considered aggressive differentiated cancers.

Prospective data are lacking on early somatostatin analog (SSA) therapy in bronchopulmonary neuroendocrine tumors (BP-NETs; typical carcinoids and atypical carcinoids (TCs and ACs)). SPINET (EudraCT: 2015-004992-62; NCT02683941) was a phase III, double-blind study of lanreotide autogel/depot (LAN; 120 mg every 28 days) plus best supportive care (BSC) vs placebo plus BSC, with an optional open-label treatment phase (LAN plus BSC). Patients had metastatic/unresectable, somatostatin receptor (SSTR)-positive TCs or ACs. Recruitment was stopped early owing to slow accrual; eligible patients from the double-blind phase transitioned to open-label LAN. The adapted primary endpoint was progression-free survival (PFS) during either phase for patients receiving LAN. Seventy-seven patients were randomized (LAN, n = 51 (TCs, n = 29; ACs, n = 22); placebo, n = 26 (TCs, n = 16; ACs, n = 10)). Median (95% CI) PFS during double-blind and open-label phases in patients receiving LAN was 16.6 (11.3; 21.9) months overall (primary endpoint), 21.9 (12.8, not calculable (NC)) months in TCs, and 13.8 (5.4; 16.6) months in ACs. During double-blind treatment, median (95% CI) PFS was 16.6 (11.3; 21.9) months for LAN vs 13.6 (8.3; NC) months for placebo (not significant); corresponding values were 21.9 (13.8; NC) and 13.9 (13.4; NC) months, respectively, in TCs and 13.8 (5.4; 16.6) and 11.0 (2.8; 16.9) months, respectively, in ACs. Patients’ quality of life did not deteriorate and LAN was well tolerated. Although recruitment stopped early and the predefined sample size was not met, SPINET is the largest prospective study to date of SSA therapy in SSTR-positive TCs and ACs and suggests clinical benefit in TCs.

¹³¹I is given in differentiated thyroid cancer (DTC) without taking into account thyroglobulin (Tg) levels at the time of ablation, whereas 6–18 months later it is a major criterion for cure. This single-center retrospective study assessed the frequency and risk factors for persistent disease on postablation whole body scan (WBS) and postoperative neck ultrasonography (n-US) and for recurrent disease during the subsequent follow-up, in patients with DTC and undetectable TSH-stimulated Tg level (TSH–Tg) in the absence of Tg antibodies (TgAb) at the time of ablation. Among 1031 patients ablated, 242 (23%) consecutive patients were included. Persistent disease occurred in eight cases (3%) (seven abnormal WBS and one abnormal n-US), all with initial neck lymph node metastases (N1). N1 was a major risk factor for persistent disease. Among 203 patients with normal WBS and a follow-up over 6 months, TSH–Tg 6–18 months after ablation was undetectable in the absence of TgAb in 173 patients, undetectable with TgAb in 1 patient and equal to 1.2 ng/ml in 1 patient. n-US was normal in 152 patients and falsely positive in 3 patients. After a mean follow-up of 4 years, recurrence occurred in two cases (1%), both with aggressive histological variants. The only risk factor for recurrence was an aggressive histological variant (P=0.03). In conclusion, undetectable postoperative TSH–Tg in the absence of TgAb at the time of ablation is frequent. In these patients, repeating TSH–Tg 6–18 months after ablation is not useful. ¹³¹I ablation could be avoided in the absence of N1 and aggressive histological variant.

The prognosis of poorly differentiated thyroid carcinomas (PDTC) defined by the Turin criteria is variable. The aim of this study on 51 PDTC patients was to determine clinical, histological and molecular prognostic factors associated with recurrence in patients with localized disease at initial treatment and with overall survival in patients with distant metastases. Of 40 patients for whom next-generation sequencing (NGS) by ThyroSeq v3 was able to be performed on historical samples, we identified high-risk molecular signature (TERT, TP53 mutations) in 24 (60%) cases, intermediate risk signature in 9 (22.5%) cases and low-risk signature in 7 (17.5%) cases. Potentially actionable mutations were identified in 10% of cases. After a median follow-up of 57.5 months, recurrence occurred in 11 (39%) of the 28 patients with localized disease. The American Thyroid Association (ATA) high risk of relapse, high mitotic count, high molecular risk signature and CD163 expression were associated with recurrence (P = 0.009, 0.01, 0.049, 0.03 respectively). After a median follow-up of 49.5 months, thyroid cancer-related death occurred in 53% of the patients with distant metastases. There was no significant prognostic factor associated with death in univariate analysis. However, none of the patients with intermediate ATA risk of recurrence and none of the patients with low-risk molecular signature died from the disease. In addition, high molecular-risk signature was associated with the presence of synchronous or metachronous distant metastasis (P = 0.007) and with poor overall survival (P = 0.01). In conclusion, ATA risk of relapse and high mitotic count was associated with higher rate of recurrence in localized PDTC. High molecular-risk signature was associated with the presence of distant metastasis and poor overall survival. Further studies are needed to determine if molecular testing adds to ATA risk stratification or response to therapy in predicting outcomes.

There is no standard for second-line chemotherapy in poorly differentiated grade 3 neuroendocrine carcinoma (G3-NEC) patients. We analyzed the antitumor efficacy of 5-fluorouracil and oxaliplatin (FOLFOX) chemotherapy in this population. A single-center retrospective analysis of consecutive G3-NEC patients treated with FOLFOX chemotherapy after failure of a cisplatinum-based regimen between December 2003 and June 2012 was performed. Progression-free survival (PFS), overall survival (OS), response rate, and safety were assessed according to RECIST 1.1 and NCI.CTC v4 criteria. Twenty consecutive patients were included (seven males and 13 females; median age 55; range 23–87 years) with a performance status of 0–1 in 75% of them. Primary location was gastroenteropancreatic in 12, thoracic in four, other in two, and unknown in two patients. There were 12 (65%) large-cell and 7 (30%) small-cell G3-NEC tumors, and 1 (5%) unknown. All patients had distant metastases. Twelve (60%) patients received FOLFOX as second-line treatment and 8 (40%) as third-line treatment or later and the median number of administered cycles was 6 (range 3–14). The median follow-up was 19 months. Median PFS was 4.5 months. Among the 17 evaluable patients, five partial responses (29%), six stable diseases (35%), and six progressive diseases (35%) were observed. Median OS was 9.9 months. Main Grade 3–4 toxicities were neutropenia (35%), thrombopenia (20%), nausea/vomiting (10%), anemia (10%), and elevated liver transaminases (10%). Our results indicate that the FOLFOX regimen could be considered as a second-line option in poorly differentiated G3-NEC patients after cisplatinum-based first-line treatment but warrant further confirmation in future larger prospective studies.