N-staging in large cell neuroendocrine carcinoma of the lung: diagnostic value of [18F]FDG PET/CT compared to the histopathology reference standard.

BACKGROUND: Large cell neuroendocrine carcinoma of the lung (LCNEC) is a rare entity occurring in less than 4% of all lung cancers. Due to its low differentiation and high glucose transporter 1 (GLUT1) expression, LCNEC demonstrates an increased glucose turnover. Thus, PET/CT with 2-[18F]-fluoro-deoxyglucose ([18F]FDG) is suitable for LCNEC staging. Surgery with curative intent is the treatment of choice in early stage LCNEC. Prerequisite for this is correct lymph node staging. This study aimed at evaluating the diagnostic performance of [18F]FDG PET/CT validated by histopathology following surgical resection or mediastinoscopy. N-staging interrater-reliability was assessed to test for robustness of the [18F]FDG PET/CT findings. METHODS: Between 03/2014 and 12/2020, 46 patients with LCNEC were included in this single center retrospective analysis. All underwent [18F]FDG PET/CT for pre-operative staging and subsequently either surgery (n = 38) or mediastinoscopy (n = 8). Regarding the lymph node involvement, sensitivity, specificity, accuracy, positive predictive value (PPV) and negative predictive value (NPV) were calculated for [18F]FDG PET/CT using the final histopathological N-staging (pN0 to pN3) as reference. RESULTS: Per patient 14 ± 7 (range 4-32) lymph nodes were resected and histologically processed. 31/46 patients had no LCNEC spread into the lymph nodes. In 8/46 patients, the final stage was pN1, in 5/46 pN2 and in 2/46 pN3. [18F]FDG PET/CT diagnosed lymph node metastasis of LCNEC with a sensitivity of 93%, a specificity of 87%, an accuracy of 89%, a PPV of 78% and a NPV of 96%. In the four false positive cases, the [18F]FDG uptake of the lymph nodes was 33 to 67% less in comparison with that of the respective LCNEC primary. Interrater-reliability was high with a strong level of agreement (κ = 0.82). CONCLUSIONS: In LCNEC N-staging with [18F]FDG PET/CT demonstrates both high sensitivity and specificity, an excellent NPV but a slightly reduced PPV. Accordingly, preoperative invasive mediastinal staging may be omitted in cases with cN0 disease by [18F]FDG PET/CT. In [18F]FDG PET/CT cN1-cN3 stages histological confirmation is warranted, particularly in case of only moderate [18F]FDG uptake as compared to the LCNEC primary.

Preoperative chest computed tomography evaluation for predicting intraoperative lung resection strongly depends on interpreters experience.

OBJECTIVES: Preoperative planning of lung resection extent is decisive for preoperative functional work-up and selection for multimodal treatment. It is mainly based on preoperative chest CT. We aimed at evaluating chest CT adequacy to predict the extent of lung resection and hypothesized a relation with CT interpreters' level of experience. MATERIALS AND METHODS: A pseudonymized CT library was built from patients who had curative intent lung resection for centrally located NSCLC. CT library was interpreted by 20 thoracic surgery residents or attendings. Interpreters were blinded to intraoperative findings and scored one point when lung resection was adequately planned. Points were summed up in a score from 0 to 20. Interpreters' experience was evaluated through nine variables: age, position (resident vs. attending), years of experience in evaluating chest CTs, number of anatomic resections and sleeve resections attended as first assistant or performed as surgeon in presence of a teaching assistant or as main surgeon/teaching assistant. Variables characterizing interpreters' experience were divided into equal sized groups. Independent sample T-test and one-way ANOVA/Tukey post hoc tests were used to compare scores between groups. RESULTS: CT library included 20 patients. Lung resections were lobectomy (n = 7, 35 %), sleeve lobectomy (n = 10, 50 %), sleeve bilobectomy (n = 2, 10 %), pneumonectomy (n = 1, 5%). Twenty interpreters scored a median of 10 (4-14). Attending surgeons had significantly higher mean scores (11.2 ±â€¯1.3) compared to residents (7.7 ±â€¯2.3, p = 0.001). All scores were significantly different between groups related to interpreters' levels of experience, except for interpreters'age. CONCLUSION: Preoperative CT evaluation for predicting intraoperative lung resection for centrally located NSCLC strongly depends on interpreters' experience.

Prognostic markers in resected large cell neuroendocrine carcinoma: a multicentre retrospective analysis.

BACKGROUND: Large cell neuroendocrine carcinomas (LCNEC) are rare pulmonary malignancies. Reported survival rates are heterogeneous and the optimal therapeutic strategy is still debated. The prognosis of LCNEC is generally inferior compared to other non-small lung cancers. In early stages, surgery is recommended but might not be sufficient alone. METHODS: We retrospectively analyzed all consecutive LCNEC patients operated at three institutions with curative intent between May 2005 and January 2017. Data retrieved from individual clinical databases were analyzed with the aim to identify prognostic parameters. RESULTS: A total of 251 patients with LCNEC underwent curative intent surgery during the observation period. The median age was 64 years, 156 patients (62.2%) were male and 88.4% were smokers. The pathologic AJCC stage was I in 136 patients, II in 77, III in 33, and IV in 5 patients. Median follow-up was 26 months. Lymphatic vessel invasion (P=0.031) was identified as significant prognostic factor by multivariable analysis. There was a trend towards decreased survival in patients with blood vessel invasion (P=0.067). Even in earlier tumor stages, adjuvant chemotherapy had a positive effect on survival. The overall 1-, 3- and 5-year survival rates were 79.2%, 48.6% and 38.8% respectively. CONCLUSIONS: Lymphatic invasion (L1) is an independent prognostic factor. Surgery in LCNEC is beneficial in early tumor stages and platinum-based adjuvant chemotherapy may help in achieving better long-term outcomes resulting in most obvious survival differences in stage Ib.