Biological correlates of the maximum 18-fluoro-2-deoxy-glucose uptake on positron emission tomography in non-small cell lung carcinoma after induction chemotherapy

Ground-glass opacity-featured lung adenocarcinoma has no response to chemotherapy

PURPOSE

We aimed to investigate the treatment effect of chemotherapy on ground-glass opacity (GGO)-featured lung adenocarcinoma radiologically and pathologically.

METHODS

This retrospective study included patients who met the following criteria: (1) presence of lung GGO lesions before chemotherapy for other concurrent malignancies; (2) underwent surgical resection of GGO-featured primary lung adenocarcinoma. The last computed tomography images before chemotherapy (CT1) and the last images before GGO resection (CT2) were reviewed to assess radiologic response. Specimens of the resected tumors were reviewed to evaluate the histopathologic response. Immunohistochemical staining of ki-67, caspase-3 and β-gal was performed and compared between these tumors and a propensity score-matched (1:1) cohort of GGO-featured lung adenocarcinoma without prior chemotherapy.

RESULTS

Forty-four patients with 55 GGO lesions were included. There were 20 mixed GGOs and 22 invasive adenocarcinomas. These patients all received at least three cycles of chemotherapy for other concurrent malignancies in breast, lung, cervix, ovary or rectum. Thirty-four (77%) patients received chemotherapy regimens that contained platinum, pemetrexed, paclitaxel, docetaxel or gemcitabine. The median interval between CT1 and CT2 was 10 months. Radiologically, all the GGO lesions either remained unchanged or enlarged. There was no chemotherapy-induced histopathologic response (necrosis, fibrosis or inflammation) in any of these tumors. The protein expression of ki-67, caspase-3 and β-gal was comparable between GGO-featured lung adenocarcinoma with or without prior chemotherapy.

CONCLUSION

GGO-featured lung adenocarcinoma has no response to chemotherapy. For these patients, chemotherapy should not be a treatment option.

Correlation of HIF-1α/HIF-2α expression with FDG uptake in lung adenocarcinoma

OBJECTIVES

Hypoxia is a key element involved in the development and progression of tumors. HIF-1α may transiently induce and mediate the response to acute and severe hypoxia, while HIF-2α may induce a longer response and may control the response to chronic and moderate hypoxia. Hypoxia increases the cellular uptake of FDG. Therefore, HIF may play an important role in the process of the cellular uptake of FDG. The aim of this study was to compare HIF-1α/HIF-2α expression with FDG uptake, Glut-1 expression, and prognosis in the patients with lung adenocarcinoma and to investigate the role of HIF-1α/HIF-2α in the uptake of FDG in lung adenocarcinoma.

METHODS

In the current work, we compared the immunohistochemical expression of HIF-1α and HIF-2α in surgical specimens of 44 patients with lung adenocarcinoma. The relationships between HIF-α expression and Glut-1 expression, FDG uptake, and clinicopathological factors, including prognosis, were analyzed.

RESULTS

There was a marginal association between HIF-1α and HIF-2α expressions (P = 0.076). We found a significant correlation between HIF-2α expression and FDG uptake (P = 0.0001). HIF-1α expression showed a marginal association with FDG uptake (P = 0.066). FDG uptake correlated more significantly with HIF-2α expression than with HIF-1α expression. A significant correlation was noticed between Glut-1 expression and both HIF-1α and HIF-2α expressions (P = 0.005 and P = 0.003, respectively). Univariate analysis of disease-free survival demonstrated that FDG uptake and HIF-2α expression, but not HIF-1α expression, were related to recurrence (P < 0.0001).

CONCLUSION

FDG uptake correlated more significantly with HIF-2α expression than with HIF-1α expression, and both FDG uptake and HIF-2α expression, but not HIF-1α expression was correlated with post-operative recurrence in the patients with lung adenocarcinoma. These results suggest that both FDG uptake and HIF-2α expression may represent a more aggressive phenotype and that HIF-2α may play a more important role than HIF-1α in the uptake of FDG in lung adenocarcinoma.

Inter-observer agreement improves with PERCIST 1.0 as opposed to qualitative evaluation in non-small cell lung cancer patients evaluated with F-18-FDG PET/CT early in the course of chemo-radiotherapy

Background

The purpose of this study is to determine whether a qualitative approach or a semi-quantitative approach provides the most robust method for early response evaluation with 2′-deoxy-2′-[¹⁸F]fluoro-d-glucose (F-18-FDG) positron emission tomography combined with whole body computed tomography (PET/CT) in non-small cell lung cancer (NSCLC).

In this study eight Nuclear Medicine consultants analyzed F-18-FDG PET/CT scans from 35 patients with locally advanced NSCLC. Scans were performed at baseline and after 2 cycles of chemotherapy. Each observer used two different methods for evaluation: (1) PET response criteria in solid tumors (PERCIST) 1.0 and (2) a qualitative approach. Both methods allocate patients into one of four response categories (complete and partial metabolic response (CMR and PMR) and stable and progressive metabolic disease (SMD and PMD)). The inter-observer agreement was evaluated using Fleiss’ kappa for multiple raters, Cohens kappa for comparison of the two methods, and intraclass correlation coefficients (ICC) for comparison of lean body mass corrected standardized uptake value (SUL) peak measurements.

Results

The agreement between observers when determining the percentage change in SULpeak was “almost perfect”, with ICC = 0.959. There was a strong agreement among observers allocating patients to the different response categories with a Fleiss kappa of 0.76 (0.71–0.81). In 22 of the 35 patients, complete agreement was observed with PERCIST 1.0. The agreement was lower when using the qualitative method, moderate, having a Fleiss kappa of 0.60 (0.55–0.64). Complete agreement was achieved in only 10 of the 35 patients. The difference between the two methods was statistically significant (p < 0.005) (chi-squared).

Comparing the two methods for each individual observer showed Cohen’s kappa values ranging from 0.64 to 0.79, translating into a strong agreement between the two methods.

Conclusions

PERCIST 1.0 provides a higher overall agreement between observers than the qualitative approach in categorizing early treatment response in NSCLC patients. The inter-observer agreement is in fact strong when using PERCIST 1.0 even when the level of instruction is purposely kept to a minimum in order to mimic the everyday situation. The variability is largely owing to the subjective elements of the method.

Electronic supplementary material

The online version of this article (doi:10.1186/s13550-016-0223-6) contains supplementary material, which is available to authorized users.