Differential Washout of FDG Activity in Two Different Inflammatory Lesions: Implications for Delayed Imaging

Prognostic Significance of SUVmax Combined With Lactate Dehydrogenase in Advanced Lung Cancer Patients Treated With Immune Checkpoint Inhibitor Plus Chemotherapy: A Retrospective Study

Purpose

This research aims to investigate the predictive capacity of PET/CT quantitative parameters combined with haematological parameters in advanced lung cancer patients treated with immune checkpoint inhibitor (ICI) plus chemotherapy.

Methods

A total of 120 patients who underwent ¹⁸F-fluorodeoxyglucose positron emission tomography/computed tomography (¹⁸F-FDG PET/CT) were enrolled before therapy. The following parameters were calculated: the maximum, mean, and peak standardized uptake value (SUVmax, SUVmean, and SUVpeak, respectively); total tumour volume (MTV) and total lesion glycolysis (TLG); and whole-body metabolic values (MTVwb, TLGwb, SUVmeanwb, and SUVmaxwb). Lactate dehydrogenase (LDH) levels, absolute neutrophil count, absolute platelet count, albumin levels and derived neutrophil to lymphocyte ratio (dNLR) were also computed. The associations between the variables and therapy outcome (evaluated by iRECIST) were analyzed.

Results

Based on iRECIST, 32 of 120 patients showed iPD, 43 iSD, 36 iPR and 9 iCR. Multivariate analysis found that SUVmax, MTVwb, LDH and absolute platelet count were associated with treatment response (P =0.015, P =0.005, P <0.001 and P =0.015, respectively). Kaplan-Meier survival analyses showed that SUVmax ≥11.42 and LDH ≥245 U/L were associated with shorter OS (P = 0.001 and P = 0.004, respectively). Multivariate Cox regression revealed that SUVmax and LDH alone were not correlated with survival prognosis (p>0.05), but the combination of SUVmax and LDH was independently associated with OS (P=0.015, P=0.001, respectively). The median survival time (MST) for the low (LDH<245 and SUVmax<11.42), intermediate(LDH<245 or SUVmax<11.42), and high(SUVmax≥11.42 and LDH≥245) groups was 24.10 months (95% CI: 19.43 to 28.77), 17.41 months (95% CI: 15.83 to 18.99), and 13.76 months (95% CI: 12.51 to 15.02), respectively.

Conclusion

This study identified that SUVmax plus LDH correlated with the survival outcome in patients with advanced lung cancer receiving PD-1/PD-L1 blockade plus chemotherapy.

18F-FDG PET/CT Can Predict Development of Thyroiditis Due to Immunotherapy for Lung Cancer

Our primary purpose was to determine whether increased ¹⁸F-FDG uptake in the thyroid gland predicts development of thyroiditis with subsequent hypothyroidism in patients undergoing immunotherapy with nivolumab for lung cancer. Secondarily, we determined whether ¹⁸F-FDG uptake in the thyroid gland correlates with number of administered cycles of nivolumab. Methods: Retrospective chart review over 2 y found 18 lung cancer patients treated with nivolumab who underwent ¹⁸F-FDG PET/CT before and during therapy. SUV_mean, SUV_max, and total lesion glycolysis of the thyroid gland were measured. SUVs were also measured for the pituitary gland, liver, and spleen. Patients underwent monthly thyroid testing. PET/CT parameters were analyzed by unpaired t testing for differences between 2 groups (patients who developed hypothyroidism and those who did not). Correlation between development of thyroiditis and number of cycles of nivolumab was also tested. Results: Six of 18 patients developed hypothyroidism. The t test comparing the 2 groups demonstrated significant differences in SUV_mean (P = 0.04), SUV_max (P = 0.04), and total lesion glycolysis (P = 0.02) of the thyroid gland. Two of 4 patients who developed thyroiditis and had increased ¹⁸F-FDG uptake in the thyroid gland had a normal TSH level at the time of follow-up ¹⁸F-FDG PET/CT. Patients who developed thyroiditis with subsequent hypothyroidism stayed longer on therapy (10.6 cycles) than patients without thyroiditis (7.6 cycles), but the trend was not statistically significant. No significant difference in PET/CT parameters was observed for pituitary gland, liver, or spleen. Conclusion:¹⁸F-FDG PET/CT can predict the development of thyroiditis with subsequent hypothyroidism before laboratory testing. Further study is required to confirm the positive trend between thyroiditis and duration of therapy.

Thalidomide for steroid-dependent chronic disseminated candidiasis after stem cell transplantation: A case report

Chronic disseminated candidiasis (CDC) is a rare and difficult-to-treat invasive fungal disease occurring mainly after prolonged and profound neutropenia. We describe the case of a 59-year-old man successfully treated with thalidomide for CDC recurrences after an autologous transplantation. We add evidence of the effectiveness of immunomodulatory drugs to manage inflammatory reconstitution immune syndrome-related refractory CDC.

Added Value of Dual-Time-Point 18F-FDG PET/CT With Delayed Imaging for Detecting Aortic Graft Infection: An Observational Study

F-FDG PET/CT is a promising tool in detecting aortic graft infection. Present study investigated the value of dual-time-point F-FDG PET/CT imaging (DTPI) with delayed imaging in assessing aortic graft infection.Twenty-nine patients with suspected aortic graft infection were prospectively enrolled in this DTPI study. Two nuclear medicine physicians read all the images and achieved consensus about the measurement of maximal standardized uptake value (SUVmax) and grading of image quality. The percentages of SUVmax change between initial and delayed images were recorded as retention index (RI); sensitivity, specificity, and accuracy were calculated based on reference standard.All the 5 infected aortic grafts had positive RIs, which were generally higher than that of noninfected grafts. Those noninfected grafts had variable RIs. Seven patients had improved image quality in delayed imaging. DTPI with delayed image detected all the infected grafts with improved specificity (88%) and accuracy (90%), providing conspicuous delineation of the infected graft extent.In conclusion, noninfected aortic grafts had more variable RIs than infected ones. DTPI might be useful for detecting aortic graft infection, improving image quality, and enhancing delineation of the infected aortic grafts.

Serial changes of FDG uptake and diagnosis of suspected lung malignancy: a lesion-based analysis

OBJECTIVE

This study prospectively evaluates the serial change of FDG uptake and its diagnostic value in malignant versus benign lung lesions in patients with suspected lung cancer.

PATIENTS AND METHODS

Patients with suspected lung malignancy underwent whole-body FDG PET/CT at 1, 2, and 3 hours after an IV injection of F-FDG. The SUVs of FDG in lung nodules and hilar/mediastinal nodes at each time point were correlated with biopsy/surgical pathologic findings.

RESULTS

There were a total of 45 malignant lesions and 80 benign lesions from 43 patients with pathologic diagnosis that were included for analysis. The SUVmax had an average of 25.5% increase in all tumor-positive lesions from 1 to 2 hours (vs 1.6% decrease in all tumor-negative lesions, P < 0.0001) and an average of 39.1% increase from 1 to 3 hours (vs 4.5% increase in all tumor-negative lesions, P < 0.0001). The receiver operating characteristic analysis showed that the 2-hour and 3-hour SUVmax had similar area under the curve and outperformed the SUVmax on the 1-hour initial imaging or retention index (RI). The optimal cutoff values to differentiate malignancy from benign lesions were 3.24 for 1-hour SUVmax, 3.67 for 2-hour SUVmax, and 4.21 for 3-hour SUVmax, with 11.6% for 1- to 2-hour RI and 23.9% for 1- to 3-hour RI. The 3-hour delayed SUVmax of 4.21 provided the best overall performance (accuracy of 88.8%). The analysis of the lesion-to-background ratio revealed that delayed imaging improved the image quality significantly, leading to much easier detection of either malignant or benign lesions.

CONCLUSIONS

Multiple time point FDG PET/CT imaging moderately improves the diagnostic accuracy of lung cancer and significantly improves the image quality.