@article {Li1685, author = {Hebei Li and Qian Wang}, title = {A clinical study of baseline PET/CT parameters in the prediction of refractory/ relapsed diffuse large B cell lymphoma of advanced stage patients}, volume = {62}, number = {supplement 1}, pages = {1685--1685}, year = {2021}, publisher = {Society of Nuclear Medicine}, abstract = {1685Introduction: Diffuse large B-cell lymphoma (DLBCL) is the most common subtype of lymphoma. Its cure rate has improved over the last two decades in the rituximab era. However, about one-third of patients are refractory/ relapsed ultimately. Early detection of such patients and applying more intensive treatment may help improve prognosis. 18F-FDG PET / CT is widely used in initial staging and post-treatment response assessment, while its value in prognosis is still challenge. The purpose of this study was to explore whether the baseline PET/CT parameters can identify refractory/ relapsed disease in advanced stage patients. Methods: Eighty-three advanced stage untreated DLBCL patients were enrolled in this study, including 43 males and 40 females, with a median age of 60 years. There were 18 cases of Ann Arbor stage III and 65 cases of stage IV. After baseline PET/CT examination, all patients received R-CHOP or R-CHOP-like regimen treatment in our hospital and were followed up for at least 3 years. Refractory/ relapsed disease was defined as progressive or stable disease during treatment, or relapse within 1 year of diagnosis after an initial CR. The tumor VOIs were semi automatically defined on the attenuation-corrected PET images by using a threshold of SUV >= 2.5 on local image features extraction (LifeX) software, with segmentation correction performed manually by consensus by two experienced nuclear medicine physicians. SUVmax, metabolic tumor volume (MTV) and tumor lesion glycolysis (TLG) were then calculated. The clinical data including Ann Arbor stage, B symptom, bulky mass, bone marrow involvement, important extranodal involvement, LDH level and NCCN-IPI score were also analyzed. Univariate and multivariate logistic regression analysis was used to identify the independent risk factors for refractory / relapsing patients. PFS and OS were estimated by the Kaplan-Meyer survival analyses, and the difference was compared using a log-rank test. Univariate and multivariate Cox regression models was used to identify the independent risk factors for PFS and OS. Results: There were 44 patients in non- refractory/ relapsed group and 39 patients in refractory/ relapsed group. The MTV and TLG of refractory/ relapsed group was significantly higher than that of non- refractory/ relapsed group (MTV: 1579.9 cm3 Vs. 484.7cm3, P =0.000; TLG: 7853.8 Vs. 3015.8, P =0.000). There was no significant difference of SUVmax between the two groups (15.9 Vs. 17.5, P= 0.248). In the univariate Logistic regression analysis, Ann Arbor stage = 4 \* ROMAN IV, B symptom, bone marrow involvement, important extranodal involvement, elevated LDH level, high NCCN-IPI score, high MTV and TLG were the independent risk factors in prediction refractory/ relapsing disease. In the multivariate Logistic regression analysis, only elevated LDH level and high TLG were the independent risk factors (elevated LDH: HR= 5.233, 95\% CI= 1.234-22.183, P=0.025; TLG\>2098: HR= 11.914, 95\% CI=3.065-46.314, P=0.000). In the univariate Cox analysis, Ann Arbor stage = 4 \* ROMAN IV, B symptom, bone marrow involvement, important extranodal involvement, elevated LDH level, high NCCN-IPI score, high MTV and high TLG were the independent risk factors for PFS. In multivariate Cox analysis, only high TLG was the independent risk factors (HR= 3.049, 95\%CI: 1.250-7.438, P=0.014). As to the OS, in the univariate Cox analysis, Ann Arbor stage = 4 \* ROMAN IV, B symptom, important extranodal involvement, elevated LDH level, high NCCN-IPI score, high MTV and high TLG were the independent risk factors. In multivariate analysis, only B symptom and elevated LDH were the independent risk factors (B symptom: HR= 3.494, 95\%CI: 1.489-8.197, P=0.004; elevated LDH: HR= 9.805, 95\% CI:1.320-72.831, P=0.026). Conclusions: High MTV and TLG in baseline PET/CT can predict the refractory/relapse disease in patients with advanced DLBCL, and can be used as important prognostic factors.}, issn = {0161-5505}, URL = {https://jnm.snmjournals.org/content/62/supplement_1/1685}, eprint = {https://jnm.snmjournals.org/content}, journal = {Journal of Nuclear Medicine} }