Hitomi Nakayama1, Yoshinobu Aisa1, Chisako Ito1, Kengo Shimazaki1, Yasushi Katsumata2, Hiroyuki Hayashi3, Tomonori Nakazato4. 1. Department of Hematology, Yokohama Municipal Citizen's Hospital, Yokohama, Japan. 2. Department of Radiology, Yokohama Municipal Citizen's Hospital, Yokohama, Japan. 3. Department of Pathology, Yokohama Municipal Citizen's Hospital, Yokohama, Japan. 4. Department of Hematology, Yokohama Municipal Citizen's Hospital, Yokohama, Japan. Electronic address: n-tomo@eurus.dti.ne.jp.
Abstract
INTRODUCTION: Posttherapy positron emission tomography/computed tomography (PET/CT) scanning in patients with malignant lymphoma remains controversial. We aimed to evaluate the utility of achieving histologic verification of positive PET/CT findings in the follow-up of patients with malignant lymphoma. PATIENTS AND METHODS: A total of 771 PET/CT scans were performed as posttherapy follow-up in 190 lymphoma patients who had experienced a complete remission at our institution. Fifty-two patients (27.3%) had (18)F-fludeoxyglucose-positive lesions on posttherapy PET/CT, and a histologic diagnosis was carried out in 32 cases (16.8%). Ten patients (5.2%) exhibited relapse of lymphoma. Twelve lesions in 11 patients (5.8%) were proven to be second primary malignancies (SPM). Eleven patients (5.8%) were proven to have benign or normal tissue lesions. RESULTS: Among the 32 histologically verified PET/CT-positive patients, the symptomatic PET/CT-positive patients (n = 10; 4 SPM, 6 lymphoma relapse) had a significantly shorter overall survival rate than the asymptomatic PET/CT-positive patients (n = 22; 7 SPM, 4 lymphoma relapse, 11 benign/normal tissue lesions) (2-year overall survival, 48.2% vs. 100%, respectively; P < .001). CONCLUSION: This study emphasizes that the histologic diagnosis should be confirmed in posttherapy PET/CT-positive patients via biopsy before adjusting the treatment regimen as a result of the high false-positive rate, including unexpected SPM or benign/normal tissue lesions.
INTRODUCTION: Posttherapy positron emission tomography/computed tomography (PET/CT) scanning in patients with malignant lymphoma remains controversial. We aimed to evaluate the utility of achieving histologic verification of positive PET/CT findings in the follow-up of patients with malignant lymphoma. PATIENTS AND METHODS: A total of 771 PET/CT scans were performed as posttherapy follow-up in 190 lymphomapatients who had experienced a complete remission at our institution. Fifty-two patients (27.3%) had (18)F-fludeoxyglucose-positive lesions on posttherapy PET/CT, and a histologic diagnosis was carried out in 32 cases (16.8%). Ten patients (5.2%) exhibited relapse of lymphoma. Twelve lesions in 11 patients (5.8%) were proven to be second primary malignancies (SPM). Eleven patients (5.8%) were proven to have benign or normal tissue lesions. RESULTS: Among the 32 histologically verified PET/CT-positive patients, the symptomatic PET/CT-positive patients (n = 10; 4 SPM, 6 lymphoma relapse) had a significantly shorter overall survival rate than the asymptomatic PET/CT-positive patients (n = 22; 7 SPM, 4 lymphoma relapse, 11 benign/normal tissue lesions) (2-year overall survival, 48.2% vs. 100%, respectively; P < .001). CONCLUSION: This study emphasizes that the histologic diagnosis should be confirmed in posttherapy PET/CT-positive patients via biopsy before adjusting the treatment regimen as a result of the high false-positive rate, including unexpected SPM or benign/normal tissue lesions.