Early FDG-PET imaging after radical radiotherapy for non–small-cell lung cancer: Inflammatory changes in normal tissues correlate with tumor response and do not confound therapeutic response evaluation

Is <sup>18</sup>F-FDG-PET/CT a Valid Non-Invasive Predictor for Regression Grade after Neoadjuvant Treatment in Patients with NSCLC Stage III?

“…This is correlative to data by Fischer et al who showed a detection limit of PET in the magnitude of 10 5 to 10 6 malignant cells [40] [41]. Hence, false negative results may occur if there is a low vital tumor cell density leading to very low PET signals in the voxels [42]. According to data by Fischer et al false negative results are also possible due to small or well-differentiated malignancies, such as bronchioalveolar carcinoma or carcinoid [40] [41].…”

18F-FDG PET/CT following chemoradiation of uterine cervix cancer provides powerful prognostic stratification independent of HPV status: a prospective cohort of 105 women with mature survival data

“…In brief, a CMR was defined as no tracer uptake or the background level of FDG activity within the treated area of the disease, a PMR as residual FDG activity within the treated area of the disease, and PMD as increased intensity or distribution of FDG-avid disease. Post-irradiation inflammation was differentiated from residual tumour by pattern recognition of geographic regions of uptake demarcated by the high-dose treatment volume, an approach applied in previous studies by our group [10,11].…”

Radiation Changes Do Not Interfere With Postchemoradiation Restaging of Patients With Rectal Cancer by FDG PET/CT Before Curative Surgical Therapy

“…The reader determined the degree of radiation change (0-3) using the scoring criteria detailed below. These criteria had been adapted to rectal cancer from a prior study evaluating the effect of chemoradiation on FDG PET in lung cancer (14). This involved visual comparison of the intensity of FDG uptake in tissues in the rectum adjacent to the site of the primary tumor as identified in the baseline study, with the background colonic uptake outside of the radiation field and with nonrectal tissues inside the radiation field.…”

“…For other tumors such as head and neck cancer (11) and lymphoma (12), the current advice is that the early post-CRT inflammatory response causes sufficient numbers of false-positive results to limit PET being performed <2 months post-CRT. However this advice remains controversial, as others have found little impact of postradiation changes on assessment of therapeutic response (13,14).…”