Cancer immunotherapy: imaging assessment of novel treatment response patterns and immune-related adverse events.

Cancer immunotherapy is changing the imaging evaluation of cancer treatment response and treatment-related toxic effects. New emerging patterns of treatment response and treatment-related toxic effects after treatment with immunomodulating agents have been observed. Treatment response after immunomodulatory therapy can be associated with significantly delayed decrease in tumor size, and new or enlarging tumors observed soon after completion of treatment may not reflect disease progression. In addition, activation of the immune system to fight cancer may lead to unwanted autoimmune-mediated toxic effects that could be mistaken for metastatic disease or misdiagnosed as a non-treatment-related process and delay appropriate clinical management. Radiologists must recognize the novel treatment response patterns and the wide range of autoimmune toxic effects, which should not be mistaken for treatment failure or metastatic disease progression.

End-therapy positron emission tomography for treatment response assessment in follicular lymphoma: a systematic review and meta-analysis.

PURPOSE: Use of 2[(18)F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) in postchemotherapy response assessment in follicular lymphoma is still a controversial issue. Here, we conducted the first systematic review and meta-analysis to determine the predictive value of FDG-PET in predicting outcome after chemotherapy of follicular lymphoma. EXPERIMENTAL DESIGN: Comprehensive literature search in Ovid-MEDLINE and EMBASE databases was performed to identify studies which evaluate predictive value of end-therapy PET and/or computed tomography (CT) in patients with follicular lymphoma. To quantitatively compare the predictive value of PET and CT, pooled hazard ratios (HRs) comparing progression-free survival (PFS) between patients with positive and negative results were adopted as the primary indicators for meta-analysis. To explore the efficiency in determining complete remission (CR), pooled CR rates of PET- and CT-based response criteria were calculated. Pooling of these parameters was based on the random-effects model. RESULTS: Review of 285 candidate articles identified eight eligible articles with a total of 577 patients for qualitative review and meta-analysis. The pooled HRs of end-therapy PET and CT were 5.1 [95% confidence interval (CI), 3.7-7.2] and 2.6 (95% CI, 1.2-5.8), respectively, which implies that PET is more predictive of PFS after chemotherapy than CT. The pooled CR rates of PET- and CT-based response criteria were 75% (95% CI, 70-79%) and 63% (95% CI, 53-73%), respectively, which implies that PET is more efficient in distinguishing CR (without residual disease) from other states with residual disease. In addition, qualitative systematic review indicates the same findings. CONCLUSIONS: Consistent evidence favoring PET-based treatment assessment should be considered in the management of patients with follicular lymphoma.

New Response Evaluation Criteria in Solid Tumors (RECIST) guidelines for advanced non-small cell lung cancer: comparison with original RECIST and impact on assessment of tumor response to targeted therapy.

OBJECTIVE: The purpose of this article is to compare the recently published revised Response Evaluation Criteria in Solid Tumors (RECIST) guidelines (version 1.1) to the original guidelines (RECIST 1.0) for advanced non-small cell lung cancer (NSCLC) after erlotinib therapy and to evaluate the impact of the new CT tumor measurement guideline on response assessment. MATERIALS AND METHODS: Forty-three chemotherapy-naive patients with advanced NSCLC treated with erlotinib in a single-arm phase 2 multicenter open-label clinical trial were retrospectively studied. CT tumor measurement records using RECIST 1.0 that were generated as part of the prospective clinical trial were reviewed. A second set of CT tumor measurements was generated from the records to meet RECIST 1.1 guidelines. The number of target lesions, best response, and time to progression were compared between RECIST 1.1 and RECIST 1.0. RESULTS: The number of target lesions according to RECIST 1.1 decreased in 22 patients (51%) and did not change in 21 patients (49%) compared with the number according to RECIST 1.0 (p < 0.0001, paired Student's t test). Almost perfect agreement was observed between best responses using RECIST 1.1 and RECIST 1.0 (weighted kappa = 0.905). Two patients with stable disease according to RECIST 1.0 had progressive disease according to RECIST 1.1 criteria because of new lesions found on PET/CT. There was no significant difference in time to progression between RECIST 1.1 and RECIST 1.0 (p = 1.000, sign test). CONCLUSION: RECIST 1.1 provided almost perfect agreement in response assessment after erlotinib therapy compared with RECIST 1.0. Assessment with PET/CT was a major factor that influenced the difference in best response assessment between RECIST 1.1 and RECIST 1.0.

Surveillance imaging of Hodgkin lymphoma patients in first remission: a clinical and economic analysis.

BACKGROUND: The majority of patients with Hodgkin lymphoma (HL) achieve disease remission after primary therapy. To the best of the authors' knowledge, no consensus exists for postremission surveillance imaging. METHODS: Retrospectively analyzed were 192 adult patients with classic HL in first remission. Events were defined as recurrent HL or secondary malignancies. Primary outcome was positive predictive value (PPV) of surveillance positron emission tomography/computed tomography (PET/CT) and CT scans in event detection. Secondary outcomes were costs and radiation exposures of surveillance scans. RESULTS: Sixteen events (12 recurrent HL cases and 4 secondary malignancies) were detected during a median follow-up of 31 months. The PPV of surveillance PET/CT was 22.9% compared with 28.6% for CT (P=.73). Factors that were found to significantly improve the PPV of scans in detecting recurrent HL included PET and CT concordance, involvement of a prior disease site, or the occurrence of a radiographic abnormality within 12 months. There were too few events to determine whether event detection by PET/CT versus CT or the presence of symptoms at the time of event detection affected overall outcomes. The cost to detect a single event was approximately $100,000. Radiation exposure to detect a single event was 146.6 millisieverts per patient for each of 9 patients. CONCLUSIONS: For patients with HL in first disease remission, surveillance radiography appears to be expensive, with limited clinical impact. Surveillance CT is generally adequate.

Role of PET/CT scanning in initial and post-treatment assessment of Hodgkin disease.

The add-on value of F18-fluorodeoxyglucose PET, particularly when combined with CT, to the conventional workup in managing patients with Hodgkin disease has now been well documented. This article reviews the use of these imaging modalities in the initial staging and post-treatment assessment of Hodgkin disease.