Assessment Of Residual Masses Research Articles

Monitoring and Predicting Response to Therapy with 18F-FDG PET in Colorectal Cancer: A Systematic Review

Molecular imaging with (18)F-FDG PET has been proven useful in the management of colorectal cancer. (18)F-FDG PET plays a pivotal role in staging before surgical resection of recurrent colorectal cancer and metastases, in the localization of recurrence in patients with an unexplained rise in serum carcinoembryonic antigen levels, and in the assessment of residual masses after treatment. Currently, there is increasing interest in the role of (18)F-FDG PET beyond staging. The technique appears to have significant potential for the characterization of tumors and for the prediction of prognosis in the context of treatment stratification and early assessment of tumor response to therapy. This systematic review provides an overview of the literature on the value of (18)F-FDG PET for monitoring and predicting the response to therapy in colorectal cancer. The review covers chemotherapy response monitoring in advanced colorectal cancer, monitoring of the effects of local ablative therapies, and preoperative radiotherapy and multimodality treatment response evaluation in primary rectal cancer. Given the added value of (18)F-FDG PET for these indications, implementation in clinical practice and systematic inclusion in therapeutic trials to exploit the potential of (18)F-FDG PET are warranted.

The role of FDG PET in the management of lymphoma: what is the evidence base?

[18F]Fluorodeoxyglucose positron emission tomography (18F-FDG PET) is playing an increasing role in the management of both Hodgkin and non-Hodgkin lymphoma, offering potential advantages in the accuracy of disease assessment at a number of points in the management pathway. This review evaluates the current level of confidence in the use of PET technology in (1) initial staging, (2) the assessment of early response to chemotherapy, (3) the assessment of residual masses at completion of initial treatment, (4) follow-up, and (5) radiotherapy planning.

FDG-PET in colorectal cancer.

[18F]Fluorodeoxyglucose (FDG) positron emission tomography (PET) is a useful imaging tool in the evolving management of patients with colorectal carcinoma. This technique is able to measure and visualize metabolic changes in cancer cells. This feature results in the ability to distinguish viable tumor from scar tissue, in the detection of tumor foci at an earlier stage than possible by conventional anatomic imaging and in the measurement of alterations in tumor metabolism, indicative of tumor response to therapy. Nowadays, FDG-PET plays a pivotal role in staging patients before surgical resection of recurrence and metastases, in the localization of recurrence in patients with an unexplained rise in serum carcinoembryonic antigen and in assessment of residual masses after treatment. In the presurgical evaluation, FDG-PET may be best used in conjunction with anatomic imaging in order to combine the benefits of both anatomical (CT) and functional (PET) information, which leads to significant improvements in preoperative liver staging and preoperative judgment on the feasibility of resection. Integration of FDG-PET into the management algorithm of these categories of patients alters and improves therapeutic management, reduces morbidity due to futile surgery, leads to substantial cost savings and probably also to a better patient outcome. FDG-PET also appears to have great potential in monitoring the success of local ablative therapies soon after intervention and in the prediction and evaluation of response to radiotherapy, systemic therapy, and combinations thereof. This review aims to outline the current and future role of FDG-PET in the field of colorectal cancer.

18-FDG-PET as a Prognostic Indicator in the Treatment of Aggressive Non-Hodgkin's Lymphoma-Comparison with CT

Less than 50%, of newly diagnosed patients with aggressive histology Non-Hodgkin's Lymphoma (NHL) are cured with standard treatment. The ability to accurately monitor response to treatment is crucial in order to select out patients who need more intensive or salvage treatment. This study assesses the accuracy of FDG-PET as compared to CT in remission assessment following treatment of aggressive NHL, and its value in estimating relapse-free survival. It also evaluates the prognostic value of early interim PET scan in prediction of treatment outcome. Forty-nine adult patients with biopsy-proven aggressive NHL between September 1993 and December 1997 were included. All patients had pre-treatment FDG-PET demonstrating increased uptake in sites of disease. Forty-five patients had a post-treatment PET to assess remission status and 4 had an interim but not a post-treatment PET. Thirty-three of these patients also had a pre- and a post-treatment CT scan. Twenty-three of the 49 patients had an interim PET during chemotherapy to assess early response. PET and CT scan results were correlated with relapse data to examine their accuracy in remission assessment and prediction of prognosis. The median follow-up duration is 30 months.Overall the result of post-treatment PET scan appears to predict diseasc outcome, with relapse rates of 100% (919) and 17% (6/36) for positive and negative PET respectively [p<0.001]. In a subgroup of 33 patients, direct comparison of post-treatment PET and CT shows that PET was more accurate than CT in assessing remission status following treatment. Relapse rate was 100% for positive PET and only 18% for negative PET (p<0.001). compared to 41% and 25%. for patients with positive and negative CT respectively (p<0.1). PET was particularly useful in assessment of residual masses seen on CT scan. The interim PET provided valuable information regarding early assessment of response and long-term prognosis, with no relapses in patients with no or minimal residual uptake compared to 87.5% relapse rate in patients with persistent PET activity (p<0.001). FDG-PET is an accurate method of assessing remission and estimating prognosis following treatment of aggressive NHL, with positive and negative predictive accuracies of 100% and 82% respectively. PET is more accurate than CT in assessing remission and prediction of relapse-free survival. An interim PET scan after 2-3 cycles of chemotherapy predicts the long-term outcome early-on and has a high negative predictive value (100%). This may assist to separate at an early stage good-prognosis patients who are likely to be cured with standard chemotherapy from those patients with poorer prognosis who require alternative treatment.

Are 18fluorodeoxyglucose positron emission tomography and magnetic resonance imaging useful in the prediction of relapse in lymphoma residual masses?

Treatment of both Hodgkin's disease (HD) and non-Hodgkin's lymphoma (NHL) frequently results in a residual mass visible radiologically. Such patients may receive radiotherapy unnecessarily because the residual mass may represent benign fibrotic tissue rather than residual active lymphoma. Radiotherapy has been shown to have significant short and more worrying long-term toxicity. Refining the criteria for its use would be a major advance. A number of clinical investigations have been evaluated to more accurately determine the nature of such lesions, including erythrocyte sedimentation rate (ESR), magnetic resonance imaging (MRI) and high-dose gallium-67 scanning (HDGS) but none has proven utility. 18[F]-fluorodeoxyglucose positron emission tomography (FDG-PET) is an imaging technique that has been shown to be useful in distinguishing fibrosis from residual active disease in solid tumours. The aim of this study was to compare FDG PET and MRI in the assessment of residual masses following treatment for lymphoma. Patients with NHL/HD who had a residual mass following chemotherapy were eligible for this study. Patients had a combination of MRI and/or PET. All scans were completed within 5 months of the end of treatment. Patients were followed-up for relapse. 56 patients had an MRI scan, 24 had a PET scan and 22 patients had both investigations. Overall sensitivity and specificity, respectively, were for MRI 45% and 74%, PET 50% and 69%, and PET/MRI concurring 50% and 67%. There was a trend for improved relapse-free survival (RFS) with a negative result of both MRI and PET, but this was not statistically significant. The predictive value for both tests failed to reach statistical significance. Subgroup analysis suggests that PET may be better at predicting relapse in patients with NHL, especially those with masses above the diaphragm. There is no convincing evidence that either MRI or PET or the combination can reliably predict relapse within residual masses after treatment for lymphoma. A negative PET scan however appears to be more informative than a positive result and may well aid clinical decision making. There are a number of factors that may produce false-positive results, including post-treatment inflammatory changes, the sensitivity of the test in the setting of minimal residual disease and the heterogeneity of the histological subtypes studied. A negative PET (or MRI) result in lymphoma residual masses following therapy may negate the necessity for further therapy such as chemotherapy or radiotherapy and their concomitant toxicities.

Progress in medical imaging of lymphoma and Hodgkin's disease.

Noninvasive imaging methods are the cornerstone of the conventional staging of patients with Hodgkin's disease and non-Hodgkin's lymphoma. Gallium-67 scintigraphy has become an important and essential imaging method, especially in the restaging for assessment of residual masses in patients with lymphoma. Magnetic resonance imaging will be used in the future for confirmation of suspect local lesions. Imaging of lymphoma patients with somatostatin receptor scintigraphy will remain a secondary imaging method, which will not be as routine. Positron emission tomography with 18-F-fluorodeoxyglucose (FDG) has made the greatest steps forward and offers, when whole-body FDG-PET is used, the advantage that the entire body of the patient can be imaged. Nodal, extranodal, and bone marrow involvement have been imaged by FDG-PET with great sensitivity and specificity. Perhaps in the future, staging laparotomy for exact staging of lymphoma patients will be unnecessary, and patients will be staged solely with noninvasive staging methods.