Evaluation Of Residual Masses Research Articles

Lymphoma: imaging in the evaluation of residual masses

In the management of patients with lymphoma, imaging is essential not only for diagnosis but also to define prognosis and treatment by staging. Imaging is also used to assess the response to treatment that may affect the treatment strategy: new chemotherapeutic drug combinations and autologous stem cell transplantation. These different therapies have increased the need for higher accuracy to assess the response to treatment. Standardised imaging response criteria must be well known by radiologists involved in the management of patients with lymphoma. Criteria are mainly volumetric, and are obtained from CT scans. Functional imaging techniques have been shown to provide better information on the viability of residual masses than does CT assessment of size changes.CT remains the main imaging technique to assess response to treatment based on volumetric international criteria. New functional imaging tools evaluating perfusion (CT and MRI), and particularly glucose uptake (PET), will probably play an important role in bringing additional information on the metabolism of lymphomatous masses.

The Role of Positron Emission Tomography in the Evaluation of Residual Masses After Chemotherapy for Advanced Stage Seminoma

Treatment in patients with seminoma who have residual or recurrent masses following chemotherapy is still a matter of debate. Surgical resection is currently the most common recommendation for masses greater than 3 cm, resulting in overtreatment in up to 70% of those affected. We analyzed the accuracy of preoperative positron emission tomography for predicting viable tumor residuals in patients with seminoma. In a prospective, multicenter trial computerized tomography and FDG (2-(F-18)-fluoro-2-deoxy-D-glucose) positron emission tomography were performed before surgical resection for residual or recurrent masses in 20 patients who had undergone chemotherapy for stage IIb, IIc or III seminoma. Histopathological findings were directly correlated with positron emission tomography results. Of the patients 18 presented with residual masses and 2 had recurrent masses following chemotherapy. Histopathological assessment revealed viable tumor in 3 patients and benign lesions in 17. All patients with viable tumor were identified correctly by positron emission tomography. No false-negative results were observed but 9 patients had false-positive positron emission tomography results. This resulted in a negative predictive value of 1 (95% CI 0.63-1) and a positive predictive value of 0.25 (95% CI 0.05-0.57) for FDG-positron emission tomography in our patient cohort. Our data indicate that FDG-positron emission tomography is capable of excluding viable disease in residual masses, even those exceeding 3 cm. Therefore, it may be considered an additional tool to improve patient counseling. However, the decision to perform surgical resection of the residual mass should not be based exclusively on a positive positron emission tomography image since false-positive results appear to be common.

Histological verification of positive positron emission tomography findings in the follow-up of patients with mediastinal lymphoma

Follow-ups of patients with mediastinal lymphoma are not accurate if they rely on computed tomography (CT). Positron emission tomography (PET) has been suggested to be useful in several lymphoma settings, such as initial staging, evaluation of residual masses after therapy, and assessment of response early in the course of treatment. The aim of this retrospective study was to verify the reliability of positive PET scans of the mediastinum in following up patients with mediastinal lymphoma, using histological findings as a comparison. From January 2002 to July 2005, 151 patients with mediastinal lymphoma (57 with Hodgkin's disease [HD] and 94 with aggressive non-Hodgkin's lymphoma [NHL]) were followed-up after the end of front-line treatment. Patients with a positive PET scan of the mediastinum underwent CT scanning and surgical biopsy. In 30 (21 HD and 9 NHL) out of 151 patients (20%) a suspicion of lymphoma relapse was raised based on positive mediastinal PET scanning. Histology confirmed this suspicion in 17 (10 HD and 7 NHL) out of 30 patients (57%), whereas either benign (9 fibrosis, 3 sarcoid-like granulomatosis) or unrelated neoplastic conditions (1 thymoma) were demonstrated in the remaining 13 patients (43%). SUVmax was significantly higher among patients who had signs of relapse (17 true positive cases) than among those who stayed in remission (13 false positive cases), the median values being 5.95 (range, 3.5-26.9) and 2.90 (range, 1.4-3.3), respectively (p=0.01). We suggest that a positive PET scan of the mediastinum of a patient being followed-up for a mediastinal lymphoma should not be considered sufficient for diagnostic purposes in view of its lack of discrimination. Histological confirmation can safely be carried out with various biopsy techniques, the choice of which should be made on the basis of the findings of the clinical and imaging studies of the individual case.

18FDG-positron emission tomography in post treatment evaluation of residual mass in Hodgkin's lymphoma: Long-term results

In patients with Hodgkin's lymphoma (HL) at the end of first line therapy an accurate imaging technique with high prognostic value is needed to assess response to treatment and predict those patients who will suffer disease relapse. This technique and its results permit the quick initiation of a second line therapy in patients suffering from a progressive disease or those unresponsive to treatment avoid over-treatment of patients in complete remission or those having a non-active residual disease. We included a (18)FDG-positron emission tomography (PET) scan to the diagnostic set-up to investigate 28 patients following the end of their treatment. Fifteen patients out of the 28 (54%) had positive CT scans while 13 (46%) had negative ones. Eleven patients out of the 15 CT positive (73%) had negative PET scans and no relapse. The remaining four patients (27%) had positive PET scans with only one relapse (25%). With respect to the 13 patients who had negative CT scans, 9 patients (69%) had negative PET scans and no relapse. The remaining 4 patients (31%) had positive PET scans with 3 relapse cases (75%). In our final assessment after a median follow-up period of 45 months, starting from PET execution to the last follow-up, overall sensitivity of the CT and the PET were 25 and 100% respectively, specificity 42 and 83% respectively, positive predictive value (PPV) 7 and 50% respectively, negative predictive value (NPV) 77 and 100% respectively, and accuracy 39 and 86% respectively. In our experience, FDG-PET performed in patients after induction therapy appears to offer important additional information: FDG-PET results are predictors of prognosis giving 100% DFS in PET negative patients and 54% DSF in PET positive patients.

Gallium Scan in the Evaluation of Post Chemotherapy Mediastinal Residual Masses of Aggressive Non-Hodgkin's Lymphoma

Optimal evaluation of residual masses of non Hodgkin's lymphomas (NHL) after chemotherapy is of major importance, and gallium scan (GS) is routinely used for this purpose, particularly for mediastinal sites. However, sensitivity and specificity of GS in this setting has been diversely appreciated and needs to be more accurately defined especially if radiotherapy is not planned. A retrospective analysis selected all the patients treated in a single institution for aggressive NHL who presented a residual mass in the mediastinum after chemotherapy and who were evaluated by GS. The value of GS for distinguishing true complete responses (CR) from partial responses (PR) was analyzed in patients who were either submitted to resection of their residual mass or followed up without further treatment after GS. A residual mass with mean perpendicular diameters measuring 4.1 cm × 2.8 cm was found in 42 patients and was GS positive in 8 cases and negative in 34 cases. After GS, radiotherapy was delivered to 10 patients, but 12 patients underwent resection of their residual mass and 20 were followed up without further treatment. In the patients who did not receive radiotherapy, 3 false positive and 6 false negative GS results were disclosed. The specificity and the sensitivity of GS were 88% and 25%, and its positive predictive value and negative predictive value 40% and 78 %, respectively. GS was not sufficiently reliable to evaluate post chemotherapy residual masses. Surgical resection of residual masses should be considered particularly in young patients. Patients in true CR should be spared pointless radiotherapy and its late side effects, while patients in PR may benefit from further intensified chemotherapy followed by radiotherapy.

Role of 67Ga scintigraphy in localization of lymphoma.

This review deals with the applications of 67Gallium (Ga) scintigraphy for the initial staging and follow-up during and after treatment of patients with Hodgkin's or non-Hodgkin's lymphoma (NHL). During the last decade, the technique of visualization has been largely improved by using higher doses and additional tomography. Here, the indications for 67Ga scintigraphy in comparison with CT and MRI are discussed. The conditions resulting in false positive and false negative results have been outlined. 67Ga may detect unusual involved sites during staging procedures. However, the major contribution to the management of Hodgkin's disease and NHL is the evaluation of residual masses, because 67Ga uptake reflects the metabolic activity of the tumor. The review ends with an additional short overview of other radionuclide imaging methods useful for malignant lymphoma.

Gallium scans in the evaluation of residual masses after chemotherapy for seminoma.

To assess the ability of gallium scans to determine whether residual masses consist of viable tumor or necrotic fibrous tissue after chemotherapy for seminoma. Thirty-two patients were enrolled and 27 were assessable. Patients receiving first-line or salvage chemotherapy had gallium scans performed during their first and last scheduled course of chemotherapy and results were compared with restaging computed tomographic (CT) scans and subsequent clinical outcome. Of 27 assessable patients, 22 received first-line chemotherapy (group A) and five salvage chemotherapy (group B). Eight patients were not gallium-avid before chemotherapy despite obvious clinical and radiographic evidence of metastatic seminoma. Eighteen of 19 gallium-positive patients had a persistent mass postchemotherapy on abdominal CT. Of 16 patients in group A whose tumors were gallium-avid, all 16 had normalized gallium scans after chemotherapy. However, two of these 16 patients recurred in their original disease site. In group B, there were three patients with gallium-avid tumors and all three had normalized scans postchemotherapy. Two patients who were not gallium-avid (one each in group A and B) also developed recurrent disease. Twenty-four of 27 patients are alive with no evidence of active disease at a median follow-up time of 18 months, including 20 with more than 1 year of follow-up data. Eight of 27 patients had false-negative gallium scans at the time of diagnosis. All nineteen gallium scans that were initially positive reverted to normal after chemotherapy. Two of 19 patients' follow-up gallium scans were false-negative. We therefore feel that gallium scans have minimal value in the prechemotherapy or postchemotherapy evaluation of metastatic seminoma.