Is CT scan still necessary for staging in Hodgkin and non-Hodgkin lymphoma patients in the PET/CT era?

Abstract

The addition of PET/CT to CT changed the management decisions in approximately a quarter of NHL and a third of HD patients, mostly in early disease stages. Thus, PET/CT performed as the initial staging procedure may well obviate the need for additional diagnostic CT in the majority of patients.

PET-CT for staging and early response: results from the Response-Adapted Therapy in Advanced Hodgkin Lymphoma study

“…PET-CT altered staging in 20% of patients compared with the standard approach, which is at variance with earlier reports that suggested stage change occurred more often in patients with early stage rather than advanced disease. 10,20 Upstaging occurred more frequently than downstaging, with extranodal disease accounting for 74% of the upstaged scans, mostly due to an increased sensitivity of PET for detecting bone marrow involvement. Baseline and response scans were compared, and the findings were correlated with other imaging, where available, to determine the etiology of lesions that accounted for the discrepancy in stage.…”

“…3,10,20 The truth as to whether lesions identified only on PET represent lymphoma is difficult to determine as biopsy of discrepant lesions is rarely performed. Correlative imaging, treatment response, follow-up, biopsy, or a combination usually serves as a reference standard.…”

“…[11][12][13][14][15][16] Previous publications compared imaging techniques but do not report the impact of imaging on the more relevant final clinical stage, inclusive of bone marrow biopsy, and some publications included patients with HL and non-Hodgkin lymphoma (NHL). [17][18][19][20][21] Response assessment with the 5-PS has been reported by a number of investigators to have good interobserver agreement in a training set of 50 patients, 22 in a study of 260 advanced HL patients with international expert readers, 23 and in pediatric HL. 24 The 5-PS also improves the positive predictive value of PET compared with previous International Harmonization Criteria.…”

PET-CT staging of DLBCL accurately identifies and provides new insight into the clinical significance of bone marrow involvement

“…Positron emission tomography (PET), increasingly combined with computed tomography (PET-CT), is now a routine part of staging DLBCL, owing to its ability to accurately evaluate both nodal and extranodal disease sites (including skeletal involvement), assign stage, and quantify prognosis. [4][5][6][7] Recently, a large retrospective study of marrow disease in DLBCL cases treated with R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) reported that histologic evidence of DLBCL in staging marrow biopsy adversely affected overall survival (OS) and event-free survival, independent of the IPI. 8 We first examined PET as a method to assess bone marrow involvement in Hodgkin lymphoma (HL) and NHL in 1998 9 and reported that bone marrow involvement in both diseases may have a metastatic pattern, apparent as focal areas of increased 18F-fluorodeoxyglucose (FDG) uptake, or a more diffuse pattern of involvement with uniform FDG uptake throughout the marrow space.…”

Positron Emission Tomography Scanning in the Management of Hodgkin Lymphoma Patients: A Single-Institution Experience

“…This probably results from the higher costs of PET-CT compared to CT, the small number of PET-CT centers in the region, and the lack of well-defined recommendations concerning PET-CT implementation in routine practice. It is noteworthy that in one recent study PET-CT imaging -in comparison with CT alone -was shown to upstage the disease among patients initially diagnosed as stage I or II [15]. However, the official recommendations concerning the use of PET-CT in initial HL staging are slightly inconsistent.…”