Examining the Value of Routine Imaging for Patients with Aggressive NHL in Remission
Examining the Value of Routine Imaging for Patients with Aggressive NHL in Remission
Abstract & Commentary
By William B. Ershler, MD, INOVA Fairfax Hospital Cancer Center, Fairfax, VA; Director, Institute for Advanced Studies in Aging, Washington, DC.
Synopsis: Of 108 patients with relapsed aggressive lymphoma, approximately 20% were discovered by routine surveillance while asymptomatic. Compared to the 80% who developed symptoms or abnormal findings on physical exam, those with surveillance-imaging-detected recurrence had a more optimal score on the International Prognostic Index (IPI) and a slightly better (albeit not statistically significant) 5-year event-free survival. Routine screening might identify recurrent disease at a time at which tumor burden is less and treatment success would be more likely, but other explanations are also possible. Although commonly practiced, the utilization of routine surveillance imaging (by CT or PET) has yet to be proven of demonstrable value in the management of aggressive NHL.
Source: Liedtke M, et al. Surveillance imaging during remission identifies a group of patients with more favorable aggressive NHL at time of relapse: a retrospective analysis of a uniformly-treated patient population. Ann Oncol. 2006;17:909-913.
Patients with aggressive NHL who have relapsed after initial chemotherapy can be effectively treated with intensive chemotherapy and autologous stem cell transplantation and such an approach has resulted in 5-year event-free survival of up to 40%.1 The current study from the Lymphoma Service at Memorial Sloan-Kettering evaluated the role of surveillance imaging in detection of relapsed disease with the premise that those relapses recognized by routine surveillance (ie, in asymptomatic patients) as opposed to coincident with new symptoms or palpable mass, would have more favorable treatment outcomes.
One hundred eight patients with relapsed aggressive NHL were treated with a standardized ICE regimen followed (for most) with autologous stem cell transplant between the years 1993 and 2000. Outcome data were available at a median time of 5 years. The investigators performed a retrospective analysis to determine whether patients discovered to have relapse by routine surveillance were more successfully treated than those who presented with symptoms or a new mass.
Twenty percent of relapses were detected by routine imaging while 80% were identified by reported symptoms or abnormalities on exam. If the relapse were discovered by routine surveillance, patients were 4.1 times more likely to have low-risk disease (based upon an age-adjusted International Prognostic Index taking into consideration LDH, stage and performance status) and had a slight (but not significant) increase in 5-year survival.
The authors interpreted the data to suggest routine surveillance imaging can identify a population of patients with a more favorable outcome. However, they also highlighted the complications inherent in an analysis such as this and, therefore, recommended that a prospective trial be undertaken to establish the optimal post remission strategy with regard to follow-up imaging for patients with aggressive NHL.
Commentary
Occasionally practice patterns develop that are not truly evidence based. Such may be the case for routine imaging studies (CT or PET scans) obtained at fixed intervals (3 months, 6 months or yearly) for patients with lymphoma in remission. Liedtke and colleagues make the case for continuing this practice because in the current series, patients who were discovered by routine scans had a better IPI score and a slightly better response to treatment. This runs counter to other, smaller series, in which no distinct advantage was observed for those who were found to have relapsed lymphoma on the basis of imaging studies while asymptomatic.2,3 The current series had the advantage of being somewhat larger and clinical outcomes were more comparable because all patients were treated similarly (ICE plus stem cell transplant).
Yet, cautions were raised by the authors themselves, and by Drs. Armitage and Loberiza in an accompanying editorial that would to temporize any firm conclusion from the current retrospective analysis.4 Certainly, patients who develop disease between scheduled 'routine' imaging studies are more likely to have biologically more aggressive tumors and thus be associated with more symptoms and worse prognosis. Furthermore, there is the issue of 'lead time artifact' which could explain why those who were discovered by routine surveillance would have a longer survival. Armitage and Loberiza go on to provide a mathematical model which after a few reasonable assumptions, concluded that approximately 1 in 45 surveillance tests would yield a positive CT result in asymptomatic NHL patients in remission and that this abnormal finding was only 14% likely to reflect actual disease. In contrast, abnormal CT scans for those with symptoms were almost 90% indicative of disease recurrence.
The authors call for more extensive evaluation of the question, but Armitage and Loberiza go one step further and conclude that routine imaging for patients in complete remission who are asymptomatic without abnormal physical findings and who have normal laboratory studies is probably not appropriate based upon the existing data. One wonders whether this controversy will make it to the clinic.
References
1. Philip T, et al. Autologous bone marrow transplantation as compared with salvage chemotherapy in relapses of chemotherapy-sensitive non-Hodgkin's lymphoma. N Engl J Med. 1995;333:1540-1545.
2. Weeks JC, et al. Value of follow-up procedures in patients with large-cell lymphoma who achieve a complete remission. J Clin Oncol. 1991;9:1196-1203.
3. Elis A, et al. Detection of relapse in non-Hodgkin's lymphoma: role of routine follow-up studies. Am J Hematol. 2002;69:41-44.
4. Armitage JO, Loberiza FR. Is there a place for routine imaging for patients in complete remission from aggressive lymphoma? Ann Oncol. 2006;17:883-884.
Of 108 patients with relapsed aggressive lymphoma, approximately 20% were discovered by routine surveillance while asymptomatic.Subscribe Now for Access
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