End of Chemotherapy Re-evaluation

End of Chemotherapy Re-evaluation

Restaging is carried out at the end of chemotherapy. The purpose of restaging is to assess the degree of response to initial chemotherapy. Although complete response can be defined as absence of disease by clinical examination and/or imaging studies, complete response in Hodgkin lymphoma trials is often defined by more than a 70% to 80% reduction of disease and a change from initial positivity to negativity on either gallium or PET scanning.[1,2] This definition is necessary in Hodgkin lymphoma because fibrotic residual is common, particularly in the mediastinum. In some studies such patients are designated as having an unconfirmed complete response.

Recently, many centers have switched functional imaging from gallium to PET scanning.[3-5] There is a growing consensus from adult studies that PET scanning may identify more sites of initial disease than gallium scans, and that PET scanning is more accurate than gallium scanning in detecting viable Hodgkin lymphoma in posttherapy residual masses. Timing of PET scanning after completing therapy is an important issue. For patients treated with chemotherapy alone, PET scanning should be performed a minimum of 3 weeks post therapy completion. For patients whose last treatment modality was radiation therapy, PET scanning should be performed 8 to 12 weeks post radiation.[6] A study testing the sensitivity and specificity of conventional imaging (CT or magnetic resonance imaging) and PET scans in children with Hodgkin lymphoma showed that side-by-side comparison or image fusion could improve the staging accuracy over either modality alone. [7] Currently, either PET or gallium scanning is acceptable; however, caution should be used in making the diagnosis of relapsed disease based solely on imaging because false-positive results are not uncommon.[8-11]

References

1. Brisse H, Pacquement H, Burdairon E, et al.: Outcome of residual mediastinal masses of thoracic lymphomas in children: impact on management and radiological follow-up strategy. Pediatr Radiol 28 (6): 444-50, 1998.  [PUBMED Abstract]
   
   
2. Weihrauch MR, Re D, Scheidhauer K, et al.: Thoracic positron emission tomography using 18F-fluorodeoxyglucose for the evaluation of residual mediastinal Hodgkin disease. Blood 98 (10): 2930-4, 2001.  [PUBMED Abstract]
   
   
3. Hueltenschmidt B, Sautter-Bihl ML, Lang O, et al.: Whole body positron emission tomography in the treatment of Hodgkin disease. Cancer 91 (2): 302-10, 2001.  [PUBMED Abstract]
   
   
4. Wiedmann E, Baican B, Hertel A, et al.: Positron emission tomography (PET) for staging and evaluation of response to treatment in patients with Hodgkin's disease. Leuk Lymphoma 34 (5-6): 545-51, 1999.  [PUBMED Abstract]
   
   
5. Bangerter M, Moog F, Buchmann I, et al.: Whole-body 2-[18F]-fluoro-2-deoxy-D-glucose positron emission tomography (FDG-PET) for accurate staging of Hodgkin's disease. Ann Oncol 9 (10): 1117-22, 1998.  [PUBMED Abstract]
   
   
6. Juweid ME, Stroobants S, Hoekstra OS, et al.: Use of positron emission tomography for response assessment of lymphoma: consensus of the Imaging Subcommittee of International Harmonization Project in Lymphoma. J Clin Oncol 25 (5): 571-8, 2007.  [PUBMED Abstract]
   
   
7. Furth C, Denecke T, Steffen I, et al.: Correlative imaging strategies implementing CT, MRI, and PET for staging of childhood Hodgkin disease. J Pediatr Hematol Oncol 28 (8): 501-12, 2006.  [PUBMED Abstract]
   
   
8. Nasr A, Stulberg J, Weitzman S, et al.: Assessment of residual posttreatment masses in Hodgkin's disease and the need for biopsy in children. J Pediatr Surg 41 (5): 972-4, 2006.  [PUBMED Abstract]
   
   
9. Levine JM, Weiner M, Kelly KM: Routine use of PET scans after completion of therapy in pediatric Hodgkin disease results in a high false positive rate. J Pediatr Hematol Oncol 28 (11): 711-4, 2006.  [PUBMED Abstract]
   
   
10. Rhodes MM, Delbeke D, Whitlock JA, et al.: Utility of FDG-PET/CT in follow-up of children treated for Hodgkin and non-Hodgkin lymphoma. J Pediatr Hematol Oncol 28 (5): 300-6, 2006.  [PUBMED Abstract]
    
    
11. Meany HJ, Gidvani VK, Minniti CP: Utility of PET scans to predict disease relapse in pediatric patients with Hodgkin lymphoma. Pediatr Blood Cancer 48 (4): 399-402, 2007.  [PUBMED Abstract]