A recent article in the Annals of Oncology reports that Positive Emission Tomography (PET Scan) performed after two or three cycles of chemotherapy is an early and accurate predictor of progression-free survival and overall survival in patients with Hodgkin’s lymphoma.
Hodgkin’s lymphoma (HL) is a malignancy in which cancerous cells arise from the cells of the lymphatic system. The lymphatic system, a drainage system within the body, performs the two primary functions of maintaining fluid balance and producing cells called lymphocytes, which fight infection. Lymphomas are divided into two types: non-Hodgkin’s lymphoma and Hodgkin’s lymphoma. Hodgkin’s lymphoma is characterized by the presence of Reed-Sternberg cells, which are identified under a microscope. Non-Hodgkin’s lymphoma (NHL) includes a large group of various types of cancers of the lymph and immune system.
Current treatment options include surgery, chemotherapy and radiation. Other treatments, such as high-dose chemotherapy and radiation with stem cell transplantation, are being studied in clinical trials. Fortunately, long-term survival for Hodgkin’s lymphoma is achieved in approximately 80 to 90 percent of patients. Treatment, however, can leave people with long-term side effects and some patients may be cured with less therapy than is currently being administered. By evaluating the course of treatment with PET scans, the treatment regimen can be evaluated for effectiveness. PET scans are often used to detect additional sites of cancer, which may be too small to be seen with a CT scan, in the diagnosis and evaluation of Hodgkin’s lymphoma. During a PET scan, a radioactive substance is administered to the patient, which is then absorbed by the cancer cells. This process makes areas of increased activity visible to the radiologist.
This recent study evaluated the benefit of PET scans after two or three cycles of chemotherapy to determine if any predictive value could be obtained from the results. A total of 85 patients diagnosed with Hodgkin’s lymphoma underwent PET scanning after either two or three cycles of chemotherapy.
After receiving two or three cycles of chemotherapy, 63 of the 85 had negative PET scans, nine had minimal residual disease and 13 patients had scans indicative of gross disease. The average period of follow up was 3.3 years. During that time, three of the PET-negative patients and one of the patients with minimal residual disease relapsed. Among the 13 patients with PET positive disease, nine had progressive disease and two died. Extensive analysis showed a significant correlation between early PET scan results and progression free and overall survival. However, all advanced stage patients with PET scans showing positive disease after two or three cycles of chemotherapy relapsed within two years.
Researchers concluded that PET scans after two or three cycles of chemotherapy are predictive of disease-free and overall survival rates. However, patients with positive PET scans at high risk for recurrent disease may wish to consider more aggressive treatment or participation in a clinical trial.
Reference: Hutchings M, Mikhaeel N, Fields P, et al. Prognostic Value of Interim FDG-PET After Two or Three Cycles of Chemotherapy in Hodgkin’s Lymphoma. Annals of Oncology. 2005; 1160-1168.