Study: CT adds little value for some leukemia patients

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CT imaging provided minimal utility in the follow-up of patients diagnosed with chronic lymphocytic leukemia (CLL), according to a study published in the January issue of Blood.

Most recent response criteria suggest a clear role for CT imaging in most lymphoid malignancies. However, CT imaging criteria for CLL are unclear with the National Cancer Institute Working Group criteria recommending CT imaging “when clinically indicated,” offered Barbara F. Eichhorst, MD, of the Center for Integrated Oncology at the University of Cologne in Germany, and colleagues.

The recent Institute Working Group CLL criteria aimed to curb CT use in CLL by limiting imaging to pre-and post-treatment scans, two CT studies, in clinical trials. The researchers noted that this recommendation has not yet been substantiated.

Eichhorst and colleagues undertook a meta-analysis of 1,372 CLL patients in three clinical trials between 1999 and 2006 to better determine the role of CT and reassessed response and progression during follow-up.

CT studies were performed in 52 percent of patients, ultrasound exams in 85 percent and chest x-rays in 55 percent. Researchers compared clinical parameters and treatment outcome of patients undergoing imaging with those without imaging.

When the researchers evaluated disease progression (PD), they found 481 cases of PD in treatment or follow-up. Of this group, physical exam and/or blood work detected progression in 77 percent and imaging detected progressed in 15 percent, with CT responsible for 9 percent and ultrasound for 6 percent.

The authors noted minimal impact of CT on relapse treatment. Among the 176 patients undergoing relapse treatment, two patients were retreated based on imaging data.

Although pretreatment CT and ultrasound studies were employed to detect bulky disease in 91 percent of patients, the response rates, progression free survival and overall survival did not differ among patients with and without bulky disease.

Eichhorst and colleagues did observe that CT had an impact on prognosis of complete remissions when they compared patient groups with differently defined complete remissions. In the first group, complete remission was based on a normal physical exam, normal peripheral blood count and bone marrow biopsy. In the second group, additional CT imaging was used to confirm complete remission.

“[P]rogression free survival at 75 percentile was 36 months in the group of patients with complete remissions by clinical examination and bone marrow biopsy versus 49 months in the group of patients with additionally negative CT scans,” wrote Eichhorst.

“The majority of events defined as disease progression was detected by physical exam and/or blood count. Moreover, and more importantly, the results of the imaging methods rarely influenced the decision to initiate relapse treatment after first line therapy,” the authors said.

They further suggested that the findings might prevent unnecessary radiation exposure and reduce healthcare costs. Finally, Eichhorst and colleagues pointed out that novel biological markers, including fluorescence in situ hybridization, IgHV mutational status, ZAP 70, CD 38 and the serum markers beta 2-microglobulin and serum thymidine kinase, may provide a method for detailed evaluation of individual prognosis.