The utility of serial complete blood count monitoring in patients receiving radiation therapy for localized prostate cancer

Abstract 

Purpose: It is standard practice in our department to monitor weekly complete blood counts (CBCs) in patients receiving definitive radiation therapy for prostate cancer. The clinical utility and cost effectiveness of this practice has not been analyzed.

Methods and Materials: The charts of all prostate cancer patients treated with radiation therapy between January 1994 and July 1996 at the Veterans Administration Hospital, Philadelphia, PA were reviewed. CBC values were available for 89 patients. Patients received a median dose of 68 Gy using a four-field box technique and megavoltage photons. Whole-pelvic radiotherapy followed by a conedown to the prostate was administered to 29 patients. Fifty-nine patients received radiation to the prostate alone or prostate and seminal vesicles. Fifty-seven patients received concurrent hormonal therapy which included luteinizing hormone-releasing hormone (LHRH) agonist, antiandrogens, or both.

Results: No patient experienced a drop in their hemoglobin, white blood cells (WBCs), or platelets below critical nadirs (defined as WBC < 2 counts × 1000/mm³, hemoglobin < 8 g/dl, platelet < 50 counts × 1000/mm³) at any point during treatment. Thirty-one percent, 25%, and 47% of patients experienced declines of > 50 in platelets, > 2 in WBCs, and > 1 in hemoglobin, respectively. Eight clinical, treatment-related, and pathologic parameters were examined as prognostic factors for a drop of > 2 in hemoglobin, > 2 in WBCs, and > 50 in platelets. Only stage (T3 and above) was significantly associated with a > 2 hemoglobin decline. The use of hormonal therapy was associated with a platelet drop of > 50. None of the 8 prognostic factors were associated with decline of > 2 in WBCs. In the urban area surrounding the Philadelphia Veterans Administration Medical Center, the cost of obtaining a CBC is approximately $30. However, if staff time is considered, the cost of obtaining a weekly CBC during prostate cancer radiotherapy approached $400 per patient.

Conclusion: These results suggest that weekly monitoring of CBCs in prostate cancer patients undergoing definitive radiotherapy may not be necessary. We recommend a baseline CBC be performed, and if normal, no other monitoring unless clinically indicated. This strategy would result in a cost savings approaching $30,000 per 100 treated patients. Further research on the cost effectiveness and utility of serial blood tests in patients receiving partial body radiation therapy is needed.

Keywords:  Complete blood counts, Bone marrow toxicity, Radiotherapy toxicity