Low Incidence of Thromboembolism in Asian Multiple Myeloma Patients Treated with Thalidomide: Do We Really Need Prophylaxis for Thromboembolism in Asian Population?

Purpose: Patients with multiple myelma (MM) are at increased risk for developing thromboembolism (TE) compared with the general population. Introduction of thalidomide into the treatment of MM has resulted in the surprising increase of TE. We planned to identify incidence of TE and risk factors for the development of TE in Korean MM patients.

Patients and Methods: Retrospective medical records review of Korean MM registry from 25 centers in Korea between 1997 and 2007 was performed. We assessed the incidence of arterial and venous TE in MM patients during thalidomide treatment. Potential risk factors for TE included disease status at thalidomide administration, concomitant use of other chemotherapeutic agents or steroid, past medical history and TE prophylaxis. Kaplan-Meier method for time variable from the first date of thalidomide to development of TE was used.

Results: A total number of 360 MM patients (median age 61, range 32–88) received thalidomide. 23, 62 and 265 patients had stage ±, II, and III disease according to Durie-Salmon Staging respectively at the diagnosis, which was equivalent to 79, 146 and 112 patients for stage ±, II and III by International Staging System. 156 patients received thalidomide as frontline therapy, while 153 and 48 patients received thalidomide for progressive disease and relapsed disease respectively. 243, 139, 172 and 60 patients experienced treatment with steroid, alkylating agents, anthracyclin and bortezomib prior to thalidomide respectively. 9 patients had previous history of TE before thalidomide administration. 135 patients received aspirin as prophylaxis for TE while 3 and 2 patients received warfarin and low molecular weight heparin as prophylaxis. Median follow up duration was 29.2 months and median duration of thalidomide use was 8.13 months. During thalidomide treatment, 249 (69%) patients stopped thalidomide due to unsatisfactory effect or intolerable toxicity. 14 patients (3.9%) developed TE, where 12 with the venous TE and 2 with the arterial TE. There was no TE-related mortality. Site of the venous TE included lung (7 patients), lower extremity (4 patients), upper extremity (1 patient) and neck (1 patient). One patient had pulmonary and lower extremity TE at the same time. Arterial embolism developed in the cerebral and peripheral artery respectively. No single clinical parameter such as MM status, past medical history and treatment regimen was predictive marker for development of TE. Incidence of TE in patients who received thalidomide as a frontline therapy (7/156) was not different from that in patients who received thalidomide for progressive or relapsed disease (7/201, p=0.296). Prophylactic treatment for TE did not influence the development of TE (p=0.942).

Conclusion: Incidence of TE during thalidomide treatment in Korean MM patients was low. No single clinical parameter was proven as a risk factor for TE. The prophylactic anticoagulation in Korean MM patients who will be treated with thalidomide is not necessary.