Objectives: In a prospective randomized Canadian trial, addition of radionuclide strontium (89Sr) to external radiotherapy (ER) was found to prolong the time to further ER by 15 weeks (35 versus 20, P = 0.006) compared to ER alone in patients with hormone-refractory metastatic prostate cancer (HRMPC). The total direct lifetime costs within the Swedish health care system for the following two treatment strategies was estimated as follows: (a) ER initially and in the event of relapse and (b) ER + 89Sr initially and ER in the event of relapse.
Methods: Calculation of lifetime costs was based on the initial total treatment cost and the probability of future treatment costs. In a retrospective analysis, the average cost of a relapse treated with ER alone was calculated from the actual care consumption of 79 consecutive patients from the south of Sweden who received ER because of skeletal pain due to HRMPC. The costs related to ER included skeletal scintigraphy, ER, outpatient visits, inpatients days, and travel to the treatment center. When 89Sr was added, the cost also included the radionuclide and its administration. Costs in Swedish currency (SEK) were based on the regional tariff for 1993 (U.S. $1 = SEK 8.30).
Results: The initial cost for one relapse treated with ER alone was estimated to be SEK 31,011 (U.S. $3736) per patient resident within county (close to hospital) and SEK 48,585 (U.S. $5854) per patient resident out of county (far from hospital). The corresponding figure for initial addition of 89Sr to ER was SEK 43,426 (U.S. $5232) and 61,000 (U.S. $7349), respectively. However, comparison between estimated lifetime cost for the two treatment strategies indicated potential cost savings with initial addition of 89Sr to 3% SEK 2720 (U.S. $328) and 7% SEK 11,290 (U.S. $1360), respectively.
Conclusions: Strontium-89 as initial supplement to ER for palliation of pain in HRMPC is beneficial both from the patient and lifetime health service costs perspectives.