160 I. J. Radiation Oncology • Biology • Physics Volume 42, Number 1 Supplement, 1998 71 THE COST-EFFECTIVENESS OF 3D CONFORMAL RADIATION THERAPY COMPARED WITH CONVENTIONAL TECHNIQUES FOR PATIENTS WITH CLINICALLY LOCALIZED PROSTATE CANCER Eric M. Horwitz, M.D., Alexandra L. Hanlon, M.S., Wayne H. Pinover, D.O., and Gerald E. Hanks, M.D. Department of Radiation Oncology, Fox Chase Cancer Center, Philadelphia, Pennsylvania Purpose: We have previously demonstrated the advantages of 3D conformal radiation therapy (3DCRT) in improved rates of biochemical (bNED) control in certain subsets of patients with clinically localized prostate cancer. However in this era of cost-consciousness and limited resources, the cost effectiveness of 3DCRT compared with conventional external beam irradiation (CRT) remains unexamined. The purpose of this study is to determine if the improved bNED control of 3DCRT translates into cost-effectiveness compared to CRT. Materials and Methods: Between 10/1/89 and 11/30/91, 193 patients with clinically localized prostate cancer received definitive external beam irradiation at Fox Chase Cancer Center. The median pretreatment PSA and Gleason score were 15.9 ng/ml and 6, and 9.7 ng/ml and 5, respectively for the CRT and 3DCRT patients. The median dose was 70.2 Gy for the CRT patients and 70.1 Gy for the 3DCRT patients. No patients received hormonal therapy either prior to, during, or after treatment unless local or distant failure was documented, bNED failure was defined according to the guidelines of the ASTRO Consensus Statement on PSA After Radiation Therapy. The 1998 Medicare fee schedule was used to determine treatment cost and to provide a reference for a national comparison. Complete costs for pre-treatment work-up, treatment and follow-up were tabulated for each patient. The Lin method of estimating medical costs (Biometrics 53:419-434;1997) was used to analyze and compare costs between groups. To minimize the bias of censoring, the entire time period of the study was partitioned into 1 year intervals and the mean total cost (MTC) was estimated by the sum of the Kaplan-Meier estimator for the probability of dying in each interval multiplied by the sample mean of the total costs from the observed deaths in that interval. The estimated MTC is a function of the costs incurred during pretreatment work-up, treatment, and the first 8 years of follow-up for these two groups of patients. The median follow-up was 72 months (range: 3-118 months). Results: The overall 5 year actuarial rate of bNED control was 41% and 53%, respectively for the CRT and 3DCRT patients (t7= 0.03). The MTC for the CRT patients was $10,544.53. For the 3DCRT patients, the MTC was $8,955.48. The median cost was stratified for pre-treatment work-up and treatment and was $1,246.23 (range: $850.06-$1,5231.90) and $9,026.27 (range: $7,571.41-$10,381.36), respectively for the CRT patients. For the 3DCRT patients, the median cost for pre-treatment work-up and treatment was $1,631.39 (range: $587.97-$9,530.87) and $10,277.08 (range: $8,967.63-$10,851.40), respectively. Table 1 shows the estimated MTC by treatment technique and the sample mean of the total costs from the observed deaths for the two patient groups by follow-up interval. Table 1. Estimated MTC By Treatment Technique and Mean Of The Total Costs From Observed Deaths By Follow-Up Year MTC [ l 2 3 4 5 6 7 8 CRT Patients $10,544.53[ $9,800.63 $14,917.95 $17,693.49 $13,577.23 $20,152.81 $25,979.22 $13,250.63 $59,635.01 3DCRT Patients $8~955.48 $17,259.00 $17~720.75 $21~553.99 $18r845.90 $23~732.78 $24~250.38 $237656.54 $18r826.75 As the time interval following treatment increased, the total cost, including work-up and treatment, for the 3DCRT patients remained constant while the CRT patients costs continued to increase. This was related to continued treatment failures and the increased costs were due to additional therapy (hormones, palliative radiation, etc.) to treat metastatic disease. Conclusions: Work-up and treatment costs were greater for patients treated with 3DCRT compared with patients treated with conventional techniques. However, with longer follow-up, the mean cost of treatment was less for patients treated with 3DCRT. The greater long-term cost for the CRT patients was due to the use of hormonal and other treatment modalitias to treat metastatic disease. Because of improved rates of bNED control for these patients and the increased costs associated with the treatment of recurrent disease following CRT, 3DCRT was cost-effective for patients with clinically localized prostate cancer. 72 ASSESSING PATIENT PREFERENCES FOR AXILLARY DISSECTION: A FORMAL OUTCOMES ANALYSIS 3 24 124 Galper SR 1, Lee S 2, Tan ML 1, Troyan S , Kaelin CM ', Harris JR. ' ', Weeks JC" lJoint Center for Radiation Therapy, 2Dana-Farber Cancer Institute, 3Beth Israel Deaconess Medical Center, 4Brigham and Women's Hospital, Harvard Medical School, Boston, MA PURPOSE/OBJECTIVES: Axillary lymph node dissection (ALND) offers more precise prognostic information than alternative strategies for managing the axilla, and may alter treatment recommendations. However, it is also associated with subsequent arm dysfunction and little is known about patients' preferences regarding these trade-offs. We devised a formal outcomes tool to assess these preferences. MATERIALS AND METHODS: We surveyed 82 randomly selected women who had undergone ALND for invasive breast cancer (Group 1) and 62 women treated without ALND for ductal carcinoma-in-situ (DCIS) (Group 2). Preferences were assessed using hypothetical scenarios which asked subjects to imagine that they had just been diagnosed with invasive breast cancer and to identify the minimum benefit in (1) local control, (2) survival, and (3) impact on treatment recommendations they would require to accept a 40% risk of mild arm dysfunction. The (4) value of prognostic information that would not alter treatment recommendations was measured by asking the maximum risk of arm dysfunction subjects would accept with ALND. RESULTS: Both groups of women required high rates of local control before they would accept the sequelae of ALND (median of 90% and 100% in Groups 1 and 2, respectively), and substantial improvements in survival (median of 3% and 10% in Groups 1 and 2, respectively). Women in Group 1 would choose ALND for only a 1% chance of altering treatment recommendations; Group 2 subjects required a 25% probability. Women in Group 1 were willing to accept an arm dysfunction risk of 80% to obtain prognostic information, but Group 2 subjects would only accept a 10% risk of arm dysfunction. 68% of women in Group 1 and 29% of women in Group 2 would agree to undergo ALND assuming it would result in a 40% risk of mild upper arm dysfunction, just to gain prognostic information. Overall, for 94% of women in Group 1 and 63% of women in Group 2, the level of benefit subjects would require in order to accept ALND was within the range of values reported for this procedure in the literature in at least one of the areas assessed (local control, survival, impact of information on treatment recommendations or prognostic information that would not change treatment recommendations). In all scenarios, there was considerable interpatiant variability, not predicted by clinical or sociodemographic Characteristics. CONCLUSIONS: The strongest factor motivating women's preferences for ALND was the opportunity to obtain prognostic information even if it would not alter treatment recommendations. For the large majority of women with invasive cancer and the majority of women with DCIS, the potential benefits of ALND were sufficient to outweigh the risks of this procedure. However, women varied considerably in their preferences, highlighting the need to tailor decisions regarding management of the axilla to individual patient values.