Proceedings of the 40th Annua l ASTRO Meet ing

69 A DECISION ANALYSIS ON THE OPTIMAL MANAGEMENT STRATEGY FOR FAVORABLE PROGNOSIS, EARLY-STAGE HODGKIN'S DISEASE

Andrea K. Ng, MD 1, Jane C. Weeks, MD, MSc 2, Peter M. Mauch, MD l, Karen M. Kuntz. ScD 3.

From the Joint Center for Radiation Therapy I and Dana-Farber Cancer Institute 2, Harvard Medical School, Department of Health Policy and Management, Harvard School of Public Health 3

Objective: To perform a decision analysis, comparing the life expectancy and quality-adjusted life expectancy of early-stage, favorable prognosis Hodgkin's disease (HD) managed with and without staging laparotomy, incorporating data on treatment outcomes of HD in the modem era.

Methods: We constructed a decision-analytic model to compare laparotomy versus no laparotomy for a hypothetical cohort of 25-year old patients with clinical stage I-II, favorable prognosis HD. I ra laparotomy was performed and pathological stage (PS) I-II disease was found, the treatment options were mantle and paraaortic (MPA) radiation therapy, mantle radiation therapy alone, chemotherapy alone or combined modality therapy (CMT). If the patient was upstaged to PS III-IV, the treatment alternatives were chemotherapy alone or CMT. The therapeutic options for the clinically-staged patient included MPA-splenic radiation therapy, chemotherapy alone or CMT. Markov models were used to simulate the lifetime clinical course of patients, whose prognosis depended on the true pathological stage and initial treatment. Baseline probability estimates used in the model were derived from results of published studies. Each model consisted of a number of health states including remission, refractory disease, relapse, secondary leukemia, secondary solid tumor, and secondary non-Hodgkin's tymphoma. The annual probabilities of transition from one state to another were conditional upon the disease stage and treatment received. In each cycle, depending on their health states, patients were at risk of dying from natural causes, treatment-related cardiac causes, HD or secondary malignancies. Short-term quality of life adjustments for procedures and treatments, as well as long-term quality of life adjustments for the different health states were incorporated. Sensitivity analyses were performed to determine how the optimal decision was changed by modifying the baseline estimates.

Results: The life expectancy was 36.67 years for the laparotomy strategy and 35.92 years for no laparotomy, yielding a net expected benefit of 0.75 years for laparotomy staging. The corresponding quality-adjusted life expectancies for the two strategies were 35.97 and 35.38 quality- adjusted life years (QALYs) respectively, resulting in a net expected benefit of Iaparotomy staging of 0.59 QALYs. Sensitivity analysis showed that the decision of laparotomy versus no laparotomy was heavily influenced by the quality-of-life weight assigned to the post-taparotomy state. Other variables that affected the decision included risk of upstaging, perioperative mortality of laparotomy, salvage rate after radiation therapy, and secondary solid tumor risks after CMT. The optimal treatment strategies for PS I-1I, PS III1A and PS III2-IVA patients were MPA radiation therapy, CMT and chemotherapy alone, respectively. Sensitivity analysis at the treatment decision for PS I-II patients showed that the treatment of choice for PS I-II patients changed from MPA radiation therapy to mantle radiation therapy alone when the relapse rate after mantle radiation therapy alone was close to that after MPA radiation therapy, or when the secondary solid tumor risk after mantle radiation therapy alone was 70% of that after MPA radiation therapy.

Conclusions: Our model predicted that on average, for a 25-year-old patient, proceeding with staging laparotomy resulted in a gain in life expectancy of 9 months, or 7 quality-adjusted life months. Although the survival differences were not large, the results suggest that there remains a role for surgical staging in the management of early-stage HD. Development of a decision model allows weighing of the different short-term and long-term risks and benefits involved in the staging and treatment of these patients. When applying the results to individual patients, however, it is important to consider their personal risk profiles, as well as attitudes towards quality of life after laparotomy and splenectomy.

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7O PATIENT SELF-ASSESSED HEALTH RELATED QUALITY OF LIFE IN LOCALIZED PROSTATE CARCINOMA: RADICAL PROSTATECTOMY VERSUS EXTERNAL BEAM RADIOTHERAPY

Timothy Campbell', Madeline McCarren ~, Carol Ferrans ~, Faith Davis ~, Srinivasan Vijayakumar '~ ' University of Chicago," University of Illinois at Chicago

Purpose/Objective: Prostate cancer is the most common cancer in men with more than 330,000 cases diagnosed in 1997. The number of men treated for prostate cancer by radical prostatectomy or radiotherapy has risen dramatically. Common choices presented to patients for treatment of organ confined prostate cancer include radical prostateetomy or external beam radiotherapy. There are no compelling data that either modality is superior in terms of cure. Treatment choices are commonly based on morbidity and treatment impact on quality of life. Previous comparisons of quality of life have compared groups with significantly different ages and disease burden. The objective of this study is to compare health related quality of life (HRQOL) in patients with localized prostate cancer treated by radical prostatectomy or external beam radiotherapy who were suitable candidates for either treatment. Materials & Methods: Patients with localized prostate cancer treated with a single modality of either external beam radiotherapy or radical prostateetomy who were eligible for either modality were selected by chart review. Patients specifically met the following criteria: treatment by a single modality, primary therapy between 1990-1996, localized prostate cancer, no myocardial infarction six months prior to treatment, no chronic congestive heart failure, no chronic lung disease and adequate renal function. Localized prostate cancer was defined as T2b or less (AJCC 1992), PSA </=20.0 ng/ml and Gleason score </=7 with no evidence of bony metastases. Approximately 200 radiotherapy patients meeting these criteria were selected to compare with a similar number of surgery patients. Instruments were chosen to measure both general and disease specific HRQOL. General quality of life was measured with "The Ferrans and Powers Quality of Life Index (QLI) Cancer Version." Disease Specific quality of life was measured with the "UCLA Prostate Cancer Index (PCI)." A final open-ended question asked, "Has the treatment of your prostate cancer affected your life? If yes, please tell us how?" Results: The QLI has a reported Cronbaeh's alpha ranging form 0.86 to 0.98 showing high internal consistency reliability. A test-retest correlation of 0.87 supports temporal reliability for a two-week interval. Strong correlations have been found between the overall QLI score and the Campbell, Converse and Rodgers' (1976) measure of life satisfaction. The PCI measures urinary, bowel and sexual function and bother. Face validity has been assessed by focus groups with patients and by physician review. Test-retest reliability is supported by the reported Pearson product-moment correlations equal to or exceeding 0.70. Cronbach's alpha exceeds 0.70 for PCh The anticipated response rate to the surveys is 70%. Conclusion: It is anticipated that surgery patients and radiotherapy patients have different issues affecting health related quality of life after therapy for localized prostate cancer. Data comparing health related quality of life in similar groups of patients treated by either modality should aid in selection of therapy.