Abstract
Purpose
This paper applies the Dynamically Modified Outcomes (DYNAMO) model to a clinical trial of two chemotherapeutic regimens on global health-related quality of life (GHRQL) in hormone-refractory prostate cancer.
Methods
DYNAMO identifies the causal influences operating in a clinical trial and their mediation, moderation, and modulation by uncontrolled variables. The Southwest Oncology Group trial S9916 randomized assignment to mitoxantrone plus prednisone (M + P) versus docetaxel plus estramustine (D + E) treatments. In this application, we examine baseline-adjusted impacts of worst pain (McGill Pain Questionnaire) on GHRQL (EORTC Quality of Life Questionnaire-C30) at 10 weeks.
Results
The average treatment levels of pain did not differ, hence, the average mediated effect of treatment on GHRQL was zero. Nonetheless, M + P reduced the impact (the relational outcome) of pain on GHRQL by 54% relative to D + E. Individual variation in the relational outcome (modulation) was of the same magnitude as the average difference between the groups. Performance status moderated the direct effects of treatment, with D + E being more effective in good, but not poor, performance strata.
Conclusions
The DYNAMO approach comprehensively accounted for treatment effects. Rather than a single average effect, there were three distinct treatment effects: one direct effect for each performance status level and a direct effect on the relationship between pain and GHRQL.
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Notes
These standard adjustments have no effect on the interpretation of the key features of the model, but merely condition responses on baseline values.
Abbreviations
- DYNAMO:
-
Dynamically Modified Outcomes
- M + P:
-
Mitoxantrone plus prednisone
- D + E:
-
Docetaxel plus estramustine
- GHRQL:
-
Global health-related quality of life
- SWOG:
-
Southwest Oncology Group
- PS:
-
Performance status (0 = fully active; 1 = restricted in physically strenuous activity, but ambulatory and able to do light work; 2 = ambulatory and capable of self-care, but unable to carry out any work activities; 3 = capable of limited self-care, confined to bed or chair for more than 50% of waking hours; 4 = completely disabled)
- MPQ:
-
McGill Pain Questionnaire
- EORTC QLQ-C30 PR25:
-
European Organization for Research and Treatment of Cancer Quality of Life Questionnaire Core 30 and Prostate Cancer Module
- DCE:
-
Direct causal effect
- ACE:
-
Average causal effect
- ICE:
-
Individual causal effect
References
Donaldson, G. W. (2003). General linear contrasts on latent variable means: Structural equation hypothesis tests for multivariate clinical trials. Statistics in Medicine, 22, 2893–2917. doi:10.1002/sim.1558.
Donaldson, G. W., & Moinpour, C. M. (2002). Individual differences in quality-of-life treatment response. Medical Care, 40(6 Suppl), III39–III53. doi:10.1097/00005650-200206001-00007.
Moinpour, C. M., Donaldson, G. W., & Redman, M. W. (2007). Do general dimensions of quality of life add clinical value to symptom data? Journal of the National Cancer Institute. Monographs, 37, 31–38. doi:10.1093/jncimonographs/lgm007.
Petrylak, D. P., Tangen, C. M., Hussein, M. H. A., Lara, P. N., Jr., Jones, J. A., Taplin, M. E., et al. (2004). Docetaxel and estramustine compared with mitoxantrone and prednisone for advanced refractory prostate cancer. The New England Journal of Medicine, 351(15), 1513–1520. doi:10.1056/NEJMoa041318.
Berry, D. L., Moinpour, C. M., Jiang, C. S., Ankerst, D. P., Petrylak, D. P., Vinson, L. V., et al. (2006). Quality of life and pain in advanced stage prostate cancer: Results of a Southwest Oncology Group randomized trial comparing docetaxel and estramustine to mitoxantrone and prednisone. Journal of Clinical Oncology, 24(18), 2828–2835. doi:10.1200/JCO.2005.04.8207.
Laird, N. M., & Ware, J. H. (1982). Random-effects models for longitudinal data. Biometrics, 38, 963–974.
Curran, P. J., & Hussong, A. M. (2003). The use of latent trajectory models in psychopathology research. Journal of Abnormal Psychology, 112(4), 526–544. doi:10.1037/0021-843X.112.4.526.
Singer, J. D., & Willett, J. B. (2003). Applied longitudinal data analysis: Modeling changes and event occurrence. New York: Oxford University Press.
Kline, R. B. (2005). Principles and practice of structural equation modeling. New York: Guilford Press.
Sinibaldi, V. J., Carducci, M. A., Moore-Cooper, S., Laufer, M., Zahurak, M., & Eisenberger, M. A. (2002). Phase II evaluation of docetaxel plus one-day oral estramustine phosphate in the treatment of patients with androgen independent prostate carcinoma. Cancer, 94(5), 1457–1465. doi:10.1002/cncr.10350.
Tannock, I. F., Osoba, D., Stockler, M. R., Ernst, D. S., Neville, A. J., Moore, M. J., et al. (1996). Chemotherapy with mitoxantrone plus prednisone or prednisone alone for symptomatic hormone-resistant prostate cancer: A Canadian randomized trial with palliative end points. Journal of Clinical Oncology, 14(6), 1756–1764.
Melzack, R. (1987). The short-form McGill pain questionnaire. Pain, 30, 191–197. doi:10.1016/0304-3959(87)91074-8.
Aaronson, N. K., Ahmedzai, S., Bergman, B., Bullinger, M., Cull, A., Duez, N. J., et al. (1993). The European Organization for Research and Treatment of Cancer QLQ-C30: A quality-of-life instrument for use in international clinical trials in oncology. Journal of the National Cancer Institute, 85(5), 365–376. doi:10.1093/jnci/85.5.365.
Fayers, P. M., Aaronson, N. K., Bjordal, K., Groenvold, M., Curran, D., Bottomley, A., et al. (2001). EORTC QLQ-C30 scoring manual. Brussels: EORTC.
Borghede, G., & Sullivan, M. (1996). Measurement of quality of life in localized prostatic cancer patients treated with radiotherapy. Development of a prostate cancer-specific module supplementing the EORTC QLQ-C30. Quality of Life Research, 5, 212–222. doi:10.1007/BF00434743.
Muthén, L. K., & Muthén, B. (1998–2005). Mplus user’s guide. Los Angeles: Muthén & Muthén.
Pearl, J. (2000). Causality: Models, reasoning, and inference. Cambridge: Cambridge University Press.
Baron, R. M., & Kenny, D. A. (1986). The moderator–mediator variable distinction in social psychological research: Conceptual, strategic, and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182. doi:10.1037/0022-3514.51.6.1173.
Judd, C. M., & Kenny, D. A. (1981). Process analysis: Estimating mediation in treatment evaluations. Evaluation Review, 9, 602–618. doi:10.1177/0193841X8100500502.
MacKinnon, D. P., Fairchild, A. J., & Fritz, M. S. (2007). Mediation analysis. Annual Review of Psychology, 58, 593–614. doi:10.1146/annurev.psych.58.110405.085542.
Albert, J. M. (2008). Mediation analysis via potential outcomes models. Statistics in Medicine, 27(8), 1282–1304. doi:10.1002/sim.3016.
Kraemer, H. C., Wilson, G. T., Fairburn, C. G., & Agras, W. S. (2002). Mediators and moderators of treatment effects in randomized clinical trials. Archives of General Psychiatry, 59(10), 877–883. doi:10.1001/archpsyc.59.10.877.
Kraemer, H. C., Lowe, K. K., & Kupfer, D. J. (2005). To your health: How to understand what research tells us about risk. New York: Oxford University Press.
Kraemer, H. C., Stice, E., Kazdin, A., Offord, D., & Kupfer, D. (2001). How do risk factors work together? Mediators, moderators, and independent, overlapping, and proxy risk factors. The American Journal of Psychiatry, 158(6), 848–856. doi:10.1176/appi.ajp.158.6.848.
Edwards, D. (1995). Introduction to graphical modeling. New York: Springer-Verlag.
Edwards, D. (1995). MIM release 3.2. Boston: Free Software Foundation.
Acknowledgments
The authors would like to thank the patients who contributed HRQL data to S9916 and the Clinical Research Associates at the Southwest Oncology Group institutions who monitored the submission of the HRQL forms. We recognize the contributions of Dr. Donna L. Berry, the HRQL Study Coordinator for S9916, and Dr. Daniel P. Petrylak, the therapeutic trial study coordinator.
Funding sources: This investigation was supported in part by the following PHS Cooperative Agreement grant numbers awarded by the National Cancer Institute, DHHS: CA38926, CA32102, CA37135, CA25224, CA46441, CA37981, CA45808,CA27057, CA12644, CA68183, CA22433, CA35261, CA58861, CA20319, CA46113, CA58882, CA76447, CA04919, CA16385, CA35090, CA03096, CA67663, CA45450, CA35431, CA45807, CA58416, CA14028, CA45377, CA63845, CA42777, CA46136, CA11083, CA35119, CA58658, CA46282, CA76129, CA46368, CA35176, CA86780, CA46462, CA35192, CA35178, CA67575, CA63844, CA12213, CA74647, CA35128, CA35996, CA58686, CA13612, CA45461, CA58723, CA63848, CA35281, CA63850, CA76132, CA74811, and supported in part by Aventis.
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Moinpour, C.M., Donaldson, G.W. & Nakamura, Y. Chemotherapeutic impact on pain and global health-related quality of life in hormone-refractory prostate cancer: Dynamically Modified Outcomes (DYNAMO) analysis of a randomized controlled trial. Qual Life Res 18, 147–155 (2009). https://doi.org/10.1007/s11136-008-9433-3
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DOI: https://doi.org/10.1007/s11136-008-9433-3