Relationship between delay in radiotherapy and biochemical control in prostate cancer

Kwan, Winkle; Pickles, Tom; Duncan, Graeme; Liu, Mitchell; Paltiel, Chuck

doi:10.1016/j.ijrobp.2006.05.043

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Volume 66, Issue 3 , Pages 663-668, 1 November 2006

Relationship between delay in radiotherapy and biochemical control in prostate cancer

Winkle Kwan, M.B.B.S., F.R.C.P.C.
- Radiation Therapy Program of the B.C. Cancer Agency, Fraser Valley Centre, Surrey, British Columbia (B.C.), Canada
- Reprint requests to: Winkle Kwan, M.B.B.S., F.R.C.P.C., British Columbia Cancer Agency, Fraser Valley Centre, 13750 96th Avenue, Surrey, B.C., Canada V3V 1Z2. Tel: (604) 930-4032; Fax: (604) 930-4065;
Tom Pickles, M.D., F.R.C.P.C.
- Radiation Therapy Program of the B.C. Cancer Agency, Vancouver Centre, Vancouver, British Columbia (B.C.), Canada
Graeme Duncan, M.D., F.R.C.P.C.
- Radiation Therapy Program of the B.C. Cancer Agency, Vancouver Centre, Vancouver, British Columbia (B.C.), Canada
Mitchell Liu, M.D., F.R.C.P.C.
- Radiation Therapy Program of the B.C. Cancer Agency, Fraser Valley Centre, Surrey, British Columbia (B.C.), Canada
Chuck Paltiel, M.Sc.
- Biostatistics Program of the B.C. Cancer Agency, Vancouver, British Columbia (B.C.), Canada

Received 6 October 2005; received in revised form 18 May 2006; accepted 29 May 2006. published online 31 August 2006.

Purpose: The aim of this study was to investigate whether a delay in radiotherapy is associated with a poorer biochemical control for prostate cancer.

Methods: The time to treatment (TTT) from diagnosis of prostate cancer to radiotherapy was analyzed with respect to prostate-specific antigen (PSA) control in 1024 hormone-naive patients. The Kaplan-Meier PSA control curves for patients with TTT less than the median were compared with those for patients with TTT greater than the median in 3 predefined risk groups. Statistical significant differences in PSA control were further analyzed using Cox multivariate analysis with pretreatment PSA, Gleason score, T stage, and radiotherapy dose as covariates.

Results: The median TTT and median follow-up are 3.7 months and 49 months respectively. Patients with a longer TTT have a statistically significant better PSA control than patients with a shorter TTT if they have intermediate- or high-risk disease. However in multivariate analysis TTT was not found to be significant in predicting PSA control, with pretreatment PSA and Gleason score emerging as highly significant in predicting PSA failure in both intermediate- and high-risk disease.

Conclusion: In this study in prostate cancer patients in British Columbia, there was no evidence that a longer time interval between diagnosis and radiotherapy was associated with poorer PSA control.

Keywords: Prostate carcinoma , Delay , Radiotherapy , Prostate-specific antigen outcome