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Improved biochemical relapse-free survival with increased external radiation doses in patients with localized prostate cancer: the combined experience of nine institutions in patients treated in 1994 and 1995.
Int J Radiat Oncol Biol Phys. 2005 Feb 01; 61(2):415-9.IJ

Abstract

PURPOSE

To study the radiation dose-response as determined by Kaplan-Meier prostate-specific antigen (PSA) disease-free survival (PSA-DFS) estimates in patients with stage T1-T2 prostate cancer treated within a 2-year period (1994-1995).

METHODS

Nine institutions combined data on 4839 patients with stage T1 and T2 adenocarcinoma of the prostate who received > or =60 Gy external beam radiation therapy (RT) as sole treatment. No patient received neoadjuvant androgen deprivation or planned adjuvant androgen deprivation. Of the 4839 patients, 1325 were treated in 1994 and 1995; 1061 were treated with <72 Gy and 264 with > or =72 Gy. The median RT doses for the <72 Gy and the > or =72 Gy groups were 68.4 Gy and 75.6 Gy, respectively. The median follow-up for the <72 Gy and the > or =72 Gy groups were 5.8 and 5.7 years, respectively. Risk groups, defined on the basis of T stage, pretherapy PSA level, and biopsy Gleason score (GS), were as follows: low risk--T1b, T1c, T2a, GS < or =6 and PSA < or =10 ng/mL; intermediate risk--T1b, T1c, T2a, GS < or =6 and PSA >10 ng/mL but < or =20 ng/mL or T2b, GS < or =6 and PSA < or =20 ng/mL or GS 7 and PSA < or =20 ng/mL; high risk--GS 8-10 or PSA >20 ng/mL. The endpoint for outcome analysis was PSA-DFS at 5 years after therapy using the American Society for Therapeutic Radiology and Oncology failure definition.

RESULTS

Patients receiving > or =72 Gy had significantly more advanced cancers. The proportion of stage T2b/T2c cancers in the > or =72 Gy group was 42% compared with 32% in the <72 Gy group (p = 0.027). The mean pretherapy PSA was 11.4 ng/mL in the > or =72 Gy group compared with 10.7 ng/mL in the <72 Gy group (p = 0.001). The proportion of GS > or =8 cancers in the > or =72 Gy group was 9% compared with 7% in the <72 Gy group (p = 0.309). Overall, 15% of patients receiving <72 Gy had high-risk disease, compared with 22% of patients receiving > or =72 Gy (p = 0.034). The > or =72 Gy group had a greater number of follow-up PSA levels (mean 10.6/patient) compared with the <72 Gy group (mean 9.6/patient) (p = 0.007). For all 1325 patients, the 5- and 8-year PSA-DFS estimates were 64% and 62%, respectively. The 5-year PSA-DFS estimates for <72 Gy vs. > or =72 Gy were 63% vs. 69%, respectively (p = 0.046). Multivariate analysis for factors affecting PSA-DFS was performed for all cases using the following variables: pretherapy PSA (continuous), biopsy GS (continuous), stage (T1 vs. T2), radiation dose (continuous), and radiation technique (three-dimensional conformal vs. conventional). Pretreatment PSA (p < 0.001, chi-square 112.2), GS (p < 0.001, chi-square 12.8), radiation dose (p < 0.001, chi-square 13.5), and stage (p = 0.007, chi-square 7.2) were independent predictors of outcome. Radiotherapy technique was not (p = 0.50).

CONCLUSION

Differences in PSA-DFS estimates observed in multiple retrospective series have been attributed to differences in follow-up duration between patients treated to conventional doses (longer follow-up intervals) and those treated to higher doses (shorter follow-up intervals). In this report, the median follow-up duration in the > or =72 Gy group was essentially identical to the <72 Gy group, because the study included a large number of patients treated consecutively during a narrow time range (1994-1995). With similar follow-up duration, higher than conventional radiotherapy doses were associated with improved PSA-DFS when controlled for the influence of pretreatment PSA levels, biopsy GS, and clinical T stage.

Authors+Show Affiliations

Department of Radiation Oncology, M. D. Anderson Cancer Center Orlando, Orlando, FL 32806, USA. kupelian@orhs.orgNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Multicenter Study

Language

eng

PubMed ID

15667961

Citation

Kupelian, Patrick, et al. "Improved Biochemical Relapse-free Survival With Increased External Radiation Doses in Patients With Localized Prostate Cancer: the Combined Experience of Nine Institutions in Patients Treated in 1994 and 1995." International Journal of Radiation Oncology, Biology, Physics, vol. 61, no. 2, 2005, pp. 415-9.
Kupelian P, Kuban D, Thames H, et al. Improved biochemical relapse-free survival with increased external radiation doses in patients with localized prostate cancer: the combined experience of nine institutions in patients treated in 1994 and 1995. Int J Radiat Oncol Biol Phys. 2005;61(2):415-9.
Kupelian, P., Kuban, D., Thames, H., Levy, L., Horwitz, E., Martinez, A., Michalski, J., Pisansky, T., Sandler, H., Shipley, W., Zelefsky, M., & Zietman, A. (2005). Improved biochemical relapse-free survival with increased external radiation doses in patients with localized prostate cancer: the combined experience of nine institutions in patients treated in 1994 and 1995. International Journal of Radiation Oncology, Biology, Physics, 61(2), 415-9.
Kupelian P, et al. Improved Biochemical Relapse-free Survival With Increased External Radiation Doses in Patients With Localized Prostate Cancer: the Combined Experience of Nine Institutions in Patients Treated in 1994 and 1995. Int J Radiat Oncol Biol Phys. 2005 Feb 1;61(2):415-9. PubMed PMID: 15667961.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Improved biochemical relapse-free survival with increased external radiation doses in patients with localized prostate cancer: the combined experience of nine institutions in patients treated in 1994 and 1995. AU - Kupelian,Patrick, AU - Kuban,Deborah, AU - Thames,Howard, AU - Levy,Larry, AU - Horwitz,Eric, AU - Martinez,Alvaro, AU - Michalski,Jeff, AU - Pisansky,Thomas, AU - Sandler,Howard, AU - Shipley,William, AU - Zelefsky,Michael, AU - Zietman,Anthony, PY - 2004/01/15/received PY - 2004/05/05/revised PY - 2004/05/13/accepted PY - 2005/1/26/pubmed PY - 2005/3/11/medline PY - 2005/1/26/entrez SP - 415 EP - 9 JF - International journal of radiation oncology, biology, physics JO - Int. J. Radiat. Oncol. Biol. Phys. VL - 61 IS - 2 N2 - PURPOSE: To study the radiation dose-response as determined by Kaplan-Meier prostate-specific antigen (PSA) disease-free survival (PSA-DFS) estimates in patients with stage T1-T2 prostate cancer treated within a 2-year period (1994-1995). METHODS: Nine institutions combined data on 4839 patients with stage T1 and T2 adenocarcinoma of the prostate who received > or =60 Gy external beam radiation therapy (RT) as sole treatment. No patient received neoadjuvant androgen deprivation or planned adjuvant androgen deprivation. Of the 4839 patients, 1325 were treated in 1994 and 1995; 1061 were treated with <72 Gy and 264 with > or =72 Gy. The median RT doses for the <72 Gy and the > or =72 Gy groups were 68.4 Gy and 75.6 Gy, respectively. The median follow-up for the <72 Gy and the > or =72 Gy groups were 5.8 and 5.7 years, respectively. Risk groups, defined on the basis of T stage, pretherapy PSA level, and biopsy Gleason score (GS), were as follows: low risk--T1b, T1c, T2a, GS < or =6 and PSA < or =10 ng/mL; intermediate risk--T1b, T1c, T2a, GS < or =6 and PSA >10 ng/mL but < or =20 ng/mL or T2b, GS < or =6 and PSA < or =20 ng/mL or GS 7 and PSA < or =20 ng/mL; high risk--GS 8-10 or PSA >20 ng/mL. The endpoint for outcome analysis was PSA-DFS at 5 years after therapy using the American Society for Therapeutic Radiology and Oncology failure definition. RESULTS: Patients receiving > or =72 Gy had significantly more advanced cancers. The proportion of stage T2b/T2c cancers in the > or =72 Gy group was 42% compared with 32% in the <72 Gy group (p = 0.027). The mean pretherapy PSA was 11.4 ng/mL in the > or =72 Gy group compared with 10.7 ng/mL in the <72 Gy group (p = 0.001). The proportion of GS > or =8 cancers in the > or =72 Gy group was 9% compared with 7% in the <72 Gy group (p = 0.309). Overall, 15% of patients receiving <72 Gy had high-risk disease, compared with 22% of patients receiving > or =72 Gy (p = 0.034). The > or =72 Gy group had a greater number of follow-up PSA levels (mean 10.6/patient) compared with the <72 Gy group (mean 9.6/patient) (p = 0.007). For all 1325 patients, the 5- and 8-year PSA-DFS estimates were 64% and 62%, respectively. The 5-year PSA-DFS estimates for <72 Gy vs. > or =72 Gy were 63% vs. 69%, respectively (p = 0.046). Multivariate analysis for factors affecting PSA-DFS was performed for all cases using the following variables: pretherapy PSA (continuous), biopsy GS (continuous), stage (T1 vs. T2), radiation dose (continuous), and radiation technique (three-dimensional conformal vs. conventional). Pretreatment PSA (p < 0.001, chi-square 112.2), GS (p < 0.001, chi-square 12.8), radiation dose (p < 0.001, chi-square 13.5), and stage (p = 0.007, chi-square 7.2) were independent predictors of outcome. Radiotherapy technique was not (p = 0.50). CONCLUSION: Differences in PSA-DFS estimates observed in multiple retrospective series have been attributed to differences in follow-up duration between patients treated to conventional doses (longer follow-up intervals) and those treated to higher doses (shorter follow-up intervals). In this report, the median follow-up duration in the > or =72 Gy group was essentially identical to the <72 Gy group, because the study included a large number of patients treated consecutively during a narrow time range (1994-1995). With similar follow-up duration, higher than conventional radiotherapy doses were associated with improved PSA-DFS when controlled for the influence of pretreatment PSA levels, biopsy GS, and clinical T stage. SN - 0360-3016 UR - https://www.unboundmedicine.com/medline/citation/15667961/Improved_biochemical_relapse_free_survival_with_increased_external_radiation_doses_in_patients_with_localized_prostate_cancer:_the_combined_experience_of_nine_institutions_in_patients_treated_in_1994_and_1995_ L2 - https://linkinghub.elsevier.com/retrieve/pii/S036030160400817X DB - PRIME DP - Unbound Medicine ER -