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Preliminary observations on biochemical relapse-free survival rates after short-course intensity-modulated radiotherapy (70 Gy at 2.5 Gy/fraction) for localized prostate cancer

      Abstract

      Math Eq: To compare the preliminary biochemical relapse-free survival rates between short-course intensity-modulated radiotherapy (SCIM-RT) delivering 70 Gy in 28 fractions and three-dimensional conformal radiotherapy (3D-CRT) delivering 78 Gy in 39 fractions.
      Math Eq: Between January 1998 and December 1999, 166 patients were treated with SCIM-RT and 116 with 3D-CRT. The SCIM-RT cases were treated to 70 Gy (2.5 Gy/fraction) using 5 intensity-modulated fields using a dynamic multileaf collimator. The BAT transabdominal ultrasound system was used for localization of the prostate gland in all SCIM-RT cases. The 116 3D-CRT cases were treated to 78.0 Gy (2.0 Gy/fraction). The study sample therefore comprised 282 cases; 70 Gy in 28 fractions is equivalent to 78 Gy in 39 fractions for late-reacting tissues, according to the linear-quadratic model. The median follow-up for all cases was 25 months (range 3–42). The median follow-up was 21 months for the SCIM-RT cases (range 3–31) and 32 months for the 3D-CRT cases (range 3–42). The follow-up period was shorter for the SCIM-RT cases, because SCIM-RT was started only in October 1998. Biochemical relapse was defined as 3 consecutive rising prostate-specific antigen levels after reaching a nadir. The analysis was then repeated with a more stringent definition of biochemical control: reaching and maintaining a prostate-specific antigen level of ≤0.5 ng/mL. Radiation Therapy Oncology Group toxicity scores were used to assess complications.
      Math Eq: For the 282 patients, the biochemical relapse-free survival rate at 30 months was 91% (95% confidence interval 88–95%). The biochemical relapse-free survival rate at 30 months for 3D-CRT vs. SCIM-RT was 88% (95% confidence interval 82–94%) vs. 94% (95% confidence interval 91–98%), respectively. The difference was not statistically significant between the two treatment arms (p = 0.084). The multivariate time-to-failure analysis using the Cox proportional hazards model for clinical parameters showed the pretreatment prostate-specific antigen level (p <0.001) and biopsy Gleason score (p <0.001) to be the only independent predictors of biochemical relapse. Clinical T stage (p = 0.66), age (p = 0.15), race (p = 0.25), and neoadjuvant androgen deprivation (p = 0.66) were not independent predictors of biochemical failure. SCIM-RT showed only a trend toward a better outcome on multivariate analysis (p = 0.058). Late rectal toxicity was limited; the actuarial combined Grade 2 and 3 late rectal toxicity rate at 30 months was 5% for SCIM-RT vs. 12% for 3D-CRT (p = 0.24). Grade 3 late rectal toxicity (rectal bleeding requiring cauterization) occurred in a total of 10 patients. The actuarial Grade 3 late rectal toxicity rate at 30 months was 2% for the SCIM-RT cases and 8% for the 3D-CRT cases (p = 0.059). Late urinary toxicity was rare in both groups.
      Math Eq: With the currently available follow-up period (≤30 months), the hypofractionated intensity-modulated radiotherapy schedule of 70.0 Gy delivered at 2.5 Gy/fraction had a comparable biochemical relapse profile with the prior 3D-CRT schedule delivering 78.0 at 2.0 Gy/fraction. The late rectal toxicity profile has been extremely favorable. If longer follow-up confirms the favorable biochemical failure and low late toxicity rates, SCIM-RT will be an alternative and more convenient way of providing dose escalation in the treatment of localized prostate cancer.

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      References

        • Hanks G.E.
        Conformal radiotherapy for prostate cancer.
        Ann Med. 2000; 32: 57-63
        • Kupelian P.A.
        Improvement in overall survival for patients with localized prostate cancer with higher than standard radiation doses.
        J Urol. 1999; 161: 386
        • Kupelian P.A.
        • Buchsbaum J.C.
        • Reddy C.A.
        • et al.
        Radiation dose response in patients with favorable localized prostate cancer (Stage T1-T2, biopsy Gleason < or = 6, and pretreatment prostate-specific antigen < or = 10).
        Int J Radiat Oncol Biol Phys. 2001; 50: 621-625
        • Kupelian P.A.
        • Mohan D.S.
        • Lyons J.
        • et al.
        Higher than standard radiation doses (72 Gy or greater) with or without androgen deprivation in the treatment of localized prostate cancer.
        Int J Radiat Oncol Biol Phys. 2000; 46: 567-574
        • Zelefsky M.J.
        • Leibel S.A.
        • Gaudin P.B.
        • et al.
        Dose escalation with three-dimensional conformal radiation therapy affects the outcome in prostate cancer.
        Int J Radiat Oncol Biol Phys. 1998; 41: 491-500
        • Lyons J.A.
        • Kupelian P.A.
        • Mohan D.S.
        • et al.
        Importance of high radiation doses (72 Gy or greater) in the treatment of stage T1-T3 adenocarcinoma of the prostate.
        Urology. 2000; 55: 85-90
        • Brenner D.J.
        • Hall E.J.
        Fractionation and protraction for radiotherapy of prostate carcinoma.
        Int J Radiat Oncol Biol Phys. 1999; 43: 1095-1101
        • D’Souza W.D.
        • Thames H.D.
        Is the alpha/beta ratio for prostate cancer low?.
        Int J Radiat Oncol Biol Phys. 2001; 51: 1-3
        • Duchesne G.M.
        • Peters L.J.
        What is the alpha/beta ratio for prostate cancer? Rationale for hypofractionated high-dose-rate brachytherapy.
        Int J Radiat Oncol Biol Phys. 1999; 44: 747-748
        • King C.R.
        • Fowler J.F.
        A simple analytic derivation suggests that prostate cancer alpha/beta ratio is low.
        Int J Radiat Oncol Biol Phys. 2001; 51: 213-214
        • Mohan D.S.
        • Kupelian P.A.
        • Willoughby T.R.
        Short-course intensity-modulated radiotherapy for localized prostate cancer with daily transabdominal ultrasound localization of the prostate gland.
        Int J Radiat Oncol Biol Phys. 2000; 46: 575-580
        • Kupelian P.A.
        • Willoughby T.R.
        Short-course intensity-modulated radiotherapy for localized prostate cancer.
        Cancer J Sci Am. 2001; 7: 421-426
        • Pollack A.
        • Zagars G.K.
        • Smith L.G.
        • et al.
        Preliminary results of a randomized radiotherapy dose-escalation study comparing 70 Gy with 78 Gy for prostate cancer.
        J Clin Oncol. 2000; 18: 3904-3911
        • D’Amico A.
        Radiation and hormonal therapy for locally advanced and clinically localized prostate cancer.
        Urology. 2001; 58: 78-82
        • Wei J.T.
        • Dunn R.L.
        • Litwin M.S.
        • et al.
        Development and validation of the expanded prostate cancer index composite (EPIC) for comprehensive assessment of health-related quality of life in men with prostate cancer.
        Urology. 2000; 56: 899-905
        • Ware J.E.
        • Kosinski M.
        • Keller S.D.
        SF-12. 3rd ed. Quality Metric Incorporated, Lincoln, RI1998
        • Martinez A.A.
        • Pataki I.
        • Edmundson G.
        • et al.
        Phase II prospective study of the use of conformal high-dose-rate brachytherapy as monotherapy for the treatment of favorable stage prostate cancer.
        Int J Radiat Oncol Biol Phys. 2001; 49: 61-69
        • Sohayda C.
        • Kupelian P.A.
        • Levin H.S.
        • et al.
        Extent of extracapsular extension in localized prostate cancer.
        Urology. 2000; 55: 382-386
        • Davis B.J.
        • Pisansky T.M.
        • Wilson T.M.
        • et al.
        The radial distance of extraprostatic extension of prostate carcinoma.
        Cancer. 1999; 85: 2630-2637
        • Logue J.P.
        • Cowan R.A.
        • Hendry J.H.
        Hypofractionation for prostate cancer.
        Int J Radiat Oncol Biol Phys. 2001; 49: 1522-1523
        • Zelefsky M.J.
        • Leibel S.A.
        • Kutcher G.J.
        • et al.
        Three-dimensional conformal radiotherapy, and dose escalation.
        Semin Radiat Oncol. 1998; 8: 107-114
        • Zelefsky M.J.
        • Fuks Z.
        • Wolfe T.
        • et al.
        Locally advanced prostatic cancer.
        Radiology. 1998; 209 ([In Process Citation]): 169-174

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