Prostate cancer is the most common cancer in men in the US and the second most common cancer in men worldwide.¹ In 2006, over 230,000 men will be diagnosed with prostate cancer in the US and 60% of these cases will be early stage organ-confined disease.²

Prostate cancer surgery (radical prostatectomy) has been the most common approach to treating prostate cancer, although brachytherapy (low dose rate with permanent seed implant or high dose rate, HDR) is approaching or surpassing surgery as treatments for prostate cancer. Androgen deprivation therapy, external beam radiation therapy (conventional or IMRT), and high intensity focused ultrasound (HIFU) are also alternative prostate cancer treatments for.³

Using the CyberKnife System to Treat Prostate Cancer
The CyberKnife® System is currently being used as monotherapy treatment for early stage prostate cancer or as a boost following conventional radiation therapy in place of IMRT or brachytherapy.⁴ The CyberKnife System can reproduce the conformality for organ coverage achievable with brachytherapy or IMRT^{4, 5} and can track and compensate for organ motion during treatment delivery. Because of similar conformality and dose fractionation, local control and complication rates are expected to be similar to HDR brachytherapy.^{4, 5} A low-ratio for prostate cancer indicates that a hypofractionated treatment regimen delivered via radiosurgery might be more effective than conventional external beam fractionation.⁶

Low-Risk Organ-Confined Prostate Cancer
(Courtesy Naples Community Hospital, Naples, FL)

Sample CyberKnife treatment plans for prostate.

In this case there was a significant reduction in PSA post CyberKnife treatment with a stable PSA of 0.2 ng/ml at 12 months.

REFERENCES

1. International Agency for Research on Cancer. GLOBOCAN 2002 Database Lyon, France, 2002. http://www-dep.iarc.fr/globocan/database.htm

2. American Cancer Society. Cancer Facts and Figures 2006. Atlanta: American Cancer Society, 2006. LINK

3. Lowrance WT, Chang SS. Advancing prostate cancer: treatment options for the urologist. Urol Clin North Am 2006;33(2):211-217, vii.

4. Medbery CA, Young MM, Morrison AE, Archer JS, D’Souza MF, Parry C. CyberKnife Monotherapy for Prostate Cancer. In: Mould RR, Bucholz RD, Gagnon GJ, et al., eds. Robotic Radiosurgery Sunnyvale, CA: CyberKnife Society, 2005:325-31.

5. King C, Cotrutz C. Hypofractionated Radiotherapy for Localized Prostate Cancer: Therapeutic Rationale & Feasibility of the CyberKnife. In: Mould RR, Bucholz RD, Gagnon GJ, et al., eds. Robotic Radiosurgery Sunnyvale, CA: CyberKnife Society Press, 2005.

6. King CR, Fowler JF. A simple analytic derivation suggests that prostate cancer alpha/beta ratio is low. Int J Radiat Oncol Biol Phys 2001;51(1):213-4.