Shortened Radiation Therapy Recommended in New Prostate Cancer Guideline
The American Society for Radiation Oncology (ASTRO), American Society of Clinical Oncology (ASCO), and American Urological Association (AUA) developed a new guideline that suggests hypofractionated radiation therapy as an alternative to conventional radiation for early-stage prostate cancer.
The guideline has been published in Journal of Clinical Oncology (Online October 11, 2018; doi:10.1200/JCO.18.01097) and also appears in Practical Radiation Oncology as well as The Journal of Urology.
The target population for this new guideline are patients who choose treatment instead of surveillance and have opted for external beam radiation therapy (EBRT) instead of radical prostatectomy, brachytherapy, or other treatment options for localized prostate cancer. To develop the guideline, 16 expert clinicians, researchers, and a patient advocate reviewed studies published from December 2001 through March 2017. Key recommendations include:
- For men who have opted for EBRT, moderate hypofractionation (fraction size of 240-340 centigray (cGy)) should be offered as an alternative to conventional fractionation (180-200 cGy) regardless of cancer risk group, patient age, comorbidity, anatomy, or baseline urinary function.
- Ultrahypofractionation (≥500 cGy) guidance varies by prostate-cancer risk. For low-risk patients who have opted for EBRT, it may be offered as an alternative to conventional fractionation. For intermediate-risk disease, patients are strongly encouraged to enroll in a clinical trial or multi-institutional registry. For high-risk disease, ultrahypofractionation outside of a trial or registry should not be offered. Recommendations for ultrahypofractionation were graded by the panel as "conditional," reflecting the limited base of current evidence on this approach.
- Recommendations also address the technical aspects of planning and delivering hypofractionated prostate radiation, including target and normal tissue volumes, dose constraints, margin definitions and delivery techniques. The expert panel universally recommends the use of image-guided radiation therapy and avoidance of non-modulated conformal techniques.
Fraction sizes between 340 and 500 cGy were outside the scope of the guideline due to a lack of available literature. Also excluded from the guideline are treatment for locally advanced or metastatic disease, post-operative radiation, salvage therapy, and re-irradiation.
"Conclusive evidence from several large, well-designed randomized trials now confirms that dose escalation can almost universally benefit men with early-stage prostate cancer who choose to manage their disease with external radiation," said Howard Sandler, MD, FASTRO, FASCO, Cedars-Sinai Medical Center (Los Angeles, CA), and co-chair of the guideline panel, in a press release (October 11, 2018). "Significant advances in treatment planning and delivery have enabled oncologists to deliver more powerful, life-saving doses of radiation in fewer visits and without compromising quality of life."—Zachary Bessette