ESOU 2019: Modern Radiotherapy for Prostate Cancer Treatment

Prague, Czech Republic ( Dr. De Meerlander, a radiation oncologist, presented on modern radiotherapy for prostate cancer treatment – and some pearls every urologist and urologic oncologist should know.

Unfortunately, when radiotherapy is discussed for prostate cancer, it is all lumped together in one general category “radiotherapy.” However, there are drastic differences in the radiotherapy given, and below are the key features that should be asked about and/or described to truly understand the treatment given.

  1. The Dose
- There is a clear dose-response with tumor control – every gray of radiation is associated with an incremental increase in tumor control

  1. Hormonal modulation
- Bolla et al. EORTC study clearly demonstrated that the addition of hormones to RT increased overall survival
            - RT without hormone therapy is inadequate therapy
- Minimum 2 years ADT needs to be given – only cut short if the patient can’t tolerate it or refuses, but should be the standard of care
- Bolla study was criticized for not having an ADT alone arm – but Widmark et al SPCG-7 study answered that question. RT+ADT was better than ADT alone.
- ADT is a radiosensitizer – mechanism was only really understood 2 years ago

  1. The Length of administration
- CHHiP trial (Dearnaley et al.) recently demonstrated that hypofractionated (higher doses but fewer fractions) was as effective as standard RT – and this trend is likely to continue to even shorter treatment durations
- He believes treatment of primary PCa will be shortened eventually to 3-5 days!

  1. Modality
- In this section, he started by noting that higher doses of primary tumor treatment were associated with lower distant metastases rates – hence better primary tumor control limited future metastatic disease spread. Like others, he believes this is due to reduced cross-talk between the primary tumor and micrometastatic sites.
- As such, there is increased interest in maximizing the dosage of radiation to the primary tumor – while reducing morbidity
- However, he also pointed out that the most common site of tumor recurrence following RT to the prostate is where the original tumor was – not in another region of the prostate. That has led to increased efforts to increase radiation doses to the primary lesion and reduce radiation to the rest of the prostate (a “boost” to the dominant lesion)

            This is achieved in many different ways:
           - HDR and LDR brachy is one method
           - FLAME – “focal lesion ablative microboost” is another that is being evaluated

Yet, all these modalities are grouped together when talking about RT for prostate cancer. Therefore, he wants to remind the audience that when talking about RT, always know the radiation dose, the schedule and the specifics of the modality – so you can compare results appropriately. Radiotherapy for the prostate is rapidly changing!

Presented by: Gert De Meerleer, MD, Ph.D, Universitair Ziekenhuis Leuven, Department of Radiation Oncology, Ghent, Belgium

Written by: Thenappan Chandrasekar, MD. Clinical Instructor, Thomas Jefferson University, Twitter: @tchandra_uromd, @TjuUrology, at the 16th Meeting of the European Section of Oncological Urology, #ESOU19, January 18-20, 2019, Prague, Czech Republic
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