As most regular readers and experienced prostate cancer advocates will be aware, there is a constant stream of published case series reporting data on outcomes of men treated with a variety of different types of radiation therapy for localized prostate cancer … but very little data (actually near to none) comparing one type to another.
The types of radiation therapy now being used for first-line therapy include:
- Old-fashioned, photon-based, three-dimensional conformal beam radiation therapy (3D-CRT), which is not (or at least should not really be) recommended any more today for truly organ-confined prostate cancer.
- Photon-based, intensity-modulated radiation therapy (IMRT), which can be targeted in a variety of ways
- Photon-based, image-guided radiation therapy (IGRT)
- Proton-beam radiation therapy (of varied types, depending on how it is targeted to the prostate)
- Permanent-implant seeds (standard low-dose-rate “brachytherapy”)
- Temporary implant, high-dose-rate brachytherapy (HDR)
- Stereotactic body radiation therapy (most commonly, CyberKnife radiation therapy)
- So-called RapidArc radiation therapy (which is a “short course” type of IMRT)
- So-called TomoTherapy (an integrated method for planning, imaging, and delivery of radiation therapy)
Now all of these different types of radiation therapy appear to work reasonably well in terms of killing cancer in the prostate among men with low-risk, organ-confined disease (although many of the men being treated this way might do just as well on active surveillance), but they all appear to have somewhat different risks for side effects, based on the dose delivered, the accuracy with which it is targeted, and other methods used to protect rectal and associated tissues. In addition, the clinical outcomes of men with intermediate- and high-risk prostate cancer treated with these methods appear to vary as well.
All that the various case series can tell us is that men treated at specific doses of radiation at specific institutions over specific time frames with specific types of radiation therapy techniques have definable outcomes. They tell us little to nothing about how patients in series A treated at institution B over time frame C to D compare to patients in series W treated at institution X over time frame Y to Z. Why? Because we can rarely compare apples to apples.
It is time for the American Society for Radiation Oncology (ASTRO) and the National Institutes of Health (NIH) to step up to the plate and do something about this. If one makes the naive assumption that a key goal of radiation oncologists is to offer men the best possible radiation treatment for prostate cancer, it is high time that we had data that allowed us to know which form of radiation treatment really is the best. To do this we need a national prostate cancer radiation therapy registry that includes data on hundreds (better still thousands) of men treated with different types of radiation therapy and for whom standardized data are collected and entered over time. Such data would include (at a minimum):
- The patients’ diagnostic characteristics (PSA level, clinical stage, clinical Gleason score, and other biopsy-based pathological data)
- Dates of all treatments
- The type of radiation therapy given, in detail, along with the dose level and other relevant criteria
- Whether neoadjuvant or adjuvant androgen deprivation therapy was given in association with the radiation therapy, and if so what type and for exactly how long
- The follow-up PSA data over time (according to a standard set of criteria)
- Data on side effects associated with treatment during therapy, at 3 months, at 6 months, at 12 months, at 2 years, and at 5 years
- Whether salvage androgen deprivation therapy (or other salvage therapy) was required, and if so what, when, and why
- If possible, prostate cancer-specific and overall mortality data
Now many institutions may also want to collect other specific data for their research as well … and that is fine. However, we would suggest that ASTRO, the NIH, and other grant-giving bodies could make it clear that (say) beginning in 2015 no grants will be given for any clinical research into the effectiveness and safety of any form of radiation therapy for prostate cancer unless such research includes the compilation of data into such a database. Furthermore, the Radiation Therapy Oncology Group (RTOG), which oversees most of the clinical trials for radiation therapy in America, should insist that all data on all patients treated for localized prostate cancer in RTOG-sponsored trials should also be entered into this database.
Such a database would be (a) prospective; (b) standardized; and (c) evaluable over time. It could be used to compare outcomes of patients in series A treated at institution B over time frame C to D to patients in series W treated at institution X over time frame Y to Z. Better still, it could be used to compare outcomes of all patients treated using radiation type E at dose F (at any institution) to patients treated using radiation type R at dose S over time frame T to U. In other words, it is a system that would allow us to compare apples to apples as opposed to the current mess. Furthermore, the FDA could consider making approval of new radiation technology used in the treatment of prostate cancer contingent on the submission of data to this national registry in order to establish whether the new technology really was any better than current technology.
The “New” Prostate Cancer InfoLink does not expect ASTRO or all members of the radiation oncology community to embrace this idea with enthusiasm, and it is certainly not the perfect solution to a very complex problem. But it would be a beginning. And if the radiation oncology were to “go there” … maybe the urologic oncology community might go there with them, and we could build a real national prostate cancer registry and do away with all of the separate funding of case series using different study criteria … few of which are of any value to the patients whose bodies are “donated” to the cause of academic publication. Such a real, prospective, national prostate cancer treatment registry could encompass data on all forms of treatment for localized prostate cancer, and get past the old-fashioned, competitive, institutional databases which have more to do with institutional prestige and marketing than they do with improving patient care.