Radiation Oncology May Head Toward Personalization

Radiation Oncology May Head Toward Personalization

Dr. Steven E. Finkelstein
Ongoing advancements in radiation oncology were among the highlights of the 2018 ASCO Annual Meeting. Approximately 80% of all patients with cancer receive radiation therapy as part of their treatment, Steven E. Finkelstein, MD, FACRO, of the Advanced Urology Institute, said. It makes sense, then, that radiation is being investigated in combination with numerous other therapies, such as immunotherapy, to develop more effective treatments. The ASCO Daily News spoke with Dr. Finkelstein about what he felt were key advances in the field and some of the hot topics discussed during the 2018 ASCO Annual Meeting.

Q: What data from the 2018 ASCO Annual Meeting struck you as particularly thought-provoking?

Dr. Finkelstein: Ralph R. Weichselbaum, MD, was this year’s David A. Karnofsky Memorial Award recipient. His address demonstrated a track record of going from preclinical work to the clinic, showing that radiation can be more than what we’ve classically thought it can be. Dr. Weichselbaum talked about how radiation therapy is causing exciting advancements in immunotherapies. For instance, the ability to treat oligometastatic disease with radiation oncology and potentially lead not only to local control benefits, but also systemic benefits, makes this a truly exciting time to be in our field. Dr. Weichselbaum explained that ablative therapy may be able to cure patients with oligometastatic and oligoprogressive disease and suggested that future goals and areas of investigation should concentrate on improving the interaction of radiotherapy and immunotherapy. More work is necessary in using metastasis-directed ablative therapies to cure or decrease tumor cell burden.

Q: Almost every sector of oncology has benefitted from personalized medicine. How will personalized medicine impact the treatment of cancers with radiation therapy protocols in the future?

Dr. Finkelstein: The central principle of personalized medicine is that cancer therapy should be tailored based on individual hemobiology. Until now, precision medicine has been focused almost entirely on genetically targeted therapeutic development. As a result, external beam radiation therapy, stereotactic body radiation therapy (SBRT), or other advanced techniques have not traditionally been considered in the era of precision medicine.

I believe it’s the ability to measure the patient’s individual sensitivity or resistance to radiotherapy and then use that information to inform the radiation prescription dose that may be key in the future. As we continue to develop personalized medicine, we want to personalize each treatment based on the individual’s specific tumor biology.

Dr. Felix Feng
Q: What are your thoughts on the role of radiation therapy in oncology 5 years from now?

Dr. Finkelstein: Five years from now we’re going to use technologies that employ genomic signatures that can identify an individual patient’s genetic predisposition to respond to radiation therapy. We’ll also use technologies that can estimate the required radiation dose to match the intrinsic radiosensitivity of an individual tumor. That will be where personalization occurs.

Q: What other innovations did you hear about at the Annual Meeting this year?

Dr. Finkelstein: Felix Feng, MD, was the discussant for several abstracts presented this year on the use of therapeutics and imaging in prostate cancer.1-3 One key point in these studies that Dr. Feng eloquently discussed was that although there is strong rationale for intensifying systemic therapy for M0 prostate cancer, better patient selection is necessary to optimize the benefit-to-risk ratio of treatment intensification. He noted that imaging and genomic approaches are promising technologies to improve patient selection.

In going after a target, it’s becoming essential to pick the right targets. We struggled for years in the field of prostate cancer because our imaging was not optimal. We know single-
photon emission CT technetium-99 bone scans are not the most robust ways to find the sites of disease. Other imaging modalities have lagged behind in other solid tumor cancers. But they now seem to be converging to help guide advances over the course of the next 5 to 10 years. 

Dr. Ralph R. Weichselbaum
Classically, we’ve had limited options for advanced prostate cancer, but within the past few years, we’ve had six novel therapies approved, many with survival benefits. That’s creating an incredibly exciting time to be treating M0 and M1 castration-resistant prostate cancer. Dr. Feng’s comments emphasized that there is a strong rationale to integrate systemic therapy in treating prostate cancer. We’re able to move the target up so now we’re looking closer at the M0 space and better patient selection.

Prostate cancer serves us well as a model system for other disease sites, and I’m looking forward to seeing these exciting advances disseminate rapidly throughout the multiconnective field of cancer care. What I heard and saw emphasized at the Annual Meeting is that radiation oncology will continue to be an important part of that.

We’ve heard contrarian trial results that note postradiation systemic therapy with docetaxel in intermediate high-risk prostate cancer may not be beneficial, but we know docetaxel can be effective in other prostate cancer disease states.1 My take-home is that as clinicians, we can’t generalize everything. We need to focus and hone in on precision medicine and the imaging pieces to enhance patient selection for various treatments.

Q: You touched on SBRT. What are your thoughts about those presentations this year?

Dr. Finkelstein: There were several abstracts that aligned with Dr. Weichselbaum’s address that spoke about the nuances of giving SBRT in a variety of disease settings. Again, results differ when analyzing individual disease sites and how a specific disease site will potentially behave when we use advanced radiation approaches combined with immunotherapy.

As a result, I’ve now started to think about radiation oncology as a much more important focused individualized procedure. I want to encourage the idea that radiation may be similar to chemotherapy in that it should be nuanced accordingly for individual patients in certain settings for certain disease types.

–Michelle Dalton, ELS