expert roundtables

Monitoring Patients With Advanced Prostate Cancer: How Frequently Should Scans and Biomarkers Be Obtained?

by Glen Gejerman, MD, Daniel J. George, MD, William K. Oh, MD, and Neal D. Shore, MD, FACS

Overview

The kinetics of disease progression in metastatic castration-resistant prostate cancer (mCRPC) can be subtle. Therefore, clinicians may miss the opportunity to use drugs such as radium-223 or chemotherapy, or they may initiate such therapies very late in the disease course. Here, experts discuss a necessary balance between obtaining imaging studies and drawing blood for biomarkers, on the one hand, and clinical observation with high-quality patient discussions and good history taking, on the other.

Q:

When monitoring a patient with mCRPC, how often should one obtain imaging studies or draw blood for biomarkers?

Expert Commentary

Oliver Sartor, MD

C. E. and Bernadine Laborde Professor of Cancer Research
Medical Director, Tulane Cancer Center
Associate Dean for Oncology
Tulane University School of Medicine
New Orleans, LA

The kinetics of the disease really determine a lot for me. There are some people who are responding really, really well. We don’t need to see them as frequently, and we don’t need to scan them as frequently. Then, there are others who are having less robust responses, or even disease progression, and we have to be very vigilant. I personally individualize my approach. I don’t have a “scan every 3 months” approach, or anything like that, in contrast to what is often encountered when a patient is participating in a clinical trial. I customize my monitoring approach based on the individual patient and his individual set of circumstances.

Glen Gejerman, MD

Co-Director, Urologic Oncology
Medical Director, TomoTherapy
John Theurer Cancer Center
Hackensack, NJ

I would agree with that. A patient’s expectations regarding monitoring can also be important. For instance, if you consider a patient who is now receiving monthly infusions of radium-223, he may have been living with prostate cancer for 10 years or more prior to this point. As such, he may have learned to put a great deal of stock in his PSA levels. It’s really important for the clinician to point out to such a patient that the PSA levels are not necessarily going to change with radium-223 treatment, but that that doesn’t mean the therapy is not working. Often, a patient may be looking for a number, a value, to help determine if he is improving or if his disease is remaining steady. As part of his monthly blood work, I will look at his alkaline phosphatase levels. Often, I will see a reduction in those levels in patients who are having good responses to the radium-223. Frequently, communicating that finding encourages the patient to “hang in there” and continue treatment. Patients often want to see something objective that indicates that their treatment is working.

The answer is not necessarily to increase the number of scans, but it may be to review the patient’s symptoms and functional status regularly (look for a change in his functional status and a change in his ability to continue to stay as active as usual). Those are the things that we tend not to pick up on very well. Very few of us use those kinds of serial, longitudinal, patient-reported outcome tools. But, actually, they may be more sensitive at detecting changes that may signal the need to switch to the next therapy, or the need to add therapies such as radium-223. By detecting this need early enough in the disease course, the patient may have a relatively good performance status, and there is a greater likelihood that there will be sufficient opportunity to administer all 6 cycles of radium-223. This kind of monitoring and detection is a very critical piece, and yet it’s one of the areas in which we’re still falling short in the field. Even I catch myself sometimes being late with these therapies. So, it’s difficult, even for people who see many cases of advanced prostate cancer. I can imagine for the clinician who doesn’t see the patient as regularly, it may be even more difficult to know when to switch or add a therapy.

William K. Oh, MD

Chief Medical Science Officer, Sema4
Clinical Professor of Medicine
Division of Hematology and Medical Oncology
Icahn School of Medicine at Mount Sinai
New York, NY

I think we all struggle with the question of how to define “what is late?” If we see a very symptomatic patient who might die within the next 6 to 12 months, and we have a very effective treatment that reverses the cancer that may be causing him to be so symptomatic and have such a poor performance status, then we might change the natural history of the disease. Just the idea that we can even predict how these patients will always do is, I think, a little bit of a fallacy. We clinicians pride ourselves on knowing what’s going to happen next with patients. But, as we know, some people fall off the cliff very suddenly or unexpectedly, or without our knowledge, and some people do much better than we expect.

Regarding the question of how often do we see a patient or how often do we monitor a patient, I’ll refer clinicians to a paper that will be put forth from a conference that several of us participated in: the St. Gallen Advanced Prostate Cancer Consensus Conference. During the conference, several very practical questions were asked. For example, in a hormone-sensitive setting, how often would we see these patients, and how often would we administer laboratory tests? And, then we would ask the same question for castration-resistant prostate cancer (CRPC). Most of us on the call would agree that, in hormone-sensitive prostate cancer – outside of the patient coming in every 3 weeks, let’s say for docetaxel chemotherapy, for CHAARTED (Chemo-Hormonal Therapy Versus Androgen Ablation Randomized Trial for Extensive Disease in Prostate Cancer) or STAMPEDE (Systemic Therapy in Advancing or Metastatic Prostate Cancer: Evaluation of Drug Efficacy) – we would probably see patients at intervals of somewhere between 3 and 6 months. I generally see those patients every 3 months if I’m just monitoring them and they are otherwise doing well. In a CRPC or mCRPC setting, again, just generally speaking, we are more concerned about progression even between visits, even if they are doing well on a drug like abiraterone or enzalutamide, and we are probably seeing those patients once a month to once every other month. I’d refer people to results from some of these consensus conferences. However, even though they are consensus conferences, there is generally not a single consensus on any of this if there’s a lack of level 1 evidence. But, I believe that we are seeing patients with CRPC more often because the tools we have are not perfect. For example, in a patient who is getting a 6-month course of radium-223, I think it would be a big mistake not to see the patient during his radium course. I don’t think that any of us would ever send a patient to a radiation oncologist or to nuclear medicine to give the whole 6-month course and not see the patient at all during this time. There is a great need for clear standards, outside of, say, checking the complete blood count on a monthly basis, so that we can better determine what the optimal methods for monitoring such a patient may be.

References

Advanced Prostate Cancer Consensus Conference website. http://www.prostatecancerconsensus.org. Accessed June 5, 2017.

Love C, Din AS, Tomas MB, et al. Radionuclide bone imaging: an illustrative review. Radiographics. 2003;23(2):341-358.

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