Brian F. Chapin, MD
No prostate cancers are exactly alike, explains Brian F. Chapin, MD, adding that practicing physicians must individualize patient care based on the information they obtain from risk stratification.
Active surveillance remains an important measurable method for patients with low-risk prostate cancer to avoid overtreatment, he says, but optimizing its use presents many challenges.
“How do you identify those patients?” asks Chapin, who spoke on the topic during the 2017 OncLive®
State of the Science Summit on Genitourinary Malignancies. “How do you avoid missing patients who may have more aggressive disease, either hiding in places so that it was not identified at the initial evaluation, or something that might show up over the course of the patient’s life.”
In an interview during the meeting, Chapin, assistant professor, Department of Urology, Division of Surgery, The University of Texas MD Anderson Cancer Center, discussed the importance of active surveillance in patients with prostate cancer at a low risk of developing metastases. He also highlights the benefits of surgery and radiation as active treatment methods for patients with locally advanced disease.
OncLive: Please provide an overview of your discussion on early-stage prostate cancer.
I was asked to speak about early diagnosis and treatment for early prostate cancer. Specifically, the focus on the talk was about prostate cancer screening, discussing some of the limitations to what we have toward prostate cancer screening with the use of prostate-specific antigen (PSA) testing and digital rectal exam, and then focusing on the use of transrectal ultrasound biopsy, as well as the MRI-fusion guided biopsies in order to identify prostate cancer.
Once the cancer is identified, we go over the risk stratification for prostate cancer and how we identify patients who we would like to treat with active surveillance versus treatment with radiation or prostatectomy.
This talk focused on the low-risk population, trying to identify them, and explaining that we are identifying a group of patients who are likely to have low-risk metastatic potential, and a low chance of having their prostate cancer progress to the point of needing additional treatment for systemic manifestations of the disease.
How do you decide whether a patient should undergo active surveillance or active treatment?
The ways we risk stratify patients into the low-risk category, which is mainly the group that we will put on an active surveillance program, is mostly by Gleason scoring. This is a pathologic assessment of the tumor, and we identify Gleason score 6—which is grade 3 + 3 tumors—as being low risk and having low metastatic potential.
There are other factors that fit in, such as PSA and digital rectal exam, which we use to categorize patients in the low-risk group. Then, at The University of Texas MD Anderson Cancer Center, for example, we primarily use a protocol-based program where we do a confirmatory biopsy within 6 months of the original biopsy, and planned assessments every 6 months with a digital rectal exam and PSA test.
Every 1 to 2 years, we do a repeat biopsy and/or MRI-scan imaging to help us better assess the patient’s situation and make changes, as there are changes in the patient's disease.
How has the use of active surveillance changed the landscape of prostate cancer?
There has been a large increase in the number of patients going onto an active surveillance program. We have seen an increase nationally, where it used to only be a small proportion of men. Now, we are seeing that up to 40% of men who are diagnosed with low-risk tumors are going onto an active surveillance program.
There has been a shift. People, I think, have a new appreciation for the fact that not all prostate cancers are the same. There are prostate cancers that are indolent and are unlikely to cause significant problems. Patients are becoming more aware of that, so they are seeking out other options and not just going with the original recommendation that may be for active treatment.
How do you have this particular conversation with patients—that they have cancer, but it’s not something that actually needs to be treated?
It’s a difficult conversation, especially because the system that we use to assess the tumors is a little bit confusing. Typically, the lowest grade you can have on a biopsy is a Gleason 6 tumor, but patients automatically assume that theirs is a middle-grade tumor because 1 through 5 happens before 6.