One-fifth of men with high-risk localized prostate cancer (PCa) receive treatment that is not standard of care, according to a new study presented at the American Urological Association’s 2019 annual meeting in Chicago.

These non-standard treatments—androgen deprivation therapy (ADT) alone or external beam radiation therapy (EBRT) without ADT—are more likely to be used in black patients and those with low income or who are uninsured, according to investigators.

“Both of these treatments on their own have not been shown to improve survival, and thus are not standard of care,” investigator Allison May, MD, a urology resident at St. Louis University School of Medicine in Missouri, told Renal & Urology News. “Our analysis also demonstrated that patients being treated with ADT alone had the lowest survival, even lower than patient who chose not to undergo any treatment.”

In a retrospective study using the National Cancer Database (NCDB), Dr May and her colleagues identified 149,343 patients with high-risk localized PCa. Of these, 30,686 (20%) received non-standard of care treatment with EBRT alone or ADT alone. The proportion of men who received these treatments decreased from 22.9% in 2005 to 18.7% in 2015.

On multivariable analysis, each 1-year increase in age was associated with a 6% increased risk of receiving EBRT or ADT alone. Black race, uninsured status, and low income were associated with 41%, 53%, and 13% increased risk, respectively, the investigators reported. Other risk factors included treatment at low-volume centers and a Charlson Comorbidity Index of 2 or higher.

The mean 5-year overall survival rate was 55.6% for men receiving ADT alone compared with 92.7% for men receiving definitive treatment with radical prostatectomy and 80.7% for those received EBRT plus ADT.

The investigators considered patients to have high-risk PCa if they had cT3 tumors, a PSA greater than 20 ng/mL, or Gleason score 8-10 cancer.

Dr May said it is possible that many patients treated with non-standard treatment had other reasons to be treated with these approaches, such as other co-morbid conditions that would make standard treatment difficult to tolerate. “However, we did find that African-American patients and those with low income, uninsured, or treated at low-volume facilities were all more likely to undergo non-standard of care therapy. We believe this represents a significant disparity and warrants further investigation,” Dr May said.

Marc C. Smaldone, MD, Associate Professor of Urologic Oncology at Fox Chase Cancer Center in Philadelphia, said there are no hard and fast best practice standards for managing high-risk localized PCa. RP plus adjuvant/salvage radiotherapy or primary radiotherapy plus 1 to 3 years of ADT are both acceptable options. “However, primary radiotherapy without hormones or ADT alone are not acceptable using contemporary best practice guidelines and represent substandard care,” Dr Smaldone said.

Medical oncologist Biren Saraiya, MD, who is with the Prostate Cancer Program at Rutgers Cancer Institute of New Jersey in New Brunswick, said high-risk localized PCa accounts for 15% of all new PCa cases treated with an intent to cure. Two recent retrospective studies as well as some prospective studies have shown the benefit of multimodality therapies.2,3 “This current abstract reports disappointingly high rates of single modality therapy,” Dr. Saraiya said. “The authors report about 18%-22% of patients receiving only 1 modality of therapy, EBRT or ADT. Given this is a dataset from NCDB, there are limitations, including not knowing what the goals of care were—whether the intent of treatment was cure or palliation.”

Urologic oncologist Jeffrey W. Nix, MD, Assistant Professor of Surgery and Director of Robotic Surgery at the University of Alabama at Birmingham, said it is important to look carefully at the characteristics of groups of patients who are not getting that same treatment. It is clinicians’ responsibility to provide high-level care for all patients. “However, we must proceed with caution in our interpretation of this complex population level data,” Dr Nix said. “Of course, there are confounders to this data, and any dataset for that matter, that we must be careful about studying and understanding before we make assumptions about the reasons for the associations that are present,” he said.

For example, he pointed out that the NCDB calculates patient income level based on median household income for patients’ zip codes at the time of diagnosis. Therefore this variable may reflect income as an isolated variable, but it also may reference access to care as a factor of distance from the nearest care facility, presence of good primary care, whether or not the patient lives in a Medicaid non-expansion state, and so on.

Medical oncologist Otis W. Brawley, MD, Professor of Oncology and Epidemiology at Johns Hopkins University in Baltimore, said these new findings are very much on target and consistent with a number of studies over the years. “This is the appropriate way to do such a study. Indeed, the only way one can study practice patterns is retrospectively; a prospective study is not possible.” Dr Brawley said.

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References

  1. May A, Trierweiler J, Guduru A, et al. National trends in management of localized high risk prostate cancer. Presented at the American Urological Association’s 2019 annual meeting in held May 3-6 in Chicago. MP72-08 https://doi.org/10.1097/01.JU.0000557140.81154.3a
  2. Jang TL, Patel N, Faiena I, et al. Comparative effectiveness of radical prostatectomy with adjuvant radiotherapy versus radiotherapy plus androgen deprivation therapy for men with advanced prostate cancer. Cancer 2018;124:4010-4022.  https://www.ncbi.nlm.nih.gov/pubmed/30252932
  3. Rosenthal SA, Hu C, Sartor O, et al. Effect of chemotherapy with docetaxel with androgen suppression and radiotherapy for localized high-risk prostate cancer: The randomized phase III NRG Oncology RTOG 0521 Trial. J Clin Oncol. 2019;37:1159-1168. https://www.ncbi.nlm.nih.gov/pubmed/30860948