New research reveals that a notable portion of men diagnosed with grade group 1 (GG1) prostate cancer may face higher-risk disease, challenging the long-held perception that GG1 cancers are uniformly slow-growing.
A study published in JAMA Oncology found that roughly one in six men with GG1 prostate cancer actually have intermediate- or high-risk disease. The findings suggest that relying solely on biopsy grade may underestimate disease severity and highlight the heterogeneous nature of GG1 outcomes.
“There’s good rationale to remove the cancer label for GG1 patients: the majority are low risk at diagnosis, and active surveillance is the preferred approach,” said Dr. Neal Patel, lead author and urologic oncologist at Weill Cornell Medicine.
“However, our data show that some men with GG1 disease have adverse clinical features that may increase their risk of metastasis, and this group needs further study before any changes to labeling are considered.”
The study analyzed outcomes in 117,162 men diagnosed with localized GG1 prostate cancer between 2010 and 2020 using U.S. cancer registry data. Among them, 10,440 had favorable intermediate-risk disease, 3,145 had unfavorable intermediate-risk disease, and 4,539 had high-risk disease.
Adverse pathology at prostatectomy was identified in 867 men with high-risk GG1 disease. Prostate cancer–specific mortality ranged from 2.4% in unfavorable intermediate-risk GG1 cases to 4.7% in high-risk GG1, rates comparable to higher-grade GG2 cases.
Dr. Patel emphasized that while the majority of GG1 patients remain low-risk, “there is a subset of patients who are not low risk and have not been well represented in active surveillance studies. Before removing the cancer label, we must better understand this population.”
Grade groups are determined by how abnormal cancer cells appear under a microscope and how likely they are to grow and spread. GG1 indicates cells that closely resemble normal tissue and are generally slower growing, guiding treatment decisions and prognosis.
Researchers noted limitations, including the inability to account for the use of prostate MRI. While MRI can help identify higher-grade cancers, it is not foolproof. “Ensuring patients receive state-of-the-art imaging and care from multidisciplinary teams specializing in prostate cancer is critical,” Patel said.
The study underscores the need for careful risk assessment before changing how GG1 prostate cancer is classified and supports continued use of individualized treatment planning, particularly for men considering active surveillance.
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