Prostate Cancer Cases Are Growing More Serious

The study covered in this summary was published on ResearchSquare.com as a preprint and has not yet been peer reviewed.

Key Takeaways

• In the past decade, the incidence of T1a/b prostate cancer has remained stable, but clinically significant T1a/b disease has increased over time. 

• Across all risk groups and accounting for age and comorbidity status, patients diagnosed with T1a/b prostate cancer are more likely to enter active surveillance/watchful waiting and are less likely to be treated definitively with surgery or radiation.

Why This Matters

• The changing recommendations regarding prostate cancer screening in the U.S. during the last decade have led to changes in incidence patterns of prostate cancer, and the appropriate management of T1a/b prostate cancer is not well defined. 

• Only a few studies have previously addressed the incidence of T1a/b prostate cancer. It has remained unclear which patients with T1a/b disease benefit from definitive treatment or expectant management.

• This is the largest study examining trends in incidence, clinical significance, and treatment patterns for T1a/b prostate cancer regardless of risk group, age, and comorbidity status.

Study Design

• Using the National Cancer Database, the study looked at a dataset of 24,679 patients diagnosed with T1a/b prostate cancer between 2010 and 2017. 

• Patients with missing data for pathological T stage, prostate specific antigen (PSA), or Gleason score were removed from analysis.

• Clinically significant disease was defined as Gleason grade group ≥ 2.

• Treatment modalities were assessed for primary treatment after diagnosis only.  To reduce treatment bias, a second analysis of treatment modality proportions for patients between 62 and 68 years of age was completed. Patients in this age group were eligible for all treatment modalities. 

Key Results

• Of the 24,679 patients identified, 15,186 had T1a disease and 9493 had T1b disease.

• T1a/b prostate cancer represented 3.5% of all prostate cancer without a change in incidence over time.

• The likelihood of T1a/b prostate cancer being clinically significant increased over time, from 38.8% in 2010 to 44.1% in 2017 (P < .001). Similarly, the chance of being diagnosed with T1a/b non-clinically significant disease decreased from 61.3% in 2010 to 55.9% in 2017.

• Patients diagnosed with T1a/b disease were significantly older (mean age 72.2 ± 9.6 vs 64.2 ± 8.1; P < .001) than patients diagnosed with T1c disease.

• Accounting for age and risk, patients with diagnosed T1a/b disease were less likely to be treated definitively with surgery or radiation compared with patients with T1c disease (low risk — 6.9% [T1a] vs 17.6% [T1b] vs 67.5% [T1c]; P < .001); (intermediate risk — 21.6% [T1a] vs 30.4% [T1b] vs 86.2% [T1c]; P < .001); (high risk — 28.4% [T1a] vs 26.3% [T1b] vs 78.2% [T1c]; P < .001).

• Across all risk groups, patients with T1a/b disease were more likely to enter active surveillance/watchful waiting compared with T1c patients. In comparison to T1b, patients with T1a disease across all risk groups were more likely to enter active surveillance/watchful waiting.

Limitations

• Variations between institutions for the National Cancer Database reporting and coding may have affected the analyzed dataset.

• Long-term oncological outcomes and functional outcomes were not obtained because the data was not coded in the National Cancer Database.

• The National Cancer Database only included data for Commission on Cancer-accredited facilities and may not have been generalizable to other countries.

Disclosures

• The study received no commercial funding.

• The authors disclosed no relevant financial relationships.

This is a summary of a preprint research study, “Trends in Diagnosis and Treatment of T1a, T1b Prostate Cancer in the United States, 2010-2017,” led by Eyal Kord, MD, MPH,  Virginia Mason Medical Center, Seattle, Washington, and published on ResearchSquare.com. This study has not yet been peer reviewed. The full text can be found on ResearchSquare.com.

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