Benjamin Chung

M.D, M.S.

Stanford University

Associate Professor

PLCO (Learn more about this study)

PLCO-1321

Sep 7, 2023

The primary treatment in localized prostate cancer and outcomes in PLCO: a target trial emulation study

Prostate cancer is the second leading cancer and the third leading cause of cancer-related death among men in the United States. In 2020, approximately 192,000 men received a diagnosis of prostate cancer and 33,000 died of the cancer. For localized prostate cancer, the primary treatment options include watchful waiting, active surveillance, radiotherapy, or surgery. The treatment options are chosen according to several factors, including tumor stage, patient’s preference, age, or health conditions. However, the relative effectiveness of the treatment options for localized prostate cancer remains unclear. A recent randomized controlled trial (The ProtecT Trial - Evaluating the Effectiveness of Treatments for Clinically Localized Prostate Cancer) conducted in United Kingdom has found that a risk of prostate cancer–specific mortality was similar when comparing definitive treatment options such as radiotherapy or surgery to active surveillance after 15 years of median follow-up [1]. As such, more evidence on identifying the best treatment for patients who have localized prostate cancer is necessary.

We plan to emulate the target trial of the primary treatment options for prostate-specific antigen (PSA)-detected localized prostate cancer and prostate cancer–specific and all-cause mortality using the PLCO dataset in an intent-to-treat analysis. We specify the protocol of the target trial to answer the causal question of interest and plan to conduct subgroup analyses to assess differential effects on the mortality according to the prespecified subgroups in the target trial such as age, localized prostate cancer stage or grade, and baseline PSA levels. We plan to perform additional subgroup analyses according to other potential confounders such as smoking, body mass index, diet, other clinical comorbidities, and medication use, which are available in the PLCO dataset, related to the risk of mortality. Given the availability of the primary treatments and potential confounder data in the PSA-detected population, the prostate cancer PLCO dataset appears to be the dataset most relevant to this research project.

1. Investigate the 15-year risk of prostate cancer-specific and all-cause mortality after initiation of treatment for localized prostate cancer (i.e., active monitoring, surgery, or radiotherapy).

2. Assess the differential effects on outcomes of localized prostate cancer between the treatment options according to cancer stage or grade, baseline PSA levels, lifestyle factors, comorbidities, or other medication use in subgroup analyses.