Localized Therapy Improves Prognosis in Some Men With Metastatic Prostate Cancer

Localized treatment focusing on the primary tumor in men with metastatic prostate cancer has the potential to meaningfully impact the prognosis and survival of patients, according to a study published in Clinical Genitourinary Cancer.

Prostate cancer is the second-most diagnosed form of cancer among men globally. For patients with metastatic prostate cancer (mPCa), the first treatment is typically androgen deprivation therapy (ADT) to stunt prostate cancer growth; however, ADT tends to be less effect because prostate cancers become less sensitive to it over time. It is theorized that forms of localized treatment on the primary tumor may more effectively slow down the production, spread, and growth of cancerous cells and distant metastases.

Jiatong Zhou et al. sought to better understand the effect of localized treatment on patients with mPCa and analyze its impact on patients with differing levels of prostate-specific antigens (PSA)—which they believe to be an important indicator for assessing tumor burden.

The researchers gathered information from the 2010-2015 Surveillance Epidemiology and End Results (SEER) database. They only included patients in this study with a diagnosis of mPCa that metastasized to distant lymph nodes (M1a), bones (M1b), and other organs such as the brain, liver and lungs (M1c).

A total of 3500 patients with mPCa were included, of which 25.8% (902) received local treatment and 74.2% (2598) did not for various reasons. Local treatment consisted of either radical prostatectomy (RP), radiotherapy (RT), or a combination of the 2 (RP + RT). Among these patients, 79.9% (2798) were diagnosed with bone metastases while 13.5% (472) experienced metastases in other organs.

Results found that patients with mPCa who underwent local treatment had the potential for better overall survival (OS; P = .013) but this treatment did not hav a positive effect on prolonging cancer-specific survival (CSS; P = .068). After 10 years of follow-ups, there was no evidence for significant impact of better CSS in patients with mPCa.

Within the first 2 years of local treatment, patients had higher rates of cancer-specific death (P = .008), whereas those without local treatment experienced higher rates of cancer-specific death beyond the 2 years (P < .001).

There was no evidence to indicate a significant difference in OS between patients who had or did not have local treatment in the first 2 years; however, beyond this point patients who underwent local treatment did have better OS rates than those who did not (P < .001). The authors noted that patients over the age of 60 years generally had worse prognoses compared with younger patients, as did Black patients, and patients of other races compared with White patients.

Since previous results did not indicate that local treatment prolonged the survival of patients, researchers conducted further analysis to take differing PSA levels into account. In their search, only patients with PSA levels less than 10 ng/ml experienced prolonged OS and CSS (all P < 0.05).

Of the patients with PSA levels lower than 10 ng/ml, researchers found that local treatment only benefited the OS and CSS of patients with M1b diagnoses (all P < 0.05).

Within the three local treatment groups—RP, RT, and RP + RT—most patients received RT alone. This group experienced the worst prognosis related to OS and CSS (all P < 0.05). Patients who underwent RP experienced better OS and CSS than the other groups (all P < .05).

Researchers noted multiple limitations to their study including its retrospective nature, which could have resulted in some of information being missing or biased. They also noted that chemotherapy data was not considered in their data collection, they did not distinguish between different types of RT, and they could not obtain the endocrine treatment records for all patients included.

“Although local treatment could not bring good benefits to the prognosis of patients as an independent prognostic factor,” the authors reiterated the importance of considering this treatment in certain instances as they “believed that RP had an significantly positive impact on the prognosis of mPCa with low level PSA, especially in patients with M1b.”

Reference

Zhou J, Cao Y, Chen H, Wu Y, Ding J, Qi J. Local treatment associated with prognosis among men with metastatic prostate cancer: a SEER-based study. Clinical Gen Ca. 2023;21(3):e204-e215. doi:10.1016/j.clgc.2023.01.006