Choosing Treatment Intensification in Metastatic Castration-Sensitive Prostate Cancer

Key Takeaways:

• Guidelines recommend adding an androgen receptor pathway inhibitor (ARPI), with or without docetaxel, to hormone therapy for most patients with metastatic castration-sensitive prostate cancer (mCSPC).
• In a US cohort with de novo metastatic disease, about one-third of patients diagnosed in 2023 did not receive treatment intensification.
• Disease volume, timing of metastases, fitness for chemotherapy, and BRCA2, PTEN, and PSMA status now shape which regimen fits.

Adding systemic therapy to androgen deprivation therapy (ADT) improves survival in metastatic castration-sensitive prostate cancer (mCSPC), but practice has trailed the evidence. In a US clinical database of 3,684 patients with de novo metastatic disease diagnosed from 2014 to 2023, 58.4 percent received treatment intensification. The rate rose from 32.5 percent in 2014 to 67.5 percent in 2023. Older patients, patients with poorer performance status, and Black patients were less likely to receive it.¹

The guideline baseline

The American Urological Association/Society of Urologic Oncology (AUA/SUO) guideline recommends offering an androgen receptor pathway inhibitor (ARPI) with ADT to most patients with mCSPC. Options include abiraterone plus prednisone, apalutamide, or enzalutamide. No comparative efficacy data exist among the intensification options.²

Doublet or triplet

For select patients, AUA/SUO recommends a triplet of ADT, docetaxel, and either abiraterone plus prednisone or darolutamide. The best candidates resemble the trial populations: de novo metastatic disease and no major comorbidities.² In PEACE-1, adding abiraterone to standard care improved radiographic progression-free survival (rPFS) and overall survival, with an increase in hypertension. The overall survival hazard ratio (HR) was 0.82 in the full trial population.² Among patients whose standard care included docetaxel, the overall survival HR was 0.75.³ In ARASENS, 1,306 patients received ADT and docetaxel with darolutamide or placebo. Darolutamide lowered the risk of death by 32.5 percent (HR 0.68; 95 percent confidence interval [CI], 0.57 to 0.80). Grade 3 or 4 adverse events occurred in 66.1 percent (darolutamide) versus 63.5 percent (placebo), and neutropenia was the most common in both groups.⁴

Neither trial compared the triplet with an ARPI doublet. European Association of Urology (EAU) guidelines state that ADT plus an ARPI remains the standard when no homologous recombination repair (HRR) or PTEN alteration is documented. For those patients, the choice is between the doublet and adding docetaxel.³ AUA/SUO advises weighing age and comorbidities, since chemotherapy toxicity may be harder on older patients.²

Volume and timing

High-volume disease is usually defined by CHAARTED criteria: visceral metastases, or 4 or more bone metastases with at least 1 outside the vertebral column or pelvis.³ Most triplet evidence comes from high-volume, de novo disease. In ARASENS, 77 percent of patients had high-volume disease, and the overall survival benefit in the small low-volume subgroup was less clear.³ For metastases that appear after curative-intent local therapy, the role of a triplet remains undefined.² Prostate-directed radiotherapy is a separate option for de novo disease with the prostate in place. AUA/SUO states that clinicians may offer radiotherapy to the prostate with ADT, with or without an ARPI, in select patients, and the supporting benefit was seen in low-volume disease.²

Biomarker-directed options

In December 2025, the US Food and Drug Administration (FDA) approved niraparib and abiraterone plus prednisone for BRCA2-mutated mCSPC. In an exploratory analysis of 323 patients with BRCA2 mutations in the AMPLITUDE trial, the rPFS HR was 0.46.⁵ The 2026 AUA/SUO amendment states that clinicians may offer ADT, abiraterone, and niraparib to patients with mCSPC and HRR gene alterations, particularly BRCA2 (expert opinion).² In June 2026, the FDA approved capivasertib, an AKT inhibitor, with abiraterone and prednisone for PTEN-deficient metastatic disease that is androgen pathway modulation-naive or -sensitive, a newer FDA label term that broadly corresponds to mCSPC. Median rPFS was 33.2 (capivasertib plus abiraterone) versus 25.7 months (placebo plus abiraterone) in the CAPItello-281 trial.⁶ Overall survival data were immature for both combinations, and treatment requires upfront molecular or immunohistochemistry testing.³

The 177Lu-PSMA-617 label now includes use with an ARPI for prostate-specific membrane antigen (PSMA)-positive metastatic disease in the same androgen pathway modulation-naive or -sensitive setting. In the PSMAddition trial, adding radioligand therapy to an ARPI improved rPFS (HR 0.72; 95 percent CI, 0.58 to 0.90). Overall survival data were immature. Eligible patients had at least 1 metastatic lesion on conventional imaging and PSMA uptake greater than in normal liver on positron emission tomography (PET).⁷

Guideline positions differ. The National Comprehensive Cancer Network (NCCN) lists radioligand therapy plus an ARPI as useful in certain circumstances for PSMA-positive mCSPC. It notes that some panel members advocate waiting for more mature follow-up, given the lack of an overall survival benefit, moderate acute toxicity, and uncertain late toxicity.⁸ The 2026 AUA/SUO amendment describes earlier use in castration-sensitive disease as an area of ongoing research, and the March 2026 EAU update addresses radioligand therapy only in castration-resistant disease.^2,3

Monitoring by regimen

Abiraterone requires checks for mineralocorticoid excess, with blood pressure, potassium, and fluid retention symptoms monitored at least monthly, plus monitoring for adrenocortical insufficiency and hepatotoxicity.⁹ Labels for apalutamide, darolutamide, and enzalutamide include warnings for ischemic heart disease or cardiovascular events and seizure.^10-12 AUA/SUO suggests abiraterone plus prednisone as an option for patients with a seizure disorder.² Docetaxel carries a boxed warning for treatment-related mortality, hepatotoxicity, neutropenia, hypersensitivity, and fluid retention.¹³ In AMPLITUDE, grade 3 or 4 adverse events were more frequent with niraparib compared to placebo (75 percent versus 59 percent), led by anemia.³ Radioligand therapy can cause myelosuppression and renal toxicity and requires radiation safety precautions.⁷

Decisions at diagnosis

Establish the extent of disease and whether it is de novo or following local therapy. Assess fitness for docetaxel, cardiovascular risk, and seizure history. AUA/SUO recommends offering germline testing to all patients with advanced prostate cancer, plus somatic tumor testing when disease is metastatic.² Order these tests in time to inform the first regimen, since HRR- and PTEN-directed options require results before treatment starts.³ Then obtain PSA every 3 to 6 months after starting ADT.²