Prostate Cancer Working Group offers New Recommendations

by Kiernan Mehan | Oct 20, 2026 | Prostate Cancer

PCWG is the Prostate Cancer Working Group, an association of experts who meet to discuss and advise on Prostate Cancer research. 

PCGW4, their recommendations for 2026, are not merely new terms for old concepts.  There are fundamental changes in how to describe prostate cancer. These are meant mostly for research communication – at least until they percolate into the clinical world, which has started to happen.

PCGW4 emphasizes describing prostate cancer according to its measurable characteristics rather than relying only on broad disease labels, by calling for reports to clarify metastatic status, specify imaging methods used, provide the testosterone levels, describe symptoms and prior treatments, provide genetic features when relevant, and be very specific when describing the manifestation of progression.

Here are some of the PCGW4 recommendations:

• Nonmetastatic cancer should be qualified according to the imaging used to establish the absence of metastases. A patient may have no metastases on conventional CT and bone scanning but have lesions detected by PSMA PET. Reports should therefore identify the imaging modality and, for PET, the tracer used. (Ed: addressing an old gripe heard often at AnCan).
•  Bone scan progression should use prostate cancer-specific confirmatory criteria designed to account for flare
• PSMA PET findings and other next-generation imaging should identify the modality, tracer, and interpretation criteria and should not automatically be combined with conventional imaging endpoints.
• PSA decline on treatment response of at least 50 percent (PSA50) is a commonly reported outcome and ordinarily requires confirmation, but it should not be equated with objective radiographic response or assumed to be a surrogate for survival
• Treatment history should be clear and complete: identify the drugs received, disease setting, duration, response, and reason for discontinuation. Simple therapy labels may be inadequate when patients receive combinations or continue one component while changing another.

Let’s touch on some other PCGW4 recommendations and clarifications before getting to terminology below:

• Patient-reported outcomes, such as symptoms, pain, physical functioning, quality of life, treatment burden, and toxicity, should be incorporated alongside survival and imaging outcomes. That’s our voices they are talking about.
• Oligometastatic and oligoprogressive disease should be similarly pre-defined. PCWG4 recognizes this state, but stresses the need for standard definitions (e.g., number and location of metastases, imaging modality), the number and location of lesions, timing of disease, and imaging modality.
• Composite endpoints, which we often see in research, should be prespecified, clinically justified, and reported together with their individual components. It encourages combining PSA,  radiographic, and symptomatic progression.
• Polyprogression: Term introduced for situations where progression occurs in multiple metastatic sites simultaneously.

Now let’s address the terminology….

PCWG4 uses “APM” to mean androgen pathway modulator, an umbrella term for treatments that inhibit androgen production or androgen receptor signaling.  This means the “ides” and abiraterone, which we might have called ARPI or ARSI.

• APM naïve (APMn) means the patient has never received an APM.
• APM exposed means the patient previously received an APM. This term does not by itself indicate whether the cancer responded or progressed.
• APM sensitive (APMs) means the cancer demonstrates clinical benefit or disease control during APM treatment. The specific response criteria and treatment setting should be stated.
• APM resistant (APMr) means the cancer progresses during APM treatment despite continued castrate testosterone levels. Resistance should be linked to the particular drug and disease setting rather than assumed to apply equally to every APM.

Here are some closely related terms you’ll see

• Primary APM resistance means progression from the beginning of APM treatment.
• Acquired APM resistance means the cancer initially benefits from an APM but later progresses.
• APM rechallenge means using an APM again after previously discontinued, ordinarily after intervening treatment or a meaningful treatment free interval.

The APM category generally does not refer to the foundational medical Androgen Deprivation Therapy including Estradiol/E2 (ADT), nor surgical castration used to maintain low testosterone.
Because PCWG terminology is intended for precise research reporting, authors should name the individual drug, disease state, prior exposure, response, and reason for discontinuation rather than relying on an APM label alone. Terms such as APM resistant should not be interpreted as proving resistance to every drug in the class.

Old vs New

• mHSPC is now mAPMs or mAPMn.
• nmHSPC is now nmAPMs or nmAPMn – per stated imaging technique
• mCRPC is now mAPMr
• nmCRPC is nmAPMr. –  per stated imaging technique

‘n’ or ‘nm’ should be clarified by which imaging made the call, so while AnCan doesn’t much care for ‘nm’ we now know what produced that designation.

APMr should explain the testosterone level.

Progression explains the criteria used:

• Clinical Progression: Now separated from biochemical (PSA) and radiographic progression. Clinical progression emphasizes symptom development or worsening.
• PSA Progression: Now standardized for use with next-generation imaging and early relapse scenarios.
• Radiographic Progression: Criteria refined for both bone and soft tissue lesions, especially with the adoption of next-generation imaging (NGI).

PSA, radiographic, symptomatic, and other forms of progression should be documented specifically. PSA progression should follow prespecified criteria and does not by itself necessarily require discontinuation of an otherwise beneficial treatment.

Remember, this is all designed to standardize language used ONLY to describe prostate cancer clinical trials. So what does that have to do with the patient, and why should our Gents be concerned about wrapping your head around these terms? Rick tells us why…