New imaging criteria declare immediate progression if a patient develops 6 or more new lesions. For 5 or fewer, the old rule requiring a confirmatory scan applies. This change prevents keeping patients on ineffective therapy just to meet trial criteria while preventing premature declarations for minimal changes.
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The emergence of positive data from trials like PATINA creates a dilemma for oncologists treating patients who are already stable on an older maintenance therapy. The consensus suggests not altering a successful regimen to avoid disrupting patient stability, revealing a cautious approach to integrating new evidence into established care.
A blinded central radiology review is not the absolute gold standard for assessing patient progression. Expert clinicians argue their holistic assessment, incorporating the patient's clinical status and other biomarkers alongside scans, provides critical context that a disconnected reviewer lacks.
The term "oligometastatic" is problematic because it's "imaging agnostic," failing to distinguish between lesions found on highly sensitive PSMA PET versus conventional scans, which carry different prognoses. The working group advocates for the more precise term "PSMA-positive BCR" to define this specific disease state.
With pirtobrutinib, time to next treatment often exceeds progression-free survival. This discrepancy exists because disease progression is frequently slow and asymptomatic, meaning clinicians do not need to switch therapies immediately upon seeing radiographic changes, allowing for longer treatment duration.
A study switching therapy based on ctDNA-detected ESR1 mutations revealed patients felt significantly better after the switch, even without visible tumor progression on scans. This counterintuitive finding suggests molecular progression has a subclinical impact on quality of life, supporting proactive, biomarker-driven treatment changes before patients clinically deteriorate.
Traditional endpoints like progression-free survival (PFS) incentivize continuous treatment. The NCI group proposes "treatment-free survival," a novel metric that quantifies time spent *off* therapy. This endpoint better captures the patient experience and rewards treatments that provide durable responses after a finite course.
The influential "2+2 rule" on bone scans, which accounts for treatment "flare," wasn't an arbitrary threshold. It was proposed as a working hypothesis to be tested and validated through numerous clinical trials. This exemplifies the data-driven, iterative process behind the PCWG criteria.
Data from the CAPItello trial showed a significant number of patients with PTEN deficiency experienced radiological progression without a corresponding PSA increase. This challenges the standard reliance on PSA for monitoring in high-risk prostate cancer and suggests a need for more frequent, personalized imaging protocols to detect progression earlier.
Experts believe molecular tests like Decipher and PTEN status are superior to simply counting bone lesions for guiding treatment. While not yet standard practice for all decisions, this represents a significant shift towards using underlying tumor biology to determine therapy, like adding docetaxel.
The introduction of highly sensitive PSMA PET scans means established endpoints like Metastasis-Free Survival (MFS) may no longer be valid. A metastasis detected by PET likely has a different, better prognosis than one found with older imaging, requiring new validation for this key endpoint.