Frailty, initial attrition and the potential use of novel platinum-free options for non-small-cell lung cancer in the real-world setting

Problem Statement
Non-small-cell lung cancer (NSCLC) remains a leading cause of cancer mortality, with prognosis often complicated by advanced age and poor clinical condition at diagnosis. These factors frequently limit therapeutic options, particularly the applicability of platinum-based chemotherapy, which remains a cornerstone of first-line treatment. While single-agent chemotherapy or vinorelbine monotherapy offers limited survival benefits for frail patients, they are often accompanied by toxicity. Conversely, while immune-checkpoint inhibitors (ICIs) like atezolizumab have emerged as alternatives for platinum-ineligible patients, the real-world prevalence of eligibility criteria and the reliability of these criteria in guiding therapeutic decisions remain unclear. Furthermore, a significant "initial attrition" rate exists where patients diagnosed with metastatic NSCLC die or deteriorate before receiving any systemic therapy, a phenomenon not yet fully characterized in the context of modern therapeutic landscapes.

Methodology
This study is a single-center, retrospective chart review conducted at the Thoraxklinik Heidelberg, Germany, covering the period from January 2018 to December 2023. The study population consisted of 2,592 consecutive patients admitted with newly diagnosed stage IV lung cancer, of which 2,031 had histologically confirmed NSCLC. The analysis focused on two primary cohorts: a "main study population" of 1,306 patients with PD-L1 Tumor Proportion Score (TPS) 0-49%, and a subset of 507 patients with PD-L1 TPS ≥50%.

The study evaluated:

1. Actual therapeutic allocation and outcomes, with a specific emphasis on patients not receiving platinum.
2. The prevalence and characteristics of patients meeting the Summary of Product Characteristics (SmPC) criteria for atezolizumab (approved by the EMA for platinum-ineligible patients). These criteria include: age >80 years; ECOG Performance Status (PS) ≥3; or ECOG PS 2/age ≥70 combined with specific comorbidities (cardiac, vascular, nervous, psychiatric, renal, metabolic, or respiratory).
3. The predictive value of clinical parameters (age, ECOG PS, comorbidity scores like CCI, ACCI, and SCS) and SmPC criteria in determining platinum eligibility and the potential for monoimmunotherapy.

Statistical analyses included comparisons of treatment rates, survival outcomes (Overall Survival - OS), toxicity profiles, and the calculation of Area Under the Curve (AUC) values to assess the predictability of clinical scores.

Key Contributions and Results

• High Initial Attrition: Approximately 26% of patients with histologically confirmed NSCLC did not receive systemic anticancer treatment. Of these, 20% received Best Supportive Care (BSC) for medical reasons (mBSC), 4.2% chose BSC, and 6% died before treatment initiation. Attrition was significantly higher (79%) in patients who did not undergo PD-L1 testing.
• Impact of Monoimmunotherapy: The availability of monoimmunotherapy (e.g., pembrolizumab for PD-L1 ≥50%) modestly increased the overall treatment rate for PD-L1 ≥50% patients (79.1% vs. 73.6% for PD-L1 0-49%). This increase was primarily driven by a reduction in BSC by patient choice (1.8% vs. 4.5%) rather than a reduction in mBSC or early death, which remained largely unchanged.
• SmPC Criteria in Real-World Practice:
  • 38% (501/1306) of the main study population met the atezolizumab SmPC criteria.
  • SmPC patients faced a significantly higher risk of attrition: a 4.0-fold higher risk of mBSC, a 2.3-fold higher risk of early death, and a 2.8-fold higher risk of BSC by choice compared to non-SmPC patients. Only 53.5% of SmPC patients received systemic therapy.
  • Among SmPC patients who did receive platinum, outcomes were inferior to non-SmPC patients: shorter median OS (9.6 vs. 11.3 months), higher toxicity, and more frequent dose reductions and discontinuations.
  • A critical finding was that SmPC patients receiving a low platinum dose ratio (≤60% of the full dose across 4 cycles, corresponding to carboplatin AUC ≤3) had a median OS of 5.1 months. This survival rate was statistically indistinguishable from patients receiving single-agent chemotherapy (5.1 months) and significantly worse than those receiving full-dose platinum (15.5 months).
• Predictive Performance: While SmPC criteria correlated better with platinum use than individual comorbidity scores, their ability to predict individual patient outcomes (such as platinum discontinuation or low-dose requirement) remained modest (AUC ~0.71 for treatment allocation, ~0.61 for discontinuation).
• Barriers to Treatment: Patients who eventually received mBSC or died early often experienced clinical deterioration during the workup period. Factors associated with this attrition included older age, worse ECOG PS, higher comorbidity scores, and longer time intervals from initial contact to biopsy or treatment initiation.

Significance and Claims
The paper concludes that the high initial attrition rate of ~25% in NSCLC is primarily driven by rapid clinical deterioration during the diagnostic workup, a phenomenon that occurs despite the generally slower growth of NSCLC compared to other malignancies. The mere availability of monoimmunotherapy is expected to reduce this attrition only modestly (by approximately 5%) for patients with PD-L1 0-49%, as it does not fully address the medical reasons for ineligibility or the speed of deterioration.

The authors propose that the integration of SmPC criteria into daily clinical algorithms could serve as a practical "red flag" to identify patients at high risk for:

1. Death without systemic therapy: Approximately 20% of patients (46.5% of SmPC patients) currently die without treatment, despite initial intent to treat.
2. Platinum overtreatment: Approximately 10% of patients (those with low platinum dose ratios) receive platinum with outcomes similar to single-agent chemotherapy but with higher toxicity.

The study suggests that optimizing patient workflows (e.g., faster diagnostics, wider adoption of liquid biopsies) is essential to mitigate attrition. Furthermore, it highlights the need for better stratification tools, such as Comprehensive Geriatric Assessment (CGA) or predictive biomarkers, to distinguish between SmPC patients who might safely tolerate platinum and those who would benefit more from novel platinum-free options like monoimmunotherapy. The authors emphasize that as new platinum-free therapies (e.g., bispecific antibodies, antibody-drug conjugates) emerge, addressing the problem of initial therapeutic allocation and attrition will become increasingly critical.