Introduction

• Myelosuppressive hematological adverse events (HAEs; anemia, neutropenia, and/or thrombocytopenia) are common complications of chemotherapy among patients with cancer¹
• Cytotoxic chemotherapy remains the cornerstone of treatment for extensive-stage small cell lung cancer (ES-SCLC)^2–4

Objective

• To assess health care resource utilization (HCRU), costs, and treatment patterns associated with myelosuppressive HAEs among patients with ES-SCLC treated with chemotherapy in the community oncology setting

Methods

DATA SOURCE

• This retrospective observational study was conducted using structured data from The US Oncology Network's iKnowMed electronic health record system
• Data on vital status from the Social Security Administration's Limited Access Death Master File and HCRU data from the Financial Data Warehouse were included

STUDY POPULATION

• Adult patients with ES-SCLC who initiated chemotherapy between January 1, 2015, and December 31, 2019, were stratified into 2 study cohorts on the basis of the presence of grade ≥ 3 HAEs after chemotherapy initiation (index date; Figure 1)
  • The cohort with grade ≥ 3 HAEs comprised patients who had ≥ 1 of the following events after index: grade ≥ 3 anemia (hemoglobin <8.0 g/dL), grade ≥ 3 neutropenia (absolute neutrophil count <1000/μL), or grade ≥ 3 thrombocytopenia (platelets <50,000/μL)⁵
  • The cohort without grade ≥ 3 HAEs comprised patients who had no grade ≥ 3 anemia, grade ≥ 3 neutropenia, or grade ≥ 3 thrombocytopenia events after index
  • The first course of chemotherapy initiated after diagnosis of ES-SCLC was defined as chemotherapy initiation; patients must have had no evidence of receiving any chemotherapy within the 12 months prior to diagnosis
• Patients were followed longitudinally from the index date until December 31, 2020, death, or the last patient record, whichever occurred first
• Patients diagnosed with other primary tumors or enrolled in clinical trials during the study period were excluded

OUTCOME AND ANALYSIS

• HAEs were identified using laboratory values from iKnowMed on the basis of Common Terminology Criteria for Adverse Events version 5.0 definitions⁵
• The prevalence and frequency of HAEs (by type and grade), treatment patterns, HCRU (including supportive care utilization [granulocyte colony-stimulating factor {G-CSF}, erythropoiesis-stimulating agents {ESAs}, intravenous {IV} hydration]), and health care costs during the follow-up period were evaluated for both cohorts. Costs were adjusted to the year 2021⁶

FIGURE 1. STUDY DESIGN OVERVIEW

Results

DEMOGRAPHIC AND CLINICAL CHARACTERISTICS

• The study population included 778 patients who had ≥ 1 grade ≥ 3 HAE and 596 patients who did not have a grade ≥ 3 HAE after chemotherapy initiation. Demographic and clinical characteristics at baseline are shown in Table 1

TABLE 1. DEMOGRAPHIC AND CLINICAL CHARACTERISTICS AT BASELINE

MYELOSUPPRESSIVE EVENTS

• Among 778 patients in the grade ≥ 3 HAE cohort, 47.3% of patients had grade ≥ 3 anemia, 58.9% had grade ≥ 3 neutropenia, and 37.3% had grade ≥ 3 thrombocytopenia within 12 months post index
  • Mean numbers of events within 12 months post index were 2.0, 1.8, and 2.4 for patients who experienced grade ≥ 3 anemia, grade ≥ 3 neutropenia, and grade ≥ 3 thrombocytopenia, respectively
• 12.2% of patients with grade ≥ 3 HAEs had evidence of major bleeding events (platelets < 20,000/μL)
• Grade ≥ 3 leukopenia and lymphopenia events also occurred in a notable number of patients (Table 2)

TREATMENT PATTERNS

• Almost all patients (> 99%) received first-line chemotherapy at index (approximately 80% received a platinum-/etoposide-containing regimen and 15% received platinum/etoposide in combination with immunotherapy) in both cohorts
• Patients with grade ≥ 3 HAEs had a higher proportion of dose reductions (46.7% vs 32.2%), treatment holds (12.7% vs 5.9%), and treatment delays between 14–60 days (92.3% vs 84.3%) after chemotherapy initiation (all P < 0.001) compared with patients without grade ≥ 3 HAEs (Table 2)

TABLE 2. TREATMENT OUTCOMES DURING FOLLOW-UP

HCRU FOR HAE MANAGEMENT

• 43.1% of patients with grade ≥ 3 HAEs were eligible for RBC transfusions and 3.9% were eligible for platelet transfusions as indicated by laboratory values (Table 2)
• Patients with grade ≥ 3 HAEs were more likely to receive therapeutic G-CSF than patients without grade ≥ 3 HAEs (37.8% vs 18.1%; P <0.01), and prophylactic G-CSF use was similar among both cohorts (38.7% vs 49.8%; P = 0.40; Table 2, Figure 2)
  • Receiving G-CSF within 1–3 days after chemotherapy initiation was considered prophylactic use
  • Receiving G-CSF ≥ 4 days after chemotherapy initiation was considered therapeutic use
• The total costs within 12 months post index were higher for patients with grade ≥ 3 HAEs than for those without ($40,896 vs $33,631; P < 0.01; Figure 3)
• Patients with grade ≥ 3 HAEs had a mean of 10.7 outpatient visits within 12 months post index, versus 7.7 outpatient visits for those without grade ≥ 3 HAEs (P < 0.01; Table 3)
• Compared with patients without grade ≥ 3 HAEs, patients with grade ≥ 3 HAEs also had greater:
  • G-CSF use (64.1% vs 57.2%; mean number of administrations 3.5 vs 2.4; mean cost per patient $10,943 vs $8821; all P < 0.01; Table 3, Figure 3) within 12 months after the index date
  • ESA use (18.6% vs 4.9%; mean number of administrations 0.7 vs 0.1; mean cost per patient $787 vs $152; all P < 0.01; Table 3, Figure 3) within 12 months after the index date
  • IV hydration use (46.0% vs 30.4%; mean number of administrations 2.3 vs 1.2; mean cost per patient $159 vs $36; all P < 0.01; Table 3, Figure 3) within 12 months after the index date

FIGURE 2. G-CSF USE IN PATIENTS WITH AND WITHOUT GRADE ≥ 3 HAEs

TABLE 3. HCRU WITHIN 12 MONTHS AFTER THE INDEX DATE – PER PATIENT

FIGURE 3. HEALTH CARE COSTS WITHIN 12 MONTHS AFTER THE INDEX DATE – PER PATIENT

Limitations

• Results were based on data from community oncology settings and may not be generalizable beyond this setting
• Data in the inpatient settings were not captured; inpatient costs or costs for transfusions were not included