Impact of HA-PCI on self-reported cognitive functioning and brain metastases in small-cell lung cancer: Pooled findings of NCT01780675 and PREMER trials.

BACKGROUND

Cognitive decline is an arising concern in patients who need cranial irradiation. We used the pooled longitudinal individual patient data of two phase III trials: NCT01780675 and PREMER to investigate whether hippocampal avoidance (HA)-PCI is associated with improved self-reported cognitive functioning (SRCF) compared with PCI without increasing brain metastases (BM) development within the HA area.

METHODS

Patients with stage I-IV small cell lung cancer (SCLC) were randomized to PCI or HA-PCI. SRCF was assessed and contrast enhanced brain magnetic resonance imaging (MRI) was performed at baseline and up to 24 months follow-up. SRCF and BM incidence after (HA)-PCI were compared between arms. Self reported cognitive impairment was defined as SCRF < 75.

RESULTS

In total, 318 patients were randomized. Longitudinal generalized estimating equation (GEE) analysis showed that HA-PCI neither had a significant impact on SRCF (β = 1.41, p = 0.52) nor on cognitive impairment (OR 0.81, 95 %CI 0.53-1.25, p = 0.34). The median follow up was 41.7 (95 %CI 35.7-47.6) months, during which 61 patients developed BM (PCI arm: 30, HA-PCI arm: 31, p = 0.9). BM site was solitary in 15 patients (PCI arm: 7, HA-PCI arm: 8, p = 0.8). Nine of the 61 patients had BM within the HA area (PCI arm: 4, HA-PCI arm: 5, p = 1.0). The BM incidence was not significantly different between arms (subdistribution hazard ratio [sHR] 1.03, 95 %CI 0.62-1.70, p = 0.91).

CONCLUSION

HA-PCI did not preserve longitudinal SRCF but did also not increase the risk of BM. Additional strategies should be investigated to further improve the therapeutic ratio of PCI.

TRIALS REGISTRATION: ClinicalTrials.gov (NCT01780675) ClinicalTrials.gov (NCT02397733).