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TOPLINE:

The benefit of prophylactic cranial irradiation in small cell lung cancer (SCLC) might be limited to patients with preexisting brain metastases, suggesting a role for active surveillance instead of routine irradiation.

METHODOLOGY:

• Patients with SCLC routinely undergo prophylactic cranial irradiation following first-line therapy to prevent brain metastases and prolong survival.
• However, as systemic treatments and brain imaging continue to improve, the value of prophylactic cranial irradiation has been called into question.
• To gauge the benefit of prophylactic cranial irradiation in the modern era, investigators conducted a meta-analysis of 109 studies published as recently as 2023 that compared overall survival with and without prophylactic cranial irradiation in patients with SCLC.
• Only nine studies used MRI to confirm that patients did not have preexisting brain metastases before prophylactic cranial irradiation.

TAKEAWAY:

• Prophylactic cranial irradiation was associated with longer survival in all patients (hazard ratio [HR], 0.59; P < .001).
• Patients with limited stage disease (HR, 0.60) and extensive-stage disease (HR, 0.59) also had significantly better overall survival following prophylactic cranial irradiation.
• However, in studies that ruled out preexisting brain metastases using MRI, the overall survival benefit in patients who underwent prophylactic cranial irradiation was not statistically significant (HR, 0.74; P = .08). Still, prophylactic cranial irradiation was associated with a decreased incidence of brain metastases in this subgroup.

IN PRACTICE:

The findings indicated that prophylactic cranial irradiation is associated with a survival benefit, but that benefit may be limited to patients who already have brain metastases. Overall, this finding "suggests that the survival benefit previously reported in studies may be due to the therapeutic rather than prophylactic effect of cranial irradiation in patients with subclinical brain metastases," the authors concluded.

The findings should prompt physicians to reconsider routine use of prophylactic cranial irradiation and to consider active surveillance imaging "to limit unnecessary exposure to cranial radiation and the attendant risk of neurotoxicity," the authors added.

SOURCE:

The work, led by Karolina Gaebe of the University of Toronto, Toronto, Ontario, Canada, was published last month in eClinicalMedicine.

LIMITATIONS:

Most studies were retrospective and observational and of poor quality, leading to confounding and selection bias. Studies varied in terms of design, inclusion criteria, follow-up, and treatment schedules. Neurotoxicity and quality of life outcomes were underreported.

DISCLOSURES:

There was no external funding. The two senior investigators reported ties to AstraZeneca, Pfizer, XPan Medical, and Alkermes.

M. Alexander Otto is a physician assistant with a master's degree in medical science and a journalism degree from Newhouse. He is an award-winning medical journalist who worked for several major news outlets before joining Medscape Medical News. Alex is also an MIT Knight Science Journalism fellow. Email: aotto@mdedge.com