Prophylactic cranial irradiation in small-cell lung cancer: findings from a North Central Cancer Treatment Group Pooled Analysis.
BACKGROUND
This pooled analysis evaluated the outcomes of prophylactic cranial irradiation (PCI) in 739 small-cell lung cancer (SCLC patients with stable disease (SD) or better following chemotherapy ± thoracic radiation therapy (TRT) to examine the potential advantage of PCI in a wider spectrum of patients than generally participate in PCI trials.


METHODS
Three hundred eighteen patients with extensive SCLC (ESCLC) and 421 patients with limited SCLC (LSCLC) participated in four phase II or III trials. Four hundred fifty-nine patients received PCI (30 Gy/15 or 25 Gy/10) and 280 did not. Survival and adverse events (AEs) were compared.


RESULTS
PCI patients survived significantly longer than non-PCI patients {hazard ratio [HR] = 0.61 [95% confidence interval (CI): 0.52-0.72]; P < 0.0001}. The 1- and 3-year survival rates were 56% and 18% for PCI patients versus 32% and 5% for non-PCI patients. PCI was still significant after adjusting for age, performance status, gender, stage, complete response, and number of metastatic sites (HR = 0.82, P = 0.04). PCI patients had significantly more grade 3+ AEs (64%) compared with non-PCI patients (50%) (P = 0.0004). AEs associated with PCI included alopecia and lethargy. Dose fractionation could be compared only for LSCLC patients and 25 Gy/10 was associated with significantly better survival compared with 30 Gy/15 (HR = 0.67, P = 0.018).


CONCLUSIONS
PCI was associated with a significant survival benefit for both ESCLC and LSCLC patients who had SD or a better response to chemotherapy ± TRT. Dose fractionation appears important. PCI was associated with an increase in overall and specific grade 3+ AE rates.
Department of Radiation Oncology, Mayo Clinic, Scottsdale. Electronic address: sschild@mayo.edu.
S E
SE
Schild
Section of Biomedical Statistics and Informatics, Mayo Clinic, Rochester.
N R
NR
Foster
Section of Biomedical Statistics and Informatics, Mayo Clinic, Rochester.
J P
JP
Meyers
Division of Medical Oncology, Mayo Clinic.
H J
HJ
Ross
Michigan Cancer Research Consortium, Ann Arbor.
P J
PJ
Stella
Department of Radiation Oncology, Mayo Clinic, Rochester.
Y I
YI
Garces
Department of Radiation Oncology, Mayo Clinic, Rochester.
K R
KR
Olivier
Department of Medical Oncology, Mayo Clinic, Rochester.
J R
JR
Molina
Department of Radiation Oncology, Luther Hospital Eau Claire.
L R
LR
Past
Department of Radiation Oncology, Mayo Clinic, Rochester.
A A
AA
Adjei
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016371:Cranial Irradiation; D018572:Disease-Free Survival; D019583:Dose Fractionation, Radiation; D006801:Humans; D008175:Lung Neoplasms / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D008875:Middle Aged; D055752:Small Cell Lung Carcinoma / Q000188:drug therapy / Q000401:mortality / Q000532:radiotherapy*; D015996:Survival Rate; D016896:Treatment Outcome