Practice guideline on prophylactic cranial irradiation in small-cell lung cancer

To develop an evidence-based clinical practice guideline that would address the following questions: (a) What is the role of prophylactic cranial irradiation (PCI) in patients with limited or extensive stage small-cell lung cancer (SCLC) who have achieved complete remission in response to induction therapy (chemotherapy or chemoradiotherapy)? (b) What dose and fractionation schedules of PCI are optimal? (c) Does the use of PCI in patients with SCLC in complete remission affect quality of life? Survival, disease-free survival, quality of life, and adverse effects were the outcomes of interest.

A systematic review of the published literature was undertaken to provide the data for an evidence-based practice guideline.

Six randomized controlled trials and one fully published individual patient data meta-analysis were included in the systematic review of the evidence. For patients who have achieved complete response after induction therapy, there is evidence of a disease-free survival benefit (4 of 6 trials) and an overall survival benefit (meta-analysis). There is insufficient evidence to make a definitive recommendation with respect to dose. There is some indication that 30-36 Gy in 2-3 Gy per fraction, or a biologically equivalent dose, may produce a better outcome than a lower dose or less aggressive fractionation regimen. The schedule commonly used in Canada is 25 Gy in 10 fractions over 2 weeks. Data from further research, including a trial currently ongoing that compares 25 Gy in 10 fractions with 36 Gy in 18 fractions, will be required to determine optimal dose of PCI. There is insufficient evidence to make recommendations concerning the optimal timing of PCI in relation to the administration of chemotherapy. Lung DSG members generally felt that it should be given as soon as possible after completion of chemotherapy. There is evidence from trials with data for up to 2 years of follow-up that prophylactic cranial irradiation does not produce significant late neurotoxicity. There is evidence from one trial that prophylactic cranial irradiation does not have a detrimental effect on quality of life in the first 12 months following the completion of therapy. There is insufficient evidence to comment on the long-term effects of prophylactic cranial irradiation on quality of life.

For adult patients with limited or extensive SCLC who achieve a complete remission with induction therapy, PCI is recommended.