Immunotherapy (excluding checkpoint inhibitors) for stage I to III non-small cell lung cancer treated with surgery or radiotherapy with curative intent

BACKGROUND

Non-small cell lung cancer (NSCLC) is the most common lung cancer, accounting for approximately 80% to 85% of all cases. For people with localised NSCLC (stages I to III), it has been speculated that immunotherapy may be helpful for reducing postoperative recurrence rates, or improving the clinical outcomes of current treatment for unresectable tumours. This is an update of a Cochrane Review first published in 2017 and it includes two new randomised controlled trials (RCTs).

OBJECTIVES

To assess the effectiveness and safety of immunotherapy (excluding checkpoint inhibitors) among  people  with localised NSCLC of stages I to III who received curative intent of radiotherapy or surgery.

SEARCH METHODS

We searched the following databases (from inception to 19 May 2021): CENTRAL, MEDLINE, Embase, CINAHL, and five trial registers. We also searched conference proceedings and reference lists of included trials.

SELECTION CRITERIA

We included RCTs conducted in adults (≥ 18 years) diagnosed with  NSCLC stage I to III after surgical resection, and those with unresectable locally advanced stage III NSCLC receiving radiotherapy with curative intent. We included participants who underwent primary surgical treatment, postoperative radiotherapy or chemoradiotherapy if the same strategy was provided for both intervention and control groups.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected eligible trials, assessed risk of bias, and extracted data. We used survival analysis to pool time-to-event data, using hazard ratios (HRs). We used risk ratios (RRs) for dichotomous data, and mean differences (MDs) for continuous data, with 95% confidence intervals (CIs). Due to clinical heterogeneity (immunotherapeutic agents with different underlying mechanisms), we combined data by applying random-effects models.

MAIN RESULTS

We included 11 RCTs involving 5128 participants (this included 2 new trials with 188 participants since the last search dated 20 January 2017). Participants who underwent surgical resection or received curative radiotherapy were randomised to either an immunotherapy group or a control group. The immunological interventions were active immunotherapy Bacillus Calmette-Guérin (BCG) adoptive cell transfer (i.e. transfer factor (TF), tumour-infiltrating lymphocytes (TIL), dendritic cell/cytokine-induced killer (DC/CIK), antigen-specific cancer vaccines (melanoma-associated antigen 3 (MAGE-A3) and L-BLP25), and targeted natural killer (NK) cells. Seven trials were at high risk of bias for at least one of the risk of bias domains. Three trials were at low risk of bias across all domains and one small trial was at unclear risk of bias as it provided insufficient information. We included data from nine of the 11 trials in the meta-analyses involving 4863 participants. There was no evidence of a difference between the immunotherapy agents and the controls on any of the following outcomes: overall survival (HR 0.94, 95% CI 0.84 to 1.05; P = 0.27; 4 trials, 3848 participants; high-quality evidence), progression-free survival (HR 0.94, 95% CI 0.86 to 1.03; P = 0.19; moderate-quality evidence), adverse events (RR 1.12, 95% CI 0.97 to 1.28; P = 0.11; 4 trials, 4126 evaluated participants; low-quality evidence), and severe adverse events (RR 1.14, 95% CI 0.92 to 1.40; 6 trials, 4546 evaluated participants; low-quality evidence).  Survival rates at different time points showed no evidence of a difference between immunotherapy agents and the controls. Survival rate at 1-year follow-up (RR 1.02, 95% CI 0.96 to 1.08; I2 = 57%; 7 trials, 4420 participants; low-quality evidence), 2-year follow-up (RR 1.02, 95% CI 0.93 to 1.12; 7 trials, 4420 participants; moderate-quality evidence), 3-year follow-up (RR 0.99, 95% CI 0.90 to 1.09; 7 trials, 4420 participants; I2 = 22%; moderate-quality evidence) and at 5-year follow-up (RR 0.98, 95% CI 0.86 to 1.12; I2 = 0%; 7 trials, 4389 participants; moderate-quality evidence).  Only one trial reported overall response rates. Two trials provided health-related quality of life results with contradicting results.  AUTHORS' CONCLUSIONS: Based on this updated review, the current literature does not provide evidence that suggests a survival benefit from adding immunotherapy (excluding checkpoint inhibitors) to conventional curative surgery or radiotherapy, for people with localised NSCLC (stages I to III). Several ongoing trials with immune checkpoints inhibitors (PD-1/PD-L1) might bring new insights into the role of immunotherapy for people with stages I to III NSCLC.