Effect of prolonged subcutaneous administration of interleukin-2 on the circadian rhythms of cortisol and beta-endorphin in advanced small cell lung cancer patients

Interleukin-2 has been shown to stimulate cortisol secretion in man. Owing to its immunosuppressive properties, an increase in cortisol levels during interleukin-2 cancer immunotherapy could potentially counteract induced activation of the antitumor immune response. Few data are available about cortisol secretion secondary to prolonged interleukin-2 administration. To investigate the problem, we evaluated cortisol circadian rhythms in 7 consecutive metastatic small cell lung cancer patients who received interleukin-2 subcutaneously for 4 weeks (daily dose: 6 x 10(6) x IU/m2). Venous blood samples were drawn at 8.00 a.m., 4.00 p.m. and 12.00 p.m., before interleukin-2, and after each week until the end of the cycle. Beta-endorphin levels were also measured on the same samples. Four patients were evaluated during a second interleukin-2 cycle. Mean cortisol levels increased during interleukin-2 therapy, but were significantly higher than those seen in basal conditions after the first week of treatment. Moreover, cortisol peaks observed during the second cycle of therapy were not significantly different from those seen during the first cycle. Mean beta-endorphin levels increased in response to interleukin-2 administration, but the increase did not reach statistical significance. The early cortisol rise progressively decreased as treatment continued. This suggests that the interleukin-2-induced cortisol rise has no relevant clinical importance in antagonizing the activation of an effective antitumor immune response during cancer immunotherapy with interleukin-2