Pelvic irradiation-induced eosinophilia is correlated to prognosis of cervical cancer patients and transient elevation of serum interleukin 5 level.

PURPOSE

To determine the significance of eosinophilia and serum interleukin 5 (IL-5) levels induced by radiotherapy in patients with gynecological cancer.

MATERIALS AND METHODS

First, we examined changes in the number of eosinophils before and during radiotherapy in 145 patients with cervical cancer who underwent external radiotherapy and brachytherapy. Eosinophilia was defined as > or =10% eosinophils or > or =500 eosinophils/mm3. Next, we determined serum IL-5 levels prospectively in 20 patients, comprising 18 cases of cervical cancer, one of uterine corpus cancer, and one of vaginal cancer.

RESULTS

Eosinophilia was seen in 88 patients (61%). Patients with advanced disease stage IV showed 32% eosinophila, lower than those of stage I (63%), II (69%), and III (65%) disease patients (p=0.03). The 5-year cause-specific survival rate was 76% for patients with eosinophilia (+) and 53% for patients without eosinophilia (p=0.0003). Thus, eosinophilia correlates to stage classification and a good prognosis. Of the 20 patients studied prospectively, the six with elevated serum IL-5 level at one week (6/20=30%) all showed eosinophilia (100%), whereas only six of the other 14 patients had eosinophilia (43%, p=0.04).

CONCLUSION

Radiotherapy induced transient elevation of serum IL-5 levels and is related with eosinophilia, which is correlated to prognosis.