Can grade 2 neutropenia predict the risk of grade 3 neutropenia in metastatic colorectal cancer patients treated with chemotherapy?

Neutropenia is a major factor affecting continuation of chemotherapy for colorectal cancer. In many clinical trials, a neutrophil count of >1500 is targeted for continuation; for a count of <1500, medication is commonly discontinued. However, there is no definitive evidence supporting the need for a neutrophil count of 1500 for continuation of chemotherapy. In the clinical trials that we conducted, we discontinued chemotherapy when the neutrophil count was <1000 (grade 3); for a count of 1000–1500 (grade 2), chemotherapy was continued. Therefore, even practical treatment uses the same setting. Our aim was to examine neutrophil counts during continuation of chemotherapy in colorectal cancer patients with counts of 1000–1500 and to assess the need for discontinuation of medication for neutrophil counts in this range. Moreover, we examined neutrophil counts during the previous course of chemotherapy when they fell below 1000.

The study included 144 patients who received XELOX + bevacizumab therapy and XELOX therapy for advanced or recurrent colorectal cancer.

Thirty (20.8 %) patients had neutrophil counts of 1000–1500. One (3.3 %) of 30 patients had a neutrophil count of <1000 during the following course of chemotherapy. Moreover, among the patients with neutrophil counts of <1000, 27.3 % had counts of 1000–1500 during the previous course of chemotherapy and 72.7 % had counts of >1500.

Based on these results, grade 2 neutropenia cannot predict the risk of grade 3 neutropenia. Continuation of chemotherapy in patients with neutrophil counts of 1000–1500 may be appropriate, and discontinuation of therapy is not always required.