The relationship between the radiation dose of pelvic-bone marrow and lymphocytic toxicity in concurrent chemoradiotherapy for cervical cancer.

OBJECTIVE

The purpose of this study is to verify the correlation between medium and low radiation doses of the pelvic-bone marrow and the incidence of lymphocytic toxicity during concurrent chemoradiotherapy for cervical cancer.

MATERIALS AND METHODS

This research included 117 cervical cancer patients, who received concurrent chemoradiotherapy. Radiotherapy included external-beam radiation therapy and brachytherapy. The dosimetry parameters include the Volume receiving 5 Gy (V5), 10 Gy (V10), 20 Gy (V20), 30 Gy (V30), 40 Gy (V40), 50 Gy (V50), and the mean dose (D mean) of the bone marrow. Lymphocytic toxicity was calculated from lowest lymphocytic count after two cycles of concurrent chemotherapy.

RESULTS

During concurrent chemoradiotherapy, the incidence of lymphocytic toxicity is 94.88%. The incidence of grade 3-4 toxicity is 68.38%. Multivariate analysis findings show that the dosimetry parameters V5, V10, V20, and V30 are significantly correlated with lymphocytic toxicity. The patients are divided into small-volume subgroups and large-volume subgroups based on the cutoff values. The relative risk of both grade 1-4 and grade 3-4 lymphocytic toxicity is significantly lower in the small-volume subgroups than in the large-volume subgroups (P < 0.05). Kaplan-Meier analysis shows that the incidence of both grade 1-4 and grade 3-4 lymphocytic toxicity of the small-volume subgroups is significantly lower than that of the large-volume subgroups (P < 0.05).

CONCLUSION

There is a significant correlation between a medium and low dose of pelvic-bone-marrow radiation and incidence of lymphocytic toxicity. Reducing the volume of medium and low radiation doses could effectively reduce incidence of lymphocytic toxicity.