Identification of pelvic dose-volumetric parameters that predict acute bone marrow suppression in concurrent chemoradiotherapy for cervical cancer

Abstract

Objective To identify the dose-volumetric parameters associated with acute bone marrow suppression in concurrent chemoradiotherapy for cervical cancer, and provide the reference standard for the radiotherapy planning. Methods In total, 155 patients concurrently receiving chemoradiotherapy for cervical cancer were enrolled in this study. The pelvis was contoured for each patient in radiotherapy treatment planning system and divided into three subsites: lumbosacral spine, ilium, and lower pelvis. The pelvic dose volume parameters were analyzed using univariate analysis (Chi-Square and t test), and multivariate analysis (Logistic regression model). Dose volume parameters include V5, V10, V15, V20, V25, V30, V35, V40, V45, V50 and the average dose (Dmean). Results The percentage of patients that developed acute bone marrow suppression (≥grade 2) was 87.7%(136/155). The univariate analysis revealed that pelvic V5, V10, V15, V20, ilium V15, lower pelvis V15 of patients with acute bone marrow suppression (≥grade 2) were significantly higher than those of < grade 2 patients (t=-2.277, -2.142, -3.475, -2.018, -2.963, -2.741, P<0.05). Multiple regression analysis indicated that pelvic V15 was associated with acute bone marrow suppression (OR=1.728. P<0.05). The threshold of pelvic V15 was 88% as determined by receiver operating curve (ROC). Conclusions The results show that Pelvic V15 is associated with acute bone marrow suppression in concurrent chemoradiotherapy for cervical cancer and is thus an independent risk factor. To better predict and control acute bone marrow suppression, pelvic V15 should be carefully controlled below 88% in treatment planning to reduce the incidence of acute bone marrow suppression. Key words: Cervical cancer; Dose volume parameters; Acute bone marrow suppression