Analysis Of Hematologic Toxicity And Bone Marrow Dosimetry In Cervical Cancer Patients Treated With Concurrent Chemotherapy And Extended Field Intensity Modulated Radiotherapy

BACKGROUND AND PURPOSE:Cervical cancer is one of the most common neoplasm of female reproductive system.As the standard treatment for patients with locally advanced disease,chemoradiotherapy especially with extended field significantly improves the prognosis both for preventive and definite purposes.In cases with extended field radiotherapy,the hematologic toxicity is more prominent and potentially able to deter or even interrupt the treatment schedule,therefore threatening the curative intent.In that light,the purpose of this study was to identify and evaluate the predictive factors of hematological toxicity in patients with locally advanced cervical cancer.METHODS:We analyzed 50 patients who received concurrent chemotherapy with extended-field radiotherapy at Peking Union Medical College Hospital.Pelvic bone marrow was contoured as three subsets for each patient:lumbosacral spine,ilium and lower pelvis.Complete dose-volume histograms were retrieved and dimensionally reduced using principal component analysis.Toxicity was graded according to Common Terminology Criteria for Adverse Events 3.0.In order to make full use of the dose-volume histograms,instead of intermittent sampling,we introduced principal component analysis for detecting the range of doses at which the relative irradiation volumes held most promise as predictive factors for toxicity.Multivariate regression model was used to test associations between the toxicity and dosimetry and other possibly relevant clinical factors.RESULTS:76%(38/50)of the patients developed grade 3 or worse hematologic toxicity.68%(34/50)of the patients presented with grade 2 or worse anemia.Logistic regression in combination with principal component analysis showed the significant correlation between V25-34 of lower pelvis and grade 2 or worse anemia(OR 2.12,95%CI 1.03-4.34,p=0.042).Receiver operating characteristic curve demonstrated LP-V30≥52.16%was the cutoff point with the most sensitivity and specificity(OR 7.94,95%CI 1.88-33.49,p=0.005).No other significant correlation was found between toxicity and both the clinical and dosimetry factors.CONCLUSION:Patients with locally advance cervical cancer receiving extended-field intensity modulated radiotherapy with concurrent platinum-based chemotherapy are subject to serious hematologic toxicity.Low-dose irradiation volumes of lower pelvis correlated with grade 2 or worse anemia more than other dosimetry factors.More studies need to be done before conclusions on the proper contouring methods and dosimetry predictive factors can be drawn.