THE RELATIONSHIP BETWEEN PELVIC BONE DOSE AND HEMATOTOXICITY IN PROSTATE CANCER PATIENTS
ilyas anil kilinc,
Turkey
PO-1366
Abstract
THE RELATIONSHIP BETWEEN PELVIC BONE DOSE AND HEMATOTOXICITY IN PROSTATE CANCER PATIENTS
Authors: ilyas anil kilinc1
1ankara university, The Department of Radiation Oncology, Ankara, Turkey
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Purpose or Objective
Definitive or adjuvant/salvage pelvic RT can be used in treatment of prostate cancer.Hematotoxicity can be seen in patients who
underwent pelvic RT since approximately %50-55 of bone marrow activity takes
place in pelvic bone.In this study,we aimed to investigate the
relationship between all pelvic bone dose parameters and subacute/chronic
hematotoxicity in patients with prostate cancer who underwent pelvic
RT
Material and Methods
74 patients treated with adjuvant/salvage
or definitive pelvic RT between 2012-2020 were retrospectively evaluated.All pelvic bone was later contoured in with the upper
border:L5 vertebra and crista iliaca;the lower border at levels of the
inferior pubic ramus and femoral neck.The differential DVH parameters of this pelvic bone V3,V5,V10,V20,V30,V40,V50 and mean doses
were subsequently calculated.WBC,hemoglobin(Hb),lymphocyte,neutrophil and PLT values were measured from hemogram parameters
of the patients before treatment,6-12 months(subacute) and 12-18 months(chronic) after treatment.Hematotoxicity assessment was performed
according to the Common Terminology Criteria for Adverse Events v5.0. If there was a grade 2 or higher toxicity in any of the whole
blood parameters,it was accepted as hematotoxicity(HT2+) and relationship between late hematotoxicity and doses of pelvic bone
was evaluated.Chi-square and Fisher's exact tests were used for analysis
for categorical variables among independent groups
Results
vPSA levels were median 11.93(4-375)ng/dl; the median dose
of RT to the prostate or tumor bed was 74(64-78)Gy,and the median
dose of pelvic lymphatics alone was 46(44-54,4) Gy.IMRT and VMAT technique
was used in 57 and 16 patients, respectively.The subacute blood results of 71
patients and chronic blood results 63 patients were obtained.A significant
time-dependent decrease in values of WBC,Hb,PLT,lymphocytes,neutrophils
were observed(p<0.001).As a result in comparison
of these 5 individual parameters,the values of subacute and chronic period
differed statistically significantly compared to the values before RT,while there was no difference between the values of subacute
and chronic periods.HT2+ was observed in 29 patients and in 15 patients during
subacute and chronic period,respectively.The median values for V3-V5-V10-V20-V30-V40-V50
of the pelvic bone were %97-%92-%86-%74-%58-%40-%17,respectively and the
mean dose of pelvic bone was 33.4 Gy.When the relationship of all pelvic bone
dose parameters was examined,no statistically significance was found between
subacute or late HT2+ or any subgroup with toxicity.Variables such as type
of treatment (postoperative vs definitive),age(≤65vs>65),pelvic dose(≤46vs>46),hormone therapy usage(≤12 vs >12 months),RT
technique(VMAT vs IMRT) were also associated with subacute/chronic
hematotoxicity
Conclusion
A low decrease in blood values can be observed in
prostate cancer patients undergoing pelvic RT in subacute or late period.In our study,no significant relationship was shown between pelvic bone doses and hematotoxicity