Clinical and dosimetric predictors of late rectal bleeding of prostate cancer after TomoTherapy intensity modulated radiation therapy

Abstract

IntroductionRectal bleeding after radiotherapy impacts the quality of life of long‐term surviving prostate cancer patients. We sought to identify factors associated with late rectal bleeding following intensity modulated radiation therapy (IMRT) using TomoTherapy for prostate cancer.MethodsWe retrospectively analysed 82 patients with localised prostate cancer treated with TomoTherapy. Most patients (95.1%) received neoadjuvant and concurrent hormone therapy. Forty‐two patients (51.2%) graded as high risk using D'Amico's classification underwent radiotherapy involving the pelvic nodal area. Late bleeding complications were quantified using the Common Terminology Criteria for Adverse Events v4.0. Multiple clinical and dosimetric factors were considered with reference to rectal bleeding.ResultsThe median follow‐up period was 538 (range, 128–904) days. Grades 1, 2 and 3 rectal bleeding were observed in 14 (17.1%), four (4.9%) and one (1.2%) patient respectively. In multivariate analysis, the following factors were significantly associated with Grade ≥1 late rectal bleeding: volume, mean dose (P = 0.012) and rectal V30 (P = 0.025), V40 (P = 0.011), V50 (P = 0.017) and V60 (P = 0.036). When exclusively considering Grade 2–3 rectal bleeding, significant associations were observed with the use of anticoagulants or antiaggregates (P = 0.007), rectal V30 (P = 0.021) and V40 (P = 0.041) in univariate analysis.ConclusionsOur results suggested that the intermediate rectal dose‐volume (V30–V60) was a significant predictor for mild to severe late rectal bleeding (Grade ≥1). Rectal dose‐volumes >V70, which represented the volume of the highest doses, were not predictive in this study.

Long-term Tumor Control and Late Toxicity in Patients with Prostate Cancer Receiving Hypofractionated (2.2 Gy) Softtissue- matched Image-guided Intensity-modulated Radiotherapy

“…In studies using HT with conventional fractionation, incidence of late grade 2 or more GI and GU toxicity ranged from 6.1-9.7% and from 1.2-10.7%, respectively (20,27,28), and bRFS rates at 3-5 years were almost ≥90% (20,28). Tomita et al reported outcomes of HT at a median dose of 78 Gy in 2 Gy fractions for prostate cancer.…”

Evaluation of plan quality and robustness of IMPT and helical IMRT for cervical cancer

“…As the most dominant OAR in cervical radiotherapy, the dose range of rectum has much clinical significance. For instance, studies show that rectum bleeding is associated with rectum high dose range [ 24]. The popular Lyman-Kutcher-Burman (LKB) NTCP model was used to fit the dose volume relationship to the clinical data [25,26].…”

Late rectal bleeding after volumetric-modulated arc therapy for localised prostatic cancer

“…We reported the long-term outcome concerning locally advanced prostate cancer patients treated with radiation therapy using VMAT, mainly late adverse events such as rectal bleeding. Previous studies have reported that the incidence of late rectal bleeding ranges from 5% to 24%, of which approximately 2% were grade 3 patients 5,6,[9][10][11][12][13][14][15][16][17] (Table 7). In our study, late rectal bleeding occurred in 19% of patients, of whom 5.5% and 1.4% were classified as grades 2 and 3, respectively, a finding that was similar to previous studies.…”

“…Many prostate cancers occur in elderly individuals aged ≥70 years, and many patients receive anticoagulant therapy for cardiovascular disease prior to radiation therapy. For at-risk patients such as those undergoing concomitant anticoagulant therapy 16 and with severe diabetes, careful treatment options are necessary. Currently, we have reduced the prescribed dose to 72 Gy for at-risk patients.…”

“…Using our method, the CTV margin was 5 mm in all directions, while that in other reports ranged from 6 to 10 mm. 5,10,12,16,19 Another factor may have been that we performed IGRT using kilovoltage CT (KV-CT) for all patients. When comparing the IGRT images, Elekta Synergy uses KV-CT, while Tomo uses megavoltage-CT (MV-CT).…”