Pelvic Dose Research Articles

Dosimetric Analysis of Limiting Pelvic Bone Dose in Intensity-modulated Radiotherapy for Cervical Cancer

Numerous studies have indicated the significant importance of pelvic dose in the radiotherapy process for cervical cancer patients. However, research on the actual pelvic bone dose in the treatment of cervical cancer patients using different techniques is currently relatively limited. In this study, we selected 50 postoperative cervical cancer patients. For each patient, three treatment plans with pelvic dose constraints were designed: sIMRT, VMAT, and HT. Statistical analysis was conducted on the target area and organ at risk parameters of the three groups of plans. The results indicate that all three treatment plans meet the clinical requirements. Regarding organs at risk, compared to the sIMRT and VMAT groups, the HT group showed a reduction of 11.85% and 11.07%, respectively, in V40 of bladder. Additionally, compared to the sIMRT and HT groups, the VMAT group exhibited a reduction of 14.94% and 9.53%, respectively, in V10 of pelvic bone. Furthermore, compared to the sIMRT and HT groups, the VMAT group showed a reduction of 10.76% and 6.75%, respectively, in V20 of pelvic bone, and these differences were also statistically significant (t = 21.630, t = –16.621, P < 0.05). In summary, individualized treatment design can be conducted in clinical practice based on the specific conditions of patients.

Radiotherapy Management of Locally Advanced Cervical Cancer during the COVID-19 Era: A Single Centre Report on Treatment Approach, Brachytherapy Fractionation and Timing

Background: The COVID-19 pandemic had a catastrophic impact on healthcare. Keeping an optimal cancer care routine has been challenging. For cervical cancer (CC) patients external beam radiotherapy (EBRT) and brachytherapy (BT) are key elements for radical treatment. Oncological treatment delays have represented a major issue during the pandemic. Overall treatment time (OTT) is a well-known prognostic factor for CC. Thus, we decided to evaluate radiotherapy timing and modalities, and OTT trends for locally advanced cervical cancer (LACC) patients treated at our center during the Pandemic. Methods: We retrospectively collected and analyzed data of patients treated for LACC at our Center, (Department of Oncology, Radiation Oncology, S.Anna Hospital, Turin, Italy), during the COVID-19 pandemic. Results: Between March 2020 and March 2022, 36 patients were treated. All patients underwent EBRT (median pelvic dose 48 Gray (Gy)). Concurrent chemotherapy (ChT) was administered in 31/36 patients. High Dose Rate (HDR) BT boost was delivered to 32/36 patients. BT schedules adopted were: 28 Gy in 4 fractions (18 cases, 56.2%), 26 Gy in 4 fractions (5 cases, 15.6%), 21 Gy in 3 fractions (4 cases, 12.5%), 18 Gy in 3 fractions (3 cases, 9.3%), 24 Gy in 4 fractions (one case, 3.2%), 12 Gy in 2 fractions plus 11 Gy in 2 fractions (one case, 3.2%). Most of the patients (25/32, 78.1%) received one fraction per week; 6 patients (18.1%) 2 fractions per week and one patient 3 fractions per week. Median OTT was 74 days (57–99). The median interval from EBRT to HDR-BT was 14 days (6–54). Four patients tested positive for COVID-19 between EBRT and BT. At a median follow-up of 10.7 months (range 1.8–20.3), a complete response was obtained in 25 patients (69.5%), a partial response in 8 cases (22.2%), and a disease progression in two patients (5.5%). Conclusions: in terms of radiotherapy management of LACC, brachytherapy resulted as the most affected by the restrictions due to the pandemic. We adopted different schedules and fractionations to optimize the resources available and to keep providing an optimal care. A be-weekly fractionation emerged as a promising option for LACC during the pandemic, with a good toxicity profile.

Patient-Reported Rectal QOL with Pelvic Nodal Irradiation ± Involved Pelvic Nodal Boost to 75 Gy EQD2 in Men with Prostate Cancer

<h3>Purpose/Objective(s)</h3> The study was designed to compare patient-reported acute and late rectal function quality of life (RQOL) between men with local or regional prostate cancer treated with or without an involved pelvic nodal simultaneous integrated boost (SIB). It is hypothesized that men receiving pelvic nodal radiotherapy at 50.4 Gy in 28 fractions (Pelv50) have similar RQOL as men receiving the same pelvis dose plus the addition of involved pelvic nodal SIB to 67.2 Gy in 28 fractions (Pelv67). <h3>Materials/Methods</h3> Rectal toxicity was assessed using the Merrick Rectal Function Assessment Score (R-FAS). The R-FAS consists of nine questions and a scoring range of 0-27, with higher scores indicating poorer bowel function. Patients with measures -180 days and up to 730 days from the start of RT were included in the analysis. SIB targets included radiographically apparent nodal GTVs plus a 5mm margin. Pelvic nodal contours extended from aortic bifurcation through the bilateral obturator nodes. An EQD2 of 75 Gy to involved nodal targets was calculated for the Pelv67 group based on 28 fractions of 2.4 Gy with an α/β ratio of 1.5. Patients were dichotomized by treatment received (Pelv50 vs. Pelv67). Non-parametric kernel regression was modeled with R-FAS score as the dependent variable and time from RT and treatment cohort as the independent variables, with improved Akaike information criterion to determine optimal bandwidth. Marginal means and 95% confidence intervals were predicted at 90-day intervals from timepoint 0 with 50 bootstrapping replications. <h3>Results</h3> There was no difference in baseline age or baseline Charlson Comorbidity Index between the two cohorts. There was no significant difference in mean R-FAS over the entire time interval between the two cohorts (Pelv67 vs. Pelv50: 0.4 points, p=0.17). There is no significant difference in R-FAS score at any discrete timepoint between Pelv67 and Pelv50 as the 95% confidence intervals overlap (Table). <h3>Conclusion</h3> Pelvic nodal irradiation with a simultaneous integrated boost to 67.2 Gy in 28 fractions (EQD2=75 Gy) was associated with similar rates of RQOL compared to standard pelvic irradiation from the patient's perspective. This study suggests that dose escalation using a pelvic nodal SIB technique to 75Gy EQD2 is safe despite the proximity of the rectum and bowel to SIB targets.

PO-1366 The relationship between pelvic bone dose and hematotoxicity in prostate cancer patients

PO-1366 The relationship between pelvic bone dose and hematotoxicity in prostate cancer patients

MO-0554 Pelvic dose accumulation from time-successive prostate and lymph node radiation (NCT02274779)

MO-0554 Pelvic dose accumulation from time-successive prostate and lymph node radiation (NCT02274779)

Safety of accelerated hypofractionated whole pelvis radiation therapy prior to high dose rate brachytherapy or stereotactic body radiation therapy prostate boost

BackgroundTo evaluate acute and late genitourinary and gastrointestinal toxicities and patient reported urinary and sexual function following accelerated, hypofractionated external beam radiotherapy to the prostate, seminal vesicles and pelvic lymph nodes and high dose rate (HDR) brachytherapy or stereotactic body radiation therapy (SBRT) prostate boost.MethodsPatients at a single institution with NCCN intermediate- and high-risk localized prostate cancer with logistical barriers to completing five weeks of whole pelvic radiotherapy (WPRT) were retrospectively reviewed for toxicity following accelerated, hypofractionated WPRT (41.25 Gy in 15 fractions of 2.75 Gy). Patients also received prostate boost radiotherapy with either HDR brachytherapy (1 fraction of 15 Gy) or SBRT (19 Gy in 2 fractions of 9.5 Gy). The duration of androgen deprivation therapy was at the discretion of the treating radiation oncologist. Toxicity was evaluated by NCI CTCAE v 5.0.ResultsBetween 2015 and 2017, 22 patients with a median age of 71 years completed accelerated, hypofractionated WPRT. Median follow-up from the end of radiotherapy was 32 months (range 2–57). 5%, 73%, and 23% of patients had clinical T1, T2, and T3 disease, respectively. 86% of tumors were Gleason grade 7 and 14% were Gleason grade 9. 68% and 32% of patients had NCCN intermediate- and high-risk disease, respectively. 91% and 9% of patients received HDR brachytherapy and SBRT prostate boost following WPRT, respectively. Crude rates of grade 2 or higher GI and GU toxicities were 23% and 23%, respectively. 3 patients (14%) had late or persistent grade 2 toxicities of urinary frequency and 1 patient (5%) had late or persistent GI toxicity of diarrhea. No patient experienced grade 3 or higher toxicity at any time. No difference in patient-reported urinary or sexual function was noted at 12 months.ConclusionsAccelerated, hypofractionated whole pelvis radiotherapy was associated with acceptable GU and GI toxicities and should be further validated for those at risk for harboring occult nodal disease.

Prognostic impact of neutrophilia and lymphopenia on survival in anal cancer treated with definitive concurrent chemoradiotherapy: a retrospective multicenter study.

This study evaluated the prognostic value of leukocyte, lymphocyte, and neutrophil counts in anal cancer patients undergoing concurrent chemoradiotherapy (CCRT). Multi-institutional retrospective data review included 148 non-metastatic anal cancer patients treated with definitive CCRT with 5-fluorouracil plus mitomycin C between the year 2001 and 2019. The median radiation dose to the primary tumor was 54Gy with a median pelvic dose of 45Gy. Median follow-up duration was 56months, and complete blood cell counts were analyzed from baseline to 1year after the completion of radiotherapy. Although most patients showed a normal number of blood cells before treatment, 6.1% and 4.1% of patients showed leukocytosis (> 10,000/μl) and neutrophilia (> 7500/μl), respectively. After the initiation of treatment, seven patients (4.7%) displayed grade 4 lymphopenia (< 200/μl) at 1 month. Patients with initial leukocytosis showed inferior progression- and locoregional progression-free survival, and neutrophilia was a prognostic factor in all survival outcomes. Grade 4 lymphopenia at 1month was also significantly associated with overall, progression-, and distant metastasis-free survival. On multivariate analyses, baseline neutrophilia was associated with 56.8-, 22.6-, 10.7-, and 23.0-fold increased risks of death, disease relapse, locoregional progression, and distant metastasis, respectively. Furthermore, lymphocytes < 200/μl at 1month was linked to 6.8-, 5.4-, and 6.3-fold increased risks for death, disease relapse, and distant metastasis, respectively. The number of leukocytes, lymphocytes, and neutrophils readily acquired from routine blood tests before and during treatment could be an independent prognostic factor of survival in patients with anal cancer.

Cervical Cancer Patient Reported Gastrointestinal Outcomes: Intensity/Volumetric Modulated vs. 3D Conformal Radiation Therapy

To evaluate gastrointestinal (GI) patient reported outcomes (PROs) in cervical cancer patients treated with definitive radiotherapy (RT), comparing 3D conformal RT (3DCRT) vs. intensity modulated /volumetric modulated arc therapy (IMRT/VMAT).A retrospective analysis of cervical cancer patients treated with curative intent RT between 2015-2018 was performed. GI PROs were collected at baseline, during RT (acute), ≤12 weeks after RT (subacute), and > 12 weeks after RT (late) using the Prospective Outcomes and Support Initiative (POSI) which includes validated questions from EPIC Bowel 2, PRO-CTAE, and EORTC QLQ CX24. GI PROs evaluated three symptom domains: bowel problems (BP), bowel bother (BB), and abdominal problems (AP).The cohort included 167 patients. The median age was 48 (27-86), 74% had squamous cell carcinoma, and 51% had FIGO stage I/II disease. All patients received brachytherapy, 99% received a 45Gy elective pelvic dose, 31% had para-aortic fields, and 97% received concurrent chemotherapy. 100 (60%) patients were treated with IMRT/VMAT and 67 (40%) with 3DCRT. The median follow-up was 24 (5-67) months. In the BP domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +2.29 vs. +1.82 (P = 0.55) during RT, +0.9 vs. -1.15 (P = 0.01) ≤12 weeks after RT, and +0.72 vs. -0.82 (P = 0.01) > 12 weeks after RT. In the BB domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +3.58 vs. +3.16 (P = 0.67) during RT, +2.18 vs. -0.10 (P = 0.02) ≤12 weeks after RT, and +1.98 vs. -0.03 (P = 0.01) > 12 weeks after RT. In the AP domain, mean changes in symptom scores compared to baseline for 3DCRT vs. IMRT/VMAT were +2.52 vs. +2.01 (P = 0.32) during RT, +1.41 vs. -0.38 (P = 0.02) ≤12 weeks after RT, and +1.29 vs. -0.31 (P = 0.01) > 12 weeks after RT. On multivariable analysis 3DCRT was associated with greater mean changes in subacute and late symptom scores in BP (subacute 0.29 (0.08-0.51), P = 0.01; late 0.22 (0.03-0.41), P = 0.02), BB (subacute 0.32 (0.04-0.61), P = 0.03; late 0.26 (0.03-0.48), P = 0.03), and AP (subacute 0.27 (0.05-0.48), P = 0.01; late 0.24 (0.08-0.40), P = 0.01) compared to IMRT/VMAT. Age, smoking status, prior abdominal surgery, FIGO stage, RT volume (pelvic vs. para-aortic), and use of external beam boost were not associated with symptom score changes (P > 0.05). Three-year estimates of overall survival, local control, and regional control were 87%, 97%, 86% in the IMRT/VMAT cohort and 91% (P = 0.32), 97% (P = 0.99), and 92% (P = 0.26) in the 3DCRT cohort, respectively.Cervical cancer patients treated with IMRT/VMAT had significantly less worsening of their GI PRO symptom scores compared to baseline in all three GI domains ≤12 weeks and > 12 weeks after RT. 3DCRT was associated with greater subacute and late patient reported GI toxicity.

Definitive Radiotherapy for Patients With Anal Squamous Cell Carcinoma: A Retrospective Cohort Study.

BackgroundAnal squamous cell carcinoma accounts for less than 2-3% of all digestive system carcinomas. The present study aimed to determine the clinical characteristics, treatment patterns, and treatment outcomes of patients at our institution.MethodologyWe reviewed the clinical data of all consecutive patients with anal squamous cell carcinoma who were treated with definitive radiotherapy in our department between July 2009 and July 2020. Radiotherapy was delivered in 1.8-2 Gy daily fractions to a whole pelvic dose ranging from 45 to 50 Gy, followed by boost radiotherapy of 10-15 Gy, resulting in a total dose of approximately 60 Gy. Concurrent chemotherapy with radiotherapy included 5-fluorouracil/mitomycin C or 5-fluorouracil/cisplatin.ResultsA total of 14 patients with a median age of 61.5 years (range: 45-85 years) were analyzed. There were nine women and five men. The clinical T stage was T1 in two patients, T2 in six patients, T3 in two patients, and T4 in four patients. The clinical N stage was N0 in four patients and N1 in 10 patients. Patients with clinical stage III disease comprised 79% of the entire study population. For the entire cohort, the five-year overall survival rate was 83.3% and the five-year progression-free survival rate was 48.5%. One patient experienced grade 3 fecal incontinence, and the others experienced no radiation-induced severe delayed adverse events.ConclusionsThe results of our study demonstrated that definitive radiotherapy with or without chemotherapy for patients with anal squamous cell carcinoma is an effective and feasible treatment.

Renal Sympathetic Nerve Activity and Heart Rate Responses to Renal Pelvic Infusion of Bradykinin and Capsaicin in Rats Exposed to Intermittent Hypoxia

Renal oxidative stress and inflammation are evident in individuals with obstructive sleep apnea and in animals exposed to intermittent hypoxia (IH). It is known that kidney injury alters renal afferent nerve activity disrupting reno-renal reflex mechanisms. This study investigated reno-renal reflex changes in response to intra-renal pelvic infusion of bradykinin and capsaicin in rats exposed to IH. Wistar rats were exposed to 96 cycles of IH (6% O2, n=10) or to normoxia (sham, 21% O2, n=11) daily for 14 days. On day 15, rats were anesthetized (induction: urethane, α-chloralose and sodium pentobarbitone mixture i.p. (416, 27 and 33mg/kg), maintenance: urethane and α-chloralose mixture i.v. (62 and 4mg/kg)) to record cardiovascular parameters, renal sympathetic nerve activity (RSNA), and urine flow (UF). Intra-renal pelvic infusion of three doses of bradykinin (53µg/kg, 141µg/kg, 247µg/kg, for 5 min at 20µl/min in random order) was performed, and was repeated following the blockade of bradykinin receptors 1 (BK1R) and 2 (BK2R). Finally, an intra-renal pelvic infusion of capsaicin (0.133µg/kg) was performed. During infusions, changes in blood pressure, heart rate (HR) and contralateral RSNA were recorded. Urine samples were collected from the contralateral kidney. Data are expressed as mean±SD and were analyzed using t-test or ANOVA, where appropriate. IH rats were hypertensive (128±17 vs. 112±22mmHg) with elevated HR (440±37 vs. 403±42bpm), and increased basal UF (56±18 vs. 26±12µl/min/kg); all p<0.05. IH rats had increased resting RSNA, but this was not statistically significant (% of max: 19.6±6.4 vs. 14.8±7.2, p=0.105). All intra-renal pelvic doses of bradykinin augmented RSNA in IH and sham rats (all p<0.05), without changes in blood pressure during infusions. However, UF during bradykinin infusion was unchanged in IH and sham rats. Increases in RSNA and HR in response to 247µg/kg bradykinin were blunted in IH rats compared with shams (RSNA p=0.005; HR p=0.021), with diminished increase in RSNA most evident during the last three mins of infusion (% of baseline: 126±20 vs. 108±5%, p=0.016) and attenuated increase in HR during the last 30s of infusion (∆HR: +7±7 vs. +18±15bpm, p=0.05). This was also evident by a decrease in the area under RSNA curves (AUC) in IH rats compared with shams (1884±970 vs. 5437±3950%.s, p=0.046). AUC analysis revealed that increases in RSNA in response to bradykinin were attenuated during BK1R blockade (p=0.012), and greater suppression of bradykinin-induced increase in RSNA was observed following concurrent BK2R blockade (p=0.005). Intra-pelvic infusion of capsaicin induced a similar increase in HR, RSNA and UF in IH and sham rats. Protein expression of bradykinin and TRPV1 receptors in kidney tissue was equivalent between groups. However, in isolated renal pelvic wall, BK2R expression was 53% less in IH (n=4) compared with sham (n=4), but not statistically significant (p=0.120), which might be related to the small sample size. Our results indicate a blunted reflex increase in RSNA and HR in response to intra-pelvic bradykinin in IH rats, which could be due to down-regulation of the BK2R pathway.

Outcomes of rectal cancer patients treated using Polish II neoadjuvant short course radiation therapy and chemotherapy approach in comprehensive cancer center.

e16088 Background: Neoadjuvant short-course (SC) radiation (RT) followed by fluoropyrimidine based chemotherapy prior to surgery (Polish II approach) is a less utilized treatment in the United States for rectal cancer. Based on data suggesting equivalent or improved outcomes at lower cost compared to the long course neoadjuvant chemoradiation, our team started utilizing this approach for rectal cancer management at Simmons Comprehensive Cancer Center. We aim to document our experience with Polish II approach at NCI-designated comprehensive cancer center program. Methods: A retrospective review of stage I-IV rectal cancer patients, seen at an academic center or the Dallas County safety net hospital and treated at Simmons Comprehensive Cancer Center from Nov 2017 to Dec 2019. Patients were treated with neoadjuvant SC-RT followed by 3 cycles of FOLFOX prior to surgery and followed by adjuvant FOLFOX. Descriptive data for demographic, radiation, chemotherapy and surgery, hospitalizations, 30 day post-surgery admission, time to relapse, and laboratory parameters was collected. Results: Thirty-nine patients met the inclusion criteria (average age 58 years; 74% men/26% women). Forty-six percent of patients were Hispanic, 28.2% White, 15.4% African American and 7.7% Asian. The majority of patients had stage IIIB (46.2%), followed by IIIC (17.9%), IIA (12.8%), IIIA (7.7%), while rest were stage I, IVA or unknown (5.1%). All patients received 5 x 5 SC-RT, 100% completed 3 cycles of planned neoadjuvant FOLFOX (12.8% received 4-8 cycles) and 36/39 (92%) of patients underwent planned surgery. Median duration from SC-RT to chemotherapy was 12 days, and from chemotherapy to surgery was 37 days. Hospitalization occurred in 3 patients (7.7%) during neoadjuvant therapy, and in 8 patients (20.5%) within 30 days post-surgery. Complete pathological response was seen in 6 patients (16.6%) and near-complete pathological response in 3 patients (8.3%). Relapse occurred in 10.3% patients at time of data acquisition. Grade 3 and 4 neutropenia, anemia, and thrombocytopenia in neoadjuvant phase was observed in 8.6%, 25.7%, and 2.8% patients, respectively. Conclusions: In rectal cancer patients treated at a comprehensive cancer center, neoadjuvant Polish-II approach was feasible and well tolerated. Pathological response rates were comparable to historical data. SC-RT based neo-adjuvant therapy approach should be favored due to lower pelvic radiation dose, tolerance and convenience to patients.

Effects of radiation therapy on clonal hematopoiesis.

12062 Background: Clonal hematopoiesis (CH), characterized by recurrent somatic mutations in blood, is a common age-associated condition that portends an increased risk of myeloid neoplasms and cardiac disease. Oncologic therapies appear to promote CH, including ionizing radiation therapy (RT) (OR = 1.4, p &lt; 10−6) and systemic DNA-damaging agents (OR = 1.2, p = 8x10−4). How various RT parameters (e.g. target site, dose, fractionation, modality) may influence CH is unknown. Methods: CH mutations were identified via targeted, deep-coverage next-generation sequencing from paired peripheral blood and tumor samples (MSK-IMPACT). CH was defined as a somatic blood mutation with a minimum variant allele frequency of 2%. Putative driver mutations (CH-PD) were identified from OncoKB and other published sources. Clinical and RT characteristics were abstracted from medical records. To account for differences in RT dose and fractionation, equivalent radiation dose in 2 Gy fractions (EQD2) with an α/β ratio of 3 for late effects was calculated. Univariate and logistic regression modeling for associations between clinical and treatment parameters and CH were performed. Results: We identified 2,195 patients who received RT before blood draw and 7,832 who did not, encompassing 57 histologies. A median of 267 days elapsed between the end of RT and blood draw. After RT, 22% of patients had at least one CH-PD mutation (n = 486). The most common single anatomic sites radiated were pelvis, chest wall/breast, and head and neck. Conventional RT was used in 2% (n = 46), 3D-conformal in 14% (n = 308), intensity modulated RT in 36% (n = 787), volumetric modulated arc RT in 12% (n = 263), multiple techniques in 26% (n = 560), and unknown in 11% (n = 231). There was no association between RT modality and presence of CH-PD (p &gt; 0.05 for all between group comparisons of modality). On multivariate regression after controlling for age, race, time from diagnosis to blood draw, smoking status, and for chemotherapy class, cytotoxic, immune, or targeted therapies in the entire cohort, EQD2 was associated with CH-PD (p = 0.012x10−3). Evaluating EQD2 by irradiated anatomic site, total pelvic dose by EQD2 in 10 Gy increments remained significantly associated with CH-PD (OR = 1.07, p = 0.0046), as was head and neck EQD2 (OR = 1.046, p = 0.032). Conclusions: CH-PD was associated with higher radiation dose for pelvic or head and neck RT, but not other anatomic sites after controlling for systemic therapies. RT modality was not associated with CH-PD. Ongoing work will directly evaluate the bone marrow dosimetry of various treatment approaches using phantom-based modeling.

Evaluation and prediction of pelvic dose in postoperative IMRT for cervical cancer

Objective To evaluate and predict the pelvic dose by analyzing two pelvic contour definitions and identify the influencing factors of the pelvic dose in postoperative IMRT for cervical cancer, aiming to provide reference for postoperative pelvis-sparing IMRT for cervical cancer. Methods Sixty cervical cancer patients receiving postoperative IMRT with unrestricted pelvic dose were selected. Two sets of pelvic contours (pelvic anatomy and pelvic Mell) were delineated as per the anatomical and Mell methods. The dose relationship between two methods was analyzed after redesigning the treatment plan by limiting dose of pelvic anatomy. The correlation analysis was performed by Pearson’s correlation method. The factors affecting the pelvic anatomy dose were identified by Logistic multivariate regression analysis and a dose prediction model was subsequently established. Results The volumes of pelvic anatomy and pelvic Mell were 925.82 cm3 and 1141.20 cm3(P=0.000). There was a significant correlation between them (r>0.622, P=0.000). The dose of pelvic anatomy was significantly higher than that of pelvic Mell. The relationship of V10, V20 and V30 between them was y=-8+ 1.01x, y=-13+ 1.05x and y=-4+ 0.9x, respectively. The dose limits of pelvic Mell recommended by literatures(V10<90%, V20<75%, V30<60%) were translated into V10<97%, V20<83% and V30<70%, respectively. The pelvic anatomy dose was significantly reduced after dose limiting. The V10, V20, V30 and Dmean were significantly decreased by 3.64%, 12.69%, 12.02% and 6.93%(P=0.000, 0.000, 0.000), respectively. Multivariate analysis showed that the overlapping volume of pelvic anatomy within PTV was an independent influencing factor of pelvic anatomy dose (P<0.05). Patients with a relative overlapping volume of less than 18% could easily meet the dose limiting requirement. Conclusions Both two pelvic contour definitions can be applied in postoperative pelvis-sparing IMRT for cervical cancer. Use of pelvic dose limiting can significantly reduce the IMRT dose. The overlapping volume of the pelvis within PTV is an independent influencing factor of pelvic dose. Patients whose overlapping volume within the PTV relative to pelvis is less than 18% can easily meet the dose limiting requirement. Key words: Cervical cancer/intensity-modulated radiotherapy; Pelvis; Dosimetry

Gonad shielding in pelvic radiography: modern optimised X-ray systems might allow its discontinuation

ObjectiveAs gonad shielding is currently under debate, this study evaluates the practice, from its introduction in about 1905 until today.MethodsThe literature was searched for developments in shielding and insights into the effects of ionising radiation on gonads. Based on own pre-1927 dose reconstructions, reported doses after 1927, a 2015-report from the European Union and recent own measurements, the effects of technological evolution and optimisation on radiation dose and hereditary risk were assessed.ResultsIn the 1900s, gonad shielding was first applied to prevent male sterility, but was discontinued when instrumental developments led to reduced radiation doses. In the 1950s, concerns about hereditary risks intensified and gonad shielding was recommended again, becoming routine worldwide. Imaging-chain improvements over time were considerable: in 2018, the absorbed dose was 0.5% of its 1905 value for the testes and 2% for the ovaries, our optimised effective dose a factor five lower than the value corresponding to the current EU diagnostic reference level, and the reduction in detriment-adjusted risk by shielding less than 1 × 10−6 for women and 5 × 10−6 for men.ConclusionsAssessment of pelvic doses revealed a large reduction in radiation risks facilitated by technological developments. Optimisation likewise contributed, but unfortunately, its potential was never adequately exploited. Today, using a modern and optimised X-ray system, gonad shielding can be safely discontinued for women. For men, there might be a marginal benefit, but potential negative side-effects may well dominate. Discontinuation of gonad shielding seems therefore justifiable.

Combined external pelvic chemoradiotherapy and image-guided adaptive brachytherapy in treatment of advanced cervical carcinoma: experience from a single institution.

PurposeExternal pelvic chemoradiotherapy and image-guided adaptive brachytherapy (IGABT) were studied in advanced cervical carcinomas. Treatment modalities were defined and related to outcomes and side effects.Material and methodsFrom a single cancer center, 138 patients with advanced cervical cancer were recruited. All patients were treated with external radiotherapy and IGABT. A dosimetric study was performed and related to treatment outcome and side effects. Toxicity of the organs at risk was evaluated by the CTCAE-grading system.ResultsThe median follow-up was 44 months. More than 60% of the tumors were FIGO stage IIB-IIIB and 82% were squamous cell carcinomas. Largest tumor size (width) was in mean 41 mm and 27% had lymph node spread. The mean total external dose was 51 Gy, and the mean total dose to the high-risk clinical target volume (HRCTV) was 88 Gy. In 130 patients (94%), weekly cisplatin was given in 4-6 cycles. The median number of brachytherapy fractions was four, and in 86 patients, interstitial needles were applied. The primary local control was 97% and 94% after four local recurrences. The overall pelvic control was 89%. The overall recurrence rate was 25% and distant metastases rate was 22%. The overall 5-year survival rate was 65% and cancer-specific survival rate was 69%. Prognostic factors were FIGO stage and total brachytherapy dose (D90) to HRCTV. Late serious toxicity of the bladder and intestine were rare, occurring in only 3% of patients.ConclusionsThe local and pelvic control rates were excellent in this series. The IGABT was an important part of the treatment schedule and could probably not be replaced by increasing the external pelvic dose. Adenocarcinomas seemed to benefit from the addition of interstitial needles. Late serious toxicity was rare.

Individually customised parametrial boost for locally advanced cervical cancer: is 2D planned external beam radiotherapy useful?

AbstractAim:Pelvic wall control and toxicity was retrospectively assessed in patients who received individually customised parametrial boost (PMB) for locally advanced cervical cancer with 2D planned external beam radiotherapy. Outcomes of a dose-escalated combined boost were also evaluated.Materials and methods:Toxicity and pelvic wall recurrence was evaluated over a median period of 24 months between two groups who received different pelvic wall doses. One group was randomised to receive either intracavitary brachytherapy (ICRT) with an external beam PMB using a customised midline shield, or a dose-escalated combined boost with interstitial brachytherapy (ISBT) and PMB. The comparator group received no PMB.Results:At 24 months, pelvic wall recurrence occurred in 2/112 and 40/130 with and without PMB, respectively (p &lt; 0·000001). No significant difference in toxicity was noted between boost versus no-boost groups (p = 0·56). Combined ISBT/PMB dose escalation showed no significant difference in pelvic wall recurrence compared with PMB alone (p = 0·49).Findings:Individually customised 2D PMBs with 3D image-based ICRT was safe and improved pelvic wall control in locally advanced cervix cancer. Dose-escalated combined boosts offered no significant benefit over standard boost doses.

Highlights From the Circulation Family of Journals.

Highlights From the Circulation Family of Journals.

Extended Protective Shield Under Table to Reduce Operator Radiation Dose in Percutaneous Coronary Procedures

Different tools and devices are effective to reduce operator radiation exposure at thorax level during percutaneous coronary procedures, but the operator radiation dose received at pelvic region still remains high. Our aim was to evaluate the efficacy of under-the-table adjunctive shields to reduce operator radiation exposure during percutaneous coronary procedures Methods and Results: The EXTRA-RAD study (Extended Protective Shield Under Table to Reduce Operator Radiation Dose in Percutaneous Coronary Procedures) is a prospective, single-center, randomized study. Patients who underwent transradial coronary procedures were randomized into 2 groups: group 1 (standard arrangement) and group 2 (adjunctive anti-rx shield under the angiographic table). In group 2, a further randomization was performed to compare 2 different under-the-table shields (a small curtain and a drape). A total of 205 procedures (122 diagnostic coronary angiographies and 83 percutaneous coronary interventions) performed in 157 patients by 4 different operators were included without significant differences in clinical and procedural characteristics between groups. The use of adjunctive shields was associated with lower radiation dose compared with no shield at pelvic region (42 µSv [14-98] in group 1, 13 µSv [5-27] in group 2; P<0.0001) and also at thorax level (4 µSv [1-13] in group 1, 2 µSv [1-4] in group 2; P=0.001). The reduction in dose was observed in all the operators. No significant differences were observed in pelvic dose using the 2 different shields ( P=0.183). The use of adjunctive anti-rx shields under the angiographic table during transradial coronary procedures is associated with a significant lower radiation dose to operators at pelvic and thorax level. URL: https://www.clinicaltrials.gov . Unique identifier: NCT03259126.

PO-0815: Correlation between pelvic bone marrow radiation dose and hematologic toxicity in cervical cancer

PO-0815: Correlation between pelvic bone marrow radiation dose and hematologic toxicity in cervical cancer

Preoperative Intensity-modulated Chemoradiation Therapy with Simultaneous Integrated Boost in Rectal Cancer: 2-year Follow-up Results of Phase II Study.

BackgroundThe aim of the study was to investigate the feasibility and safety of experimental fractionation using intensity modulated radiation therapy with a simultaneous integrated boost (IMRT-SIB) to shorten the overall treatment time without dose escalation in preoperative radiochemotherapy of locally advanced rectal cancer.Patients and methodsBetween January 2014 and November 2015, a total of 51 patients with operable stage II-III rectal adenocarcinoma were treated. The preoperative treatment with intensity modulated radiation therapy (IMRT) and a pelvic dose of 41.8 Gy and simultaneously delivered 46.2 Gy to T2/3 and 48.4 Gy to T4 tumour in 22 fractions, with standard concomitant capecitabine, was completed in 50 patients out of whom 47 were operated. The median follow-up was 35 months.ResultsThe rate of acute toxicity G ≥ 3 was 2.4%. The total downstaging rate was 89% and radical resection was achieved in 98% of patients. Pathologic complete response (pCR) was observed in 25.5% of patients, with 2-year local control (LC), disease free survival (DFS), and overall survival (OS) of 100% for this patient group. An intention-to-treat analysis revealed pN to be a significant prognostic factor for DFS and OS (P = 0.005 and 0.030, respectively). LC for the entire group was 100%, and 2-year DFS and OS were 90% (95 % CI 98.4–81.6) and 92.2% (95% CI 99.6–84.7), respectively.ConclusionsThe experimental regime in this study resulted in a high rate of pCR with a low acute toxicity profile. Excellent early results translated into encouraging 2-year LC, DFS, and OS.