Radiation-induced lumbosacral plexopathy and pelvic insufficiency fracture: A case report of unique coexistence of complications after radiotherapy for prostate cancer.

Case reports of plexopathy after prostate cancer are usually neoplastic. Radiation-induced lumbosacral plexopathy and insufficiency fractures have clinical significance due to the need to differentiate them from tumoral invasions, metastases, and spinal pathologies. Certain nuances, including clinical presentation and screening methods, help distinguish radiation-induced plexopathy from tumoral plexopathy. This case report highlights the coexistence of these two rare clinical conditions. Herein, we present a 78-year-old male with a history of radiotherapy for prostate cancer who developed right foot drop, severe lower back and right groin pain, difficulty in standing up and walking, and tingling in both legs over the past month during remission. The diagnosis of lumbosacral plexopathy and pelvic insufficiency fracture was made based on magnetic resonance imaging, positron emission tomography, and electroneuromyography. The patient received conservative symptomatic treatment and was discharged with the use of a cane for mobility. Radiation-induced lumbosacral plexopathy following prostate cancer should be kept in mind in patients with neurological disorders of the lower limbs. Pelvic insufficiency fracture should also be considered if the pain does not correspond to the clinical findings of plexopathy. These two pathologies, which can be challenging to diagnose, may require surgical or complex management approaches. However, in this patient, conservative therapies led to an improvement in quality of life and a reduction in the burden of illness.

Dosimetric evaluation of ovaries and pelvic bones associated with clinical outcomes in patients receiving total body irradiation with ovarian shielding.

Total body irradiation (TBI) with ovarian shielding is expected to preserve fertility among hematopoietic stem cell transplant (HSCT) patients with myeloablative TBI-based regimens. However, the radiation dose to the ovaries that preserves ovarian function in TBI remains poorly understood. Furthermore, it is uncertain whether the dose to the shielded organs is associated with relapse risk. Here, we retrospectively evaluated the relationship between fertility and the dose to the ovaries, and between relapse risk and the dose to the pelvic bones. A total of 20 patients (median age, 23 years) with standard-risk hematologic diseases were included. Median follow-up duration was 31.9 months. The TBI prescribed dose was 12 Gy in six fractions for three days. Patients' ovaries were shielded with cylinder-type lead blocks. The dose-volume parameters (D98% and Dmean) in the ovaries and the pelvic bones were extracted from the dose-volume histogram (DVH). The mean ovary Dmean for all patients was 2.4 Gy, and 18 patients recovered menstruation (90%). The mean ovary Dmean for patients with menstrual recovery and without recovery were 2.4 Gy and 2.4 Gy, respectively, with no significant difference (P = 0.998). Hematological relapse was observed in five patients. The mean pelvis Dmean and pelvis D98% for relapse and non-relapse patients were 11.6 Gy and 11.7 Gy and 5.6 Gy and 5.3 Gy, respectively. Both parameters showed no significant difference (P = 0.827, 0.807). In conclusion, TBI with ovarian shielding reduced the radiation dose to the ovaries to 2.4 Gy, and preserved fertility without increasing the risk of relapse.

Predictive factors of posttreatment fracture by definitive radiotherapy for uterine cervical cancer.

PURPOSE: Fractures are known to shorten life expectancy and worsen the quality of life. The risk of fractures after radiation therapy in cervical cancer patients is known to be multifactorial. In this study, we examined risk factors for fractures in cervical cancer patients, especially by evaluating bone densities and DVH parameters for fractured bones. MATERIALS AND METHODS: For 42 patients, clinical characteristics, pretreatment CT bone densities, and radiation dose were compared between patients with and without fractures. RESULTS: Posttreatment fractures occurred in 25 bones among ten patients. Pretreatment CT bone densities were significantly lower in patients with fractures (P < 0.05-0.01 across sites, except for the ilium and the ischium). Although DVH parameters were also significantly associated with fractures in univariate analysis, only CT densities were significantly associated with fractures in multivariate analysis. CONCLUSION: Pretreatment CT densities of spinal and pelvic bones, which may reflect osteoporosis, have a significant impact on the risk for posttreatment fractures.

An easy way to determine bone mineral density and predict pelvic insufficiency fractures in patients treated with radiotherapy for cervical cancer.

PURPOSE: The aim of this study was to investigate whether bone mineral density (BMD) as measured in planning computed tomographies (CTs) by a new method is a risk factor for pelvic insufficiency fractures (PIF) after radio(chemo)therapy (R(C)T) for cervical cancer. METHODS: 62 patients with cervical cancer who received definitive or adjuvant radio(chemo)therapy between 2013 and 2017 were reviewed. The PIF were detected on follow-up magntic resonance imaging (MRI). The MRI of the PIF patients was registered to the planning CT and the PIF contoured. On the contralateral side of the fracture, a mirrored structure of the fracture was generated (mPIF). For the whole sacral bone, three lumbar vertebrae, the first and second sacral vertebrae, and the PIF, we analyzed the BMD (mg/cm3), V50Gy, Dmean, and Dmax. RESULTS: Out of 62 patients, 6 (9.7%) had a fracture. Two out of the 6 patients had a bilateral fracture with only one of them being symptomatic. PIF patients showed a significantly lower BMD in the sacral and the lumbar vertebrae (p < 0.05). The BMD of the contoured PIF, however, when comparing to the mPIF, did not reach significance (p < 0.49). The difference of the V50Gy of the sacrum in the PIF group compared to the other (OTH) patients, i.e. those without PIF, did not reach significance. CONCLUSION: The dose does not seem to have a relevant impact on the incidence of PIF in our patients. One of the predisposing factors for developing PIF after radiotherapy seems to be the low BMD. We presented an easy method to assess the BMD in planning CTs.

[Pelvic irradiation and hematopoietic toxicity: A review of the literature]. / Irradiation pelvienne et toxicité hématopoïétique : revue de la littérature.

Pelvic bone marrow is the site of nearly 50% of total hematopoiesis. Radiation therapy of pelvic lymph node areas, and cancers located near the bony structures of the pelvis, exposes to hematological toxicity in the range of 30 to 70%. This toxicity depends on many factors, including the presence or absence of concomitant chemotherapy and its type, the volume of irradiated bone, the received doses, or the initial hematopoietic reserve. Intensity modulated radiation therapy allows the optimisation of dose deposit on at risk organs while providing optimal coverage of target volumes. However, this suggests that dose constraints should be known precisely to limit the incidence of radiation side effects. This literature review focuses firstly on pelvic lymph node areas and bony volumes nearby, then on the effects of irradiation on bone marrow and the current dosimetric constraints resulting from it, and finally on hematological toxicities by carcinologic location and progress in reducing these toxicities.

Prostate or bone? Comparing the efficacy of image guidance surrogates for pelvis and prostate radiotherapy using accumulated delivered dose.

INTRODUCTION: This study assessed the impact of dosimetry to both the target and normal tissue when either bony anatomy (BA) or prostate (PRO) was used as surrogates for image guidance for pelvis and prostate radiotherapy using a dose accumulation process. METHODS: Thirty patients who were prescribed 50-54Gy to the pelvic lymph nodes (PLN) and 78Gy to the prostate/seminal vesicles were included. Daily acquired CBCTs were rigidly registered to the CT using BA and PRO to simulate two different treatment positions. The accumulated delivered dose (DAcc) of PLN, prostate, bladder and rectum for each surrogate were compared with the planned dose. Deviation from the planned dose (ΔDAcc-Plan) of >5% was considered clinically significant. RESULTS: Prostate was displaced from bony anatomy by > 5 mm in 96/755 fractions (12.7%). Deviation between the mean DAcc and the planned dose for PLN and prostate was <2% when either BA or PRO was used. No significant deviation from planned dose was observed for bladder (p > 0.2). In contrary, DAcc for rectum D50 was significantly greater than the planned dose when BA was used (Mean ΔDAcc-Plan = 6%). When examining individual patient, deviation from the planned dose for rectum D50 was clinically significant for 18 patients for BA (Range: 5-21%) and only 8 patients for PRO (Range: 5-8%). CONCLUSIONS: The use of either BA or PRO for image guidance could deliver dose to PLN and prostate with minimal deviation from the plan using existing PTV margins. However, deviation for rectum was greater when BA was used.

Simple calculation using anatomical features on pre-treatment verification CT for bladder volume estimation during radiation therapy for rectal cancer.

BACKGROUND: Despite detailed instruction for full bladder, patients are unable to maintain consistent bladder filling during a 5-week pelvic radiation therapy (RT) course. We investigated the best bladder volume estimation procedure for verifying consistent bladder volume. METHODS: We reviewed 462 patients who underwent pelvic RT. Biofeedback using a bladder scanner was conducted before simulation and during treatment. Exact bladder volume was calculated by bladder inner wall contour based on CT images (Vctsim). Bladder volume was estimated either by bladder scanner (Vscan) or anatomical features from the presacral promontory to the bladder base and dome in the sagittal plane of CT (Vratio). The feasibility of Vratio was validated using daily megavoltage or kV cone-beam CT before treatment. RESULTS: Mean Vctsim was 335.6 ± 147.5 cc. Despite a positive correlation between Vctsim and Vscan (R2 = 0.278) and between Vctsim and Vratio (R2 = 0.424), Vratio yielded more consistent results than Vscan, with a mean percentage error of 26.3 (SD 19.6, p < 0.001). The correlation between Vratio and Vctsim was stronger than that between Vscan and Vctsim (Z-score: - 7.782, p < 0.001). An accuracy of Vratio was consistent in megavoltage or kV cone-beam CT during treatment. In a representative case, we can dichotomize for clinical scenarios with or without bowel displacement, using a ratio of 0.8 resulting in significant changes in bowel volume exposed to low radiation doses. CONCLUSIONS: Bladder volume estimation using personalized anatomical features based on pre-treatment verification CT images was useful and more accurate than physician-dependent bladder scanners. TRIAL REGISTRATION: Retrospectively registered.

Comparison of prostate verification with implanted gold markers in tissue surrounding the prostate and pelvic bony anatomy for external beam radiation therapy following low-dose-rate brachytherapy: a prospective clinical trial.

We aimed to investigate whether gold marker implantation in the tissue surrounding the prostate could accurately monitor setup errors during external beam radiation therapy (EBRT) following low-dose-rate (LDR) brachytherapy. Thirty-eight patients had confirmed intermediate- or high-risk prostate cancer and received EBRT following LDR brachytherapy. In >175 computed tomography imaging sessions, the average values of the weekly setup error during EBRT to the prostate centroid at the time of gold marker matching in the surrounding tissue of the prostate and pelvic bone matching were measured and then compared using the Wilcoxon signed-rank test. Gold marker matching in the surrounding tissue of the prostate estimated setup errors better than those estimated by bone matching (3D displacement = 2.7 ± 2.0 vs 3.8 ± 2.6 mm, P < 0.01). Overall, the standard deviation of systematic (Σ) and random (σ) setup error was lower with gold marker matching than with bone matching (3D displacement = 1.8 and 1.1 mm vs 2.1 and 1.6 mm, respectively). With gold marker matching, the setup error of the position of the prostate centroid was smaller, and the optimal setup margin was lower than that with bone matching (2Σ + 0.7σ and 2.5Σ + 0.7σ of 3D displacement = 4.3 and 5.2 mm vs 5.3 and 6.4 mm, respectively). This high-precision radiotherapy approach placing gold markers in the surrounding tissue of the prostate can allow more accurate setup during EBRT following LDR brachytherapy.

Assessment of the results and hematological side effects of 3D conformal and IMRT/ARC therapies delivered during craniospinal irradiation of childhood tumors with a follow-up period of five years.

BACKGROUND: Craniospinal irradiation (CSI) of childhood tumors with the RapidArc technique is a new method of treatment. Our objective was to compare the acute hematological toxicity pattern during 3D conformal radiotherapy with the application of the novel technique. METHODS: Data from patients treated between 2007 and 2014 were collected, and seven patients were identified in both treatment groups. After establishing a general linear model, acute blood toxicity results were obtained using SPSS software. Furthermore, the exposure dose of the organs at risk was compared. Patients were followed for a minimum of 5 years, and progression-free survival and overall survival data were assessed. RESULTS: After assessment of the laboratory parameters in the two groups, it may be concluded that no significant differences were detected in terms of the mean dose exposures of the normal tissues or the acute hematological side effects during the IMRT/ARC and 3D conformal treatments. Laboratory parameters decreased significantly compared to the baseline values during the treatment weeks. Nevertheless, no significant differences were detected between the two groups. No remarkable differences were confirmed between the two groups regarding the five-year progression-free survival or overall survival, and no signs of serious organ toxicity due to irradiation were observed during the follow-up period in either of the groups. CONCLUSION: The RapidArc technique can be used safely even in the treatment of childhood tumors, as the extent of the exposure dose in normal tissues and the amount of acute hematological side effects are not higher with this technique.

Pelvic bone marrow sparing intensity modulated radiotherapy reduces the incidence of the hematologic toxicity of patients with cervical cancer receiving concurrent chemoradiotherapy: a single-center prospective randomized controlled trial.

PURPOSE: To test the efficacy and feasibility of pelvic bone marrow sparing intensity modulated radiotherapy (PBMS-IMRT) in reducing grade 2 or higher hematological toxicity (HT2+) for patients with cervical cancer treated with concurrent chemoradiotherapy. METHODS AND MATERIALS: A total of 164 patients with Stage Ib2-IIIb cervical cancer were prospectively enrolled from March 2018 to March 2019 at a single center and were randomly allocated into the PBMS group or the control group. The control group received weekly cisplatin concurrently with IMRT, followed by intracavitary brachytherapy. The PBMS group additionally received PBM dose constraint. The dosimetric parameters of the pelvic bone (PB) and the subsites including hip bone (HIP) and lumbosacral spine (LSS) and the corresponding bone marrow were recorded. The endpoint of the trial was acute hematologic or gastrointestinal toxicity. Receiver operating characteristic curves were used to derive optimal dosimetric planning constraints. RESULTS: Eighty-two patients in the PBMS group and 82 in the control group were enrolled for statistical analysis. The incidence of HT2+ in the PBMS group was 50.0%, significantly lower than the 69.5% incidence in the control group (P = 0.02). Patients with PB V40 ≥ 28% were more likely to experience HT2+ (OR = 2.85, P = 0.006), while the incidence of grade 2 or higher gastrointestinal toxicity (GT2+) events did not differ significantly between the two groups (P > 0.05). Dosimetric parameters of LSS showed stronger associations with HT2+ than other subsites. The patients with LSS V10 ≥ 87% and LSS mean ≥ 39 Gy were more likely to experience HT2+ (OR = 3.13, P = 0.001;OR = 3.03, P = 0.002, respectively). CONCLUSION: PBMS-IMRT reduced HT compared with IMRT alone. Efforts to maintain LSS V10 < 87%, LSS mean < 39 Gy and PB V40 < 28% simultaneously may reduce the risk of HT2 +. TRIAL REGISTRATION: The trial was registered with Chinese clinical trial registry ( ChiCTR1800015069 ).

A Multi-atlas Approach for Active Bone Marrow Sparing Radiation Therapy: Implementation in the NRG-GY006 Trial.

PURPOSE: Sparing active bone marrow (ABM) can reduce acute hematologic toxicity in patients undergoing chemoradiotherapy for cervical cancer, but ABM segmentation based on positron emission tomography/computed tomography (PET/CT) is costly. We sought to develop an atlas-based ABM segmentation method for implementation in a prospective clinical trial. METHODS AND MATERIALS: A multiatlas was built on a training set of 144 patients and validated in 32 patients from the NRG-GY006 clinical trial. ABM for individual patients was defined as the subvolume of pelvic bone greater than the individual mean standardized uptake value on registered 18F-fluorodeoxyglucose PET/CT images. Atlas-based and custom ABM segmentations were compared using the Dice similarity coefficient and mean distance to agreement and used to generate ABM-sparing intensity modulated radiation therapy plans. Dose-volume metrics and normal tissue complication probabilities of the two approaches were compared using linear regression. RESULTS: Atlas-based ABM volumes (mean [standard deviation], 548.4 [88.3] cm3) were slightly larger than custom ABM volumes (535.1 [93.2] cm3), with a Dice similarity coefficient of 0.73. Total pelvic bone marrow V20 and Dmean were systematically higher and custom ABM V10 was systematically lower with custom-based plans (slope: 1.021 [95% confidence interval (CI), 1.005-1.037], 1.014 [95% CI, 1.006-1.022], and 0.98 [95% CI, 0.97-0.99], respectively). We found no significant differences between atlas-based and custom-based plans in bowel, rectum, bladder, femoral heads, or target dose-volume metrics. CONCLUSIONS: Atlas-based ABM segmentation can reduce pelvic bone marrow dose while achieving comparable target and other normal tissue dosimetry. This approach may allow ABM sparing in settings where PET/CT is unavailable.

Radiation-Induced Insufficiency Fractures After Pelvic Irradiation for Gynecologic Malignancies: A Systematic Review.

PURPOSE: To identify and define the incidence, risk factors, clinical characteristics, and treatment approaches to pelvic insufficiency fractures (PIFs) that develop as a consequence of pelvic radiation therapy for gynecologic malignancies. MATERIALS AND METHODS: A systematic literature review (PubMed and Embase indexed from January 1, 1980, to May 1, 2020) of studies describing PIFs that result from radiation therapy for gynecologic malignancies. A random-effects model weighted by the inverse variance was used to calculate the pooled crude incidence, actuarial incidence, and proportion of symptomatic PIFs, and to evaluate the relationship between PIF incidence and various risk factors. RESULTS: Thirty-eight studies describing PIFs following radiation therapy for gynecologic malignancies were reviewed. A meta-analysis of 6488 patients (37 studies) identified the crude incidence of PIF as 9.4% (95% confidence interval [CI] 6.8%-12.4%), and a meta-analysis of 2131 patients (9 studies) identified the 5-year actuarial incidence of PIF as 15.3% (95% CI 7.5%-25.0%). Factors that significantly correlated with increased risk of PIF development included evidence of osteoporosis (P < .001), postmenopausal state (P < .001), and history of diabetes mellitus (P = .005). Median time to PIF development ranged from 8 to 39 months after radiation therapy with the sacrum being the most frequent location for fracture development (60%). From 18 studies, 58.5% (95% CI 50.6%-66.2%) of PIFs were symptomatic, with pain as the most common presenting symptom of PIFs. Conservative management was used more than bone-directed therapies for treatment of PIFs (85% and 6% of patients, respectively). CONCLUSIONS: PIFs cause significant morbidity in gynecologic cancer patients after radiation therapy. In this systematic review, we discuss the incidence and risk factors associated with PIF development as it relates to the different detection methods, radiation techniques, doses, and gynecologic cancers treated. Additional studies are needed to further define prevention and treatment approaches for insufficiency fractures.

Risk of Pelvic Fracture With Radiation Therapy in Older Patients.

PURPOSE: Older patients undergoing radiation therapy (RT) for pelvic malignancies are at increased risk for pelvic fracture, which is associated with significant morbidity and mortality. RT techniques such as brachytherapy or intensity modulated RT (IMRT) allow for more conformal dose distributions, but it is not known whether the risk for pelvic fracture varies by RT modality. METHODS AND MATERIALS: This observational cohort study involved 28,354 patients ≥65 years old, treated with RT for pelvic malignancies. We evaluated the relative risk of pelvic fracture by type of RT when accounting for baseline factors. To test for nonspecific effects, we also evaluated risk of nonpelvic fractures in the same population. RESULTS: The 5-year incidence of pelvic fractures was 12.7% (95% confidence interval [CI], 11.6%-13.8%), 11.8% (10.8%-12.8%), and 3.7% (3.4%-4.0%) for patients with gastrointestinal, gynecologic, and prostate cancer, respectively. On multivariable analysis, being treated with IMRT (hazard ratio, 0.85; 95% CI, 0.73-0.99) or brachytherapy therapy alone (hazard ratio, 0.43; 95% CI, 0.34-0.54) was associated with a reduced hazard for pelvic fractures compared with 3D conformal radiation therapy in female patients. In contrast, there was no association with RT modality and the hazard for nonpelvic fractures among females. There was no significant association between pelvic fractures and IMRT or brachytherapy for male patients. White race, advanced age, and higher comorbidity were associated with an increased hazard for pelvic fracture. CONCLUSIONS: IMRT and brachytherapy were associated with a reduced risk of pelvic fractures in older women undergoing RT for pelvic malignancies. Pelvic insufficiency fracture risk should be considered when treating with pelvic RT.

Pelvic Insufficiency Fractures After External Beam Radiation Therapy for Gynecologic Cancers: A Meta-analysis and Meta-regression of 3929 Patients.

PURPOSE: To estimate the overall rate, symptomatic proportion, and most common sites of pelvic insufficiency fracture (PIF) after external beam radiation therapy for gynecologic cancers based on posttreatment computed tomography, magnetic resonance imaging, positron emission tomography, or bone scintigraphy. METHODS AND MATERIALS: A systematic search of databases (PubMed and EMBASE) was performed (CRD42019125679). The pooled summary of overall PIF and the proportion of symptomatic cases were calculated using the random-effects model weighted by the inverse variance. A multivariate meta-regression was performed to evaluate potential sources of heterogeneity regarding PIF fractures. RESULTS: Twenty-one studies met the inclusion criteria (total 3929 patients). Five hundred four patients developed PIF, translating to an overall rate of 14% (95% confidence interval, 10%-18%, based on 21 studies). Among these cases with PIF, the proportion of symptomatic patients was 61% (95% confidence interval, 52%-69%, based on 14 studies). The total number of PIFs was 704 (mean, 1.72 PIFs per each patient to develop PIF, based on 14 studies). More recent series (P = .0074) and the use of intensity modulated radiation therapy (P = .0299) were associated with lower fracture rates. The most common fracture sites were sacroiliac joint (39.7%), body of the sacrum (33.9%), pubis (13%), lumbar vertebra (7%), iliac bone (2.8%), acetabulum (2.1%), and femoral head/neck (1.5%). The median time to fracture was 7.1 to 19 months after radiation therapy. CONCLUSIONS: The incidence of PIF after radiation therapy for gynecologic cancers is high (14%), with the majority affecting the sacral bone or joint (73.6%), although this risk appears to be lower with intensity modulated radiation therapy. Posttreatment bone surveillance is warranted in this population because nearly 40% of patients were asymptomatic at the time of PIF diagnosis.

Dosimetric Considerations for Ytterbium-169, Selenium-75, and Iridium-192 Radioisotopes in High-Dose-Rate Endorectal Brachytherapy.

PURPOSE: To investigate differences between prescribed and postimplant calculated dose in 192Ir high-dose-rate endorectal brachytherapy (HDR-EBT) by evaluating dose to clinical target volume (CTV) and organs at risk (OARs) calculated with a Monte Carlo-based dose calculation software, RapidBrachyMC. In addition, dose coverage, conformity, and homogeneity were compared among the radionuclides 192Ir, 75Se, and 169Yb for use in HDR-EBT. METHODS AND MATERIALS: Postimplant dosimetry was evaluated using 23 computed tomography (CT) images from patients treated with HDR-EBT using the 192Ir microSelectron v2 (Elekta AB, Stockholm, Sweden) source and the Intracavitary Mold Applicator Set (Elekta AB, Stockholm, Sweden), which is a flexible applicator capable of fitting a tungsten rod for OAR shielding. Four tissue segmentation schemes were evaluated: (1) TG-43 formalism, (2) materials and nominal densities assigned to contours of foreign objects, (3) materials and nominal densities assigned to contoured organs in addition to foreign objects, and (4) materials specified as in (3) but with voxel mass densities derived from CT Hounsfield units. Clinical plans optimized for 192Ir were used, with the results for 75Se and 169Yb normalized to the D90 of the 192Ir clinical plan. RESULTS: In comparison to segmentation scheme 4, TG-43-based dosimetry overestimates CTV D90 by 6% (P = .00003), rectum D50 by 24% (P = .00003), and pelvic bone D50 by 5% (P = .00003) for 192Ir. For 169Yb, CTV D90 is overestimated by 17% (P = .00003) and rectum D50 by 39% (P = .00003), and pelvic bone D50 is significantly underestimated by 27% (P = .007). Postimplant dosimetry calculations also showed that a 169Yb source would give 20% (P = .00003) lower rectum V60 and 17% (P = .00008) lower rectum D50. CONCLUSIONS: Ignoring high-Z materials in dose calculation contributes to inaccuracies that may lead to suboptimal dose optimization and disagreement between prescribed and calculated dose. This is especially important for low-energy radionuclides. Our results also show that with future magnetic resonance imaging-based treatment planning, loss of CT density data will only affect calculated dose in nonbone OARs by 2% or less and bone OARs by 13% or less across all sources if material composition and nominal mass densities are correctly assigned.

Impact of pelvic bone marrow irradiation on the hematological toxicity of subsequent chemotherapy in rectal cancer.

Preoperative radio(chemo)therapy in rectal cancer may irreversibly damage pelvic bone marrow (PBM) and impair the tolerance of subsequent chemotherapy. The aim of the study was to assess the relationship between the irradiated volume of PBM and the toxicity of subsequent 5-fluorouracil, oxaliplatin, leucovorin (FOLFOX-4) in rectal cancer. We included consecutive rectal cancer patients who received FOLFOX-4 postoperatively or due to cancer relapse. The PBM was divided into iliac (IM), lumbosacral (LSM), and lower pelvic (LPM) marrow. We assessed mean dose, and percentage of volume receiving 10%-90% (V10%-V90%) of the prescribed dose for PBM, IM, LSM, and LPM. Generalized linear model for repeated measures (GLM) was used to test an influence of dose-volumes distribution on toxicities grade 2 or higher (TOX2) and grade 3 or higher (TOX3). The two-sided t-test was used to evaluate the difference in mean dose, mean V20%, and mean V40% between patients who experienced TOX2 or TOX3 and those who did not. 39 patients met eligibility criteria. Because of the low occurrence of TOX3 (n=3), related analyses were abandoned. We found no influence of dose-volume distribution on TOX2 in GLM and no significant differences in mean dose, mean V20%, and mean V40% for PBM, IBM, LSM, and LPM between patients who experienced TOX2 and those who did not. To conclude, no relationship between doses received by PBM in preoperative radio(chemo)therapy in rectal cancer and hematological tolerance of subsequent FOLFOX-4 chemotherapy was found.

Dose to Pelvic Bone Marrow Defined with FDG-PET Predicts for Hematologic Nadirs in Anal Cancer Patients Treated with Concurrent Chemo-radiation.

PURPOSE: To investigate whether irradiated volume of pelvic active bone marrow (ACTBM) may predict decreased blood cells nadirs in anal cancer patients undergoing concurrent chemo-radiation. METHODS: Forty-four patients were analyzed and pelvic active bone marrow (ACTBM) was characterized employing 18FDG-PET. Dosimetric parameters on dose-volume histograms were correlated to nadirs with generalized linear modeling. RESULTS: ACTBM mean dose was significantly correlated to white blood cell (ß = -1.338; 95%CI: -2.455/-0.221; p = 0.020), absolute neutrophil count (ß = -1.651; 95%CI: -3.284/-0.183; p = 0.048), and platelets (ß = -0.031; 95%CI: -0.057/-0.004; p = 0.024) nadirs. Other dosimetric parameters were found to be correlated (ACTBM-V10,-V20,-V30and-V40). CONCLUSIONS: 18FDG-PET is able to define active bone marrow and may predict for decreased blood cells count nadirs.

Incorporating 18FDG-PET-defined pelvic active bone marrow in the automatic treatment planning process of anal cancer patients undergoing chemo-radiation.

BACKGROUND: To investigate whether the incorporation of 18FDG-PET into the automatic treatment planning process may be able to decrease the dose to active bone marrow (BM) for locally advanced anal cancer patients undergoing concurrent chemo-radiation (CHT-RT). METHODS: Ten patients with locally advanced anal cancer were selected. Bone marrow within the pelvis was outlined as the whole outer contour of pelvic bones or employing 18FDG-PET to identify active BM within osseous structures. Four treatment planning solutions were employed with different automatic optimization approaches toward bone marrow. Plan A used iliac crests for optimization as per RTOG 05-29 trial; plan B accounted for all pelvic BM as outlined by the outer surface of external osseous structures; plan C took into account both active and inactive BM as defined using 18FDG-PET; plan D accounted only for the active BM subregions outlined with 18FDG-PET. Dose received by active bone marrow within the pelvic (ACTPBM) and in different subregions such as lumbar-sacral (ACTLSBM), iliac (ACTIBM) and lower pelvis (ACTLPBM) bone marrow was analyzed. RESULTS: A significant difference was found for ACTPBM in terms of Dmean (p = 0.014) V20 (p = 0.015), V25 (p = 0.030), V30 (p = 0.020), V35 (p = 0.010) between Plan A and other plans. With respect to specific subsites, a significant difference was found for ACTLSBM in terms of V30 (p = 0.020)), V35 (p = 0.010), V40 (p = 0.050) between Plan A and other solutions. No significant difference was found with respect to the investigated parameters between Plan B,C and D. No significant dosimetric differences were found for ACTLSPBM and ACTIBM and inactive BM subregions within the pelvis between any plan solution. CONCLUSIONS: Accounting for pelvic BM as a whole compared to iliac crests is able to decrease the dose to active bone marrow during the planning process of anal cancer patients treated with intensity-modulated radiotherapy. The same degree of reduction may be achieved optimizing on bone marrow either defined using the outer bone contour or through 18FDG-PET imaging. The subset of patients with a benefit in terms of dose reduction to active BM through the inclusion of 18FDG-PET in the planning process needs further investigation.

Pelvic fractures after definitive and postoperative radiotherapy for cervical cancer: A retrospective analysis of risk factors.

OBJECTIVES: This study clarified the incidence of and identified the risk factors for post-radiation pelvic insufficiency fractures (PIFs) in women who received postoperative definitive or adjuvant radiotherapy (RT) for cervical cancer. PATIENTS AND METHODS: The medical records and data of imaging studies, including computed tomography scan and magnetic resonance imaging, of women with cervical cancer who received external-beam RT for the entire pelvic area between January 2003 and December 2012 at our institution were reviewed. RESULTS: A total of 533 patients with histologically diagnosed cervical cancer who received RT (298: definitive RT, 235: adjuvant RT) were included in this study. Eighty-four patients (15.8%) developed PIF in the irradiated field. Median age at onset of PIF was 72.5years (range: 54-95years), and 82 of them (98%) were postmenopausal women. Sixty-nine patients (80%) developed PIF within 3years from the completion of RT. The median time for the development of PIF was 14months (range: 1-81months). The most commonly involved fracture site was the sacral bone. Postmenopausal state, coexistence of rheumatoid arthritis, and high-dose-rate intracavitary brachytherapy (HDR-ICBT) use were significant predisposing factors for the development of PIF, according to multivariate analysis. CONCLUSIONS: The incidence rate of PIF among patients who received RT for locally advanced cervical cancer was 15.8%. The principal predisposing factors for post-radiation PIF were postmenopausal state, rheumatoid arthritis, and HDR-ICBT use. Active interventions, including bone density screening followed by medication, should be considered during the early stage of RT for women with high-risk factors of PIF.

[Extracorporeal irradiation : Reimplantation of bone segments in the treatment of malignant bone tumours]. / Die extrakorporale Bestrahlung : Replantation von Knochensegmenten bei malignen Knochentumoren.

BACKGROUND: Malignant bone tumors themselves and the wide resection required because of them may cause huge bone defects in the bone segment involved. Autologous bone grafts are a reliable option to cover these defects in many cases but their availability is limited. Besides common alternative reconstruction methods, including the use of allografts and/or prostheses, especially extracoroporeal irradiation (ECI) and reimplantation of the bone segment involved is attracting increasingly more attention nowadays. DISCUSSION: In the following, we report on indications/contraindications, details of the operative technique, as well as the recommended rehabilitation regime of ECI. Furthermore, we compare our own results with those published in the recent literature. Especially the advantages and disadvantages of this method, the risks and the complications are illustrated and critically discussed. CONCLUSION: Extracorporeal irradiation of a tumor bearing bone segment is a valuable alternative reconstruction technique following tumor resections of the pelvis, femur and tibia, with encouraging results with respect to local control, complication risks and functional outcome.