Incidence and possible aetiological factors in the development of pelvic insufficiency fractures following radical radiotherapy

Insights into pelvic insufficiency fracture following pelvic radiotherapy for cervical cancer: a comparative review

BACKGROUND

Radiotherapy (RT)-induced pelvic insufficiency fractures (PIF) are prevalent in patients with cervical cancer. Inconclusive studies on PIF after cervical irradiation create uncertainty. This review examined PIF after RT in cervical patients, including its pathobiology, likely locations of fractures, incidence, clinical symptoms, and predisposing factors. We further discussed study limitations and therapeutic possibilities of PIF.

METHODS

The following online resources were searched for relevant articles: Google Scholar and PubMed. The keywords 'pelvic insufficiency fractures', 'cervical carcinoma' and 'cervical cancer', as well as 'chemoradiotherapy', 'chemoradiation', and 'radiotherapy', were some of the terms that were used during the search.

RESULTS

Patients with PIF report pelvic pain after radiation treatment for cervical cancer; the incidence of PIF ranges from 1.7 to 45.2%. Evidence also supports that among all patients treated with pelvic radiation, those who experienced pelvic insufficiency fractures invariably had at least one sacral fracture, making it the most frequently fractured bone in the body. Menopausal status, weight, BMI, age, and treatments and diagnosis modalities can influence PIF during radiotherapy.

CONCLUSIONS

In conclusion, our comparative review of the literature highlights significant heterogeneity in various aspects of PIF following radiation for patients with cervical cancer. This diversity encompasses prevalence rates, associated risk factors, symptoms, severity, diagnosis methods, preventive interventions, and follow-up periods. Such diversity underscores the complexity of PIF in this population and emphasizes the critical need for further research to elucidate optimal management strategies and improve patient outcomes.

Pelvic insufficiency fractures and pelvic bone metastases after neoadjuvant (chemo)radiotherapy for rectal cancer

BACKGROUND

Pelvic insufficiency fractures (PIFs) are a late complication of radiotherapy for pelvic malignancies. We evaluated the incidence, radiologic findings, clinical course, and outcome of PIFs in patients treated with neoadjuvant (chemo)radiotherapy ((C)RT) for rectal cancer.

MATERIAL AND METHODS

Data of patients diagnosed with rectal cancer from a large teaching hospital treated from 2002 to 2012 were extracted from the Dutch Cancer Registry. All hospital records were reviewed for the diagnosis of PIFs or pelvic bone metastases. An expert radiologist reassessed all imaging procedures of the lower back, abdomen, and pelvis.

RESULTS

A total of 513 rectal cancer patients were identified of whom 300 patients (58.5%) were treated with neoadjuvant (C)RT (long- vs. short-course radiotherapy: 91 patients [17.7%] vs. 209 [40.7%], respectively). Twelve PIFs were diagnosed initially according to hospital records and imaging reports of all 513 patients. These 12 patients were treated with neoadjuvant (C)RT. After reassessment of all pelvic imaging procedures done in this patient group (432 patients (84.2%)), 20 additional PIFs were detected in patients treated with neoadjuvant (C)RT, resulting in a 10.7% PIF rate in irradiated patients. One PIF was detected in the group of patients not treated with neoadjuvant (C)RT for rectal cancer. This patient had palliative radiotherapy for prostate cancer and is left out of the analysis. Median follow-up time of 32 PIF patients was 49 months. Median time between start of neoadjuvant (C)RT and diagnosis of PIF was 17 months (IQR 9-28). Overall median survival for patients with PIF was 63.5 months (IQR 44-120).

CONCLUSION

PIFs are a relatively common late complication of neoadjuvant (C)RT for rectal cancer but are often missed or misdiagnosed as pelvic bone metastases. The differentiation of PIFs from pelvic bone metastases is important because of a different treatment and disease outcome.

Pelvic Insufficiency Fractures in Cervical Cancer After Radiation Therapy: A Meta-Analysis and Review

AIM

The aim of the study was to estimate the prevalence of pelvic insufficiency fractures (PIFs) after radiation therapy (RT) in patients with cervical cancer.

PATIENTS AND METHODS

A total of 3,633 patients from 15 cohort studies were included. Proportion meta-analysis was performed to estimate prevalence and subgroup analysis was performed according to imaging modalities for diagnosis of PIF. For continuous variables (age and length of follow-up), meta-regression analysis was performed.

RESULTS

Pooled prevalence estimate of PIF was 14% (95% CI=10-19). Incidence of PIF was higher in studies that used MRI as a diagnostic tool (17%, 95% CI=12-22) than non-MRI (8%, 95% CI=2-14). In meta-regression, we found a significant association of prevalence of PIF with age (p=0.021) but not with length of follow-up (p=0.118).

CONCLUSION

PIF after RT in patients with cervical cancer is not rare. Physicians need to pay attention to PIFs, especially in patients with high-risk factors for osteoporotic fracture.

Radiotherapy for Cervical Cancer in Patients with Systemic Lupus Erythematosus

OBJECTIVE

To determine the toxicity and efficacy of radiotherapy for cervical cancer in patients with systemic lupus erythematosus (SLE).

METHODS

Medical records of patients with SLE who received radiation for cervical cancer from January 2011 to January 2019 were reviewed. For definitive radiotherapy, a dose of 50.4 Gy in 28 fractions was delivered by intensity-modulated radiation therapy (IMRT) combined with high-dose-rate brachytherapy of 28 to 30 Gy in 5 fractions. A dose of 45 to 50.4 Gy in 25-28 fractions was delivered for postoperative radiation. All patients were in remission with or without a low dosage of prednisone or immunosuppressive medication. Survival data were analyzed with the Kaplan-Meier method. The incidence of severe toxicities among patients was compared with the chi-square test or Fisher's exact test.

RESULTS

Twelve patients with SLE were included in this study. Definitive radiotherapy was delivered in 7 patients with FIGO (2009) stage II-III disease. Five patients with FIGO I disease received postoperative radiation. The median follow-up time was 22.1 months. The 3-year overall survival (OS) and 3-year progression-free survival (PFS) were 77.8% and 83.3%, respectively. One patient of definitive radiotherapy and one patient of postoperative radiation died due to distant metastasis of cervical cancer. Grade 3 or higher acute and chronic reactions occurred in 58.3% and 8.3% patients, respectively. Acute grade 3 or higher toxicity correlated with the presence of chemotherapy (p = 0.045).

CONCLUSION

Modern radiotherapy for cervical cancer was well tolerated in SLE patients with remission and provided a favorable outcome.

Pelvic fractures and changes in bone mineral density after radiotherapy for cervical, endometrial, and vaginal cancer: A prospective study of 239 women

BACKGROUND

Advances in radiotherapy (RT) have led to improved oncologic outcomes for women with gynecologic cancers; however, the long-term effects and survivorship implications need further evaluation. The purpose of this study was to determine the incidence of pelvic fractures and changes in bone mineral density (BMD) after pelvic RT.

METHODS

Two hundred thirty-nine women who had pelvic RT for cervical, endometrial, or vaginal cancer between 2008 and 2015 were prospectively studied. BMD scans and biomarkers of bone turnover were obtained at the baseline and 3 months, 1 year, and 2 years after RT. Imaging studies were assessed for pelvic fractures for up to 5 years. Patients with osteopenia, osteoporosis, or pelvic fractures at any point were referred to the endocrinology service for evaluation and treatment.

RESULTS

The median age at diagnosis was 51 years; 132 patients (56%) were menopausal. The primary diagnoses were cervical (63.6%), endometrial (30.5%), and vaginal cancer (5.9%). Sixteen patients (7.8%; 95% confidence interval, 4.5%-12.4%) had pelvic fractures with actuarial rates of 3.6%, 12.7%, and 15.7% at 1, 2, and 3 years, respectively. Fractures were associated with baseline osteoporosis (P < .001), higher baseline bone-specific alkaline phosphatase (P < .001), and older age (P = .007). The proportion of patients with osteopenia/osteoporosis increased from 50% at the baseline to 58%, 59%, and 70% at 3 months, 1 year, and 2 years, respectively.

CONCLUSIONS

A high proportion of women had significant decreases in BMD after pelvic RT, with 7.8% diagnosed with a pelvic fracture. BMD screening and pharmacologic intervention should be strongly considered for these high-risk women.

Pathological fracture after radiotherapy: systematic review of literature

OBJECTIVE

To evaluate the epidemiological data and available treatments for fractures secondary to radiotherapy treatment.

METHODS

Identification of publications on pathological skeletal fractures previously exposed to ionizing radiation.

RESULTS

The incidence of fractures after irradiation varies from 1.2% to 25% with a consolidation rate of 33% to 75%, being more frequent in the ribs, pelvis, and femur. The time elapsed between irradiation and fracture occurs years after radiotherapy. Risk factors include age above 50 years, female gender, extensive periosteal detachment, circumferential irradiation, tumor size, and anterior thigh location. The etiology is still uncertain, but cellular disappearance, reduction of bone turnover and activity were observed hematopoietic as possible causes of failure of consolidation.

CONCLUSION

There is no consensus in the literature on the factors related to the development of fractures, with radiation dose, previous tumor size and periosteal detachment being suggested as potential factors.

Pharmacological interventions for the prevention of insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults

BACKGROUND

Pelvic radiotherapy is a treatment delivered to an estimated 150,000 to 300,000 people annually across high-income countries. Fractures due to normal stresses on weakened bone due to radiotherapy are termed insufficiency fractures. Pelvic radiotherapy-related interruption of the blood supply to the hip is termed avascular necrosis and is another recognised complication. The reported incidences of insufficiency fractures are 2.7% to 89% and risk of developing avascular necrosis is 0.5%. These complications lead to significant morbidity in terms of pain, immobility and consequently risk of infections, pressure sores and mortality.

OBJECTIVES

To assess the effects of pharmacological interventions for preventing insufficiency fractures and avascular necrosis in adults over 18 years of age undergoing pelvic radiotherapy.

SEARCH METHODS

We performed electronic literature searches in the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and DARE to 19 April 2017. We also searched trial registries. Further relevant studies were identified through handsearching of citation lists of included studies.

SELECTION CRITERIA

Randomised controlled trials (RCTs) or non RCTs with concurrent comparison groups including quasi-RCTs, cluster RCTs, prospective cohort studies and case series of 30 or more participants were screened. We included studies assessing the effect of pharmacological interventions in adults over 18 years of age undergoing radical pelvic radiotherapy as part of anticancer treatment for a primary pelvic malignancy. We excluded studies involving radiotherapy for bone metastases. We assessed use of pharmacological interventions at any stage before or during pelvic radiotherapy. Interventions included calcium or vitamin D (or both) supplementation, bisphosphonates, selective oestrogen receptor modulators, hormone replacement therapy (oestrogen or testosterone), denosumab and calcitonin.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed trial quality and extracted data. We contacted study authors to obtain missing data. Data were to be pooled using the random-effects model if study comparisons were similar, otherwise results were to be reported narratively.

MAIN RESULTS

We included two RCTs (1167 participants). The first RCT compared zoledronic acid with placebo in 96 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.The second RCT had four treatment arms, two of which evaluated zoledronic acid plus adjuvant androgen suppression compared with androgen suppression only in 1071 men undergoing pelvic radiotherapy for non-metastatic prostate cancer.Both studies were at a moderate to high risk of bias and all evidence was judged to be of very low certainty.The studies provided no evidence on the primary outcomes of the review and provided limited data in relation to secondary outcomes, such that meta-analyses were not possible. Both studies focused on interventions to improve bone health in relation to androgen deprivation rather than radiation-related insufficiency fractures and avascular necrosis. Few fractures were described in each study and those described were not specific to insufficiency fractures secondary to radiotherapy. Both studies reported that zoledronic acid in addition to androgen deprivation and pelvic radiotherapy led to improvements in BMD; however, the changes in BMD were measured and reported differently. There was no available evidence regarding adverse effects.

AUTHORS' CONCLUSIONS

The evidence relating to interventions to prevent insufficiency fractures and avascular necrosis associated with pelvic radiotherapy in adults is of very low certainty. This review highlights the need for prospective clinical trials using interventions prior to and during radiotherapy to prevent radiation-related bone morbidity, insufficiency fractures and avascular necrosis. Future trials could involve prospective assessment of bone health including BMD and bone turnover markers prior to pelvic radiotherapy. The interventions for investigation could begin as radiotherapy commences and remain ongoing for 12 to 24 months. Bone turnover markers and BMD could be used as surrogate markers for bone health in addition to radiographic imaging to report on presence of insufficiency fractures and development of avascular necrosis. Clinical assessments and patient reported outcomes would help to identify any associated adverse effects of treatment and quality of life outcomes.

Radiation toxicity in patients with collagen vascular disease and intrathoracic malignancy treated with modern radiation techniques

BACKGROUND AND PURPOSE

There is concern that patients with collagen vascular disease (CVD) are at higher risk of developing radiation toxicity. We analyzed radiation toxicities in patients with intrathoracic malignancy and CVD treated using modern radiotherapy.

MATERIALS AND METHODS

This single-institution retrospective study included 31 patients with CVD and 825 patients without CVD treated from 1998 to 2014. Radiation esophagitis (RE) and radiation pneumonitis (RP) were scored by RTOG scales. RE was analyzed with logistic regression and RP with Cox regression.

RESULTS

CVD patients experienced similar grade ≥3 RE compared to control patients (23% vs. 19%, p = 0.64) but more grade ≥3 RP (26% vs. 10%, p = 0.01). There was no significant association between CVD subtype and toxicities. In multivariate analysis, CVD and lung V20 >30% were associated with grade ≥3 RP. We identified V20 ≤30%, V5 ≤50%, and MLD ≤18 Gy as dose thresholds in patients with CVD. CVD patients with mild severity disease and only 1 organ system involved were at low risk for RP.

CONCLUSIONS

Patients with CVD may be at higher risk of RP. However, CVD patients may be offered curative thoracic RT with particular attention to risk-reduction strategies and maintaining recommended dose constraints as described in this study.

Impact of rheumatoid arthritis on radiation-related toxicity and cosmesis in breast cancer patients: a contemporary matched-pair analysis

PURPOSE

To evaluate the impact of rheumatoid arthritis (RA) on toxicity and cosmesis in women undergoing radiotherapy for breast cancer.

METHODS

We queried an institutional database for women with RA treated with external beam radiotherapy for breast cancer between 1981 and 2016. Matching each patient to three controls without RA was attempted. Radiation toxicity was graded using CTCAE 4.0. Cosmesis was graded using the Global Harris Scoring System of Excellent, Good, Fair, or Poor. Grade 2+ (G2+) acute and late toxicities were compared between women with RA and their matched pairs using a generalized estimating equation (GEE). Wilcoxon test and mixed effects model were used to compare the cosmesis between two groups.

RESULTS

Forty women with RA at time of radiation were matched to 117 controls. The median radiation dose was 60 Gy (50-66 Gy) and the median follow-up was 94 months (1-354 months). When comparing the women with RA to their matched pairs, there was no significant difference in the rates of G2+ acute toxicity (25.0 vs. 13.7%, O 2.1, CI 0.91-4.9) or G2+ late toxicity (7.5 vs. 4.3%, OR 1.8, CI 0.48-6.8). Mean cosmesis was between Good and Excellent for both groups of patients, although women with RA were less likely to get Excellent cosmesis compared to their matched pairs (OR 0.35, CI 0.15-0.84).

CONCLUSIONS

Among women with RA, radiation for breast cancer was well tolerated without significantly increased toxicity. Their cosmesis was generally Good to Excellent, although they might be less likely to get Excellent cosmesis compared to their matched pairs.

Aging alters bone-fat reciprocity by shifting in vivo mesenchymal precursor cell fate towards an adipogenic lineage

Bone marrow derived mesenchymal progenitor cells (MPCs) play an important role in bone homeostasis. Age-related changes occur in bone resulting in a decrease in bone density and a relative increase in adipocity. Although in vitro studies suggest the existence of an age-related lineage switch between osteogenic and adipogenic fates, stem cell and microenvironmental contributions to this process have not been elucidated in vivo. In order to study the effects of MPC and microenvironmental aging on functional engraftment and lineage switching, transplantation studies were performed under non-myeloablative conditions in old recipients, with donor MPCs derived from young and old green fluorescent protein (GFP) transgenic mice. Robust engraftment by young MPCs or their progeny was observed in the marrow, bone-lining region and in the matrix of young recipients; however, significantly lower engraftment was seen at the same sites in old recipients transplanted with old MPCs. Differentiation of transplanted MPCs strongly favored adipogenesis over osteogenesis in old recipients irrespective of MPC donor age, suggesting that microenvironmental alterations that occur with in vivo aging are predominately responsible for MPC lineage switching. These data indicate that aging alters bone-fat reciprocity and differentiation of mesenchymal progenitors towards an adipogenic fate.

Skin wound trauma, following high-dose radiation exposure, amplifies and prolongs skeletal tissue loss

The present study investigated the detrimental effects of non-lethal, high-dose (whole body) γ-irradiation on bone, and the impact that radiation combined with skin trauma (i.e. combined injury) has on long-term skeletal tissue health. Recovery of bone after an acute dose of radiation (RI; 8 Gy), skin wounding (15-20% of total body skin surface), or combined injury (RI+Wound; CI) was determined 3, 7, 30, and 120 days post-irradiation in female B6D2F1 mice and compared to non-irradiated mice (SHAM) at each time-point. CI mice demonstrated long-term (day 120) elevations in serum TRAP 5b (osteoclast number) and sclerostin (bone formation inhibitor), and suppression of osteocalcin levels through 30 days as compared to SHAM (p<0.05). Radiation-induced reductions in distal femur trabecular bone volume fraction and trabecular number through 120 days post-exposure were significantly greater than non-irradiated mice (p<0.05) and were exacerbated in CI mice by day 30 (p<0.05). Negative alterations in trabecular bone microarchitecture were coupled with extended reductions in cancellous bone formation rate in both RI and CI mice as compared to Sham (p<0.05). Increased osteoclast surface in CI animals was observed for 3 days after irradiation and remained elevated through 120 days (p<0.01). These results demonstrate a long-term, exacerbated response of bone to radiation when coupled with non-lethal wound trauma. Changes in cancellous bone after combined trauma were derived from extended reductions in osteoblast-driven bone formation and increases in osteoclast activity.

Hemorrhage trauma increases radiation-induced trabecular bone loss and marrow cell depletion in mice

Exposure to high-dose radiation results in deleterious effects on skeletal tissue. However, the effects of combined trauma such as radiation and hemorrhage on skeletal properties have yet to be elucidated. The purpose of this study was to evaluate the effects of radiation injury combined with hemorrhage on trabecular bone properties and biomarkers of bone metabolism, and to determine whether hemorrhage enhances radiation-associated bone loss. Male CD2F1 mice (10 weeks old) were exposed to one single dose of gamma radiation ((60)Co): 0 or 7.25 Gy. Two hours after irradiation, animals were bled 0% (n = 8) or 20% (n = 8) of total blood volume via the submandibular vein. Mice were euthanized 30 days after irradiation, and distal femora were analyzed using standard histomorphometry to determine changes in trabecular bone volume (BV/TV), thickness (Tb.Th), spacing (Tb.Sp), number (Tb.N) and marrow adipocyte density. Femurs from mice euthanized 1, 7 and 15 days post injury were flushed and total bone marrow cells were counted. Radiation exposure resulted in deleterious effects on distal femur BV/TV (-63%), Tb.Th (-34%), Tb.N (-45%), Tb.Sp (+125%) and adipocyte density (+286%) compared with the sham-irradiated mice (0 Gy; P < 0.05). Hemorrhage after irradiation resulted in greater deleterious effects on the distal femur with BV/TV (-13%), Tb.Th (-44%), Tb.N (-26%), Tb.Sp (+29%) and marrow adipocyte density (+33%) compared with radiation exposure only (P < 0.05). Analysis of the biomarkers of bone metabolism in serum from irradiated and hemorrhaged mice revealed significantly lower levels of osteocalcin (-60%) and procollagen type 1 amino-terminal propeptide (-36%; P1NP, biomarkers of bone formation activity), as well as elevations in sclerostin (+56%; SOST, an inhibitor of bone formation) compared with serum from irradiated only mice (P < 0.05). Additionally, the onset of bone marrow cell depletion in irradiated and hemorrhaged mice occurred earlier and to a greater extent compared to that in irradiated only mice. This study provides definitive, preliminary evidence that hemorrhage further exacerbates trabecular bone loss associated with nonlethal high-dose gamma radiation.

Pelvic insufficiency fracture after definitive radiotherapy for uterine cervical cancer: retrospective analysis of risk factors

The purpose of this study is to determine the incidence, clinical characteristics and risk factors of postradiation pelvic insufficiency fracture (PIF) in women with uterine cervical cancer. We reviewed the medical records of 126 patients who received definitive radiotherapy (RT) for uterine cervical cancer between 2003 and 2009 at our institution. Among them, 99 patients who underwent at least one computed tomography (CT) or magnetic resonance imaging of the pelvis during their follow-up at more than 6 months were included in this analysis. The relationship between the incidence of PIF and several patient- and treatment-related factors was analyzed. The median follow-up period was 21 months. Of the 126 patients, 33 (with a total of 50 lesions) were diagnosed with PIF. The 2-year cumulative incidence was 32%. Univariate analysis showed that age ≥70 years (P= 0.0010), postmenopausal state (P = 0.0013), and lower CT density of bone and bone marrow (P= 0.020) significantly related to PIF. In a multivariate analysis, of the 59 patients whose CT densities were evaluable, lower CT density was the only significant factor associated with PIF (P = 0.0026). In conclusion, postradiation PIFs were detected in a considerable number of patients after definitive RT for cervical cancer. Predisposing factors were older age, postmenopausal state, and decreased density of bone and bone marrow on CT.

ICRP publication 118: ICRP statement on tissue reactions and early and late effects of radiation in normal tissues and organs--threshold doses for tissue reactions in a radiation protection context

This report provides a review of early and late effects of radiation in normal tissues and organs with respect to radiation protection. It was instigated following a recommendation in Publication 103 (ICRP, 2007), and it provides updated estimates of 'practical' threshold doses for tissue injury defined at the level of 1% incidence. Estimates are given for morbidity and mortality endpoints in all organ systems following acute, fractionated, or chronic exposure. The organ systems comprise the haematopoietic, immune, reproductive, circulatory, respiratory, musculoskeletal, endocrine, and nervous systems; the digestive and urinary tracts; the skin; and the eye. Particular attention is paid to circulatory disease and cataracts because of recent evidence of higher incidences of injury than expected after lower doses; hence, threshold doses appear to be lower than previously considered. This is largely because of the increasing incidences with increasing times after exposure. In the context of protection, it is the threshold doses for very long follow-up times that are the most relevant for workers and the public; for example, the atomic bomb survivors with 40-50years of follow-up. Radiotherapy data generally apply for shorter follow-up times because of competing causes of death in cancer patients, and hence the risks of radiation-induced circulatory disease at those earlier times are lower. A variety of biological response modifiers have been used to help reduce late reactions in many tissues. These include antioxidants, radical scavengers, inhibitors of apoptosis, anti-inflammatory drugs, angiotensin-converting enzyme inhibitors, growth factors, and cytokines. In many cases, these give dose modification factors of 1.1-1.2, and in a few cases 1.5-2, indicating the potential for increasing threshold doses in known exposure cases. In contrast, there are agents that enhance radiation responses, notably other cytotoxic agents such as antimetabolites, alkylating agents, anti-angiogenic drugs, and antibiotics, as well as genetic and comorbidity factors. Most tissues show a sparing effect of dose fractionation, so that total doses for a given endpoint are higher if the dose is fractionated rather than when given as a single dose. However, for reactions manifesting very late after low total doses, particularly for cataracts and circulatory disease, it appears that the rate of dose delivery does not modify the low incidence. This implies that the injury in these cases and at these low dose levels is caused by single-hit irreparable-type events. For these two tissues, a threshold dose of 0.5Gy is proposed herein for practical purposes, irrespective of the rate of dose delivery, and future studies may elucidate this judgement further.

Ionizing Radiation and Bone Loss: Space Exploration and Clinical Therapy Applications

Damage to normal, nontumor bone tissue following therapeutic irradiation increases the risk of fracture among cancer patients. For example, women treated for various pelvic tumors have been shown to have a greater than 65% increased incidence of hip fracture by 5 years postradiotherapy. Another practical situation in which exposure to ionizing radiation may negatively impact skeletal integrity is during extended spaceflight missions. There is a limited understanding of how spaceflight-relevant doses and types of radiation can influence astronaut bone health, particularly when combined with the significant effects of mechanical unloading experienced in microgravity. Historically, negative effects on osteoblasts have been studied. Radiation exposure has been shown to damage osteoblast precursors. Damage to local vasculature has been observed, ranging from decreased lumen diameter to complete ablation within the irradiated volume, causing a state of hypoxia. These effects result in suppression of bone formation and a general state of low bone turnover. More recently, however, we have demonstrated in pre-clinical mouse models, a very rapid but transient increase in osteoclast activity after exposure to spaceflight and clinically relevant radiation doses. Combined with long-term suppression of bone formation, this skeletal damage may cause long-term deficits. This review will present a broad set of literature outlining our current set knowledge of both clinical therapy and space exploration exposure to ionizing radiation. Additionally, we will discuss prevention of the initial osteoclast-mediated bone loss, the need to promote normal bone turnover and long-term quality of bone tissue, and our hypothesized molecular mechanisms.

Bone mineral density after concurrent chemoradiation in patients with uterine cervical cancer

OBJECTIVE

The aim of this study was to examine the bone mineral density (BMD) of women with cervical cancer treated with chemoradiation and to compare the outcomes with those of women with myomas treated by hysterectomy.

METHODS

The BMDs of 43 women with cervical cancer treated with concurrent chemoradiation (CCRT) were measured by dual-energy x-ray absorptiometry (L-spine and proximal femur) and compared with those of 43 matched control women with the same age distribution and body mass index. Medical records were reviewed retrospectively. Both women with cervical cancer and control women had reached menopause or had a history of bilateral salpingo-oophorectomy.

RESULTS

The lowest T scores for BMD were significantly lower in the women with cervical cancer treated with CCRT compared with the control women (P = 0.017). The serum total alkaline phosphatase was significantly higher in women with cervical cancer treated with CCRT (P = 0.027). There was no correlation between total alkaline phosphatase and BMD (L-spine and proximal femur; r = 0.089, P = 0.416). The BMDs of both the greater trochanter of the femur (P = 0.013) and L4 (P = 0.011) were significantly lower in women with cervical cancer than in the control women.

CONCLUSIONS

The results of this study suggest that postmenopausal women with uterine cervical cancer treated with CCRT have a lower BMD and are at risk for osteoporosis.

Risedronate prevents early radiation-induced osteoporosis in mice at multiple skeletal locations

INTRODUCTION

Irradiation of normal, non-malignant bone during cancer therapy can lead to atrophy and increased risk of fracture at several skeletal sites, particularly the hip. This bone loss has been largely attributed to damaged osteoblasts. Little attention has been given to increased bone resorption as a contributor to radiation-induced osteoporosis. Our aims were to identify if radiation increases bone resorption resulting in acute bone loss and if bone loss could be prevented by administering risedronate.

METHODS

Twenty-week-old female C57BL/6 mice were either: not irradiated and treated with placebo (NR+PL); whole-body irradiated with 2 Gy x-rays and treated with placebo (IR+PL); or irradiated and treated with risedronate (IR+RIS; 30 microg/kg every other day). Calcein injections were administered 7 and 2 days before sacrifice. Bones were collected 1, 2, and 3 weeks after exposure. MicroCT analysis was performed at 3 sites: proximal tibial metaphysis, distal femoral metaphysis, and the body of the 5th lumbar vertebra (L5). Osteoclasts were identified from TRAP-stained histological sections. Dynamic histomorphometry of cortical and trabecular bone was performed. Circulating TRAP5b and osteocalcin concentrations were quantified.

RESULTS

In animals receiving IR+PL, significant (P<0.05) reduction in trabecular volume fraction relative to non-irradiated controls was observed at all three skeletal sites and time points. Likewise, radiation-induced loss of connectivity and trabecular number relative to NR+PL were observed at all skeletal sites throughout the study. Bone loss primarily occurred during the first week post-exposure. Trabecular and endocortical bone formation was not reduced until week 2. Loss of bone volume was absent in animals receiving IR+RIS. Histology indicated greater osteoclast numbers at week 1 within IR+PL mice. Serum TRAP5b concentration was increased in IR+PL mice only at week 1 compared to NR+PL (P=0.05). Risedronate treatment prevented the radiation-induced increase in osteoclast number, surface, and TRAP5b.

CONCLUSIONS

This study demonstrated a rapid loss of trabecular bone at several skeletal sites after whole-body irradiation. Changes were accompanied by an increase in osteoclast number and serum markers of bone loss. Risedronate entirely prevented bone loss, providing further evidence that an increase in bone resorption likely caused this radiation-induced bone loss.

Early increase in osteoclast number in mice after whole-body irradiation with 2 Gy X rays

Bone loss is a consequence of exposure to high-dose radiotherapy. While damage to bone vasculature and reduced proliferation of bone-forming osteoblasts has been implicated in this process, the effect of radiation on the number and activity of bone-resorbing osteoclasts has not been characterized. In this study, we exposed mice to a whole-body dose of 2 Gy of X rays to quantify the early effects of radiation on osteoclasts and bone structural properties. Female C57BL/6 mice (13 weeks old) were divided into two groups: irradiated and nonirradiated controls. Animals were killed humanely 3 days after radiation exposure. Analysis of serum chemistry revealed a 14% increase in the concentration of tartrate resistant acid phosphatase (TRAP)-5b, a marker of osteoclast activity, in irradiated mice (P < 0.05). Osteoclast number (+44%; P < 0.05) and osteoclast surface (+213%; P < 0.001) were elevated in TRAP-stained histological sections of tibial metaphyses. No significant change was observed in osteoblast surface or osteocalcin concentration or in trabecular microarchitecture (i.e. bone volume fraction) as measured through microcomputed tomography (P > 0.05). This study provides definitive, quantitative evidence of an early, radiation-induced increase in osteoclast activity and number. Osteoclastic bone resorption may represent a contributor to bone atrophy observed after therapeutic irradiation.

Pelvic bone complications after radiation therapy of uterine cervical cancer: evaluation with MRI

OBJECTIVE

The purpose of this study was to assess the prevalence and distribution of radiation-induced insufficiency fractures and to investigate other bony complications of the female pelvis associated with radiation therapy using MR images.

MATERIALS AND METHODS

Two radiologists retrospectively evaluated pelvic MR images of 510 patients (mean age, 54.7 years) who underwent pelvic irradiation for uterine cervical cancer for the presence and location of insufficiency fractures by consensus. We calculated the cumulative prevalence of pelvic insufficiency fractures on the basis of their results. In addition, we identified other associated bony complications of the female pelvis by reviewing the MR images.

RESULTS

Insufficiency fractures were diagnosed in 100 patients; the 5-year cumulative prevalence was 45.2%. An insufficiency fracture was diagnosed a median of 16.9 months after radiation therapy. The fracture sites were the sacrum body and alae, medial side of the iliac bone, the roof of the acetabulum, superior rami of the pubic bone, femoral heads, and L5 vertebra. Sixty-one patients (61%) developed multiple fractures, and among them, 40 (40%) had bilateral symmetric lesions of the sacral alae. Other complications associated with the radiation therapy, as determined by evaluation of the MR images, were osteolysis and avascular necrosis of the femoral head.

CONCLUSION

Radiation-induced pelvic insufficiency fractures are a frequent complication of radiation therapy for uterine cervical cancer. Osteolysis and avascular necrosis of the femoral head were also diagnosed using MRI after radiation therapy.

Short course preoperative radiotherapy is the single most important risk factor for perineal wound complications after abdominoperineal excision of the rectum

AIM

To determine factors associated with perineal wound complications following abdominoperineal excision of the rectum (APER) for rectal adenocarcinoma and their effects on time to healing.

PATIENTS AND METHODS

We studied all cases of APER performed in our unit by four consultants over 7 years. Seven out of nine factors considered important in wound healing were analysed using logistic regression and a multivariate model was built to examine interactions. Wound persistence was calculated using the Kaplan-Meier method.

RESULTS

Data were available for 94 of 96 patients [male:female, 3:2, median age 72.5 (IQR: 64-78)]. Thirty-nine (41%) patients had 25 Gray, 3-portal, fractionated 5-day short course preoperative radiotherapy (SCPRT). Dukes stages were A (34%), B (26%), C (40%). Perineal wound complications occurred in 44 (47%), 16% of these requiring return to theatre. Local recurrences occurred in 13 (15%). There was no evidence to suggest that either patient gender, age, smoking status, preoperative albumin or haemoglobin level, or T stage were associated with the development of wound complications. The odds of wound complications for a patient who had SCPRT was over 10 times that for a patient who did not have preoperative radiotherapy (odds ratio 10.15, 95% CI: 3.80-27.05, n = 94). Seventy-four per cent of SCPRT and 96% of non-SCPRT wounds had healed by 1 year. Estimated failed wound healing rates at 30 and 90 days were 64% (95% CI: 46-78) and 48% (95% CI: 30-64) in SCPRT patients compared with 23% (95% CI: 12-35) and 9% (95% CI: 3-20) in non-SCPRT patients (log rank test P < 0.0001).

CONCLUSION

Patients who have an APER are over 10 times more likely to have a perineal wound complication if they have SCPRT than not. Two-thirds of these will not have healed by 1 month, half by 3 months and over a quarter will still remain unhealed at 1 year. This has important implications for patient management decisions. Large prospective studies are needed to evaluate the effects of a selective policy for radiotherapy administered to patients requiring APER.

Pelvic bone complications following radiation therapy of gynecologic malignancies: clinical evaluation of radiation-induced pelvic insufficiency fractures

OBJECTIVE

To investigate the incidence, clinical and imaging finding of insufficiency fractures (IF) of the female pelvis following radiation therapy.

METHODS

We reviewed the radiation oncology records of 158 patients with gynecologic malignancies who underwent external beam radiation therapy of the whole pelvis between April 1993 and March 2004. All patients underwent computed tomography (CT) scan every 6 months in follow-up after radiation therapy and magnetic resonance imaging (MRI) and radionuclide bone scan were added when the patients complained of a pelvic pain.

RESULTS

Eighteen of 158 patients (11.4%) developed IF in the irradiated field with a median interval of 6 months (range 3-51) from the completion of external beam radiation therapy. The cumulative incidence of symptomatic IF at 5 years calculated with Kaplan-Meyer methods was 13%. Median age of the patients who developed IF was 70 years (range 48-88), and all of them were postmenopausal. IF occurred in the sacloiliac joints, upper limb of pubic bone, acetabulum, sacral body and 5th lumbar vertebra. Twelve of 18 patients had multiple lesions and 8 had symmetric longitudinal fracture lines parallel to the sacroiliac joints. Avoidance of weight bearing by bed rest and analgesics provided good pain relief in all patients, although symptoms lasted from 3 to 20 months.

CONCLUSIONS

Radiation-induced pelvic IF following radiation therapy for gynecologic malignancies were frequently observed in the postmenopausal patients within 1 year after external beam radiation therapy. Symmetric fractures of the both sacroiliac joints were the characteristic pattern of pelvic IF. Knowledge of characteristic imaging pattern of IF is essential in order to rule out the bone metastasis. Therapy recommendations are conservative with analgesics.

Symptomatic osteoradionecrosis of pelvic bones in patients with gynecological malignancies-result of a long-term follow-up

The aim of this study was to assess the incidence and risk factors of pelvic fractures as a result of radiation therapy in women with gynecological cancer. We retrospectively reviewed 3530 female patients treated at our institute between 1980 and 1998 with megavoltage radiation with or without brachytherapy for cancer in the pelvic area. Eligible were patients with vulvar, vaginal, cervical, endometrial, and fallopian tube cancer. Median follow-up was 88 months (range 0-240). Emphasis was put on treatment-related and patient-related risk factors. Of the eligible 3155 patients, 15 developed symptomatic bone fracture caused by osteoradionecrosis, which makes an overall incidence of 0.44% The diagnosis was based on anamnesis, clinical course, and X-ray or computed tomography images. Median time of onset was 44 months (range 6-197). All patients had pain as the first symptom. The only independent predictive factor for developing osteoradionecrosis seemed to be preexistent osteoporosis. Other risk factors that are related to osteoporosis include higher age, postmenopausal status, or steroid treatment. We did not find any significant treatment-related predictive factor for pelvic osteoradionecrosis. Patients with osteoporosis are probably at the highest risk for developing osteoradionecrotic fractures after pelvic radiotherapy. More studies are needed to find out other endogenous predictive factors.

Influence of connective tissue diseases on the expression of radiation side effects: a systematic review

BACKGROUND AND PURPOSE

Patient related co-factors may increase the risk of radiation morbidity. Connective tissue diseases (CTD) are among the co-morbidities that are relatively well studied and have been shown to be of potential clinical relevance for radiotherapy. The aim of this systematic review is to quantify the contribution of CTD to the risk of radiation related side effects.

PATIENTS AND METHODS

Relevant publications reporting the outcome of radiotherapy in patients with CTD were retrieved according to a standardized query and evaluated for their methodology and quality of reporting, using defined quality criteria. A quantitative estimate of the relative risk of developing side effects in patients with CTD was derived from the observed proportions of responders in patients with or without CTD. Risk estimates were synthesized across studies.

RESULTS

Eight studies which include data of 9-209 patients who had CTD and were treated with radiotherapy were identified and reviewed. Three of these studies included data suited for further quantitative analysis. The test of the uni-directional hypothesis that patients with CTD had an increased risk of late effects after radiotherapy reached statistical significance, the one-tailed P-value being 0.03. The pooled relative risk was 2.0 with 95% confidence interval (0.99, 4.1).

CONCLUSIONS

CTD is associated with an increased risk of late radiation induced normal tissue reaction. The literature published to date provides some support for this assertion although most of the reports are plagued by methodological weaknesses, thus calling for a large coordinated study.

An unusual natural history of a L5-S1 spondylolisthesis presenting with a sacral insufficiency fracture

Sacral insufficiency fractures have been described in association with conditions leading to osteoporosis. No association with spondylolisthesis has been described to date. A 60-year-old patient with known lumbosacral isthmic spondylolisthesis presented with exacerbation of symptoms initially thought to be linked to her known spinal pathology. Plain radiography, computer tomography, MRI and bone scan confirmed the presence of a recent sacral insufficiency fracture with anterior angulation. Conservative treatment resulted in improvement of symptoms after 6 months. Care should be taken when considering older patients for more aggressive treatment if they present with exacerbation of back pain and sciatica in the presence of a pre-existing spondylolisthesis. A suspicion of insufficiency fracture should be raised if risk factors exist and further investigations ordered in particular if plain radiography is normal. Lumbosacral fusion might be inappropriate in this setting.

The effect of X-rays on bone: a pictorial review

The deleterious effects of X-rays on bone have been recognised for almost a century and continue to be seen today because of improved survival in patients treated for malignancy with radiotherapy with or without other treatments. In this pictorial review we present the imaging features of radiation damage to bone highlighting the differences seen in the immature skeleton and post-skeletal fusion. In the former, damage is greatest to the physis resulting in growth disturbances. In the mature skeleton there is a spectrum of changes from mild osteopenia, through disordered attempts at healing with varying degrees of sclerosis, radionecrosis which may lead to acute fractures following minimal trauma and insufficiency fractures both with refractory healing to the dreaded complication of sarcomatous transformation. The imaging appearances are illustrated and the features that help distinguish malignant change from other complications stressed.

Consolidative abdominopelvic radiotherapy after surgery and carboplatin/paclitaxel chemotherapy for epithelial ovarian cancer

PURPOSE

To assess the feasibility and morbidity of sequential cytoreductive surgery, carboplatin/paclitaxel chemotherapy, and consolidative abdominopelvic radiotherapy (APRT) in ovarian cancer.

METHODS AND MATERIALS

Between 1998 and 2000, 29 patients with optimally cytoreduced epithelial ovarian cancer were treated with carboplatin (135 mg/m2) and paclitaxel (area under the curve [AUC] of 6) followed by APRT in a prospective protocol. All patients were clinically, radiographically, and biochemically (CA-125) free of disease at the completion of chemotherapy. Abdominopelvic radiotherapy was delivered using 6 MV anterior-posterior photon fields to encompass the peritoneal cavity. Median follow-up was 4 years.

RESULTS

Two patients experienced Radiation Therapy Oncology Group Grade 3 gastrointestinal toxicity during APRT; 6 patients, Grade 3 or 4 neutropenia; and 3 patients, Grade 3 or 4 thrombocytopenia. Overall, 10 patients had Grade 3 or 4 acute toxicity. All of the acute side effects resolved after treatment was completed, and there were no serious consequences such as sepsis or hemorrhage. Abdominopelvic radiotherapy was abandoned prematurely in 3 patients. Late side effects were seen in 5 patients, including 1 small bowel obstruction, 2 symptomatic sacral insufficiency fractures, 1 case of severe dyspareunia, and 1 case of prolonged fatigue. All resolved with supportive management. The 4-year actuarial disease-free survival was 57%, and the overall survival was 92%. Eleven of 12 patients who relapsed received salvage chemotherapy, which was well tolerated.

CONCLUSIONS

Abdominopelvic radiotherapy after optimal surgery and carboplatin/paclitaxel chemotherapy is associated with an acceptable risk of acute and late side effects and does not limit subsequent salvage chemotherapy. Consolidative APRT warrants further investigation as a means of improving the outcome of patients with ovarian cancer.

Post-fracture osteolysis of the pubic bone simulating a malignancy: report of a case

Post-fracture osteolysis of the pubic bone is rare. We report a case of a 70-year-old woman with osteoporosis and a history of radiation therapy 2 years earlier. At presentation, she was found to have a bilateral sacral fracture and fractures of both pubic rami on one side. The pain persisted, and follow-up radiographs showed osteolysis of the pubic rami suggestive of metastatic disease. The development of a bony callus within 8 months established the diagnosis of benign osteolysis. About 50 cases of osteolysis at fracture sites have been reported to date, of which about a dozen occurred after radiation therapy. All the patients were elderly women with post-menopausal osteoporosis. Radiation therapy probably further increases the risk in this setting. The possibility of osteolysis at fracture sites in patients with osteoporosis should be borne in mind to avoid unnecessary and burdensome investigations that are costly and cause undue anxiety to the patients. Rest is the only effective treatment.

Unstable pelvic insufficiency fracture in a patient with rheumatoid arthritis

The occurrence of pelvic insufficiency fractures in patients with rheumatoid arthritis has not previously been well emphasized. These fractures are difficult to detect clinically, and appropriate radiological investigation is necessary for diagnosis. A 72-year-old woman with rheumatoid arthritis presented with severe left groin pain. Pelvic radiographs showed parasymphyseal fractures, and marked instability of these fractures was observed at the follow-up 2 weeks later. Computed tomographic scan of the sacrum showed a widened linear fracture gap in the left sacral ala. Because the patient's pain was so severe that she could not change position, external fixation was performed to achieve rapid pain relief and early mobilization. Although most patients with these fractures respond well to simple conservative treatments, parasymphyseal fractures combined with sacral fractures may cause disruption of the pelvic ring and occasionally need operative management.

Acute and long-term toxicity following radiotherapy alone or in combination with chemotherapy for locally advanced cervical cancer

Randomised studies in locally advanced cervical cancer patients showed that cisplatin should be given concurrently with radiotherapy, because of a better long-term survival compared to radiotherapy alone. This increases the relevance of treatment related toxicity. This review summarises the acute and long-term toxicity of radiotherapy given with or without chemotherapy for cervical cancer. Acute toxicity (all grades) of radiotherapy is reported in 61% of the patients in the rectosigmoid, in 27% as urological, in 27% as skin and in 20% as gynaecological toxicity. Moderate and severe morbidity consists of 5% to 7% gastrointestinal and 1% to 4% genitourinary toxicity. Adding chemotherapy to radiotherapy increases acute haematological toxicity to 5% to 37% of the patients and nausea and vomiting in 12% to 14%. Late effects of radiotherapy include gastrointestinal, urological, female reproductive tract, skeletal and vascular toxicity, secondary malignancies and quality of life issues. For at least 20 years after treatment, new side effects may develop. Gastrointestinal toxicity usually occurs in the first 2 years after treatment in about 10% of the patients. The incidence of moderate and severe urological toxicity can increase up to 10% and rises over time. Gynaecological toxicity usually occurs shortly after treatment while skeletal and vascular toxicity can occur years to decades later. Thus far, no increase in late toxicity has been observed after the addition of cisplatin to radiotherapy. Finally, methods to prevent or decrease late toxicity and therapeutical options are discussed. However, most randomised studies still have a limited follow-up period.

Pelvic insufficiency fracture after pelvic irradiation in uterine cervix cancer

OBJECTIVES

Pelvic insufficiency fractures (IF) are well known but uncommon and are frequently misinterpreted sequelae. The clinical features were investigated.

METHODS

Four hundred sixty-three patients, who were treated between 1994 and 2000 for uterine cervix cancer, were clinically examined. All patients had been treated with 10 or 15 MV photons, with 50.4-55.8 Gy in 28 fractions with adjuvant intent (n = 235) in addition to high-dose-rate brachytherapy 24 Gy in 6 fractions for curative treatment (n = 228). The median follow-up was 38 months.

RESULTS

Eight patients (8/463, 1.7%) developed pelvic IF 7-19 months (median, 12 months) after the treatment. Among these, seven patients (7/228, 3.1%) were treated with curative intent and one (1/235, 0.4%) was treated with adjuvant intent. All patients were postmenopausal and complained of moderate to severe pelvic pain, which resolved after 1-11 months with conservative therapy in all patients. Two of these patients also had radiation proctitis.

CONCLUSION

In women who present with pelvic pain after radiotherapy for cervical cancer, bony destruction and fractures may be indicative of a late radiation effect rather than osseous metastasis. IF are more common in the curative treatment group than in the postoperative adjuvant group.

The controversy surrounding sacral insufficiency fractures: to ambulate or not to ambulate?

Sacral insufficiency fractures are an often unsuspected cause of low back pain in elderly women with osteoporosis who have sustained minimal or no trauma. Many of the references in the literature advocate bed rest initially; however, we support early mobilization, because most of these fractures are stable and require no surgical intervention. With good pain control, patients can begin progressive ambulation with assistive devices in a supervised environment and minimize the complications of immobility.