Central nervous system atypical teratoid rhabdoid tumours: the Canadian Paediatric Brain Tumour Consortium experience

BACKGROUND

Atypical teratoid rhabdoid tumours (ATRT) are aggressive brain tumours mostly occurring in early childhood. Largest published series arise from registries and institutional experiences (1-4). The aim of this report is to provide population-based data to further characterise this rare entity and to delineate prognostic factors.

PATIENTS AND METHODS

A national retrospective study of children ⩽18years diagnosed with a central nervous system (CNS) ATRT between 1995 and 2007 was undertaken. All cases underwent central pathology review.

RESULTS

There were 50 patients (31 males; median age at diagnosis of 16.7months). Twelve patients were >36months. Infratentorial location accounted for 52% of all cases. Nineteen patients (38%) had metastatic disease. Fifteen (30%) underwent gross total resection (GTR). Ten patients (20%) underwent palliation. Among the 40 remaining patients, 22 received conventional chemotherapy and 18 received high dose chemotherapy regimens (HDC); nine received intrathecal chemotherapy and 15 received adjuvant radiation. Thirty of the 40 treated patients relapsed/progressed at a median time of 5.5months (0-32). The median survival time of the entire cohort was 13.5months (1-117.5months). Age, tumour location and metastatic status were not prognostic. Patients with GTR had a better survival (2years overall survival (OS): 60%±12.6 versus 21.7%±8.5, p=0.03). HDC conferred better outcome (2years OS 47.9%±12.1 versus 27.3%±9.5, p=0.036). Upfront radiation did not provide survival benefit. Six of the 12 survivors (50%) did not receive radiation.

CONCLUSION

The outcome of CNS ATRT remains poor. However, the use of HDC provides encouraging results. GTR is a significant prognostic factor. The role of adjuvant radiation remains unclear.

Impact of radiation avoidance on survival and neurocognitive outcome in infant medulloblastoma

Purpose

Concerns about radiotherapy-related neurocognitive sequelae in young children have led to deferral or avoidance of radiation in contemporary treatment for this fragile group of patients. We compared survival and neurocognitive outcome in two groups of infants with medulloblastoma who received adjuvant conventional craniospinal irradiation (csi) or reduced or no radiotherapy during an era of change in the philosophy of infant medulloblastoma treatment.

Patients and Methods

From 1985 to 2007, 29 patients 3 years of age or younger were diagnosed and treated with curative intent in our institution. Children treated before 1994 received adjuvant radiation with chemotherapy; subsequently, radiation was prescribed essentially for disease progression or relapse.

Results

Median age at diagnosis was 24 months (range: 1–36 months); 15 patients (52%) presented with metastatic disease at diagnosis. As part of initial treatment, 8 children received adjuvant radiotherapy with chemotherapy, and 21 children received postoperative chemotherapy only. Five children treated with chemotherapy alone are in prolonged remission. The 5-year event-free and overall survivals were 35.9% ± 9.8% and 50.2% ± 9.6% respectively. Extent of resection, metastatic status, and desmoplastic histology were not found to be significant prognostic factors.

On serial neurocognitive evaluations, patients treated with chemotherapy with or without reduced radiotherapy demonstrated improvement of intellectual function over time. Patients treated with conventional csi exhibited significantly lower intelligence quotient scores and academic performance, with the exception of receptive vocabulary.

Conclusions

Avoidance of conventional csi in treatment of very young children with medulloblastoma appears to be associated with a preserved neurocognitive profile. Neurocognitive evaluation should be integrated into the primary objectives of future infant protocols.

Accepting kidneys from older living donors: impact on transplant recipient outcomes

Older living kidney donors are regularly accepted. Better knowledge of recipient outcomes is needed to inform this practice. This retrospective cohort study observed kidney allograft recipients from Ontario, Canada between January 2000 and March 2008. Donors to these recipients were older living (≥ 60 years), younger living, or standard criteria deceased (SCD). Review of medical records and electronic healthcare data were used to perform survival analysis. Recipients received 73 older living, 1187 younger living and 1400 SCD kidneys. Recipients of older living kidneys were older than recipients of younger living kidneys. Baseline glomerular filtration rate (eGFR) of older kidneys was 13 mL/min per 1.73 m² lower than younger kidneys. Median follow-up time was 4 years. The primary outcome of total graft loss was not significantly different between older and younger living kidney recipients [adjusted hazard ratio, HR (95%CI): 1.56 (0.98-2.49)]. This hazard ratio was not proportional and increased with time. Associations were not modified by recipient age or donor eGFR. There was no significant difference in total graft loss comparing older living to SCD kidney recipients [HR: 1.29 (0.80-2.08)]. In light of an observed trend towards potential differences beyond 4 years, uncertainty remains, and extended follow-up of this and other cohorts is warranted.

Coevolution of antibody stability and Vκ CDR-L3 canonical structure

Antibodies recognize antigens through six hypervariable loops, five of which have a limited set of conformations known as canonical structures. For κ light chains, the majority of CDR-L3 [the third hypervariable loop of the light chain variable domain (V(L))] adopts the type 1 canonical structure (CS1), with a cis-proline at position 95. Here, we present the design and structural studies of the monoclonal antibody mAb15 and related mutants that contained a series of progressively germline mutations only in the heavy chain variable domain (V(H)) that ultimately led to an increase of more than 11°C in the melting temperature (T(m)) of the antigen-binding fragment (Fab). The all-trans CDR-L3 structure in the wild type is significantly different from any known CDR-L3 canonical structures. In the thermally stable mutants, the L94(L)-S95(L) peptide bond adopts an energetically unfavorable non-X-proline cis conformation, but the overall CDR-L3 loop converted to CS1. The stabilized V(H) appears to function as a specific molecular chaperone that facilitated the trans-cis isomerization of S95(L). Thus, it is plausible that proline is the evolutionary choice to maintain overall structure and stability for V(L). These results provide new insights into the evolution of CS1 and suggest a potential molecular switch mechanism at position 95 that links CDR-L3 structural diversity and antibody stability and will have implications for antibody engineering.

Surgical site infection rate is lower in laparoscopic than open colorectal surgery

OBJECTIVE

Few studies have investigated whether surgical site infection (SSI) incidence differs between laparoscopic colorectal surgery (LCS) and open colorectal surgery (OCS). This study investigated the SSI incidence using the validated UK SSI Surveillance Service (SSISS) criteria for diagnosing wound infections.

METHOD

Prospective data collection recorded patients' demographics, operative details, antibiotic use, wound evaluation and microbiological wound culture results, for consecutive patients undergoing elective resectional LCS and OCS. Postdischarge surveillance consisted of patient questionnaires sent out at 30 days and the primary care communication.

RESULTS

A total of 122 patients underwent colorectal resections over 1 year (LCS 43; OCS 79). Patients' demographics and operative case-mix were similar for both groups, including body mass index (BMI), diabetic and smoking status. Operative duration was longer in the LCS group compared with OCS group (P = 0.012, Mann-Whitney U-test), but hospital stay was shorter for LCS (P = 0.0001, Mann-Whitney U-test). The SSI rate was significantly lower in the LCS than OCS group (7%vs 25% respectively; P = 0.015, two-tailed Fisher's exact test). BMI > 30 and operation length > 4 h influenced the risk of SSI formation (P < 0.05, chi-squared test). One LCS patient required conversion to a limited laparotomy.

CONCLUSIONS

Surgical site infection incidence is significantly lower following LCS when compared with OCS. Confounding factors in this study include patient selection for LCS and nonrandomization.

Imaging diagnosis--spontaneous intramural canine duodenal hematoma

A 9-year-old neutered female Pug with a 2-week history of pancreatitis was presented for dyspnea, icterus, and intractable vomiting. Sonographically, the gallbladder, intrahepatic bile ducts, and common bile duct were distended. The pancreas was hypoechoic with hyperechoic peripancreatic fat. A mildly heterogeneous intramural mass was present in the muscularis layer of the descending duodenum. A presumptive diagnosis of pancreatitis and smooth muscle tumor of the duodenum leading to common bile duct obstruction was made. The dog died despite supportive care. Necropsy examination confirmed the presence of pancreatitis and an intramural duodenal hematoma.

RANKL inhibition improves bone properties in a mouse model of osteogenesis imperfecta

Recently, a new class of agents targeting the receptor activator of nuclear factor-kappaB ligand (RANKL) pathway has been developed for the treatment of osteoporosis and other bone diseases. In the current study, inhibition of the RANKL pathway was evaluated to assess effects on "bone quality" and fracture incidence in an animal model of osteogenesis imperfect (OI), the oim/oim mouse. Juvenile oim/oim ( approximately 6 weeks old) and wildtype (+/+) mice were treated with either a RANKL inhibitor (RANK-Fc) or saline. After treatment, bone density increased significantly in the femurs of both genotypes. Femoral length decreased with RANK-Fc in +/+ mice. Geometric measurements at mid-diaphysis in the oim/oim groups showed increases in the ML periosteal and endosteal diameters and AP cortical thickness in the treated groups. Within +/+ groups, ML cortical thickness and ML femoral periosteal diameter were significantly increased with RANK-Fc. Biomechanical testing revealed increased stiffness in oim/oim and +/+ mice. Total strain was increased with treatment in the +/+ mice. Histologically, RANKL inhibition resulted in retained growth plate cartilage in both genotypes. The average number of fractures sustained by RANK-Fc-treated oim/oim mice was not significantly decreased compared to saline treated oim/oim mice. This preclinical study demonstrated that RANKL inhibition at the current dose improved density and some geometric and biomechanical properties of oim/oim bone, but it did not decrease fracture incidence. Further studies that address commencement of therapy at earlier time points are needed to determine whether this mode of therapy will be clinically useful in OI.

Baseline Endogenous Estradiol and the Association of Hormone Therapy with Breast Cancer Risk, the Women's Health Initiative Clinical Trials

Background: The effect of exogenous hormones on breast cancer risk may depend on baseline endogenous levels of estradiol (E2). We investigated whether women with lower E2 levels will have the greatest increase in breast cancer risk during treatment with estrogen plus progestin ((E+P); combined conjugated equine estrogens (CEE) plus medroxyprogesterone acetate) or estrogen-alone ((E-alone); CEE) therapy. Additionally, we examined whether the risk of breast cancer varies by untreated levels of endogenous E2.Methods: We performed an ancillary study within the Women's Health Initiative E+P and E-alone clinical trials. We used a case-only design to test for interactions between untreated levels of E2 and hormone therapy (E+P or E-alone) on breast cancer risk. We measured baseline levels of bioavailable E2 in 346 cases of invasive breast cancer from the E+P trial and 231 cases from the E-alone trial. To estimate the risk of breast cancer by endogenous E2 levels (expressed as quartiles), we used a case-cohort design which included the cases described above in addition to a randomly selected comparison group (N=387; 203 from the E+P and 184 from the E-alone trial). Incident breast cancer cases were identified over an average follow-up of 4.1 years in the E+P trial and 5.4 years in the E-alone trial. All analyses were performed separately for the E+P and the E-alone trials.Results: In the case-only study, the effect of E+P therapy on breast cancer risk did not seem to vary by endogenous E2 quartiles (p-heterogeneity= 0.16). Breast cancer risk associated with E-alone treatment tended to be greater among women with the lowest E2 levels; however this association was not significant (hazard ratio (HR)= 1.44, 95% confidence interval (CI)= 0.79-2.59).Table 1. Effects of E+P and E-alone treatments on breast cancer risk (HR (95% CI)) by quartiles of baseline estradiol: case-only results E+PE-aloneEstradiol  Quartile 11.20 (0.80-1.80)1.44 (0.79-2.59)Quartile 20.88 (0.58-1.34)0.98 (0.58-1.67)Quartile 31.27 (0.81-2.00)0.79 (0.47-1.33)Quartile 40.67 (0.43-1.06)0.92 (0.57-1.49)P-heterogeneity0.160.51P-trend0.160.20 In the case-cohort analysis, higher endogenous E2 levels were associated with increased breast cancer risk (p-trend= 0.01), independent of hormone therapy.Table 2. Effects of baseline estradiol and hormone therapy (E+P vs. E-alone) on breast cancer risk (HR (95% CI)): case-cohort results E+PE-aloneHormone therapy treatment (Reference= placebo group)1.01 (0.96-1.07)0.84 (0.56-1.26)   Estradiol  Quartile 1 (Reference)1.001.00Quartile 21.22 (0.75-2.00)1.30 (0.77-2.17)Quartile 31.41 (0.87-2.32)1.32 (0.77-2.27)Quartile 41.85 (1.12-3.03)2.38 (1.32-4.35)P-trend0.010.01 Conclusion: The risk of breast cancer increases with higher levels of untreated endogenous E2. However, untreated E2 level does not modify the effect of E+P or E-alone therapy on breast cancer risk. Estradiol measurement is unlikely to identify women where hormone therapy may substantially increase the risk of breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 906.

Sex Hormones and Risk of Estrogen Receptor (ER)-Positive and ER-Negative Breast Cancer

Background: There is a need for improved breast cancer risk prediction by tumor estrogen receptor (ER) status. Endogenous sex hormone levels are associated with risk of overall breast cancer and the ER-positive subtype. However, the role of estradiol (E2) and testosterone (T) in the development of ER-negative tumors remains unclear. We investigated the associations of circulating levels of endogenous E2 and T with the risk of ER-positive as well as ER-negative breast cancer in postmenopausal women.Methods: We performed a case-cohort study within the Women's Health Initiative- Observational Study of postmenopausal women not taking exogenous hormones (age range: 50-79 years). Baseline endogenous levels of bioavailable E2 and T were measured using radioimmunoassays (University of Southern California, LA, CA) in 196 cases of invasive ER-positive breast cancer, 107 cases of invasive ER-negative cancer, and 560 randomly selected controls. The average follow-up time was 7.3 years.Results: After adjustment for putative risk factors, women with E2 levels in the upper three quartiles had an approximately 2-fold increased risk of ER-positive breast cancer, compared to those with E2 in the lowest quartile. These associations were only modestly decreased after adjustment for T. Higher T levels also indicated increased risk of ER-positive breast cancer; women in the third quartile of T had a 1.7-fold significantly higher risk, compared to those in the first quartile. However, this association was substantially diminished and not significant after controlling for E2.No association was observed between E2 levels and ER-negative cancer. However, women with T levels in the second, third, and fourth quartiles had lower risks of ER-negative cancer in the order of 54% (p= 0.018), 38% (p= 0.13), and 46% (p= 0.05), respectively, compared to women with T in the lowest quartile. These associations did not change materially after adjusting for E2.Table 1. Risk (Hazard Ratio (HR) and 95% CI) of ER-positive and ER-negative breast cancer by E2 and T quartiles ER-positive (HR (95% CI))ER-negative (HR (95% CI)) Model 1*Model 2**Model 1*Model 2*E2    Q11.001.001.001.00Q22.19 (1.25-3.84)2.12 (1.16-3.87)0.57 (0.29-1.12)0.72 (0.34-1.53)Q31.92 (1.10-3.35)1.74 (0.92-3.33)0.75 (0.40-1.42)1.09 (0.51-2.3)Q42.11 (1.21-3.68)1.86 (0.97-3.56)0.88 (0.48-1.62)1.36 (0.60-3.08)P for trend0.020.150.840.44T    Q11.001.001.001.00Q21.01 (0.57-1.78)0.82 (0.44-1.53)0.46 (0.24-0.88)0.45 (0.22-0.92)Q31.72 (1.04-2.84)1.36 (0.75-2.48)0.62 (0.34-1.15)0.56 (0.27-1.18)Q41.45 (0.85-2.46)1.16 (0.62-2.17)0.54 (0.29-1.00)0.44 (0.20-1.00)P for trend0.050.280.100.09*Model1: adjusted for age, race, age at menopause, alcohol use, physical activity, history of needle aspiration, lifetime use of estrogen+progestin, and time since quitting hormone therapy use. **Model2: adjusted for Model1 + sex hormones.Conclusion: Higher endogenous E2 levels were associated with increased risk of ER-positive breast cancer, independent of risk factors and T. In contrast, higher concentrations of endogenous T were related to lower risk of ER-negative breast cancer, independent of risk factors and E2. This is the first study to report an association of testosterone with ER-negative breast cancer. Further studies are needed to confirm this association.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 907.

Prevalence of Enterobius vermicularis Infection among preschool children in kindergartens of Taipei City, Taiwan in 2008

The prevalence of Enterobius vermicularis infection among preschool children was reported to be low based on a 5-year screening program in Taipei City, Taiwan. The Taipei City government intended to terminate the E. vermicularis screening program among preschool children. Thus, we were entrusted with confirming whether pinworm infections among preschool children in Taipei City had truly declined. From each of 12 administrative districts 2-3 kindergartens were randomly selected for investigation. In total, 4,349 children were examined, of which 2,537 were boys and 1,812 were girls. The cellophane tape adhered to a glass slide was used, and all examinations were done by certified medical technologists. Results indicated that the overall prevalence rate of pinworm infections was 0.62% (27/4,349). Although the infection rate was higher among boys (0.67%, 17/2,537) than in girls (0.55%, 10/1,812), no significant difference was found (chi(2) = 0.399, P = 0.62). According to the administrative district, the infection rate ranged from no positive cases of E. vermicularis infection in the Xinyi, Zhongzhen, and Wanhua Districts (0%; 0/299, 0/165, and 0/358, respectively), to 0.26% (1/131) in Songshan District, with the highest rate of 1.88% (7/373) in Wenshan District. Because the overall infection rate (0.62%, 27/4,349) in the present study was unchanged compared to that (0.40%, 197/49,541) previously reported in 2005, we propose that regular pinworm screening and treatment programs should be continued in some parts of Taipei City.