Assessment of changes in tumor heterogeneity following neoadjuvant chemotherapy in primary esophageal cancer

To assess the changes in computed tomography (CT) tumor heterogeneity following neoadjuvant chemotherapy in esophageal cancer. Thirty-one consecutive patients who received neoadjuvant chemotherapy for esophageal cancer were identified. Analysis of primary tumor heterogeneity (texture) was performed on staging and post-chemotherapy CT scans. Image texture parameters (mean grey-level intensity, entropy, uniformity, kurtosis, skewness, standard deviation of histogram) were derived for different levels of image filtration (0-2.5). Proportional changes in each parameter following treatment were obtained. Comparison between pathological tumor response and texture parameters was analyzed using Mann-Whitney U-test. The relationship between CT texture and overall survival) was estimated using the Kaplan-Meier method. Tumor texture became more homogeneous after treatment with a significant decrease in entropy and increase in uniformity (filter 1.0 and 2.5). Pretreatment (filter 1.5, P = 0.006) and posttreatment standard deviation of histogram (filter 1.0, P = 0.009) showed a borderline association with pathological tumor response. A proportional change in skewness <0.39 (filter 1.0) was associated with improved survival (median overall survival 36.1 vs. 11.1 months; P < 0.001). CT tumor heterogeneity decreased following neoadjuvant chemotherapy and has the potential to provide additional information in primary esophageal cancer.

Co-registration of cone beam CT and planning CT in head and neck IMRT dose estimation: a feasible adaptive radiotherapy strategy

OBJECTIVE

To investigate if cone beam CT (CBCT) can be used to estimate the delivered dose in head and neck intensity-modulated radiotherapy (IMRT).

METHODS

15 patients (10 without replan and 5 with replan) were identified retrospectively. Weekly CBCT was co-registered with original planning CT. Original high-dose clinical target volume (CTV1), low-dose CTV (CTV2), brainstem, spinal cord, parotids and external body contours were copied to each CBCT and modified to account for anatomical changes. Corresponding planning target volumes (PTVs) and planning organ-at-risk volumes were created. The original plan was applied and calculated using modified per-treatment volumes on the original CT. Percentage volumetric, cumulative (planned dose delivered prior to CBCT + adaptive dose delivered after CBCT) and actual delivered (summation of weekly adaptive doses) dosimetric differences between each per-treatment and original plan were calculated.

RESULTS

There was greater volumetric change in the parotids with an average weekly difference of between -4.1% and -27.0% compared with the CTVs/PTVs (-1.8% to -5.0%). The average weekly cumulative dosimetric differences were as follows: CTV/PTV (range, -3.0% to 2.2%), ipsilateral parotid volume receiving ≥26 Gy (V26) (range, 0.5-3.2%) and contralateral V26 (range, 1.9-6.3%). In patients who required replan, the average volumetric reductions were greater: CTV1 (-2.5%), CTV2 (-6.9%), PTV1 (-4.7%), PTV2 (-11.5%), ipsilateral (-10.4%) and contralateral parotids (-12.1%), but did not result in significant dosimetric changes.

CONCLUSION

The dosimetric changes during head and neck simultaneous integrated boost IMRT do not necessitate adaptive radiotherapy in most patients.

ADVANCES IN KNOWLEDGE

Our study shows that CBCT could be used for dose estimation during head and neck IMRT.

Functional variants at the 11q13 risk locus for breast cancer regulate cyclin D1 expression through long-range enhancers

Analysis of 4,405 variants in 89,050 European subjects from 41 case-control studies identified three independent association signals for estrogen-receptor-positive tumors at 11q13. The strongest signal maps to a transcriptional enhancer element in which the G allele of the best candidate causative variant rs554219 increases risk of breast cancer, reduces both binding of ELK4 transcription factor and luciferase activity in reporter assays, and may be associated with low cyclin D1 protein levels in tumors. Another candidate variant, rs78540526, lies in the same enhancer element. Risk association signal 2, rs75915166, creates a GATA3 binding site within a silencer element. Chromatin conformation studies demonstrate that these enhancer and silencer elements interact with each other and with their likely target gene, CCND1.

P4-02-05: The Regulation of Artemin Signalling by IGF-1 in Mammary Carcinoma Cells

Artemin is a neurotrophic signalling factor which belongs to the glial-derived neurotrophic factor (GDNF) family of ligands. Artemin acts as a survival, proliferation and migration factor for a number of neurological cell types, by signalling through the RET (rearranged during transfection) receptor and, in most cases, the GDNF receptor (GFR)-a3 co-receptor. Recently, a number of published studies have implicated Artemin as a potential oncogene in several cell types, including mammary carcinoma cells. Other studies further indicate that Artemin may influence cancer progression and tamoxifen resistance in some breast cancers. Available clinical data has demonstrated that increased Artemin expression is correlated with decreased overall patient survival in breast cancer patients and a poor outcome in tamoxifen treated breast cancer patients. Here we investigate interaction between the Artemin and the insulin-like growth factor-1 (IGF-1) signal transduction pathways. Using mammary carcinoma cell lines, we demonstrate that IGF-1 treatment increases the endogenous expression of both Artemin and its endogenous receptors, RET and GFRa3. Semi-quantitative RT-PCR assays demonstrated that IGF-1 stimulated mRNA expression of Artemin as well as RET and GFRa3 in wild-type MCF-7 and ZR-75-1 cells in a time-dependent and dose-dependent manner. The same effect was not observed in wild-type T47D cells where IGF-1 did not increase Artemin mRNA expression.

We also demonstrated that forced expression of Artemin in MCF-7 cells consistently enhanced the response of these cells to IGF-1 in a number of cell function assays. Forced expression of Artemin significantly enhanced IGF-1-mediated stimulation of total cell number in MCF-7 cells. Consistent with this, Artemin enhanced IGF-1-mediated stimulation of S-phase entry and cell survival. In a soft agar assay, forced expression of Artemin also enhanced IGF-1-mediated stimulation of colony formation. Conversely, depletion of Artemin expression using siRNA abrogated the response to IGF-1 stimulation in MCF-7 cells. Artemin depletion significantly decreased IGF-1-stimulated increase in total cell number by decreasing IGF-1-stimulated cell proliferation and protection from apoptotic cell death. In addition, forced expression of Artemin in MCF-7 cells reduced cell sensitivity to the IGF-1 receptor small molecule inhibitor, AG1024. In conclusion, we have demonstrated that IGF-1 increases Artemin mRNA and protein expression in the breast cancer cell lines MCF-7 and ZR-75-1 and have identified potential cross-talk between the Artemin and IGF-1 signalling pathways in MCF-7 cells.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P4-02-05.

Validation of the AJCC staging system (7th edition) in Asian patients with localized prostate cancer undergoing radical radiotherapy

112

Background: The epidemiology of prostate cancer (PCa) varies widely internationally. Although prostate cancer is usually regarded as uncommon in Asia, dramatic rises in recent years have resulted in it being ranking third by incidence in Singapore. Conventional prognostic parameters derived from Western populations have been integrated into systems such as the new AJCC seventh edition staging system, the validity of which is unclear in Asia. We thus sought to validate its performance, alongside other prognostic factors in a large Asian series of radiotherapy patients.

Methods: A retrospective review of 404 consecutive Singaporean patients receiving radical radiotherapy between 1997 and 2005 at the National Cancer Centre was performed. The primary outcome was biochemical relapse free survival (BRFS), defined by the Phoenix criteria. Prognostic risk groups were defined using AJCC seventh edition. Univariate analysis (UVA) and multivariate analysis (MVA) was performed for other putative risk factors: age, race, Gleason score, prognostic risk grouping, tumour classification, radiation delivery technique, radiotherapy dose, hormonal therapy (HT) and initial PSA.

Results: Median age was 69; median BRFS was 55 months with 71 biochemical relapses. 4 risk factors showed univariate association with BRFS: AJCC risk groups (p=0.038), T-stage (p=0.018), RT dose (p=0.025) and initial PSA value (p=0.013) with AJCC risk groups and initial PSA value remaining significant after MVA ( Table ). Harrell's c-index for AJCC risk grouping was 0.56, with no significant difference seen in outcomes between AJCC risk group II and III.

Conclusions: Our results validate the new AJCC seventh edition prostate cancer prognostic risk grouping in an Asian radiotherapy population for the first time; the actual association however is relatively weak possibly due to differences in biology, screening or epidemiology.

[Table: see text]

No significant financial relationships to disclose.

Becker expander implants: truly a long term single stage reconstruction?

Despite being more expensive than conventional tissue expanders, Becker expanders offer the advantage of single stage breast reconstruction. However, the large series in published literature which report good outcomes of Becker expanders in breast reconstruction have a mean follow up period of less than three years. This does not allow for definitive conclusions as to whether the Becker expander truly meets its design goal of a lasting single stage breast reconstruction. This study is a retrospective case note review of all patients who underwent breast reconstruction using a Becker expander at our unit from 1993 to 1998, with a mean follow up of 12.5 years. Sixty-eight Becker-only breast reconstructions were carried out following oncological and risk-reducing mastectomies, and for congenital hypoplasias. There was a high premature overall explantation rate with 68% of expanders removed by 5 years due to complications which included poor aesthetics, capsular contracture and infection. The mean time to explantation for these patients was only 23 months, and time to 50% overall expander removal ('half life') was just 30 months. On subgroup analysis, patients in the congenital hypoplasias group had a significantly better rate of expander retention with 67% remaining in situ at 10 years. In comparison, patients in the oncological and risk-reducing mastectomy groups had implant retention rates of 2% and 7% respectively. The Becker expander does not appear to meet its design purpose of lasting single stage breast reconstruction in post-mastectomy cases. In contrast, it appears to have significantly better longevity when used for congenital hypoplasias.

Effect of tibolone on breast cancer recurrence: LIBERATE trial bone sub-study

Abstract #66

LIBERATE, a randomized, placebo controlled, double blind trial studied the effect of tibolone (Livial), a tissue selective hormone replacement therapy (HRT) on breast cancer (BC) recurrence, aiming to demonstrate non-inferiority of treatment compared to placebo. In the LIFT trial of osteoporotic women, tibolone prevented BC development.&#x2028; Design and Method: Women with surgically treated BC (T1-3, N0-2, M0) within the last 5 years complaining of vasomotor symptoms, were randomly assigned to tibolone 2.5mg daily or placebo treatment for a maximum of 5 years. Adequate sample size was estimated to be &gt;1500 in each arm. A bone mineral density (BMD) sub-study of 724 patients (454 Caucasian; 270 Asian) was enrolled utilizing DXA scanning at baseline and 2 years.&#x2028; Results: Between 2002 and 2004, 3,148 women were randomized in 31 countries; 1579 to tibolone and 1569 to placebo. Mean age at randomization was 52.7 years (28.0-75.0) and mean time since surgery was 2.1 years. In total 58% of women recruited were node positive and 78% ER positive. The trial closed prematurely in July 2007, with a median follow-up of 3.1 years (0.01-4.99) per patient, because an increased risk of BC recurrence occurred on tibolone HR 1.40 (1.14-1.70; p&lt;0.001); 15.2% (237/1556) women on tibolone recurred compared to 10.7% (165/1542) on placebo. Risk for distant recurrence on tibolone was HR 1.38 (95% CI 1.09-1.74 p=0.007).&#x2028; Aromatase inhibitor (AI) users had the highest risk of recurrence on tibolone HR 2.42 (1.01-5.79) compared to tamoxifen treated women HR 1.25 (0.98-1.59). Compared to ER positive cancers HR 1.56 (1.22-2.01), ER negative cancer had no increased risk of recurrence HR 1.15 (0.73-1.80). No differences in mortality occurred between groups.&#x2028; At entry to the bone sub-study, 298 (43%) women had normal BMD, 313 (45%) osteopenia (T-score between -1 and -2.5) and 81 (11.7%) osteoporosis. Low body mass index (&lt;0.001), Asian race (p&lt;0.001) and old age at menarche predicted for low bone mass after 2 years. Tibolone increased BMD by 3.5% at the lumbar spine and 2.9% at the hip compared to placebo (both p&lt;0.001) and reduced fracture rate in the Caucasian (p=0.036) but not the Asian population. Women with normal BMD (before or at day 1) had increased recurrence on tibolone 15.1% (21/139) compared to placebo 6.9% (11/159) p=0.036, whereas no increased BC recurrence was seen in women with low BMD; 7.5% (15/201) on tibolone and 6.7% (13/193) on placebo.&#x2028; Conclusion: HRT after breast cancer treatment increases BC recurrence especially in AI treated patients. Risk of BC recurrence is elevated in BC women with normal BMD (compared to low) who take HRT.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 66.

A large-scale multi-center independent validation study of a panel of seven biomarkers for the detection of ovarian cancer

5057

Background: Previously we discovered seven serum biomarkers: ITIH4, transthyretin, ApoA1, CTAPIII, hepcidin, transferrin, and SAA, for the detection of ovarian cancer. They are fragments, cleavages, or PTMs of circulating proteins that are difficult to measure by conventional immunoassays. Using optimzed mass spectrometry assays, we evaluated these biomarkers in a large-scale multi-center study. Methods: A total of 607 serum samples from five sites were analyzed using SELDI TOF-MS protocols optimized for the seven biomarkers. They included 234 women with benign gynecologic diseases, and 373 patients with invasive epithelial ovarian cancer (101 early stage, 231 late stage, and 40 stage unknown). Among them, 165 benigns and 228 cancers had a CA125 available at time of analysis. The median and quartiles of CA125 for benign, early stage, and late or unknown stage were 26/11/57 IU, 80/22/434 IU, and 234/40/1114 IU, respectively. The biomarkers were assessed individually using the Mann-Whitney U Test. A linear composite index was derived in an unsupervised fashion using data from one site and then calculated for the remaining data using the fixed formula. ROC curve analyses were performed on data from individual sites and all sites combined. Results: All seven biomarkers individually demonstrated statistically significant differentiating power, and the majority had p-value<0.00001. AUCs of the composite index in ROC analyses for the six sites were 0.602, 0.566, 0.821, 0.813, and 0.592 in detecting cancer at all stages from benign. On the combined data, the differences in AUC between the index and CA125 were not statistically significant for the detection of cancer at all stages (AUC=0.706 vs. 0.725) or early stages only (AUC=0.534 vs. 0.653). However, the index did better at the high-sensitivity range. At a fixed sensitivity of 86%, the specificity of the index was 34% (77/226) compared to CA125 at 26% (42/163). For early stage cases, at a fixed sensitivity of 84%, the specificity of the index was 24% (55/226) compared to CA125 at 14%% (22/163). Conclusions: We validated seven previously discovered biomarkers, individually and in combination. Prospective studies and assay development are under way to further characterize their clinical utility.

[Table: see text]

Quinolone use as a risk factor for nosocomial Clostridium difficile-associated diarrhea

OBJECTIVE

To determine modifiable risk factors for nosocomial Clostridium difficile-associated diarrhea (CDAD).

DESIGN

Case-control study.

SETTING

300-bed tertiary-care hospital.

PARTICIPANTS

Hospital inpatients present during the 3-month study period.

METHODS

Case-patients identified with nosocomial CDAD over the study period were compared to two sets of control patients: inpatients matched by age, gender, and date of admission; and inpatients matched by duration of hospital stay. Variables including demographic data, comorbid illnesses, antibiotic exposure, and use of gastrointestinal medications were assessed for case- and control-patients. Conditional logistic regression was performed to identify risk factors for nosocomial CDAD.

RESULTS

27 case-patients were identified and were compared to the two sets of controls (1:1 match for each comparison set). For the first set of controls, use of ciprofloxacin (odds ratio [OR], 5.5; 95% confidence interval [CI 95], 1.2-24.8; P=.03) was the only variable that remained significant in the multivariable model. For the second set of controls, prior exposure to cephalosporins (OR, 6.7; CI 95, 1.3-33.7; P=.02) and to ciprofloxacin (OR, 9.5; CI 95, 1.01-88.4; P=.05) were kept in the final model.

CONCLUSIONS

Along with cephalosporins, prior quinolone use predisposed hospitalized patients to nosocomial CDAD. Quinolones should be used judiciously in acute-care hospitals, particularly in those where CDAD is endemic.