A Brownian energy depot model of the basilar membrane oscillation with a braking mechanism

High auditory sensitivity, sharp frequency selectivity, and spontaneous otoacoustic emissions are signatures of active amplification of the cochlea. The human ear can also detect very large amplitude sounds without being damaged, as long as the exposed time is not too long. The outer hair cells are believed to be the best candidate for the active force generator of the mammalian cochlea. In this paper, we propose a new model for the basilar membrane oscillation which describes both an active and a protective mechanism by employing an energy depot concept and a critical velocity of the basilar membrane. The compressive response of the basilar membrane at the characteristic frequency and the dynamic response to the stimulation are consistent with the experimental results. Although our model displays a Hopf bifurcation, our braking mechanism results in a hyper-compressive response to intense stimuli which is not generically observed near a Hopf bifurcation. Asymmetry seen in experimental recordings between the onset and the offset of the basilar membrane response to a sound burst is also observed in this model.

Primary chemotherapy, stereotactic radiosurgery, or whole brain radiotherapy in non-small cell lung cancer (NSCLC) patients with asymptomatic brain metastases

e19063

Background: Approximately 25 to 30% of patients with lung cancer develop brain metastases at some stage and 12∼18% at the time of initial presentation. Whole brain radiotherapy (WBRT) has long been a mainstay of treatment of brain metastases. Another treatment approach, Stereotactic radiosurgery (SRS) is a method of delivering high doses of focal irradiation to a tumor while minimizing the irradiation to the adjacent normal tissue. However, the prognosis of NSCLC patients with asymptomatic brain metastases, who are not treated with SRS or WBRT, has not been fully investigated yet. This study aimed to analyze the outcome for various treatment modalities in NSCLC patients with asymptomatic brain metastases. Methods: We reviewed the medical records of 129 patients with a histopathologically proven NSCLC and a synchronous brain metastases between January 2003 and December 2007. The patients were categorized as primary chemotherapy, primary SRS, and primary WBRT group: primary chemotherapy (78 patients), primary SRS (24 patients), and primary WBRT (27 patients). Results: With median follow-up of 30.0 months (7.2 -70.7), the median overall survival (OS) for the entire patients was 15.6 months (0.5–50.7) and the progression free survival (PFS) was 6.1 months (0.3- 53.0). The OS was 22.4m for primary SRS group, 13.9m for primary chemotherapy group, and 17.7m for primary WBRT group; p=0.86). However, patients treated with primary SRS showed trend toward prolonged survival compared to those of primary WBRT p=0.06). Subset analysis of 110 adenocarcinoma patients showed that the median OS for patients treated with primary SRS was longer than those of primary WRBT (29.3m vs 17.7m p=0.01) or primary chemotherapy (29.3m vs 14.6m p=0.04). Conclusions: These results suggest that for NSCLC patients with asymptomatic brain metastases at first diagnosis, SRS rather than primary chemotherapy or WBRT might be considered as initial treatment, especially for patients with adenocarcinoma.

No significant financial relationships to disclose.

Clinical significance of type 1 insulin-like growth factor receptor and insulin-like growth factor binding protein-3 expression in squamous cell carcinoma of head and neck

6036

Background: Type 1 insulin-like growth factor receptor (IGF-1R) plays an important role in the growth and apoptosis of cancer cell. The activities of IGF-1R are modulated by a family of high-affinity insulin-like growth factor binding proteins (IGFBPs), of which IGFBP-3 is the major serum carrier protein. The expression and significance of IGF-1R and IGFBP-3 in squamous cell carcinoma of the head and neck (SCCHN) is unknown. Methods: This study explored immunohistochemical expression of IGF-1R and IGFBP-3 in tumor samples from 131 patients with surgically resected SCCHN. Results: The positive expression of IGF-1R and IGFBP-3 was observed in 96 (73.3%) and 117 (89.3%) patients. There were no significant differences in baseline characteristics between the positive and negative expressed groups of IGF-1R and IGFBP-3. With the median follow up of 53.5 months, 3 year progression free (PFS) and overall (OS) survival rate was 64.0% and 72.9%, neither IGF-1R nor IGFBP-3 expression had prognostic values in the whole cohort. Thirty-seven (67.3%) of 55 stage IV patients demonstrated IGF-1R positivity. The subgroup analysis of in stage IV patients showed the poor PFS ( = 0.029) and OS (pp = 0.025) in IGF-1R positive groups. In a multivariate analysis using IGF-1R expression and other clinicopathological parameters, the IGF-1R expression was remained as an independent factor for PFS (p = 0.037, HR = 2.816, 95% C.I. 1.065 - 7.446) and OS (p = 0.034, HR = 3.169, 95% C.I. 1.089 - 9.225). Conclusions: Our work exhibited that IGF-1R expression is frequent in SCCHN patients and related with poor survival in advanced stage, this could support the attempts using the IGF-1R inhibitor for treatment of SCCHN.

No significant financial relationships to disclose.

EZH2 expression and correlation with Ki-67 and p53 in head and neck squamous cell carcinoma

e17018

Background: Polycomb group proteins are transcriptional repressors that silence specific sets of genes through chromatin modification. The enhancer of zeste homolog 2 (EZH2), considered a member of the polycomb group proteins, is overexpressed in aggressive forms of several malignancies. However, the role of EZH2 expression in head and neck cancer has not yet been fully determined. This study was conducted to investigate the clinical value of EZH2 expression in head and neck cancer and its correlation with Ki-67 and p53 expression. Methods: Expression of EZH2, Ki-67, and p53 was determined by immunohistochemical staining of tissue microarrays from specimens of 138 cases of head and neck squamous cell carcinoma. Results: High EZH2 expression was observed in 51.5%. 44.2% were positive for p53. The percentage of Ki-67 staining was significantly greater in the EZH2 positive group (12.37 ± 8.51) than in the EZH2 negative group (4.73 ± 6.06, p < 0.001). EZH2 expression was significantly correlated with p53 expression (p = 0.003) and smoking history (p = 0.021). However, we found no significant differences in other clinicopathological parameters (age, sex, primary tumor size, and lymph node metastasis) and survival between the EZH2 positive and negative groups. Conclusions: These results suggest that high EZH2 expression may be associated with tumor cell proliferation and cell cycle regulation in head and neck cancer.

No significant financial relationships to disclose.

A phase II trial of erlotinib in combination with gemcitabine and capecitabine in previously untreated metastatic/recurrent pancreatic cancer: Combined analysis with translational research

4607

Background: To confirm the efficacy and toxicity of erlotinib (E) in combination with gemcitabine (G) and capecitabine (C) when used as a first-line therapy in patients (pts) with metastatic/recurrent pancreatic cancer Methods: Pts with advanced pancreatic adenocarcinoma, with measurable lesion were eligible for the study. Other eligibility criteria included: no previous palliative chemotherapy, Karnofsky performance status (PS)≥50, adequate organ function. Locally advanced pancreatic cancer was excluded. E was given at a dose of 100mg daily from D1 to D28. G was given at a dose of 1000mg/m2 on D1,8,15 and C was given at a dose of 1660mg/m2/d from D1 to 21, repeated every 4 weeks. Response was assessed every 8 weeks. Tumor tissue and blood sample was analyzed for the translational research. Results: A total of 47 pts were enrolled between Feb 2007 and Feb 2008. (median age: 58 y, Karnofsky PS100/90/80/70/60 (6/26/9/5/1)). Forty three pts were evaluable for response. Partial responses were achieved in 14 patients, resulting in response rate of 32.6%. Twenty two pts (51.2%) had stable disease. Overall disease control rate was 83.7%. The PFS was 6.5 months (95% CI, 3.4–9.7) and the overall survival was 12.0 months (95% CI, 8.6–15.9). The Gr 3/4 hematologic toxicities were: neutropenia (6.8%), thrombocytopenia (3.2%), anemia (1.6%). The major Gr 3/4 nonhematologic toxicities were: nausea (1.6%), vomiting (1.6%), anorexia (5.3%), rash (0.5%). EGFR, pEGFR, TS, TP, DPD was overexpressed in 77.4%, 17.1%, 82.4%, 53.6% and 61.3% of tumor tissues respectively. EGFR amplification was not detected. Among these, the EGFR expression was significantly associated with shorter PFS and OS (p=0.029, p=0.005 respectively). K-RAS mutation was detected in 47.5%. PFS and OS were not different according to K-RAS mutation. RRM1 2455G>A, RRM1 2464G>A, CDA 79A>C, CDA 435C>T polymorphism did not influence on the PFS and OS. Conclusions: Erlotinib in combination with gemcitabine and capecitabine showed promising efficacy and good tolerability in metastatic pancreatic cancer. This efficacy was observed irrespective of K-RAS mutation, and the EGFR expression was poor prognostic factor for PFS and OS.

No significant financial relationships to disclose.

Concurrent chemoradiotherapy with weekly docetaxel and cisplatin for locally advanced head and neck cancer: Phase I study

e17026

Background: This phase I study was performed to determine maximum tolerated dose of docetaxel when administered concomitantly with radiotherapy and cisplatin in patients with locally advanced head and neck cancer. Methods: Fifteen patients were treated at varying levels of docetaxel (level 1: 0 mg/m2, level 2: 10 mg/m2, level 3: 15 mg/m2, and level 4: 20 mg/m2, once per week for a total 6 weeks) with a fixed dose of 20 mg/m2 cisplatin weekly on an outpatient basis. Radiotherapy was delivered as a standard regimen (1.8–2.0 Gy/day, 5 fraction/week) to a total dose of 66–72 Gy. Results: One out of six patients presented with dose-limiting toxicity at the 10 mg/m2/week dose of docetaxel (grade 4 febrile neutropenia which results in treatment-related death). No DLTs was noticed at the 15 mg/m2, and 20 mg/m2 dose level. Thus, the weekly docetaxel dose of 20 mg/m2 was considered as the maximum tolerated dose. Radiotherapy was completed in all patients except one, and more than 95% of the scheduled cisplatin and docetaxel were given in 93% of patients. Acute grade 3–4 toxicities were dominated by anorexia (26.7%), xerostomia (13.3%), and febrile neutropenia (6.6%). Eight (57.1%) and six (42.9%) patients had complete response and partial response. The 2-year actuarial overall survival rate and local control rate were 93.3%, and 87.5%, respectively. With a median 17.5 months (1.25–23.6) of follow-up, 13 out of 14 patients are still alive without evidence of diseases, and only one is alive with evidence of diseases. Conclusions: We determined the MTD of docetaxel to be 20 mg/m2 administered once weekly concurrently with combined with conventionally fractionated RT and weekly 10 mg/m2 CDDP. This chemoradiotherapeutic regimen serves as a promising treatment modality, in which level 3 is the recommended dose for a phase II study.

No significant financial relationships to disclose.

Risk stratification by hormonal receptor (ER, PgR) and HER2 status in small (≤1cm) invasive breast cancer: Who might be a possible candidate for adjuvant treatment?

564

Background: With the increasing use of screening mammography, the proportion of ≤ 1 cm invasive breast cancer is increasing. Identification of breast cancer molecular subtypes has resulted in a better appreciation of the biologic heterogeneity, which is not fully explained by clinicopathologic features including staging system. The aims of this study were: 1) to identify the risk factors of systemic metastases in patients with ≤ 1 cm invasive breast cancer and 2) to investigate the patients group at greatest risk of such failure even in these small tumors. Method: Data were collected retrospectively in the breast cancer registry of our institution for patients with invasive breast cancer from October 1994 to December 2004. Results: Of 4,036 patients who received curative breast cancer surgery, 466 patients who had T1a or T1b breast cancer were identified. 39 patients who received neoadjuvant chemotherapy were excluded in this study. Ipsilateral axillary lymph node involvement was found in 13% (57/427) at the time of surgery. Axillary lymph node involvement was much more common in HER-2 positive group (33% vs 11%, p < 0.0001) and triple negative (TN) group (24% vs 11%, p = 0.002) than in hormone receptor positive group. During median 61 months of follow-up, overall 10 year estimated distant relapse-free survival (DRFS) and overall survival (OS) were 95% and 92%, respectively. Multivariate analysis was conducted in 370 (T1aN0, T1bN0) patients, who had no lymph node involvement. In Cox-regression model, HER-2 positivity and triple negativity were identified as independent prognostic factors to predict DRFS [Hazard ratio (HR) 8.8, p = 0.003 for HER-2 positive group; HR 5.1, p = 0.026 for TN group] and OS (HR 5.0, p = 0.067 for HER-2 positive group; HR 11.1, p = 0.017 for TN group) in T1bN0 tumors. Limiting to T1aN0 tumors, statistical significance was not maintained. Conclusions: Even though T1aN0 and T1bN0 tumors have been known to have a relative low risk of systemic failure, anti-HER-2 directed therapy for HER-2 positive group and new innovative adjuvant systemic treatment for TN group in patients with T1bN0 tumor should be considered. Prospective adjuvant trials should be warranted in these subgroups of patients.

No significant financial relationships to disclose.

Definitive chemoradiation therapy with capecitabine in locally advanced pancreatic cancer

e15558

Background: We evaluated safety and efficacy of concurrent chemoradiotherapy (CCRT) with capecitabine in patients with locally advanced pancreatic cancer (LAPC). We also tried to devise a prognostic model for LAPC undergoing definitive CCRT. Methods: Between January 2004 and January 2008, 39 patients with LAPC treated with capecitabine CCRT were reviewed. Capecitabine was administered at 850 mg/m2 bid every day for 5 weeks. Radiotherapy was given 5 days per week, at 1.8 Gy fractions, over the 5 weeks. Results: Thirty seven (94.8%) patients completed CCRT, and 2 patients removed during the treatment for toxicity issues. Of the 36 evaluable patients, 15 (41.7 %) patients achieved partial response, and 13 (36.1 %) had a stable disease with 77.8% of disease control rate. Among the 28 patients who had achieved disease control after CCRT, 8 patients (21.6 %) received gemcitabine-based post-CCRT chemotherapy without dose reduction or delay. With median 1.8 years of follow- up, the overall survival was 14.3 months (95% confidence interval [CI]; 10.6–17.9 months). Median progression free survival was 11.1 (95% CI 7.2–15.1) for all patients, and 7.9 months (95% CI 6.6–9.2) for those not received post-CCRT chemotherapy. No patient had grade 4 hematologic or non-hematologic toxicity. Eight patients (21.6%) had severe grade 3 toxicities, 7 (18.9%) with gastrointestinal toxicity and 1 (2.7%) with hematologic toxicity. Prognostic factors for survival were serum albumin (P=0.014; relative risk [RR], 3.4; 95% CI, 1.4, 8.6), and adjuvant gemcitabine treatment (P = 0.005; RR, 3.5; 95% CI, 1.2, 10.6). The prognostic grouping resulted in three groups with significantly different prognosis: group 1 (0 adverse factor; n=8; 1-year survival, 87.5%), group 2 (1 adverse factor; n=23; 1-year survival, 52.9%) and group 3 (2 adverse factors; n=8; 1-year survival, 25.0%). Conclusions: Combined therapy with capecitabine CCRT was well tolerated. Capecitabine seems to be a promising regimen in the treatment of LAPC, in terms of response, survival, and tolerable adverse effects.

No significant financial relationships to disclose.

Prognostic role of insulin-like growth factor receptor-1 (IGFR-1) and insulin-like growth factor binding protein-3 (IGFBP-3) expression in small cell lung cancer

e22155

Background: Insulin-like growth factor receptor-1 (IGFR-1) is a cellular membrane receptor overexpressed in many tumor cell lines and in some human tumors that seems to play a critical role in anti-apoptosis by enhancing cell survival. Also, insulin-like growth factor binding protein-3 (IGFBP-3) was reported to be a growth suppressor in variable pathways. Purpose of this study was to evaluate the state IGFR-1 and IGFBP-3 expression in patients with small cell lung cancer (SCLC) and its prognostic value. Methods: We analyzed IGFR-1 and IGFBP-3 expression in 194 SCLC tissues specimens by immunohistochemical stain. The relationship between IGFR-1 and IGFBP-3 expression and cliniopathological factors was evaluated. Univariate and multivariate analyses were performed to define its prognostic significance. Results: Median age was 63 years (range 38–85), 84% were men. One hundred-seventeen patients had extensive disease (60.3%), and 77 had limited disease (39.7%). With the median follow- up duration of 49.5 months (24–82), the median progression free survival (PFS) and overall survival (OS) were 8 months (95% CI: 7.3–8.7 months), and 14.4 months (95% CI: 12.7–16 months), respectively, The IGFR-1 expression was observed in 154 of 190 tumor tissues (79.4%), whereas there was no tissue stained by IGFBP-3. Multivariate analysis showed that stage (p<0.001), response to treatment (p<0.001), LDH level (p<0.001) were the independent prognostic factors for PFS, and age (p=0.014), LDH level (p<0.001), and stage (p<0.001) for OS. The IGFR-1 positivity was not associated with PFS or OS in the whole cohort. However, 84% of 115 extensive disease patients showed IGFR-1 positivity. The subgroup analysis revealed that OS was significantly longer for patients with IGFR-1 positive compared to those with IGFR-1 negative in extensive disease (11.3% vs 0% at 2year, p=0.034). Conclusions: These results suggest that IGFR-1 expression may be useful as a prognostic marker in patients with extensive disease of SCLC.

No significant financial relationships to disclose.

Phase III trial of adjuvant capecitabine/cisplatin (XP) versus capecitabine/cisplatin/RT (XPRT) in resected gastric cancer with D2 nodal dissection (ARTIST trial): Safety analysis

4537

Background: Although the adjuvant chemoradiation therapy has gained popularity and has become the standard of care in patients with resected gastric cancer in U.S., the role of chemoradiation therapy after extended D2 dissection has been questioned. We conducted a phase III trial to compare capecitabine/cisplatin (XP) vs XP + radiotherapy (RT) in curatively D2 resected gastric cancer patients in terms of disease free survival and overall survival. Methods: Eligibility criteria were as follows: stage Ib (T1N1, T2bN0) - IV (M1 excluded), curatively ≥ D2 resected gastric adenocarcinoma. XP only: X 2,000 mg/m2/d D1∼14, CDDP 60 mg/m2 D1 repeated every 3 weeks, 6 cycles; XP + RT: X 2,000 mg/m2/d D1∼14, CDDP 60 mg/m2 D1 x 2 cycles ⋄ RT 45 Gy (25 fractions) + X 1,650 mg/m2/d during RT ⋄ X 2,000 mg/m2/d D1∼14, CDDP 60 mg/m2 D1 x 2 cycles. The primary endpoint is 3-year disease-free survival. Results: From October 2004 to April 2008, 458 patients (XP arm: 228 patients; XP/RT arm: 230 patients) were enrolled. In XP arm, 172 (75%) of 228 enrolled patients completed 6 cycles of chemotherapy. In XP + RT arm, 188 (82%) of 230 patients completed the full course of XP 2 cycles - X + RT - XP 2 cycles. Conclusions: Safety and feasibility analysis of the two arms will be reported at the meeting.

No significant financial relationships to disclose.

Prognostic impact of response to second-line chemotherapy on overall survival of patients with advanced gastric cancer

e15551

Background: It has been debated on whether tumor response to first-line chemotherapy (CT) would be reliable predictor for overall survival (OS) of cancer patients (pts). In case of advanced gastric cancer (AGC), many pts receive 2nd line CT after failure to 1st line treatment, so response to 2nd line CT as well as 1st line could affect OS. Methods: We retrieved clinical data of a total of 1,335 pts with AGC treated with palliative CT from January 2000 to December 2006 in National Cancer Center, Korea, including 757 pts who also received 2nd line CT. Responses to 1st and 2nd line CT were evaluable in 504 pts. Retrospective analysis was done to find correlation between objective tumor response to 1st and 2nd line CT and OS of the 504 pts, whom we divided into 4 groups: responders to both 1st and 2nd line CT (RR group); responders to 1st but not to 2nd line CT (RN group); responders to 2nd but not to 1st line CT (NR group); and nonresponders to both 1st and 2nd line CT (NN group). Results: Objective response rate of 1st and 2nd line CT was 41.7% and 12.3%, respectively. Responders to 1st line CT had a trend to respond to 2nd line CT (ORR of 2nd line CT in responders vs nonresponders to 1st line CT: 15.7% vs 9.9%, p = 0.049). 33/177/29/265 pts were assigned to each of RR/RN/NR/NN group, respectively. With median follow-up of 48.7 mo (range 23.2 - 93.7), median OS was 12.7 mo (95% CI 11.8–13.6). Baseline characteristics were balanced between 4 groups except higher hemoglobin and serum albumin level in RR group, younger median age in NN group, and fewer pts with poor performance status or poorly differentiated histology in NR group. Overall survival of RR, RN, NR, and NN group was 31.8 mo, 15.5 mo, 18.9 mo, and 9.2 mo, respectively (p<0.001). Multivariate analysis revealed relapsed disease after curative surgery, well-differentiated histology, absence of pulmonary metastasis, higher serum albumin level, lower serum bilirubin and alkaline phosphatase level, response to both of 1st line and 2nd line CT were reliable factors for favorable survival. Conclusions: Among the patients who received 2nd line chemotherapy for AGC, response to 2nd line CT was strongly associated with OS regardless of previous response to 1st line CT.

No significant financial relationships to disclose.

The role of oophorectomy for colon cancer with ovarian metastasis

e15113

Background: A recent study demonstrated that colorectal cancer with ovarian metastases were less responsive to chemotherapy compared to extraovarian metastases. Hence, the ovary may actually represent a “sanctuary” for metastatic cells from CRC. The aim of the study was to investigate the impact of oophorectomy on survival of colorectal cancer patients with ovarian metastasis. Methods: Between 1996 and 2008, 83 colorectal cancer patients underwent oophorectomy. For the historical control, 47 colorectal cancer patients without oophorectomy were included in the analysis. Survival and its associated factors were analyzed using Kaplan-Meier method, log-rank test and Cox-regression analysis. Results: The median age was younger (48 years) in the oophorectomy group when compared to the historical control (54 years) (P =.012). The proportion of synchronous metastasis was higher in the oophorectomy than the control group (57% vs 30%, respectively; P=.003). After a median follow-up duration of 60.8 months (range, 7.4 - 169.7 months), the median OS was significantly longer in the oophorectomy group (28.1 vs 21.2 months, oophorectomy vs non-oophoreectomy; P=.038). For ovary-specific survival (date of ovarian metastasis diagnosis to death), colorectal cancer patients with oophorectomy showed significantly favorable survival than the control group (20.8 vs 10.9 months, respectively; P<.001). At univariate analyses, no oophorectomy (P=.038), bilaterality of ovarian metastasis (P=0.032), the presence of extraovarian metastasis (P<0.001), elevated CEA (p<0.001), poor performance status (p=0.001), no palliative chemotherapy(p=0.001), no primary disease resection(p=0.005) were identified as significantly poor prognostic factors for overall survival. The no oophorectomy, no chemotherapy, extraovarian metastasis, elevated CEA, poor performance status retained statistical significance at multivariate level. (p=0.003, p=0.004, p=0.005, p=0.015, p=0.029, respectively). Conclusions: Based on this retrospective analysis, the oophorectomy significantly prolonged survival in colorectal cancer patients with ovarian metastases. A potential role of oophorectomy in the management of colorectal cancer should be prospectively studied.

No significant financial relationships to disclose.

Dynamics of gas-fluidized granular rods

We study a quasi-two-dimensional monolayer of granular rods fluidized by a spatially and temporally homogeneous upflow of air. By tracking the position and orientation of the particles, we characterize the dynamics of the system with sufficient resolution to observe ballistic motion at the shortest time scales. Particle anisotropy gives rise to dynamical anisotropy and superdiffusive dynamics parallel to the rod's long axis, causing the parallel and perpendicular mean-square displacements to become diffusive on different time scales. The distributions of free times and free paths between collisions deviate from exponential behavior, underscoring the nonthermal character of the particle motion. The dynamics show evidence of rotational-translational coupling similar to that of an anisotropic Brownian particle. We model rotational-translational coupling in the single-particle dynamics with a modified Langevin model using nonthermal noise sources. This suggests a phenomenological approach to thinking about collections of self-propelling particles in terms of enhanced memory effects.

Long-period-fiber-grating-based filter configuration enabling arbitrary linear filtering characteristics

The filtering scheme proposed here is based on transmission through a dual long-period-fiber-grating (LPFG) configuration and enables implementation of arbitrary spectral transfer functions using available inverse-scattering design algorithms, such as those widely used for fiber Bragg gratings (FBGs) operating in reflection. Besides the important technical advantage of operation in transmission, the proposed device can reach large spectral bandwidths that would be extremely challenging to reach by, e.g., FBG devices. The proposed concept is demonstrated by designing and fabricating a LPFG-based filter for synthesis of transform-limited 1.5-ps-long square-like pulses.