Qualitative analysis of a Filippov wild-sterile mosquito population model with immigration

Effectively combating mosquito-borne diseases necessitates innovative strategies beyond traditional methods like insecticide spraying and bed nets. Among these strategies, the sterile insect technique (SIT) emerges as a promising approach. Previous studies have utilized ordinary differential equations to simulate the release of sterile mosquitoes, aiming to reduce or eradicate wild mosquito populations. However, these models assume immediate release, leading to escalated costs. Inspired by this, we propose a non-smooth Filippov model that examines the interaction between wild and sterile mosquitoes. In our model, the release of sterile mosquitoes occurs when the population density of wild mosquitoes surpasses a specified threshold. We incorporate a density-dependent birth rate for wild mosquitoes and consider the impact of immigration. This paper unveils the complex dynamics exhibited by the proposed model, encompassing local sliding bifurcation and the presence of bistability, which entails the coexistence of regular equilibria and pseudo-equilibria, as crucial model parameters, including the threshold value, are varied. Moreover, the system exhibits hysteresis phenomena when manipulating the rate of sterile mosquito release. The existence of three types of limit cycles in the Filippov system is ruled out. Our main findings indicate that reducing the threshold value to an appropriate level can enhance the effectiveness of controlling wild insects. This highlights the economic benefits of employing SIT with a threshold policy control to impede the spread of disease-carrying insects while bolstering economic outcomes.

Fractional modeling of drug diffusion from cylindrical tablets based on Fickian and relaxed approaches with in vivo validation

Mathematical simulation of drug diffusion is a significant tool for predicting the bio-transport process. Moreover, the reported models in the literature are based on Fick's approach, which leads to an infinite propagation speed. Consequently, it is essential to construct a mathematical model to represent the diffusion processes for estimating drug concentrations at different sites and throughout the circulation. Thus, in this article, the diffusion process is employed to propose three models for estimating the drug release from multi-layer cylindrical tablets. A fractional model is presented based on Fick's approach, while classical and fractional Cattaneo models are presented using the relaxed principle. Various numerical methods are used to solve the specified problem. The numerical scheme's stability and convergence are demonstrated. Drug concentration and mass profiles are presented for the tablet and the external medium and compared with the in vivo plasma profiles. The results show the efficiency and precision of the proposed fractional models based on the fourth-order weighted-shifted Grünwald-Letnikov difference operator approximation. These models are compatible with the in vivo data compared with the classical Fick's one.

Prognostic significance of the genetic variant of lymphotoxin alpha (p.Thr60Asn) in egyptian patients with advanced hepatocellular carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide in terms of mortality, and susceptibility is attributed to genetic, lifestyle, and environmental factors. Lymphotoxin alpha (LTA) has a crucial role in communicating the lymphocytes with stromal cells and provoking cytotoxic effects on the cancer cells. There are no reports on the contribution of the LTA (c.179 C>A; p.Thr60Asn; rs1041981) gene polymorphism to HCC susceptibility. The main aim of this study is to investigate the association of LTA (c.179 C>A; p.Thr60Asn; rs1041981) variant with the HCC risk in the Egyptian population.

METHODS

This case-control study included 317 participants (111 HCC patients, and 206 healthy controls). The LTA (c.179 C>A; p.Thr60Asn; rs1041981) polymorphism was assessed by tetra-primer amplification refractory mutation system polymerase chain reaction (T-ARMS-PCR) technique.

RESULTS

The frequencies of the dominant and recessive models (CA + AA; AA) of the LTA (c.179 C>A; p.Thr60Asn; rs1041981) variant were statistically significant among HCC patients in comparison to controls (p = 0.01; p = 0.007; respectively). The A-allele of LTA (c.179 C>A; p.Thr60Asn; rs1041981) variant was statistically significant in HCC patients in comparison to controls (p ˂ 0.001).

CONCLUSION

The LTA (c.179 C>A; p.Thr60Asn; rs1041981) polymorphism was independently associated with an increased risk for hepatocellular carcinoma in the Egyptian population.

Genetic and biochemical studies of hepatic carcinoma in the Egyptian population

Background

Hepatocellular carcinoma (HCC), a deadly malignancy of the liver, is considered the third leading reason behind cancer deaths. It is more frequent in men than in women of ages above 50. Liver disease, leading to liver cirrhosis (LC), is mostly caused by alcoholism abuse, reaction diseases of the liver, or viral hepatitis B or C infection. Interleukin-6 (IL-6) is considered an effective pro-inflammatory cytokine, which plays a crucial role in the host defense mechanism. Its level is higher in HCC patients than in LC cases, indicating that tumor cells increase the production of cytokines. The X-ray repair cross-complementing group 1 (XRCC1) gene is a major DNA repair gene. It acts as a scaffold of various activities that are concerned in the repairing method by interacting with components of base excision repair. This study aims to measure the serum concentrations of IL6 and C-reactive protein (CRP) and investigate whether XRCC1 Arg194Trp and Arg399Gln polymorphisms are related to HCC disease.

Materials and Methods

Whole-blood DNA was extracted from 123 HCC patients and 123 healthy volunteers. Tetra-primer amplification refractory mutation system was performed in the detection of XRCC1 Arg399Gln and Arg194Trp polymorphisms.

Results

Serum concentration levels of IL-6 and CRP are significantly higher in patients with HCC than in control subjects. The allelic and genotype frequency distributions of XRCC1 (Arg399Gln and Arg194Trp) are significantly increased in HCC cases compared to healthy volunteers.

Conclusion

Arg/Gln, Arg/Trp, Gln/Gln, and Trp/Trp genotypes are associated with higher risk HCC than the Arg/Arg genotype.

Association of NOS3 (rs 2070744) and SOD2Val16Ala (rs4880) gene polymorphisms with increased risk of ESRD among Egyptian patients

BACKGROUND

Chronic kidney Failure (CKD), particularly End-Stage Renal Disease (ESRD), may be serious ill-health related to a high death rate. Uremic syndrome leads to increased oxidative stress, inflammation, and dyslipidemia. Our study aimed at identifying the association of NOS3 (rs 2070744) and SOD2 Val16Ala (rs4880) gene polymorphisms within ESRD Egyptian patients.

METHODS

This work was conducted on 100 ESRD and 16 CKD Egyptian patients who were compared to 100 healthy controls. DNA was genotyped for these variants using the (T-ARMS-PCR) technique.

RESULTS

ESRD patients showed a significant association of the genotype of NOS3 gene polymorphism compared with healthy controls (P = 0.032). In the contrast, the present study revealed that no statistically significant differences were found among the CKD, ESRD, and control groups as regards the SOD2 genotypes (P = 0.064).

CONCLUSIONS

Our findings indicated a significant association between NOS3 (rs 2070744) gene polymorphism and increased risk of ESRD and CKD among Egyptian patients.

Fat mass and obesity-associated (FTO) and leptin receptor (LEPR) gene polymorphisms in Egyptian obese subjects

BACKGROUND

Several studies addressed the contribution of fat mass and obesity-associated (FTO) and leptin receptor (LEPR) polymorphisms for the susceptibility to obesity among different ethnic subjects. The main purpose of this work is to evaluate the association of these polymorph\isms with obesity among Egyptian subjects.

SUBJECTS AND METHODS

This case-control study was carried out on 110 unrelated obese Egyptian subjects who were compared with 122 controls. Their genomic DNA was genotyped using the PCR technique.

RESULTS

The allelic frequencies of FTO rs9939609 (A) and LEPR rs1137101 (223R) were significantly higher in obese subjects compared with non-obese controls (p < .001). Comparing different phenotype frequencies including clinical, anthropometric, and biochemical parameters in obese subjects revealed no significant difference in relation to their genotype frequencies (p> .05).

CONCLUSIONS

This study designates a strong association for FTO and LEPR variants with the risk of obesity among Egyptian subjects.

Prevalence of Helicobacter pylori infection among children with primary nephrotic syndrome: a cross-sectional study

Background

Limited data are available about the prevalence of helicobacter pylori (H.pylori) infection among primary NS children.

Objectives

To assess the frequency and risk factors of H.pylori infection among children with primary NS.

Methods

A cross-sectional study was carried out in Mansoura University Children's Hospital, Egypt during the period from 2017 to 2019 including 100 NS children (NS group) and 100 healthy controls. NS group included 88 steroid sensitive (SSNS) and 12 steroid resistant (SRNS) cases. All patients were assessed for H.pylori infection using H.pylori stool antigen (HpSA) test. Statistical analysis was done using chi-square, fisher exact and Mann-Whitney tests.

Results

With regard to HpSA test results, no significant differences were detected between control and NS groups (p = 0.193) and between SSNS and SRNS groups (p = 0.286). Concerning total biopsied cases and MCD (proven plus presumed) cases, no significant differences were found between those with positive and negative HpSA test (p = 0.648 and 0.126, respectively). The high dose of steroid therapy was associated with a higher risk of H.pylori infection among NS group (Odds ratio = 3.8; 95% confidence interval = 1.3–11.3).

Conclusion

The current study negates the increased risk of H.pylori infection in children with primary NS.

Genetic polymorphisms of TP53 Arg72Pro and Pro47Ser among Egyptian patients with colorectal carcinoma

BACKGROUND

Previous reports demonstrated the role of TP53 gene polymorphisms with CRC risk among several ethnic populations. The purpose of this study is to assess the association of the TP53 Arg72Pro and Pro47Ser variants with CRC risk among Egyptian patients.

SUBJECTS AND METHODS

This work was conducted on 120 unrelated CRC Egyptian patients who were compared to 140 healthy controls. DNA was genotyped for these variants using the PCR-RFLP technique.

RESULTS

CRC patients observed a significant association of the rare genotype of TP53 Arg72Pro polymorphism compared with healthy controls. On the contrast, all genetic models showed no statistical association of TP53 Pro47Ser polymorphism among CRC patients compared with healthy controls. On the contrast, CRC patients of the TP53 gene polymorphisms indicated no significant difference regarding their clinical and laboratory markers.

CONCLUSIONS

Our findings indicate a strong association with TP53 Arg72Pro variant within increased risk of CRC among Egyptian patients.

Oxidative stress and vitamin D receptor BsmI gene polymorphism in Egyptian children with systemic lupus erythematosus: a single center study

Systemic lupus erythematosus (SLE) is an autoimmune disease with unknown exact etiology. Vitamin D receptor gene ( VDR) and oxidative stress play important roles in the pathogenesis of SLE. Here we investigated the genotypes and allelic frequencies of VDR BsmI polymorphism as well as their relationship with oxidative stress markers in Egyptian SLE children. We conducted a cross-sectional comparative study at Mansoura University Children's Hospital, Egypt from 2014 to 2018 including 100 SLE children and 100 controls. We investigated both groups for VDR BsmI polymorphism using polymerase chain reaction. Oxidative stress was assessed using malondialdehyde, glutathione S-transferase, superoxide dismutase, catalase and total antioxidant capacity. BB genotype frequency was found to be significantly higher in the SLE group ( p = 0.04, odds ratio (95% confidence interval) = 2.5 (1.01–5.9)). However, VDR B allele and b allele showed insignificant differences between SLE patients and controls ( p = 0.36, odds ratio (95% confidence interval) = 1.2 (0.8–1.8)). Lower levels of glutathione S-transferase, superoxide dismutase and total antioxidant capacity were found in the SLE group with statistically significant differences as regards glutathione S-transferase and superoxide dismutase ( p < 0.001). Serum malondialdehyde and catalase levels were significantly higher in the SLE group ( p < 0.001). No significant differences were found between VDR BsmI polymorphism (genotypes and alleles) and oxidative stress markers in the SLE group. In conclusion, BB genotype of VDR BsmI polymorphism is associated with an increased risk of SLE among Egyptian children. Oxidative stress may contribute in pathogenesis of SLE but is not associated with VDR BsmI polymorphism.

Angiotensin II type 2 receptor gene polymorphisms and serum angiotensin-converting enzyme level in Egyptian children with systemic lupus erythematosus

Background

There are no reports about the association of angiotensin II type 2 receptor ( AT2R) gene polymorphisms and susceptibility to systemic lupus erythematosus (SLE) in children.

Objective

The objective of this research is to study AT2R gene polymorphisms in exon 3 (C1593A) and intron 1 (A1675G) in Egyptian children with SLE and its correlation with disease manifestations and serum angiotensin-converting enzyme (ACE) level.

Methods

Typing of AT2R gene polymorphisms was conducted in 123 children with SLE in comparison with 100 healthy controls using the restriction fragment length polymorphism method.

Results

Significant differences were found between SLE patients and controls for A-containing genotypes (CA + AA) and A-allele frequencies of AT2R in exon 3 (C1593A) ( p = 0.01, odds ratio (OR) = 2.5, 95% confidence interval (CI) = 1.3–5.05; p = 0.01, OR = 2.2, 95% CI = 1.2–4.1, respectively). G-containing genotypes (AG + GG) and G allele of AT2R in intron 1 (A1675G) were more frequent in SLE patients compared to controls ( p = 0.01, OR = 2.3, 95% CI = 1.2–4.5; p = 0.02, OR = 2.1, 95% CI = 1.2–3.7, respectively). Serum ACE level was significantly higher in SLE patients than in controls ( p < 0.001). There was no association between AT2R gene polymorphisms and ACE level in serum. Moreover, there was no association between AT2R gene polymorphisms and SLE clinical manifestations.

Conclusion

AT2R gene polymorphisms can be considered risk factors for SLE development in Egyptian children.

Abstract P4-22-13: Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1

Background

Everolimus (EVE), an mTOR inhibitor has shown activity in HER2+ advanced breast cancer (ABC) in both preclinical and clinical studies. In the pivotal BOLERO-1 trial (NCT00876395), the progression-free survival (PFS) was not significantly different between the EVE + trastuzumab (TRAS) + paclitaxel (PAC) combination and placebo (PBO) + TRAS + PAC in the full HER2+ population (EVE, 15.0 mo vs PBO, 14.5 mo; HR=0.89; 95% CI: 0.73-1.08; p=0.1166). Although not reaching protocol defined level for statistical significance, the hormone receptor negative (HR-) subpopulation appeared to benefit from EVE, with a 7.2 mo PFS benefit vs PBO arm (EVE, 20.3 mo vs PBO, 13.1 mo; HR=0.66; 95% CI: 0.48-0.91; p=0.0049). The final exploratory overall survival (OS) analysis from the study is presented here.

Methods

In this phase 3 randomized trial, 719 women with HER2+ ABC without prior TRAS or chemotherapy in the metastatic setting were randomized 2:1 to receive either EVE (10 mg/d) or placebo (PBO) and weekly PAC+TRAS, stratified by visceral metastasis (lung, liver, peritoneal or pleural: yes vs no) and prior adjuvant or neo-adjuvant treatment with TRAS (yes vs no). As the primary objectives (PFS on full population and on HR- subpopulation) of BOLERO-1 were not met, the key secondary endpoint of OS was not formally statistically tested. However, given the results of PFS, in particular in the HR- subpopulation, a change to the OS analysis plan was made by introducing one final exploratory OS analysis at the time of study termination.

Results

At data cutoff (Dec 31, 2015), the median duration of exposure was 40.8 weeks (range: 0.6-320.4) in the EVE arm and 48.1 weeks (range: 1.1-308.0) in the PBO arm. After a median follow-up of 60.3 mo, 350 deaths were recorded in the full population, 238 (49.6%) in the EVE arm and 112 (46.9%) pts in the PBO arm. In the full population, the median OS was comparable in the EVE vs PBO arms (48.6 mo vs 50.0 mo respectively; HR = 1.13; 95% CI: 0.90-1.42). In the HR- subpopulation, 138 deaths were recorded; 88 (42.3%) pts in the EVE arm and 50 (48.5%) pts in the PBO arm. In the HR- subpopulation, the median OS in the EVE arm was longer compared to PBO arm (57.0 mo vs 41.6 mo respectively; HR = 0.83; 95% CI: 0.59-1.18). Stomatitis, diarrhea, alopecia, cough, rash, pyrexia, neutropenia, and fatigue were the most frequent adverse events (AEs) reported in EVE arm (≥35%). AEs leading to dose interruption and/or change were reported in 441 (93.4%) pts in EVE arm and 165 (69.3%) pts in the PBO arm respectively. Overall, AEs leading to treatment discontinuation were reported in 262 (55.5%) pts in EVE arm and 98 (41.2%) pts in PBO arm. Serious AEs were reported in 171 (36.2%) pts in the EVE arm and 40 (16.8%) pts in the PBO arm respectively. On treatment AE related deaths were reported for 3.6% pts in the EVE arm and 0% pts in the PBO arm.

Conclusions

The median OS was similar in the EVE vs PBO arms for overall population. However, a prolongation of 15.4 mo in median OS of HR- subpopulation was observed in the EVE arm vs PBO arm in this exploratory analysis. Pts in the EVE arm had a manageable safety, consistent with the safety profile of EVE and no new safety signals were identified.

Citation Format: Yardley D, Hurvitz S, Jiang Z-f, Toi M, Burris H, Buyse M, Slamon D, Makhson A, Elsaid A, Lerzo G, Hellerstedt B, Nuzzo F, Sohn J, Manzyuk L, Cabaribere D, Lincy J, Weimann A, Noel-Baron F, Pacaud L, Andre F. Everolimus plus trastuzumab and paclitaxel as first-line therapy in women with HER2+ advanced breast cancer: Overall survival results from BOLERO-1 [abstract]. In: Proceedings of the 2016 San Antonio Breast Cancer Symposium; 2016 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2017;77(4 Suppl):Abstract nr P4-22-13.

Non-truncating LIFR mutation: causal for prominent congenital pain insensitivity phenotype with progressive vertebral destruction?

We present a Qatari family with two children who displayed a characteristic phenotype of congenital marked pain insensitivity with hypohidrosis and progressive aseptic destruction of joints and vertebrae resembling that of hereditary sensory and autonomic neuropathies (HSANs). The patients, aged 10 and 14, remained of uncertain genetic diagnosis until whole genome sequencing was pursued. Genome sequencing identified a novel homozygous C65S mutation in the LIFR gene that is predicted to markedly destabilize and alter the structure of a particular domain and consequently to affect the functionality of the whole multi-domain LIFR protein. The C65S mutant LIFR showed altered glycosylation and an elevated expression level that might be attributed to a slow turnover of the mutant form. LIFR mutations have been reported in Stüve-Wiedemann syndrome (SWS), a severe autosomal recessive skeletal dysplasia often resulting in early death. Our patients share some clinical features of rare cases of SWS long-term survivors; however, they also phenocopy HSAN due to the marked pain insensitivity phenotype and progressive bone destruction. Screening for LIFR mutations might be warranted in genetically unresolved HSAN phenotypes.

Association of polymorphisms G(-174)C in IL-6 gene and G(-1082)A in IL-10 gene with traditional cardiovascular risk factors in patients with coronary artery disease

Interleukin-6 (IL-6) polymorphism has been associated with the genetic susceptibility to coronary artery disease (CAD) and also with the lipid profile in different populations. The present work aimed at studying the association, if any between the IL-6 (174) G/C and IL-10 (1082) G/A genes with hypertension or hyperlipidimia in Egyptian patients with CAD and the association of the IL-6 -174 G/C polymorphism with serum IL-6 levels. 108 Egyptian patients with CAD and 143 unrelated healthy subjects were included in the study. The different genotypes of IL-6 and IL-10 were detected by polymerase chain reaction. Serum levels of lipoprotein(a) [Lp(a)] and IL-6 were estimated in the patients, as well as in the healthy subjects. Increased frequency of G allele, GG and GC genotypes in IL-6, as well as decreased frequency of C allele and CC genotype were found in CAD patients, compared to healthy subjects [P = < 0.0001, OR = 3.95, 95% CI (2.16-7.22) for GG and GC vs CC genotype], [P = < 0.0001, OR = 3.44, 95% CI (2.26-5.23) for G allele]. There was an increased frequency of G allele vs A allele in IL-10 genotype in CAD patients, compared to healthy subjects [P = 0.005, OR = 1.866, 95% CI (1.2-2.9]. Higher levels of both Lp(a) and IL-6 were observed in CAD patients, compared to control subjects (P = 0.0012, P = 0.0346, respectively). Increased frequency of IL-6 -174 G-allele was implicated in a greater cardiovascular risk and the presence of G allele or homozygosity for G allele of IL-10 G/A (1082) was associated with an increased prevalence of CAD. The GC genotype and G allele in IL-6 had significant correlation with hyperlipidimic CAD patients; however, G allele in IL-6 and IL-10 showed significant association with hypertension. Thus, G allele in IL-6 and IL-10 was considered as an independent risk factor in hypertensive CAD patients.

Weekly combination chemotherapy of docetaxel and carboplatin and 5-FU in recurrent cervix cancer

16038

Background: The current phase II study assessed docetaxel/carboplatin/5FU given weekly for 24 weeks, for recurrent uterine cervix cancer. Methods: Fourty patients with histologically confirmed, recurrent uterine cervix cancer were enrolled. The patients eligible for this study had histologically confirmed, recurrent uterine cervix cancer. . Patients received weekly docetaxel 20 mg/m2 and carboplatin area under the curve (AUC) 2 weekly with bolus 5FU 500 mg/m2. The response status of the patients was assessed using the common ECOG response criteria. Results: 40 patients were entered in this study. The distribution of intial stage at first presentation was IB, 6 ; IIB, 16; IIIB, 10; IVB, 8. There were 30 squamous cell carcinomas, 6 adenocarcinomas, 4 adenosquamous cell carcinoma. : All patients were evaluable, and completed all planned therapy. The most frequent maximum toxicities during chemotherapy were Grade 2 mucositis with neutopenia. Nonhematological toxicity was generally mild, except for ubiquitous complete alopecia. Responses after 6 months included 6 patients with complete responses, 22 patients with PR and 12 patients with SD. No progression of disease was observed. Conclusions: This regimen was feasible, safe, and particularly well tolerated. Early Phase II outcomes revealed promising activity in patients completing all treatment.

No significant financial relationships to disclose.

Open-label safety and efficacy pilot trial of intraperitoneal bevacizumab as palliative treatment in refractory malignant ascites

9043

Background: One of the most burdensome complications of advanced cancer is the development of malignant ascites, impacting quality of life (QoL), gastrointestinal function, survival, and overall management costs. Recent studies have shown that malignant effusions arise in part from increased production and activity of vascular endothelial growth factors (VEGFs). VEGFs increase vascular permeability and establish an ideal environment for accumulation of malignant effusions. Methods: A pilot trial evaluating safety and efficacy of intraperitoneal administration of bevacizumab at 5 mg/kg monthly for as long as no disease progression or unacceptable toxicities are encountered. Patients with cytologically documented malignant ascites from any primary tumor refractory to standard therapy of diuretics, repeated paracentesis, and/or intraperitoneal chemotherapy were eligible. Patients were either off systemic therapy or had not had any changes in their systemic therapy for at least 4 weeks at the time of enrollment. Results: Between July 2006 and November 2006, 9 patients with refractory malignant ascites from colon cancer (3 pts), breast cancer (3 pts), uterine cancer (2 pts) and ovarian cancer (1 pt). Prior therapy included systemic chemotherapy and large volume paracentesis. Patients with ovarian and uterine cancer also received intraperitoneal cisplatin. All patients had rapid re-accumulation within 2 weeks of paracentesis before treatment. Patients were given intraperitoneal bevacizumab at 5 mg/kg monthly. Complications included grade I nausea in one patient, grade I abdominal pain in one patient, and partial small bowel obstruction in one patient that was managed conservatively. Malignant ascites resolved without reaccumulation or repeat paracentresis in 9/9 after a single intraperitoneal dose of bevacizumab over a median observation period of over two months. No objective tumor responses were observed. QoL assessment, pharmacokinetic studies of intraperitoneal Bevacizumab and pharmacodynamic studies on serum and ascites fluid VEGF are ongoing and will be reported. Conclusions: Intraperitoneal bevacizumab is a relatively safe and highly efficacious way to palliate the symptoms of refractory malignant ascites.

No significant financial relationships to disclose.

Pattern of progression and its impact on outcome in patients with gastrointestinal stromal tumors after initial response to imatinib mesylate: A retrospective multicenter long-term follow-up study

9541

Background: To investigate the clinical impact of the different types of disease progression (focal v extensive) in patients (pts) with metastatic gastrointestinal stromal tumors (GIST) after initial response to imatinib. Methods: Pts who received imatinib for metastatic GIST at three Cancer Centers and who have been followed up for at least 2.5 years were eligible for the study. Disease progression was classified as focal or extensive as defined by protocol. Responses were evaluated according to WHO criteria. Progression-free survival (PFS) and overall survival (OS) were calculated according to the Kaplan-Meier-method. In three pts with focal progressions, serial biopsies were obtained for mutation analysis. Results: Thirty-eight patients (21 men; mean age 58.4 years; range, 37–73 years) were included in the analysis. After a median follow-up of 31.8 mos, 25 of 38 (65.8%) patients had progressed. Nine of 25 progressions were classified as focal and 16 as extensive. Salvage therapies included dose escalation of imatinib with or without surgical resection. Median and 6- and 12-mos PFS were 11.3 mos, 89%, and 40% in pts with focal progression, and 2.5 mos, 39%, and 32%, in patients with extensive progression, respectively. The median OS was 22.8 mos in pts with extensive progression, and was not reached in pts with focal progression. Two subsequent focal progressions in one pt were associated with 2 different secondary KIT-mutations, whereas non-progressive disease harbored the original KIT-mutation alone. Conclusions: Imatinib resistance seems to be partial in a subset of progressing GIST pts. These pts may benefit from local treatment and imatinib continuation and further investigation of imatinib combinations with other compounds appears warranted. Extensive progression is associated with a dismal survival.

No significant financial relationships to disclose.

Induction chemotherapy (ICT) followed by pre-operative chemoradiotherapy in locally advanced rectal cancer

13531

Background: Preoperative radiotherapy (RT)with or without chemotherapy (CRT) for patients (ptns) with T3,4 rectal carcinoma is increasingly accepted.We presented, 3 yrs ago, our experience with Cisplatin-5FU-Folonic(FA)regimen (FOLFC) in patns with metastatic CR carcinoma.We proved it is comparable to other regimens with lower cost. Methods: Between 10/99 & 8/04, 104 ptns between 18 and 65 year old (PS 0–1) were assessed retrospectively (24 T3 & 80 T4). Ptns received 2 months of ICT Cis(40mg/m2 D1)+FA(200mg/m2 2hrs infusion D1,2)followed by 5FU bolus(400 mg/m2 D1,2)+5FU cont inf(1200 mg/m2 D1–2)this cycle repeated q 2 wks for 8 wks. Starting on wk 9, 5 FU-FA was given as in Mayo-clinic regimen (D1–5, D21–25) with concomitant RT 45Gy in 25 fractions followed by 9 Gy boost to primary tumor. TME was planned at 4–6 wks from completion of ICT. 2 more cycles of FOLFC was given post-operatively. Results: All ptns (104) undergoing CRT completed therapy as planned, with no treatment-related interruptions. No GIII-IV toxicity. The radiological RR (after ICT) was 75% and (4 wks after CRT) was 89% (20CRs, 73PRs). 92% of ptns had subjective R in a median of 24 days from start of ICT in terms of improvement of diarrhea/constipation (90.4%), in obstructive symptoms (40/ 50 ptns)&weight gain in 100% of ptns.Reduced rectal bleeding (100%) & pelvic pain (100%). 17 of 20 ptns who were considered to be inoperable prior to the treatment underwent TME with negative radial margins. Anastomotic leakage occurred in 8 ptns (7.7%). Wound infection occurred in 4 ptns (3.8%). Delayed complications occurred in 3 ptns one required surgery for a stomal stricture. All ptns underwent R0 resection with clear CRM. Pathological CR was found in 32 ptns and in an additional 41 ptns, only microscopic tumor foci were found on surgical specimens. After a median follow-up of 16 months, two ptns had developed LR. Conclusions: ICT followed by synchronous CRT and TME results in marked tumor regression, rapid symptomatic response and achievement of R0 resection. The majority of ptns considered inoperable prior to receiving this treatment underwent successful excision. Given the low toxicity and promising activity, this regimen is being compared to standard synchronous 5FU- pelvic chemoradiation in a randomized study.

No significant financial relationships to disclose.