Tumor-initiating stem cell shapes its microenvironment into an immunosuppressive barrier and pro-tumorigenic niche.

Tumor-initiating stem cells (TSCs) are critical for drug resistance and immune escape. However, the mutual regulations between TSC and tumor microenvironment (TME) remain unclear. Using DNA-label retaining, single-cell RNA sequencing (scRNA-seq), and other approaches, we investigated intestinal adenoma in response to chemoradiotherapy (CRT), thus identifying therapy-resistant TSCs (TrTSCs). We find bidirectional crosstalk between TSCs and TME using CellPhoneDB analysis. An intriguing finding is that TSCs shape TME into a landscape that favors TSCs for immunosuppression and propagation. Using adenoma-organoid co-cultures, niche-cell depletion, and lineaging tracing, we characterize a functional role of cyclooxygenase-2 (Cox-2)-dependent signaling, predominantly occurring between tumor-associated monocytes and macrophages (TAMMs) and TrTSCs. We show that TAMMs promote TrTSC proliferation through prostaglandin E2 (PGE2)-PTGER4(EP4) signaling, which enhances ß-catenin activity via AKT phosphorylation. Thus, our study shows that the bidirectional crosstalk between TrTSC and TME results in a pro-tumorigenic and immunosuppressive contexture.

Survivin is a prognostic marker and therapeutic target for extranodal, nasal-type natural killer/T cell lymphoma.

BACKGROUND: The relationship between survivin and extranodal, nasal-type natural killer/T cell lymphoma (ENKTCL) was unclearly established yet. We here studied the potential prognostic roles of survivin and its implication as a target in ENKTCL therapy. METHODS: ENKTCL patients' peripheral blood were collected and tested by ELISA. ENKTCL cell lines were cultured with or without survivin inhibitor and tested by MTT and Flow cytometry. According to the gene expression profiles from the ArrayExpress Archive under E-TABM-702, survivin co-regulated cluster was established by Coupled Two-way Clustering Algorithm. RESULTS: Seventeen point six percent of total 17 ENKTCL patients were serum survivin-positive. These patients had poorer outcome than that of negative cases (P<0.01). Analysis of survivin co-regulation genes in ENKTCL revealed that survivin was significantly involved in pluripotency, drug resistance, cell cycle and proliferation, indicating that it should be one of key regulators in ENKTCL and might be a latent therapeutic target. Our results just showed that YM155, a survivin inhibitor, had strong anti-tumor effect on ENKTCL cell lines in a dose dependent manner. It increased sub-G1 phase population and reduced G1- and G2-M phase populations (P<0.05). In addition, combining YM155 with DDP induced a larger decrease in cell viability than either agent alone and had a higher inhibition rate than Bliss index, suggesting their synergistic inhibition. CONCLUSIONS: We concluded that survivin was a potential prognostic marker and a critical regulatory molecule in the pathological process of ENKTCL. It would be a promising target in drugs discovery for ENKTCL therapy.

Frequent PIK3CA Mutations in Colorectal and Endometrial Tumors With 2 or More Somatic Mutations in Mismatch Repair Genes.

BACKGROUND & AIMS: Some colorectal and endometrial tumors with microsatellite instability not attributable to MLH1 hypermethylation or germline mutations contain 2 or more somatic mutations in genes encoding mismatch repair (MMR) proteins. We sought to define the molecular phenotype of this newly recognized tumor subtype. METHODS: From 2 prospective studies of the efficacy of screening for Lynch syndrome, we identified patients with colorectal and endometrial tumors who had 2 or more somatic (but not germline) mutations in genes encoding MMR proteins (double somatic). We determined the frequencies of tumor mutations in PIK3CA, BRAF, KRAS, NRAS, and PTEN by targeted next-generation sequencing and used logistic-regression models to compare them with those from patients with Lynch syndrome, MLH1-hypermethylated, or microsatellite-stable tumors. We validated our findings using independent data sets from The Cancer Genome Atlas. RESULTS: Among colorectal cancer cases, we found that 14 of 21 (67%) patients with double somatic tumors also had PIK3CA mutations, compared with 4 of 18 (22%) tumors from patients with Lynch syndrome, 2 of 10 (20%) tumors with MLH1 hypermethylation, and 12 of 78 (15%) tumors with microsatellite stability (P < .0001 for patients with double somatic tumors vs other subgroups). Mutations in PIK3CA were detected in all 13 patients with double somatic endometrial cancers (P = .04 compared with other subgroups). We did not detect BRAF mutations in patients with double somatic colorectal tumors or Lynch syndrome. We found highly similar results in a validation cohort from The Cancer Genome Atlas (113 patients with colorectal tumors, 178 endometrial tumors); 100% of double somatic cases had a somatic mutation in PIK3CA (P < .0001 compared with other subgroups). CONCLUSIONS: Most patients with colorectal or endometrial tumors with 2 or more somatic (but not germline) mutations in MMR proteins also have mutations in PIK3CA; mutations in PIK3CA are detected at substantially higher frequencies in these double somatic tumors than in other microsatellite-instability subgroups. PIK3CA mutation status might be used to identify a specific group of colorectal tumors, and to select treatment or determine prognosis.

A randomized, phase II study of the anti-insulin-like growth factor receptor type 1 (IGF-1R) monoclonal antibody robatumumab (SCH 717454) in patients with advanced colorectal cancer.

Overexpression of insulin-like growth factor receptor type 1 (IGF-1R) may promote tumor development and progression in some cancer patients. Our objective was to assess tumor uptake of fluorodeoxyglucose by positron-emission tomography in patients with chemotherapy-refractory colorectal cancer treated with an anti-insulin-like growth factor receptor type 1 (anti-IGF-1R) monoclonal antibody, robatumumab. This was a randomized, open-label study with two periods (P1 and P2). Patients were randomized 3:1 into treatment arms R/R and C/R that received, respectively, one cycle of 0.3 mg/kg robatumumab or one or more cycles of second-line chemotherapy in P1, followed in either case by 10 mg/kg robatumumab biweekly in P2. The primary measure of fluorodeoxyglucose uptake was maximum standardized uptake value (SUV(max)). The primary endpoint was the proportion of patients in the R/R arm having a mean percent decrease from baseline in SUV(max) (DiSUV) greater than 20% 12-14 days postdose in P2. Secondary endpoints included Response Evaluation Criteria in Solid Tumors (RECIST)-defined tumor response and pharmacodynamic measures of target engagement. Among 41 patients who were evaluable for the primary endpoint, seven (17%, 95% CI 7%-32%) had DiSUV greater than 20%. Fifty robatumumab-treated patients were evaluable for RECIST-defined tumor response and six (12%) had stable disease lasting greater than or equal to 7 weeks in P2. Pharmacodynamic endpoints indicated target engagement after dosing with 10 mg/kg robatumumab, but not 0.3 mg/kg. The most frequently reported adverse events were fatigue/asthenia, nausea, anorexia, and gastrointestinal disturbances. In this study, few patients with chemotherapy-refractory colorectal cancer appeared to benefit from treatment with the IGF-1R antagonist robatumumab.

Phase I adjuvant trial of sorafenib in patients with hepatocellular carcinoma after orthotopic liver transplantation.

BACKGROUND: Post-transplant hepatocellular carcinoma recurrence has been reported to be between 15-18% and is higher among patients with high-risk features (bilobar tumor, macrovascular invasion, or multifocality). There are no known treatments which reduce risk of recurrence post-transplant. Sorafenib is currently approved for the treatment of advanced hepatocellular carcinoma. The objective of this phase I trial was to establish the safety and toxicity profile of sorafenib in high-risk patients with hepatocellular carcinoma who have undergone orthotopic liver transplantation. PATIENTS AND METHODS: Patients with hepatocellular carcinoma on explant with above high risk features were eligible to start the study drug between 28 and 60 days after liver transplantation. Sorafenib was administered and escalated twice daily on three cohort dose levels: i) 400 mg/day, ii) 600 mg/day and iii) 800 mg/day. RESULTS: Four patients newly transplanted were enrolled and received standard post-transplant medications. Dose-limiting toxicity was reached at the first cohort dose, with three out of four patients experiencing grade 3 toxicities. One patient experienced emerging grade 3 hand foot skin reaction leading to discontinuation of the study drug. Duration of sorafenib in the four patients was 0.7 months, 1.6 months, 3.5 months and 1.6 months, respectively. CONCLUSION: Although a small number of patients were studied, toxicity seen at 400 mg/day is consistent with toxicity reported by a small parallel study by Siegel AB.

Peripheral blood mononuclear CD133 mRNA levels correlates with response to treatment in patients with gastrointestinal stromal tumors.

BACKGROUND: CD133 is a marker that identifies/enriches cancer stem cell implicated in tumor initiation. We hypothesize that changes in the CD133 mRNA expression levels and vascular endothelial growth factor (VEGF) may correlate tumor response in GIST. METHODOLOGY/PRINCIPAL FINDINGS: After informed consent, we obtained peripheral blood samples from 24 evaluable patients with gastrointestinal stromal tumors (GIST). There were 7 -paired samples before and after treatment, We measured CD133 mRNA levels by real time RT-PCR method and vascular endothelial growth factor (VEGF) levels by ELISA. All measurements were done in duplicates in two separate experiments. The treatment resulted in significant reduction of CD133 mRNA expression (p = 0.048) as well as the level of VEGF (p = 0.003). The mean CD133 mRNA levels for GIST patients was 615. We found no correlation between the CD133 mRNA levels and VEGF levels. (p = 0.826). Logistic regression analysis suggested a relationship between elevated CD133 mRNA levels and fitted probability of eventual progressive disease (PD) and mixed response at 37% for CD133 mRNA of 2.25, and the probability of eventual PD/MR is 84% for a CD133 of 2072 (p = 0.08). CONCLUSIONS/SIGNIFICANCE: CD133 mRNA expression levels in GIST patients measured by real time RT-PCR assay appeared to correlate with tumor response to surgery or imatinib and may be used to predict tumor progression. Additional prospective studies are warranted.

Celecoxib downregulates CD133 expression through inhibition of the Wnt signaling pathway in colon cancer cells.

CD133-positive cancer stem cells in colon cancer are resistant to conventional chemotherapy. The aim of the present study was to investigate the effect of celecoxib, a COX-2 inhibitor, on CD133 expression in HT29 and DLD1 cells. HT29 and DLD1 cells were treated with celecoxib using different concentrations and duration. CD133 expression was detected by flow cytometry, Western blotting, immunofluorescence, and quantitative real-time PCR. Wnt signaling pathway activity was measured by luciferase assay and gene expression changes were monitored using microarray analysis. HT29 cells showed significantly decreasing levels of CD133 expression with increasing concentrations of or duration of exposure to celecoxib. CD133 mRNA relative expression in HT29 and DLD1 cells also decreased with drug exposure. Furthermore, Wnt activation in HT29 and DLD1 cells decreased with celecoxib treatment. Gene expression microarray showed stemness genes, including Lgr5, Oct4, Prominin-1, Prominin-2, CXCR4, E2F8, CDK-2, were downregulated and differentiation genes, including CEACAM5, GDF, ADFP, ICAM1, were upregulated. Our results show that CD133 expression was downregulated by celecoxib through inhibition of the Wnt signaling pathway, which may be lead to cell differentiation.

A phase 2 trial of ixabepilone plus cetuximab in first-line treatment of metastatic pancreatic cancer.

BACKGROUND: The aim of this phase 2 study was to evaluate the safety and efficacy of ixabepilone plus cetuximab in patients with advanced pancreatic cancer. METHODS: Eligible patients had advanced pancreatic adenocarcinoma that was metastatic or not amenable to resection, a Karnofsky performance status ≥70%, and no prior therapy for advanced disease. Patients received ixabepilone 32 mg/m(2) (3-hour IV infusion) every 3 weeks and cetuximab 250 mg/m(2) (1-hour IV infusion) weekly. The primary efficacy end point was the 6-month survival rate. Secondary end points included tumor response rate, overall survival, progression-free survival, and tolerability. RESULTS: A total of 54 patients were enrolled on this study. The 6-month survival rate was 57% (31/54: 95% CI: 43-71%) with a median overall survival of 7.6 months (95% CI: 5.5-12.2 months). Patients who developed acneiform rash (n = 36) had a median survival of 8.8 months, compared with 2.6 months for those without rash (n = 18). Of 31 patients with measurable disease (defined as response-evaluable), 4 had confirmed partial responses and an additional 24 had stable disease. The combination was generally well-tolerated with the most common grade 3/4 hematological toxicities being leucopenia (39%) and neutropenia (33%). The most common grade 3/4 nonhematologic toxicity was fatigue (17%). CONCLUSIONS: The combination of ixabepilone and cetuximab was active and had acceptable toxicity. The efficacy results are similar to single-agent ixabepilone and gemcitabine-based combination therapies in patients with advanced pancreatic cancer. Exploratory analyses suggest a trend toward improved survival for patients who experienced rash.

CD133, Stem Cells, and Cancer Stem Cells: Myth or Reality?

CD133, a member of the prominin family, is found in a variety of tissues with at least three variants. The function of CD133 is not well understood, but its expression is subject to changes in the microenvironment cues including bioenergetic stress. Knockout of CD133 does not affect renewal, but mammary gland branching. A point mutation of CD133 (R733C) leads to retinal disorder. CD133 is found in embryonic stem cells, normal tissue stem cells, stem cell niches, and circulating endothelial progenitors as well as cancer stem cells. Maintenance of stemness in cancer may be attributable to asymmetric cell division in association with a set of embryonic expression signatures in CD133+ tumor cells. CD133 could enrich cancer stem cells, which are associated with chemo- and radiation resistance phenotype. High CD133 is associated with poor survival in a variety of solid tumors, including lung, colon, prostate, etc. Monitoring CD133+ cells in peripheral blood, and targeting CD133 in cancer, may further predict and improve the clinical outcomes.

5-Fluorouracil upregulates the activity of Wnt signaling pathway in CD133-positive colon cancer stem-like cells.

BACKGROUND AND OBJECTIVE: CD133-positive colon cancer stem like cells (CSLCs) are resistant to the conventional cytotoxic drug 5-fluorouracil (5-FU). Wnt signaling pathway plays important roles in colon cancer carcinogenesis and metastasis, and regulates the self-renewal capacity of CSLCs. In the present study, we explored the impact of 5-FU on Wnt signaling pathway of CD133-positive colon CSLCs, and the relation between Wnt signaling pathway and drug resistance of CD133-positive colon CSLCs. METHODS: Magnetic activation cell separation was used to collect CD133-positive cells from colon cancer cell line DLD1, which was transfected with luciferase reporter for Wnt signaling activity. The activity of Wnt signaling pathway was compared between CD133-positive and CD133-negative cells. After the treatment with 1 µg/mL of 5-FU, the cell proliferation rates of DLD1 cells, CD133-positive cells, and CD133-negative cells were compared. After the treatment with 1 µg/mL and 10 µg/mL of 5-FU for 48 h, Wnt activity was compared between CD133-positive and CD133-negative cells. The expression of CD133 and cell apoptosis of CD133-positive cells was detected after exposure to 50 ng/mL of dickkopf (DKK)-1, a Wnt pathway inhibitor. RESULTS: After the treatment with 5-FU, the cell proliferation rate of CD133-positive cells was higher than that of CD133-negative cells and the sensitivity of CD133-positive cells to 5-FU decreased. Wnt activity was higher in CD133-positive cells than in CD133-negative cells [(46.3 ± 0.3)% vs. (33.9 ± 2.7)%, P = 0.009]. After the treatment with 1 µg/mL and 10 µg/mL of 5-FU, Wnt activity of CD133-positive cells was (90.1 ± 10.0)% (P = 0.012) and (52.9 ± 2.5)% (P = 0.047), respectively, whereas that of CD133-negative cells was (35.5 ± 3.3)% (P = 0.434) and (26.5 ± 0.4)% (P = 0.046), respectively. CD133 expression in CD133-positive cells decreased from (87.2 ± 5.3)% to (60.6 ± 3.1)% (P = 0.022) after treatment with DKK-1, whereas the cell apoptosis rate increased from (11.8 ± 0.2)% to (28.3 ± 0.6)% (P = 0.013). CONCLUSIONS: Wnt activity is higher in CD133-positive DLD1 cells than in CD133-negative DLD1 cells. 5-FU can upregulate Wnt activity of CD133-positive colon CSLCs. Blocking Wnt activity may reverse drug sensitivity of CD133-positive cells to 5-FU.

Temporal patterns of fatigue predict pathologic response in patients treated with preoperative chemoradiation therapy for rectal cancer.

PURPOSE: To investigate whether symptom burden before and during preoperative chemoradiation therapy (CRT) for rectal cancer predicts for pathologic tumor response. METHODS AND MATERIALS: Fifty-four patients with T3/T4/N+ rectal cancers were treated on a Phase II trial using preoperative capecitabine and concomitant boost radiotherapy. Symptom burden was prospectively assessed before (baseline) and weekly during CRT by patient self-reported questionnaires, the MD Anderson Symptom Inventory (MDASI), and Brief Fatigue Inventory (BFI). Survival probabilities were estimated using the Kaplan-Meier method. Symptom scores according to tumor downstaging (TDS) were compared using Student's t tests. Logistic regression was used to determine whether symptom burden levels predicted for TDS. Lowess curves were plotted for symptom burden across time. RESULTS: Among 51 patients evaluated for pathologic response, 26 patients (51%) had TDS. Fatigue, pain, and drowsiness were the most common symptoms. All symptoms increased progressively during treatment. Patients with TDS had lower MDASI fatigue scores at baseline and at completion (Week 5) of CRT (p = 0.03 for both) and lower levels of BFI "usual fatigue" at baseline. CONCLUSION: Lower levels of fatigue at baseline and completion of CRT were significant predictors of pathologic tumor response gauged by TDS, suggesting that symptom burden may be a surrogate for tumor burden. The relationship between symptom burden and circulating cytokines merits evaluation to characterize the molecular basis of this phenomenon.

An Application of Stream Imaging Technique in the Study of Osmotic Behaviors of Multiple Cells.

Light microscopy method offers unique abilities for the determination of membrane transport properties of either single or multiple cells. A stream imaging system composed of a microfluidic device, a charge-coupled device camera, and a microscope has been developed to study the osmotic behavior of multiple cells in response toward their extracellular environment. Cells of interest were first mixed with the desired extracellular medium and streamed into a microchannel. The microchannel confines the movement of the cells in a monolayer and allows cells to move along the flow direction only. The cells then pass through a sensing zone where the images of cells were capable of being captured under a microscope. Using mouse dendritic cells (mDCs) as a model system, the membrane transport properties were investigated. The kinetics volume changes of mDCs under various extracellular conditions at room temperature (22°C) were analyzed using a biophysical model to determine water and cryoprotectant transport properties of the cell membrane. This prototype system directly allows us to observe, trace, capture, and store the sample information in terms of number, concentration, dynamic size, or shape for further analyses and documentations. We believe that the system has the potential of being used as a stand-alone equipment, or integrated into a lab-on-a-chip system, or embedded into commercialized instruments.

Cancer stem cells, endothelial progenitors, and mesenchymal stem cells: "seed and soil" theory revisited.

Isolation of putative cancer stem cells (CSCs) in various tumors has generated much excitement among researchers who consider these cells the potential "culprits" behind resistance to conventional therapy. Both cancer and cardiovascular disease are believed to be stem cell disorders involving circulating endothelial progenitors (CEPs) and mesenchymal stem cells (MSCs). CD133 and CD44, markers of CSCs in many tumors, also enrich CEPs and MSCs, respectively. We propose an integrated tumorigenesis model that involves all three interdependent stem cell (CSC, CEP, MSC) compartments by revisiting the "seed and soil" model. Developing therapeutics that can effectively target CSCs and spare normal cardiovascular tissue will remain a challenge. Preliminary laboratory and clinical data on monitoring and targeting colon CSCs, using such a modeling system, are discussed.

Elevated circulating endothelial progenitor marker CD133 messenger RNA levels predict colon cancer recurrence.

BACKGROUND: CD133 is a specific surface marker for bone marrow-derived circulating endothelial progenitors, which are vital in postnatal physiologic and pathologic (eg, tumor) angiogenesis. In this study, the authors examined whether increased levels of expression of CD133 messenger RNA (mRNA) in peripheral blood predicted disease recurrence in patients with colon cancer. METHODS: Semiquantitative real-time reverse transcriptase-polymerase chain reaction analysis was used to quantify CD133 mRNA levels in peripheral blood mononuclear cells from patients with colon cancer. The assay was developed first and tested at laboratory A (n = 34) and then was validated independently at laboratory B (n = 66). All patients were enrolled between February 2002 and December 2003. A central statistician performed the analysis. RESULTS: At laboratory A, the median CD133 mRNA level was elevated in patients with recurrent disease (4.2; range, 0.017-106.9) compared with patients without recurrence (0.0017; range, 0.0-9.51; P < .001), leading to a 14.6 odds ratio of recurrence (95% confidence interval [95% CI], 1.7-126; P = .004). At laboratory B, it was confirmed that elevated CD133 mRNA levels at a cutoff point >or=4.79 versus <4.79 were associated with an odds ratio of 22.6 for recurrence (95% CI, 1.7-291.2; P = .02). By comparison, the odds ratio for recurrence was 17.2 (95% CI, 1.8-164; P = .01) for patients with stage III-IV disease versus stage I-II disease according to the Tumor, Lymph Node, Metastasis (TNM) classification. An association also was observed between elevated carcinoma embryonic antigen levels (P = .03; 1-sided) and decreased survival (P = .035; 1-sided) with a CD133 mRNA cutoff level of >or=4.79. CONCLUSIONS: Elevated CD133 mRNA levels at >or=4.79 predicted colon cancer recurrence independent of TNM stage IV disease. Larger prospective studies comparing the current assay with standardized methodology are warranted.

Conformal radiotherapy of the dominant liver metastasis: a viable strategy for treatment of unresectable chemotherapy refractory colorectal cancer liver metastases.

OBJECTIVES: To evaluate the safety and efficacy of conformal radiotherapy (RT) of the dominant liver metastasis as palliative treatment of patients with unresectable colorectal cancer liver metastases. METHODS: We retrospectively reviewed the hospital and RT records of 17 patients with unresectable colorectal liver metastases who had been treated with palliative RT to the dominant liver metastasis at our institution. RESULTS: The median size of the dominant liver metastasis was 10 cm (range, 3-19 cm). Twelve patients (71%) had evidence of extrahepatic disease. A median of 2 (range, 0-4) prior chemotherapy regimens had been administered. Median radiation dose was 42 Gy (range, 7.5-72 Gy). Concurrent chemotherapy included celecoxib in 1 (6%), capecitabine in 6 (35%), and both agents in 9 (53%) patients. Frequencies of acute diarrhea, nausea, vomiting, fatigue, hand-foot syndrome, and neutropenia were 29%, 47%, 6%, 29%, 7%, and 0%, respectively (all grade 2 or lower; no grade 3 toxicities). No late toxicities were noted. With a median follow-up time of 9.2 months, the median actuarial overall survival time from RT was 12.6 months (95% confidence interval [CI]: 3.3-40.9 months). The actuarial in-field local control rate was 62% at 6 months. The median actuarial time to in-field, out-of-field hepatic and distant progression were 6.8, 3.9, and 4.1 month, respectively (95% CIs, 3.9-15.8, 1.8-6.3, and 1.8-11.5 months, respectively). CONCLUSIONS: Conformal RT to the dominant liver metastasis as palliative therapy for unresectable colorectal cancer liver metastases has an acceptable toxicity profile and may improve survival. This approach merits further exploration.

Preoperative chemoradiotherapy with capecitabine versus protracted infusion 5-fluorouracil for rectal cancer: a matched-pair analysis.

PURPOSE: To retrospectively compare the acute toxicity, pathologic response, relapse rates, and survival in rectal cancer patients treated with preoperative radiotherapy (RT) and either concurrent capecitabine or concurrent protracted infusion 5-fluorouracil (5-FU). METHODS: Between June 2001 and February 2004, 89 patients with nonmetastatic rectal adenocarcinoma were treated with preoperative RT and concurrent capecitabine, followed by mesorectal excision. These patients were individually matched by clinical T and N stage (as determined by endoscopic ultrasound and CT scans) with 89 control patients treated with preoperative RT and concurrent protracted infusion 5-FU between September 1997 and August 2002. RESULTS: In each group, 5 patients (6%) had Grade 3-4 toxicity during chemoradiotherapy. The pathologic complete response rate was 21% with capecitabine and 12% with protracted infusion 5-FU (p = 0.19). Of the 89 patients in the capecitabine group and 89 in the 5-FU group, 46 (52%) and 55 (62%), respectively, had downstaging of the T stage after chemoradiotherapy (p = 0.20). The estimated 3-year local control (p = 0.15), distant control (p = 0.86), and overall survival (p = 0.12) rate was 94.4%, 86.3%, and 89.8% for patients treated with capecitabine and 98.6%, 86.6%, and 96.4% for patients treated with protracted infusion 5-FU, respectively. CONCLUSION: Preoperative concurrent capecitabine and concurrent protracted infusion 5-FU were both well tolerated, with similar, low rates of Grade 3-4 acute toxicity. No significant differences were seen in the pathologic response, local and distant recurrence, or overall survival among patients treated with preoperative RT and concurrent capecitabine compared with those treated with RT and concurrent protracted infusion 5-FU.

Phase II study of capecitabine (Xeloda) and concomitant boost radiotherapy in patients with locally advanced rectal cancer.

PURPOSE: The aim of this study was to determine the efficacy of capecitabine (Xeloda), an oral fluoropyrimidine, as a radiosensitizer in the neoadjuvant treatment of locally advanced rectal cancer (LARC). METHODS AND MATERIALS: We conducted a phase II study of capecitabine (825 mg/m2 orally, twice daily continuous) with radiotherapy (52.5 Gy/30 fractions to the primary tumor and perirectal nodes) in 54 patients with LARC (node-negative > or = T3 or any node-positive tumor) staged by endoscopic ultrasound (EUS). The primary endpoint was pathologic response rate; secondary endpoints included toxicity profiles and survival parameters. RESULTS: Of the 54 patients (median age, 56.7 years; range, 21.3-78.7 years; male:female ratio, 1.7; Eastern Cooperative Oncology Group performance status 0-1: 100%), 51 patients (94%) had T3N0 or T3N1 disease by EUS. Surgery was not performed in 3 patients; 2 of these patients had metastatic disease, and the third patient refused after a complete clinical response. Of the 51 patients evaluable for pathologic response, 9 patients (18%) achieved complete response, and 12 patients (24%) had microscopic residual disease (< 10% viable cells). In addition, 26 patients of all 54 patients (51%) achieved T-downstaging, and 15 patients of 29 patients (52%) achieved N-downstaging. Grade 3/4 toxicities were radiation dermatitis (9%) and diarrhea (2%). Sphincter preservation rate for tumor < or = 5 cm from the anal verge was 67% (18/27). CONCLUSION: This regimen of radiotherapy plus capecitabine is well tolerated and is more convenient than protracted venous infusion of 5-FU. The pathologic response rate is comparable to our previous experience using protracted venous infusion 5-FU for LARC.

Retrospective study of capecitabine and celecoxib in metastatic colorectal cancer: potential benefits and COX-2 as the common mediator in pain, toxicities and survival?

OBJECTIVE: COX-2 activation may mediate capecitabine induced toxicities, eg, hand-foot syndrome (HFS) and colorectal cancer progression, both of which may be improved by concurrent celecoxib. PATIENTS AND METHODS: From October 2000 to December 2003, 66 patients with metastatic colorectal cancer received concurrent capecitabine at 1000 mg/m/d b.i.d. and celecoxib at 200 mg b.i.d. (XCEL). Twenty-four patients were chemo-naive, 42 patients were second-line; while 34 had XCEL with radiation. RESULTS: The median duration of XCEL was 7.2 months (range, 1.5-38 months). Ninety percent of Grade 2/3 HFS (17%) occurred after 6 months and incidence of grade 3/4 diarrheas was 8%. The overall response rate was 38% (95% confidence interval [CI], 26-51%), with 11 patients (17%) achieving complete responses and 2 patients (3%) with near complete responses. Six patients (9%) become resectable after sustaining treatment response. The median progression-free survival (PFS) and overall survival (OS) was 8.3 months (95% CI, 7.0-11.0 months) and 22 months (95% CI, 17.8-31.5 months), respectively. Improved median PFS of 14.5 months (P = 0.0001) and OS of 31.5 months (P = 0.005) were noted in patients with normal lactate dehydrogenase (LDH) levels (n = 37) than patients with high levels of LDH (n = 29). CONCLUSIONS: XCEL integrating radiation may improve response rate and survival and reduce toxicities, notably HFS for patients with metastatic colorectal cancer, leading to a randomized phase III study.

The addition of continuous infusion 5-FU to preoperative radiation therapy increases tumor response, leading to increased sphincter preservation in locally advanced rectal cancer.

PURPOSE: To compare the outcome from preoperative chemoradiation (CXRT) and from radiation therapy (RT) in the treatment of rectal cancer in two large, single-institutional experiences. PATIENTS AND METHODS: Between 1978 and 1995, 403 patients with localized, nonmetastatic, clinically staged T3 or T4 rectal cancer patients were treated with preoperative RT alone at two institutions. Patients at institution 1 (n = 207) were treated with pelvic CXRT exclusively, and patients at institution 2 were treated (except for 8 given CXRT) with pelvic RT alone (n = 196). In addition, a third group (n = 61) was treated with CXRT at institution 2 between 1998 and 2000 after a policy change. Both institutions delivered 45 Gy in five fractions as a standard dose, but institution 2 used 20 Gy in five fractions in selected cases (n = 26). At both institutions, concurrent chemotherapy consisted of a continuous infusion of 5-fluorouracil (5-FU) at a dosage of 1500 mg/m(2)/week. The end points were response, sphincter preservation (SP), relapse-free survival (RFS), pelvic disease control (PC), and overall survival (OS). RESULTS: Median follow-up was 63 months for all living patients at institution 1 and in the primary group of institution 2. Multivariate analysis of the patients in these groups showed that the use of concurrent chemotherapy improved tumor response (T-stage downstaging, 62% vs. 42%, p = 0.001, and pathologic complete response, 23% vs. 5% p < 0.0001), but did not significantly improve LC, RFS, or OS. Follow-up for the secondary group at institution 2 was insufficient to allow the analysis of these endpoints. In the subset of patients receiving 45 Gy who had rectal tumors < or /=6 cm from the anal verge (institution 1: n = 132; institution 2 primary: n = 79; institution 2 secondary: n = 33), there was a significant improvement in SP with the use of concurrent chemotherapy (39% at institution 1 compared with 13% in the primary group at institution 2, p < 0.0001). A logistic regression analysis of clinical prognostic factors indicated that the use of concurrent chemotherapy independently influenced SP in these low tumors (p = 0.002). This finding was supported by a 36% SP rate in the secondary group at institution 2. Thus SP increased after the addition of chemotherapy at institution 2. CONCLUSIONS: The use of concurrent 5-FU with preoperative radiation therapy for T3 and T4 rectal cancer independently increases tumor response and may contribute to increased SP in patients with low rectal cancer.

Response to preoperative chemoradiation increases the use of sphincter-preserving surgery in patients with locally advanced low rectal carcinoma.

BACKGROUND: Although controversial, some believe that preoperative chemoradiation increases the use of sphincter-preserving surgery in low rectal carcinoma patients. This article investigates the relationship between objective tumor response and sphincter preservation in low rectal carcinoma patients. METHODS: The authors reviewed the records of 238 patients with T3 or T4 low rectal carcinoma (< or = 6 cm from the anal verge) who underwent preoperative pelvic chemoradiation (45 Gy/25 fractions/5 weeks, n = 182 or 52.5 Gy/30 fractions/5 weeks, n = 56 with continuous infusion 5-fluorouracil at 300 mg/m(2), Monday to Friday) followed by mesorectal (n = 223) or local excision (n = 15). A logistic regression analysis was used to analyze the influence of objective tumor response (defined as complete clinical response) and other prognostic factors on sphincter preservation. Because degrees of partial response could not be objectively defined retrospectively, the influence of partial response on sphincter preservation could not be evaluated. RESULTS: Overall, 49% of patients (117 of 238) had sphincter-preserving surgery. The clinical complete response rate was 47%. Independent predictors of sphincter preservation included the year of surgery, tumor distance from the anal verge, circumferential tumor involvement, and response to chemoradiation. The sphincter preservation rate increased over the period of the study (from 28% [December 1989 to December 1992] to 44% [January 1993 to December 1996] to 67% [January 1997 to December 2000]). The difference in the rates of sphincter preservation according to response was most striking among patients with tumors 3 cm or less from the anal verge (44% vs. 22%, P = 0.01). The pelvic disease recurrence rate among patients undergoing sphincter-preserving surgery has been less than 10% since January 1993 and was not statistically different between the groups treated from January 1993 to December 1996 and from January 1997 to December 2000. CONCLUSIONS: There has been an increase in the use of sphincter-preserving surgery without an increase in pelvic disease recurrence over the past decade. Although not necessary for sphincter preservation, clinical response to preoperative chemoradiation independently contributed to sphincter-preserving surgery, particularly in patients with low rectal tumors.