Heterogeneic distribution of thymidine phosphorylase between primary tumors and metastatic lesions of human pancreatic ductal carcinoma: implications for the efficacy of chemotherapy with 5-FU or its derivatives

Prospective phase I study of capecitabine and oxaliplatin concurrent with radiation therapy for the treatment of locally advanced pancreatic adenocarcinoma, and retrospective comparison to concurrent 5-fluorouracil/radiation and gemcitabine/radiation

PURPOSE

The aims of this study is to determine the maximum tolerated dose of capecitabine and oxaliplatin (CAPOX) delivered concurrent with radiation therapy (RT) in the treatment of locally advanced pancreatic adenocarcinoma and to retrospectively compare outcomes with this regimen to concurrent 5-fluorouracil or capecitabine with RT (5FU-RT) or concurrent gemcitabine-based chemotherapy with RT (GEM-RT).

MATERIALS AND METHODS

Twelve patients were enrolled in a phase I study using 50.4 Gy RT concurrent with capecitabine chemotherapy (twice daily, 7 days per week) and oxaliplatin (once weekly during weeks 1, 2, 4, and 5). Capecitabine and oxaliplatin doses were 400 mg/m(2) and 50 mg/m(2), respectively, at dose level 1; 600 mg/m(2) and 50 mg/m(2) at level 2; and 600 mg/m(2) and 60 mg/m(2) at level 3. A standard dose of gemcitabine was recommended following RT or following surgery (if done). The outcomes of patients treated with this regimen were retrospectively compared to 20 patients treated with 5FU-RT and 30 patients treated with GEM-RT.

RESULTS

Dose level 3 was tolerated with acceptable toxicity. Survival in patients receiving CAPOX-RT did not differ from GEM-RT or 5FU-RT. Response of the primary tumor was observed in 38% of patients treated with CAPOX-RT, 31% of patients treated with 5FU-RT, and 66% of patients treated with GEM-RT (p = 0.03 GEM-RT versus 5FU-RT).

CONCLUSIONS

CAPOX-RT has acceptable toxicity. A retrospective comparison shows higher response rate with GEM-RT versus 5FU-RT, but this difference did not translate into improvement in overall survival.

Markers involved in resistance to cytotoxics and targeted therapeutics in pancreatic cancer

Pancreatic cancer retains a poor prognosis among the gastrointestinal cancers and remains a challenge in oncology. In 1997, gemcitabine became the standard of care in metastatic setting. In the last decades, despite a number of clinical trials assessing novel cytotoxic agents and cell signaling inhibitors, overall survival has reached a plateau that remains difficult to improve. Development of mechanisms implicated in intrinsic and acquired resistance to chemotherapy are considered to play a key role that could explain the limited benefit of most treatment in pancreatic cancers. Key molecular factors implicated in this process include: deficiencies in drugs uptake, activations of DNA repair pathways, resistance to apoptosis, and tumor microenvironment. Moreover, for cell signaling inhibitors, mutations in kinase domains, activation of alternative pathways, mutations of genes downstream of the target, activation of autocrine/paracrine pathways and/or feed-back amplification of the target represent the most important mechanisms achieving resistance of pancreatic cancer cells.

Hypoxia and angiogenesis in pancreatic cancer

BACKGROUND

Pancreatic cancer remains one of the most lethal of all solid tumours of the gastrointestinal tract. It is characterized by late diagnosis, aggressive local invasion, early metastasis and resistance to chemoradiotherapy. Increasing knowledge regarding the molecular events behind the growth and invasion of pancreatic cancer may lead to new targets for intervention.

METHODS

A search of Pubmed and Medline databases was undertaken using the keywords pancreatic cancer, gastrointestinal cancer, hypoxia, angiogenesis and anti-angiogenesis therapy.

RESULTS

Hypoxia is the driving force behind angiogenesis in pancreatic cancers. Research into angiogenesis has shown many different sites that can be targeted by agents such as tyrosine kinase inhibitors.

CONCLUSION

Anti-angiogenic therapy could be an important adjunct to conventional chemotherapy treatment of gastrointestinal neoplasia.

Molecular prognostic markers in pancreatic cancer: a systematic review

Pancreatic cancer is one of the most lethal tumours of the gastrointestinal tract. The ability to predict which patients would benefit most from surgical intervention and/or chemotherapy would be a great clinical asset. Considerable research has focused on identifying molecular events in pancreatic carcinogenesis, and their correlation with clinicopathological variables of pancreatic tumours and survival. This systematic review examined evidence from published manuscripts looking at molecular markers in pancreatic cancer and their correlation with tumour stage and grade, response to chemotherapy and long-term survival. A literature search was undertaken using PubMed and MEDLINE search engines, using the keywords p53, p21, p16, p27, SMAD4, K-ras, cyclin D1, Bax, Bcl-2, EGFR, EGF, c-erbB2, HB-EGF, TGFbeta, FGF, MMP, uPA, cathepsin, heparanase, E-cadherin, laminins, integrins, TMSF, CD44, cytokines, angiogenesis, VEGF, IL-8, beta-catenin, DNA microarray, and gene profiling. A bewildering number of biomarkers are currently under evaluation. For the most part, the evidence regarding their application as prognostic indicators is conflicting. The advent of gene microarray and mass spectrometric protein profiling offers the potential to examine many different biomarkers simultaneously. This 'protein/gene signature' could revolutionise work in this field and allow researchers to develop accurate and reproducible predictions of survival based on protein or gene profiles.

Thymidine phosphorylase profiles in nonmalignant and malignant pancreatic tissue. Potential therapeutic role of capecitabine on tumoral and endothelial cells and tumor-infiltrating macrophages

The drug capecitabine (CAP) is a thymidine Pi-deoxyribosyltransferase (TP) activated oral fluorpyrimidine that generates 5-fluorouracil (5-FU), preferentially, within tumors. Here, in 38 patients with pancreatic cancer we analyzed immunohistochemical TP expression in pancreatic cancer tissue (PCT) and adjacent nonmalignant pancreatic tissue (ANMPT). In addition, a correlation with the main clinical pathological features was made. Furthermore, TP-positive macrophages (MO) isolated from neoplastic tissue were determined. The mean of TP-positive epithelial cells and endothelial cells in terms of microvessel density was significantly higher in PCT than in ANMPT. Because pancreatic cancer is sensitive to 5-FU, TP-activated oral CAP in tumoral and endothelial cells and tumor infiltrating MO could increase the concentration of 5-FU at tumor site, thus resulting in an enhanced antitumor activity.