Adjuvant therapy for pancreatic cancer: current treatment approaches and future challenges

Cancer of the Pancreas-Actual 5, 10, and 20+Year Survival: The Lucky and Fortunate Few

Cancer of the pancreas (CaP) is a dismal, uncommon, systemic malignancy. This article updates an earlier experience of actual long-term survival of CaP in patients treated between 1991 to 2000, and reviews the literature. Survival is expressed as actual, not projected, survival.

Long-term outcomes of extended radical resection combined with intraoperative radiation therapy for pancreatic cancer

BACKGROUND/PURPOSE

Systemic and/or local recurrence often occurs even after curative resection for pancreatic cancer (PC). To prevent local relapse we adopted an extended radical resection combined with intraoperative radiation therapy in patients with PC, and all the patients were followed for more than 5 years.

METHODS

We assessed the long-term outcomes of 41 patients who underwent this combined therapy. The cumulative survival curve in this series was depicted using the Kaplan-Meier method. Statistical analyses were performed using the log-rank test.

RESULTS

The actual 5-year survival rate was 14.6%, with a median survival time of 17.6 months. Six patients have been 5-year survivors. Local recurrence occurred in only 2 patients (5.0%). Cancer-related death occurred in 32 patients, 18 of whom had liver metastases. The patients with liver metastases had a significantly shorter survival time than those with other cancer-related causes of death. Patients with n3 lymph node involvement, extrapancreatic nerve plexus invasion, and stage IV disease had significantly poorer prognoses than patients without these characteristics.

CONCLUSIONS

Our combined therapy for patients with PC contributed to local control; however, it provided no survival benefit, because of liver metastases.

mda-7/IL24 kills pancreatic cancer cells by inhibition of the Wnt/PI3K signaling pathways: Identification of IL-20 receptor-mediated bystander activity against pancreatic cancer

The melanoma differentiation-associated gene (mda-7; approved gene symbol IL24) is a tumor suppressor gene whose protein expression in normal cells is restricted to the immune system and to melanocytes. Recent studies have shown that mda-7 gene transfer inhibits cell growth and induces apoptosis in melanoma, lung cancer, breast cancer, and other tumor types through activation of various intracellular signaling pathways. In the current study, we demonstrate that Ad-mda7 transduction of human pancreatic cancer cells results in G2/M cell cycle arrest and cell killing. Cytotoxicity is mediated via apoptosis in a time- and dose-dependent manner. Tumor cell killing correlates with regulation of proteins involved in the Wnt and PI3K pathways: beta-catenin, APC, GSK-3, JNK, and PTEN. Additionally, we identify bystander cell killing activated by exposure of pancreatic tumor cells to secreted human MDA-7 protein. In pancreatic tumor cells, exogenous MDA-7 protein activates STAT3 and kills cells via engagement of IL-20 receptors. The specificity of bystander killing is demonstrated using neutralizing anti-MDA-7 antibodies and anti-receptor antibodies, which inhibit the apoptotic effects. In sum, we show that Ad-mda7 is able to induce growth inhibition and apoptosis in pancreatic cancer cells via inhibition of the Wnt/PI3K pathways and identify a novel bystander mechanism of MDA-7 killing in pancreatic cancer that functions via IL-20 receptors.

Phase I study of stereotactic radiosurgery in patients with locally advanced pancreatic cancer

PURPOSE

To determine the feasibility and toxicity of delivering stereotactic radiosurgery to patients with locally advanced pancreatic cancer.

METHODS AND MATERIALS

Patients with Eastern Cooperative Oncology Group performance status < or=2 and locally advanced pancreatic cancer were enrolled on this Phase I dose escalation study. Patients received a single fraction of radiosurgery consisting of either 15 Gy, 20 Gy, or 25 Gy to the primary tumor. Acute gastrointestinal toxicity was scored according to the Radiation Therapy Oncology Group criteria. Response to treatment was determined by serial high-resolution computed tomography scanning.

RESULTS

Fifteen patients were treated at 3 dose levels (3 patients received 15 Gy, 5 patients received 20 Gy, and 7 patients received 25 Gy). At these doses, no Grade 3 or higher acute gastrointestinal toxicity was observed. This trial was stopped before any dose-limiting toxicity was reached, because the clinical objective of local control was achieved in all 6 evaluable patients treated at 25 Gy.

CONCLUSIONS

It is feasible to deliver stereotactic radiosurgery to patients with locally advanced pancreatic cancer. The recommended dose to achieve local control without significant acute gastrointestinal toxicity is 25 Gy.

Relationship between nuclear morphometry, DNA content and resectability of pancreatic cancer

AIM: To investigate the association of nuclear morphometry and DNA content with resectability of pancreatic cancer.

METHODS: A total of 36 patients with pancreatic adenocarcinoma were divided into resectable group and unresectable group. The nuclear morphometry and DNA contents of tumor cells were analyzed by IBAS autoimagine analyzer from paraffin-embedded materials. Localization size, histological type and grade, and clinical stage of the tumor were evaluated. Factors influencing resectability of pancreatic cancer were investigated using stepwise regression analysis.

RESULTS: Statistical significance was found in nuclear DNA content (integrated optical density, IOD) of tumor cells (1.64 ± 0.41 vs 2.96 ± 0.55), DNA ploidy, ages (46.5 ± 5.3 years vs 58.6 ± 0.7 years) and tumor volumes (298.1 ± 101.5 cm³vs 634.7 ± 512.5 cm³) in both groups (P < 0.05), and no difference was found in the nuclear morphometry (P > 0.05). The rates of diploid/tetraploid and aneuploid were 66.7% and 33.3% in resectable group respectively, and 38.9% and 62.1% in unresectable group, respectively (P < 0.05). IOD (X₁₂), ploidy status (X₁₃) and clinical stage (X₃) were radical resectable indicators with statistical significance. The regression equation for resectability was Y = -9.2053 + 3.5428X₁₂ + 2.5390X₁₃ - 2.3001X₃ (RR = 0.8780, P < 0.01).

CONCLUSION: There is a high correlation between resectability of pancreatic cancers and their DNA contents, DNA ploidy status and clinical stage.

Relationship between expression of E-cadherin-catenin complex and clinicopathologic characteristics of pancreatic cancer

AIM: To investigate the expression of E-cadherin and alpha-catenin and beta-catenin in pancreatic carcinoma and its relationship with the clinicopathologic characteristics, and clarify the mechanism of invasion and metastasis of pancreatic cancer.

METHODS: The expression of E-cadherin and alpha-, beta-catenin was examined in 47 cases of infiltrative ductal adenocarcinoma of pancreas and 12 adult normal pancreatic tissues by immunohistochemical technique.

RESULTS: The immunoreactivity of E-cadherin and alpha-, beta-catenin was expressed by normal ductal and acinar cells with strong membranous staining at the intercellular border in 12 cases of adult normal pancreatic tissues. Abnormal expression of E-cadherin and alpha-, beta-catenin in 47 pancreatic carcinoma tissues was demonstrated in 53.2%, 61.7% and 68.1%, respectively. Both abnormal expression of E-cadherin and alpha-catenin significantly correlated with differentiation, lymph node and liver metastases (P < 0.05, respectively), whereas aberrant beta-catenin expression only correlated with lymph node and liver metastases (P < 0.001). Abnormal E-cadherin and alpha-, beta-catenin expression was not associated with tumor size, invasion and survival time of patients (P > 0.05, all).

CONCLUSION: Pancreatic cancer likely occurs in case of E-cadherin-catenin complex genes mutations or deletions and abnormal expression of proteins, which significantly correlate with the biologic character of the tumor and lymph node and liver metastases. It is suggested that the abnormal E-cadherin-catenin complex expression plays an important role in the development and progression of tumor, and thus may become a new marker in pancreatic cancer metastasis.

Current and future strategies for combined-modality therapy in pancreatic cancer

Treatment of pancreatic cancer remains a challenging task that often requires a multidisciplinary approach to confer optimal response and, ideally, maximize survival. A combination of locoregional approaches such as surgery and radiotherapy, along with systemic therapies for eradication of micrometastases, should be considered both for patients who are operative candidates and for those with locally advanced, unresectable disease. How best to combine these modalities in terms of schedule, timing, and choice of agents is a question that continues to be actively investigated. Some of these data are equivocal or conflicting; thus standards of care for combined-modality treatment have not been uniformly accepted to date. This article provides an overview of combined-modality therapy, focusing on the major studies that have guided our current approach to the treatment of pancreatic cancer and examining new strategies that are likely to improve outcomes and survival for patients in the future.

Taxotere resistance in SUIT Taxotere resistance in pancreatic carcinoma cell line SUIT 2 and its sublines

AIM: To investigate the specific mechanisms of intrinsic and acquired resistance to taxotere (TXT) in pancreatic adenocarcinoma (PAC).

METHODS: MTT assay was used to detect the sensitivity of PAC cell line SUIT-2 and its sublines (S-007, S-013, S-020, S-028 and TXT selected SUIT-2 cell line, S2/TXT) to TXT. Mdr1 (P-gp), multidrug resistance associated protein (MRP), lung resistance protein (LRP) and β-tubulin isotype gene expressions were detected by RT-PCR. The functionality of P-gp and MRP was tested using their specific blocker verapamil (Ver) and indomethacin (IMC), respectively. The transporter activity of P-gp was also confirmed by Rhodamine 123 accumulation assay.

RESULTS: S-020 and S2/TXT were found to be significantly resistant to TXT (19 and 9.5-fold to their parental cell line SUIT-2, respectively). RT-PCR demonstrated strong expression of Mdr1 in these two cell lines, but weaker expression or no expression in other cells lines. MRP and LRP expressions were found in most of these cell lines. The TXT-resistance in S2-020 and S2/TXT could be reversed almost completely by Ver, but not by IMC. Flow cytometry showed that Ver increased the accumulation of Rhodamine-123 in these two cell lines. Compared with S-020 and SUIT-2, the levels of β-tubulin isotype II, III expressio ns in S-2/TXT were increased remarkably.

CONCLUSION: The both intrinsic and acquired TXT-related drug resistance in these PAC cell lines is mainly mediated by P-gp, but had no relationship to MRP and LRP express ions. The increases of β-tubulin isotype II, III might be collateral changes that occur when the SUIT-2 cells are treated with TXT.