Efficacy and tolerability of limited field radiotherapy with concurrent capecitabine in locally advanced pancreatic cancer

Concurrent radiotherapy with oral fluoropyrimidine versus gemcitabine in locally advanced pancreatic cancer: a systematic review and meta-analysis

Background

Gemcitabine (GEM) is the most widely utilized systemic agent in combination with radiation therapy (RT) for treating locally advanced pancreatic cancer (LAPC) in the concurrent setting. Despite recent interest in using two novel oral fluoropyrimidines (FUs), capecitabine and S-1, in this setting, there is a lack of randomized controlled trials (RCTs) to support this approach.

Methods

Trials published between 1994 and 2014 were identified by an electronic search of public databases (Medline, Embase, and the Cochrane Library). All prospective studies were independently identified by two authors for inclusion. Demographic data, treatment response, objective response rate (ORR), progression-free and overall survival (PFS and OS, respectively), and toxicities were extracted and analyzed using comprehensive meta-analysis software (version 2.0).

Results

Twenty-three cohorts with 843 patients were included: 497 patients were treated with GEM and 346 patients were treated with oral FU. Pooled OS was significantly higher at 1 and 2 years for S-1 plus RT than for GEM plus RT (relative risk [RR] 1.27; 95% confidence interval [CI], 1.00–1.65; P=0.03; and RR 1.75; 95% CI, 1.18–2.60, P=0.002, respectively), while 1-year PFS and ORR were not significantly different between S-1 and GEM-based chemoradiotherapy (P=0.37 and P=0.06, respectively). Additionally, comparable efficacy was found between capecitabine and GEM-based chemoradiotherapy in terms of OS, PFS, and ORR. As for grade 3 and 4 acute toxicity, oral FU plus RT significantly reduced the risk of developing hematologic toxicities, nausea, and vomiting when compared to GEM plus RT (P<0.001).

Conclusions

Oral FU plus RT may be a safe and feasible regimen for patients with LAPC, with similar efficacy and low rate of toxicities compared with GEM plus RT. Our findings support the need to compare S-1 with GEM in the concurrent setting in large prospective RCTs due to its potential survival benefits.

Treatment Approaches to Locally Advanced Pancreatic Adenocarcinoma

This article focuses on the management of locally advanced pancreatic cancer, which should be treated as a distinct entity separate from metastatic disease and borderline resectable disease. Although the role, timing, and sequencing of radiation relative to systemic therapy in this disease are controversial, an emerging treatment paradigm involves induction chemotherapy, followed by consolidative chemoradiation in patients who do not progress. In addition, new chemotherapy regimens as well as novel radiosensitizers have shown promise and need to be tested further in the locally advanced setting. Advances in radiotherapy have enabled stereotactic body radiotherapy and should continue to be prospectively evaluated.

Autophagy, Warburg, and Warburg reverse effects in human cancer

Autophagy is a highly regulated-cell pathway for degrading long-lived proteins as well as for clearing cytoplasmic organelles. Autophagy is a key contributor to cellular homeostasis and metabolism. Warburg hypothesized that cancer growth is frequently associated with a deviation of a set of energy generation mechanisms to a nonoxidative breakdown of glucose. This cellular phenomenon seems to rely on a respiratory impairment, linked to mitochondrial dysfunction. This mitochondrial dysfunction results in a switch to anaerobic glycolysis. It has been recently suggested that epithelial cancer cells may induce the Warburg effect in neighboring stromal fibroblasts in which autophagy was activated. These series of observations drove to the proposal of a putative reverse Warburg effect of pathophysiological relevance for, at least, some tumor phenotypes. In this review we introduce the autophagy process and its regulation and its selective pathways and role in cancer cell metabolism. We define and describe the Warburg effect and the newly suggested "reverse" hypothesis. We also discuss the potential value of modulating autophagy with several pharmacological agents able to modify the Warburg effect. The association of the Warburg effect in cancer and stromal cells to tumor-related autophagy may be of relevance for further development of experimental therapeutics as well as for cancer prevention.

Phase II Trial of Cetuximab and Conformal Radiotherapy Only in Locally Advanced Pancreatic Cancer with Concurrent Tissue Sampling Feasibility Study

BACKGROUND

Preclinical data have indicated the anti-epidermal growth factor receptor (EGFR) agent cetuximab (Erbitux) as a radiosensitizer in pancreatic cancer, but this has not been specifically addressed in a clinical study. We report the results of an original study initiated in 2007, where cetuximab was tested with radiotherapy (RT) alone in locally advanced pancreatic cancer in a phase II trial (PACER).

METHODS

Patients (n = 21) received cetuximab loading dose (400 mg/m(2)) and weekly dose (250 mg/m(2)) during RT (50.4 Gy in 28 fractions). Toxicity and disease response end point data were prospectively assessed. A feasibility study of on-trial patient blood and skin sampling was incorporated.

RESULTS

Treatment was well tolerated, and toxicity was low; most patients (71%) experienced acute toxicities of grade 2 or less. Six months posttreatment, stable local disease was achieved in 90% of evaluable patients, but only 33% were free from metastatic progression. Median overall survival was 7.5 months, and actuarial survival was 33% at 1 year and 11% at 3 years, reflecting swift metastatic progression in some patients but good long-term control of localized disease in others. High-grade acneiform rash (P = .0027), posttreatment stable disease (P = .0059), and pretreatment cancer antigen 19.9 (CA19.9) level (P = .0042) associated with extended survival. Patient skin and blood samples yielded sufficient RNA and good quality protein, respectively.

CONCLUSIONS

The results indicate that cetuximab inhibits EGFR-mediated radioresistance to achieve excellent local control with minimal toxicity but does not sufficiently control metastatic progression in all patients. Translational studies of patient tissue samples may yield molecular information that may enable individual treatment response prediction.

Impact of omission of elective nodal irradiation on treatment outcomes in locally advanced pancreatic adenocarcinoma patients treated with definitive concurrent chemoradiotherapy

BACKGROUND

We evaluated influence of limited-field radiotherapy with no elective nodal irradiation (ENI) on outcomes and toxicity profile in patients with locally advanced pancreatic adenocarcinoma (LAPAC), treated with definitive concurrent chemoradiotherapy (C-CRT).

METHODS

Thirty-five patients with histological proof of LAPAC underwent 50.4Gy of C-CRT with 5-FU followed by maintenance gemcitabine. Target volume included primary tumor and lymph nodes that appeared to be involved on either contrast-enhanced computerized tomography or 18F-fluoro-deoxyglucose positron emission tomography.

RESULTS

No grade 4/5 acute/late toxicity was reported at median 15.7 months. Acute hematologic plus non-hematologic grade 3 toxicity was noted in 10 (28.6%) patients. At long-term, 2 patients (5.7%) experienced grade 3 gastric outlet obstructions at 8.7 and 10.9 months, respectively. No isolated regional relapses were noted. Median overall-survival (OS), progression-free survival (PFS), and locoregional-PFS (LRPFS) were 15.2, 9.1 and 7.3 months, respectively. Corresponding 1- and 2-year survival estimates were 60.0% and 20.0% for OS, 41.9% and 17.4% for LRPFS, and 34.0% and 12.7% for PFS, respectively.

CONCLUSIONS

Compared to ENI literature, first report of a limited-field C-CRT study carried out in Turkey showed that omission of ENI was relatively well tolerated without compromising survival and locoregional control rates in patients with LAPAC.

The role of radiotherapy in management of pancreatic cancer

Pancreatic cancer is one of the leading causes of cancer death. The treatment options in pancreatic cancer remain limited. This review provides an overview of the role of radiotherapy (RT) alone or in combination with systemic treatment at different settings of treatment strategy. Neoadjuvant chemoradiotherapy (CRT) may downstage the borderline resectable disease and make resection possible, which could translate to a survival benefit. Although the benefit of adjuvant CRT remains controversial due to inconsistent outcome of randomized trials, in North America it is still a common recommendation of the treatment. For locally advanced pancreatic cancer, the treatment option could either be chemotherapy or chemoradiotherapy. By using advanced radiotherapy modalities, the toxicity of RT could be reduced and RT dose escalation becomes possible to improve locoregional control.

Chemotherapy and autophagy-mediated cell death in pancreatic cancer cells

Autophagy is an evolutionarily preserved degradation process of cytoplasmic cellular constituents and plays important physiological roles in human health and disease. It has been proposed that autophagy plays an important role both in tumor progression and in promotion of cancer cell death, although the molecular mechanisms responsible for this dual action of autophagy in cancer have not been elucidated. Pancreatic ductal adenocarcinoma is one of the most aggressive human malignancies with 2-3% five-year survival rate. Its poor prognosis has been attributed to the lack of specific symptoms and early detection tools, and its relatively refractory to traditional cytotoxic agents and radiotherapy. Experimental evidence pointed at autophagy as a pancreatic cancer cell mechanism to survive under adverse environmental conditions, or as a defective programmed cell death mechanism that favors pancreatic cancer cell resistance to treatment. Here, we consider several phenotypical alterations that have been related to increase or decrease the autophagic process in pancreatic tumor cells. We specially review autophagy as a cell death mechanism in response to chemotherapeutic drugs.