Current status of chemoradiotherapy for locally advanced pancreatic cancer in Japan

Comparison of acute gastrointestinal toxicities between 3-dimensional conformal radiotherapy and intensity-modulated radiotherapy including prophylactic regions in chemoradiotherapy with S-1 for pancreatic cancer-importance of dose volume histogram parameters in the stomach as the predictive factors

The purpose of this study was to compare acute gastrointestinal (GI) toxicities in patients who underwent 3-dimensional conformal radiotherapy (3DCRT) and intensity-modulated radiotherapy (IMRT) in chemoradiotherapy (CRT) with S-1 including prophylactic regions for pancreatic cancer. We also investigated the predictive factor of acute GI toxicities in dose volume histogram (DVH) parameters. Patients who received CRT with S-1 for pancreatic cancer between January 2014 and March 2021 were included. Radiotherapy (RT) with a total dose of 50-54 Gy was delivered. We examined the differences in the frequencies of acute GI toxicity of grade 2 or higher and DVH parameters of the stomach (ST) and duodenum (DU) between the 3DCRT group and the IMRT group. The RT-related predictive factors of acute GI toxicities were investigated by univariate and multivariate analyses. There were 25 patients in the 3DCRT group and 31 patients in the IMRT group. The frequencies of acute GI toxicity of G2 or higher were 36% in the 3DCRT group and 9.7% in the IMRT group (p = 0.035). ST V50 was the most predictive factor (p = 0.001), and the incidences of acute GI toxicity of G2 or higher in ST V50 ≥ 4.1 cc and < 4.1cc were 43.7% and 7.7%, respectively. ST V40 was also a significant predictive factor of acute GI toxicity (p = 0.002). IMRT could reduce acute GI toxicities in CRT with S-1 including prophylactic regions for pancreatic cancer. Acute GI toxicities may be affected by moderate to high doses to the ST.

Aberrant glycogen synthase kinase 3β in the development of pancreatic cancer

Development and progression of pancreatic cancer involves general metabolic disorder, local chronic inflammation, and multistep activation of distinct oncogenic molecular pathways. These pathologic processes result in a highly invasive and metastatic tumor phenotype that is a major obstacle to curative surgical intervention, infusional gemcitabine-based chemotherapy, and radiation therapy. Many clinical trials with chemical compounds and therapeutic antibodies targeting growth factors, angiogenic factors, and matrix metalloproteinases have failed to demonstrate definitive therapeutic benefits to refractory pancreatic cancer patients. Glycogen synthase kinase 3β (GSK3β), a serine/threonine protein kinase, has emerged as a therapeutic target in common chronic and progressive diseases, including cancer. Here we review accumulating evidence for a pathologic role of GSK3β in promoting tumor cell survival, proliferation, invasion, and resistance to chemotherapy and radiation in pancreatic cancer. We also discuss the putative involvement of GSK3β in mediating metabolic disorder, local inflammation, and molecular alteration leading to pancreatic cancer development. Taken together, we highlight potential therapeutic as well as preventive effects of GSK3β inhibition in pancreatic cancer.

A phase II study of oral S-1 with concurrent radiotherapy followed by chemotherapy with S-1 alone for locally advanced pancreatic cancer

BACKGROUND/PURPOSE

S-1 is a new oral fluoropyrimidine anticancer agent shown to be effective for pancreatic cancer. In a previous phase I trial, we evaluated the safety of S-1 combined with radiotherapy to determine the maximum tolerated dose and dose-limiting toxicity in patients with unresectable pancreatic cancer. The recommended dose of S-1 for phase II trials of chemoradiotherapy was determined as 80 mg/m(2)/day given on days 1-21 of a 28-day cycle. This phase II study was conducted to further evaluate the efficacy and toxicity of radiotherapy combined with S-1 (UMIN000004794).

METHODS

Eligible patients had locally advanced and unresectable pancreatic cancer without distant metastases, an Eastern Cooperative Oncology Group performance status of 0-1, adequate organ and marrow functions, and no prior anticancer therapy. Patients initially received 4 weeks of chemoradiotherapy. S-1 was given orally at a dose of 80 mg/m(2)/day twice daily on days 1-21. Radiotherapy was delivered in fractions of 1.25 Gy twice daily, 5 days per week for 4 weeks (total dose: 50 Gy in 40 fractions). One month after the completion of chemoradiotherapy, S-1 was administered for 14 days followed by a 14-day rest period. This cycle was repeated as maintenance therapy until disease progression or unacceptable toxicity.

RESULTS

Fifty patients were enrolled in this phase II study. Median follow-up was 14.6 months (range 5.4-58.9 months). Forty-three patients (86%) completed the scheduled course of chemoradiotherapy. There was no treatment-related death or grade 4 toxicity. The major toxic effects were leukopenia and nausea. The objective tumor response according to the Response Evaluation Criteria in Solid Tumours criteria was partial response in 15 patients (30%) (95% confidence interval (CI), 18-45%), stable disease in 23 (46%), and progressive disease in 12 (24%). Median progression-free survival and median overall survival were 6.7 months (95% CI, 4.7-11.2 months) and 14.3 months (95% CI, 10.8-20.8 months), respectively. Survival rates at 1 and 2 years were 62 and 27%, respectively.

CONCLUSIONS

Combination therapy with S-1 and radiation in patients with locally advanced and unresectable pancreatic cancer is considered a promising, well-tolerated regimen that can be recommended as an effective treatment for locally advanced pancreatic cancer.

Antitumor effects of α-bisabolol against pancreatic cancer

In the present study, we investigated whether α-bisabolol, a sesquiterpene alcohol present in essential oils derived from a variety of plants, has antitumor effects against pancreatic cancer. α-Bisabolol induced a decrease in cell proliferation and viability in pancreatic cancer cell lines (KLM1, KP4, Panc1, MIA Paca2), but not in pancreatic epithelial cells (ACBRI515). α-Bisabolol treatment induced apoptosis and suppressed Akt activation in pancreatic cancer cell lines. Furthermore, α-bisabolol treatment induced the overexpression of early growth response-1 (EGR1), whereas EGR1 siRNA decreased the α-bisabolol-induced cell death of KLM1 cells. Tumor growth in both subcutaneous and peritoneal xenograft nude mouse models was significantly inhibited by intragastric administration of 1000 mg/kg of α-bisabolol, once a week for three weeks. The results indicate that α-bisabolol could be a novel therapeutic option for the treatment of pancreatic cancer.

Metabolic disorder, inflammation, and deregulated molecular pathways converging in pancreatic cancer development: implications for new therapeutic strategies

Pancreatic cancer develops and progresses through complex, cumulative biological processes involving metabolic disorder, local inflammation, and deregulated molecular pathways. The resulting tumor aggressiveness hampers surgical intervention and renders pancreatic cancer resistant to standard chemotherapy and radiation therapy. Based on these pathologic properties, several therapeutic strategies are being developed to reverse refractory pancreatic cancer. Here, we outline molecular targeting therapies, which are primarily directed against growth factor receptor-type tyrosine kinases deregulated in tumors, but have failed to improve the survival of pancreatic cancer patients. Glycogen synthase kinase-3β (GSK3β) is a member of a serine/threonine protein kinase family that plays a critical role in various cellular pathways. GSK3β has also emerged as a mediator of pathological states, including glucose intolerance, inflammation, and various cancers (e.g., pancreatic cancer). We review recent studies that demonstrate the anti-tumor effects of GSK3β inhibition alone or in combination with chemotherapy and radiation. GSK3β inhibition may exert indirect anti-tumor actions in pancreatic cancer by modulating metabolic disorder and inflammation.