Clinical Research Gastrointestinal Cancers

The investigators hypothesize that intensification of local therapy will lead to improvements in local control and survival in patients with unresectable and borderline resectable pancreatic cancer. We propose to do this by combining nab-paclitaxel concurrently with dose-escalated radiation therapy. In the first part of this phase I study (sub-trial 1), the nab-paclitaxel dose will be escalated while the radiation dose is held constant at a standardly accepted level. The use of this novel chemoradiotherapy regimen will take advantage of nab-paclitaxel's specific anti-tumor and anti-stromal properties, which may enhance the efficacy of radiation therapy, and thereby improve local control. After the MTD of nab-paclitaxel had been determined, a second arm in sub-trial 1 will evaluate the addition of paricalcitol to nab-paclitaxel concurrently with dose-escalated radiation therapy. In addition, after the MTD of the nab-paclitaxel is reached in sub-trial 1 arm A, in the second part of this study (sub-trial 2), we will administer nab-paclitaxel at the determined MTD concurrently with escalated doses of radiation. We will utilize IMRT or protons to safely deliver high doses of radiation while maximally sparing surrounding normal tissue. Patients will also preferentially have 2-3 fiducial markers placed in or around the tumor for daily localization. Chemotherapy before and/or after chemoradiotherapy may be given as per standard of care. Correlative tissue and serum biomarkers are an important, but optional, part of this study.