Erlotinib, Gemcitabine, and Radiation Therapy in Treating Patients With Locally Advanced Unresectable Pancreatic Cancer

Inclusion Criteria: Histologically or cytologically confirmed adenocarcinoma of the pancreas Locally advanced, unresectable disease, defined by all of the following: Obvious encasement of the celiac, hepatic, or superior mesenteric artery Encasement of the portal or superior mesenteric vein not amenable to surgical resection Extrapancreatic extension with or without regional lymph node involvement No evidence of distant metastatic disease by staging laparoscopy* Locally recurrent disease after prior curative surgery allowed provided the following are true: No prior chemotherapy or radiotherapy No evidence of distant metastatic disease by staging laparoscopy* No islet cell pancreatic cancer or lymphoma or sarcoma of the pancreas Measurable or evaluable disease Primary pancreatic tumor is considered evaluable and not measurable disease Lymph node mass considered measurable disease No known brain metastases Performance status - ECOG 0-2 More than 12 weeks WBC ≥ 3,000/mm^3 Absolute neutrophil count ≥ 1,500/mm^3 Platelet count ≥ 100,000/mm^3 Bilirubin ≤ 1.5 mg/dL AST and ALT ≤ 2.5 times upper limit of normal Creatinine ≤ 2.0 mg/dL Creatinine clearance ≥ 60 mL/min No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia No abnormalities of the cornea based on history (e.g., dry eye syndrome or Sjögren's syndrome) No congenital abnormality (e.g., Fuch's dystrophy) No abnormal slit-lamp examination using a vital dye (e.g., fluorescein or Bengal-Rose) No abnormal corneal sensitivity test (Schirmer test or similar tear production test) No Crohn's disease or inflammatory bowel disease that would preclude undergoing external beam radiotherapy Able to tolerate oral medication No requirement for IV alimentation Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception No ongoing or active infection No other concurrent uncontrolled illness No psychiatric illness or social situation that would preclude study compliance See Disease Characteristics No prior gemcitabine See Disease Characteristics See Disease Characteristics No prior epidermal growth factor receptor-targeting therapy No prior therapy for pancreatic cancer (except surgery) No concurrent commercial or other investigational agents or therapies intended to treat the malignancy No concurrent combination antiretroviral therapy for HIV-positive patients