Gemcitabine Compared With Pancreatic Enzyme Therapy Plus Specialized Diet (Gonzalez Regimen) in Treating Patients Who Have Stage II, Stage III, or Stage IV Pancreatic Cancer

DISEASE CHARACTERISTICS:

* Histologically confirmed unresectable primary or metastatic adenocarcinoma of the pancreas diagnosed within the past 8 weeks

  * Stage II-IV

PATIENT CHARACTERISTICS:

Age:

* 18 to physiologic 65

Performance status:

* ECOG 0-2

Life expectancy:

* More than 2 months

Hematopoietic:

* WBC greater than 3,000/mm\^3
* Platelet count greater than 100,000/mm\^3

Hepatic:

* Bilirubin less than 2.5 times normal
* SGOT or SGPT less than 1.5 times normal
* Albumin greater than 3.2 g/dL

Renal:

* Creatinine less than 1.5 times normal
* BUN less than 1.5 times normal

Other:

* Not pregnant or nursing
* HIV negative
* No other serious medical or psychiatric illness that would preclude study participation
* No serious infection
* Ability to eat solid food three meals per day
* No allergy or intolerance to pork
* No prior illicit drug addiction
* At least one year since prior daily alcohol use
* At least one year since prior cigarette use
* Must have supportive live-in spouse or other family member

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* Not specified

Chemotherapy:

* No prior chemotherapy
* No other concurrent chemotherapy

Endocrine therapy:

* No concurrent hormonal therapy except:

  * Steroids for antiemesis, documented CNS metastases, adrenal failure, or septic shock
  * Hormonal therapy for nondisease related conditions (e.g., thyroid replacement therapy)

Radiotherapy:

* No prior radiotherapy
* Concurrent palliative radiotherapy allowed, including to a symptomatic lesion or one which may produce disability (e.g., unstable femur or CNS lesion)

Surgery:

* Greater than 1 week since prior exploratory or palliative bypass surgery
* No prior Whipple procedure or surgical procedure for curative intent

Other:

* No oral hypoglycemic agents