This is a preliminary report of five patients diagnosed with locally advanced nonresectable pancreatic cancer who achieved improved quality of life, delay of local progression, and reduction of biomarker CA 19-9 after infusion of colloidal phosphorus 32 (³²P) and administration of combined chemoradiotherapy. A phase II trial using intratumoral colloidal ³²P delivery for nonresectable pancreatic cancer without metastases is in progress. Patients initially were given infusions of decadron followed by macroaggregated albumin and 30 mCi colloidal ³²P to the interstitial space of the tumor by two infusions 1 week apart. Through this method, doses ranging from 750,000 to 1,800,000 cGy were delivered. After administration of colloidal ³²P, external radiation to a dose of 6000 cGy minimum tumor dose, including regional lymph nodes, was given concomitantly with four intravenous infusions of 500 mg bolus 5-fluorouracil on alternating days within the first 2 weeks after initiation of external radiation. All five of these patients demonstrated cessation of local tumor growth or regression of disease on serial computed tomography scans for a minimum of 10 months from completion of therapy. Three of these patients have survived without local disease progression over 24 months from initiation of therapy, with one patient approaching 36 months. CA 19-9 values for all patients declined within weeks after completion of therapy. This new method of isotope delivery has resulted in reduction of tumor volume, normalization of the biomarker CA 19-9, and improved performance status in those patients who have localized nonresectable disease without dissemination.