Enhanced tumor targeting by an intratumoral injection of colloidal chromic 32P in two human tumors (AsPC-1 pancreas and Ls174T colon) in nude mice.
OBJECTIVE
To find the mechanisms of the ongoing clinical trials in intralesional colloidal chromic 32P (32P-CP) brachytherapy, the cellular uptake of 32P-CP, changes in tumor interstitial fluid pressure (TIFP), and tumor blood flow (TBF) using two (AsPC-1, Ls174T) human tumors were measured.


METHODS
After exposure to 32p-CP using exponential and plateau-phase cells, cells were trypsinized at various time intervals, then measured for the levels of radioactivity using a y-counter. Also measured were TIFP using the WIN technique and TBF with laser Doppler flowmetry.


RESULTS
The plateau growth-phase of both tumors showed the maximal uptake of 32P-CP at approximately 100 min. TBF decreased within 10 min after an intratumoral (i.t.) injection of 32P-CP, and reached 75% of control value by 1 h.


CONCLUSIONS
If 32P-CP was introduced i.t., it maintained highly efficient tumor targeting, mainly due to two physiological mechanisms: the high adherence of 32P-CP to the infused regions and the reduction in TBF by this therapeutic colloid.
Lee
I
I
Department of Radiation Oncology, Cooper Hospital/University Medical Center, UMDNJ-Robert Wood Johnson Medical School, Camden, New Jersey. ileez@mail.med.upenn.edu
D000230:Adenocarcinoma / Q000503:physiopathology / Q000532:radiotherapy*; D000818:Animals; D001918:Brachytherapy / Q000379:methods*; D003102:Colloids; D003110:Colonic Neoplasms / Q000503:physiopathology / Q000532:radiotherapy*; D005260:Female; D006801:Humans; D015552:Injections, Intralesional; D017078:Laser-Doppler Flowmetry; D051379:Mice; D008819:Mice, Nude; D009368:Neoplasm Transplantation; D010190:Pancreatic Neoplasms / Q000532:radiotherapy*; D010761:Phosphorus Radioisotopes / Q000493:pharmacokinetics / Q000627:therapeutic use*; D011878:Radiotherapy
D003102:Colloids; D010761:Phosphorus Radioisotopes