Responsiveness of experimental prostate carcinoma bone tumors to neutron or photon radiation combined with cytokine therapy.
OBJECTIVE
To improve the outcome of radiotherapy for prostate carcinoma bone tumors, we investigated bone tumor irradiation with photons or neutrons followed by interleukin 2 (IL-2) therapy in a tumor model.


METHODS
Implantation of PC-3 cells in nude mouse femur cavity induced a bone tumor that progressed to the formation of a palpable tumor, at the hip joint, by Day 20. Established bone tumors were irradiated with photons or neutrons, and a day later, mice were treated with IL-2 therapy for 3 weekly cycles.


RESULTS
PC-3 bone tumors responded to radiation with photons or neutrons in a dose-dependent manner. Combination of photon or neutron radiation with IL-2 therapy increased tumor growth delay, compared to that with photons or neutrons alone. Radiation alone or combined with IL-2 significantly increased mouse survival compared to that with IL-2 or no treatment. After combined therapy, a complete inhibition of bone tumor growth was observed in 45% to 50% of the mice. Histologically, the combined therapy resulted in greater tumor destruction associated with fibrosis, new bone formation, and inflammatory infiltrates than that observed with each modality alone.


CONCLUSIONS
The efficacy of tumor irradiation with neutrons or photons was enhanced by IL-2 therapy for the treatment of prostate carcinoma bone tumors.
Hillman
Gilda G
GG
Department of Radiation Oncology, Barbara Ann Karmanos Cancer Institute, Wayne State University School of Medicine and Harper Hospital, Detroit, MI 48201, USA. hilmang@karmanos.org
Maughan
Richard L
RL
Grignon
David J
DJ
Yudelev
Mark
M
Che
Mingxin
M
Abrams
Judith
J
Wang
Yu
Y
Layer
Andrey
A
Wright
Jennifer L
JL
Rubio
Johanna
J
Forman
Jeffrey D
JD
D000818:Animals; D001859:Bone Neoplasms / Q000473:pathology / Q000628:therapy*; D003131:Combined Modality Therapy; D006801:Humans; D007376:Interleukin-2 / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009502:Neutrons / Q000627:therapeutic use*; D017785:Photons / Q000627:therapeutic use*; D011471:Prostatic Neoplasms / Q000473:pathology / Q000628:therapy*; D014407:Tumor Cells, Cultured
D007376:Interleukin-2