Osteosarcoma and other neoplasms of bone. Magnetic resonance spectroscopy to monitor therapy
B. Ross, J. T. Helsper, I. J. Cox, I. R. Young, R. Kempf, A. Makepeace and J. Pennock
Nuclear Magnetic Resonance Unit, Hammersmith Hospital, London, England.
Fourteen patients with malignant tumors of bone (ten osteogenic sarcomas,
one Ewing's tumor, one giant-cell tumor, two non-Hodgkin's lymphomas), plus
one patient with a synovial cell sarcoma, who had been treated by standard
extremity-conserving chemotherapy regimens, were examined before treatment
by means of localized phosphorus 31 magnetic resonance spectroscopy.
Thirteen (86%) of 15 examinations were successful, and 100% of successful
examinations showed metabolic abnormality in the tumor. Tumors contained
excess adenosine triphosphate and inorganic phosphate, an unusual peak of
phosphomonoester, consistent with excessive glycolysis in tumors. The
intratumor pH was normal in the 12 bone tumors, but acidic in the single
soft-tissue sarcoma (pH 6.8). Metabolic response was observed in all seven
patients monitored during chemotherapy, with the earliest examinations
being performed two days after first treatment. An increase in the
inorganic phosphate level, loss of adenosine triphosphate, and loss of
phosphomonoester indicated tumor response; loss of all abnormal metabolites
(two of seven patients) indicated regression of the tumor. Tumor relapse
was accompanied by reappearance of abnormalities in the magnetic resonance
spectrum. Phosphorus 31 magnetic resonance spectroscopy offers a unique
means of determining the early response of these malignant tumors to
therapy as well as predicting their relapse.
