Dose escalation for metastatic spinal cord compression in patients with relatively radioresistant tumors.
OBJECTIVE
Radiotherapy alone is the most common treatment for metastatic spinal cord compression (MSCC) from relatively radioresistant tumors such as renal cell carcinoma, colorectal cancer, and malignant melanoma. However, the results of the "standard" regimen 30 Gy/10 fractions need to be improved with respect to functional outcome. This study investigated whether a dose escalation beyond 30 Gy can improve treatment outcomes.


METHODS
A total of 91 patients receiving 30 Gy/10 fractions were retrospectively compared to 115 patients receiving higher doses (37.5 Gy/15 fractions, 40 Gy/20 fractions) for motor function and local control of MSCC. Ten further potential prognostic factors were evaluated: age, gender, tumor type, performance status, number of involved vertebrae, visceral or other bone metastases, interval from tumor diagnosis to radiotherapy, pretreatment ambulatory status, and time developing motor deficits before radiotherapy.


RESULTS
Motor function improved in 18% of patients after 30 Gy and in 22% after higher doses (p = 0.81). On multivariate analysis, functional outcome was associated with visceral metastases (p = 0.030), interval from tumor diagnosis to radiotherapy (p = 0.010), and time developing motor deficits (p < 0.001). The 1-year local control rates were 76% after 30 Gy and 80% after higher doses, respectively (p = 0.64). On multivariate analysis, local control was significantly associated with visceral metastases (p = 0.029) and number of involved vertebrae (p = 0.043).


CONCLUSIONS
Given the limitations of a retrospective study, escalation of the radiation dose beyond 30 Gy/10 fractions did not significantly improve motor function and local control of MSCC in patients with relatively radioresistant tumors.
Rades
Dirk
D
Department of Radiation Oncology, University of Lubeck, Germany. Rades.Dirk@gmx.net
Freundt
Katja
K
Meyners
Thekla
T
Bajrovic
Amira
A
Basic
Hiba
H
Karstens
Johann H
JH
Adamietz
Irenaeus A
IA
Wildfang
Ingeborg
I
Rudat
Volker
V
Schild
Steven E
SE
Dunst
Juergen
J
D000367:Age Factors; D000704:Analysis of Variance; D002292:Carcinoma, Renal Cell / Q000532:radiotherapy / Q000556:secondary; D015179:Colorectal Neoplasms / Q000473:pathology; D019583:Dose Fractionation, Radiation; D005260:Female; D006801:Humans; D007680:Kidney Neoplasms / Q000473:pathology; D008297:Male; D008545:Melanoma / Q000532:radiotherapy / Q000556:secondary; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology / Q000528:radiation effects*; D010166:Palliative Care / Q000379:methods; D011836:Radiation Tolerance; D011879:Radiotherapy Dosage; D012189:Retrospective Studies; D012878:Skin Neoplasms / Q000473:pathology; D013117:Spinal Cord Compression / Q000209:etiology / Q000532:radiotherapy*; D013125:Spinal Neoplasms / Q000532:radiotherapy* / Q000556:secondary