Surgical resection in metastatic spinal cord compression

Abstract

In their randomised trial, Roy Patchell and colleagues (Aug 20, p 643)1Patchell RA Tibbs PA Regine WF et al.Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial.Lancet. 2005; 366: 643-648Summary Full Text Full Text PDF PubMed Scopus (1634) Google Scholar compare the effect of combined surgical decompression and radiotherapy with radiotherapy alone in patients with spinal cord compression caused by metastatic cancer. Because Patchell and colleagues deemed the inferiority of radiotherapy alone conclusive after an interim analysis, the study was prematurely ended after the inclusion of 101 patients.The two groups were well matched for most characteristics except median time from diagnosis of the primary tumour to development of metastatic epidural spinal cord compression. Such disease developed after a median of 7 months in the radiotherapy group compared with 3 months in the surgery group. We believe that this difference might constitute an important source of bias.It could reflect a difference in tumour biology between the two groups, suggesting that fewer patients with more aggressive and fast-growing tumours were allocated to the radiotherapy group than to the surgery group. Since fast-growing tumours are known to be especially sensitive to radiotherapy, patient allocation, rather than the intervention, might explain the inferiority of radiotherapy in this study.We declare that we have no conflict of interest. In their randomised trial, Roy Patchell and colleagues (Aug 20, p 643)1Patchell RA Tibbs PA Regine WF et al.Direct decompressive surgical resection in the treatment of spinal cord compression caused by metastatic cancer: a randomised trial.Lancet. 2005; 366: 643-648Summary Full Text Full Text PDF PubMed Scopus (1634) Google Scholar compare the effect of combined surgical decompression and radiotherapy with radiotherapy alone in patients with spinal cord compression caused by metastatic cancer. Because Patchell and colleagues deemed the inferiority of radiotherapy alone conclusive after an interim analysis, the study was prematurely ended after the inclusion of 101 patients. The two groups were well matched for most characteristics except median time from diagnosis of the primary tumour to development of metastatic epidural spinal cord compression. Such disease developed after a median of 7 months in the radiotherapy group compared with 3 months in the surgery group. We believe that this difference might constitute an important source of bias. It could reflect a difference in tumour biology between the two groups, suggesting that fewer patients with more aggressive and fast-growing tumours were allocated to the radiotherapy group than to the surgery group. Since fast-growing tumours are known to be especially sensitive to radiotherapy, patient allocation, rather than the intervention, might explain the inferiority of radiotherapy in this study. We declare that we have no conflict of interest. Surgical resection in metastatic spinal cord compression – Authors' replyMarcus Koch and Jacques De Keyser suggest that, if more patients with shorter intervals between diagnosis of the primary tumour and development of metastatic spinal cord compression (MSCC) had been assigned to the radiotherapy alone group, this group would have had better results. However, all evidence from retrospective studies indicates that the opposite is true. A study by Helweg-Larsen and colleagues1 found that longer intervals between diagnosis of the primary tumour and development of MSCC were associated with longer survival times (after the cord compression), and Loblaw and colleagues2 found that longer intervals were associated with more favourable ambulatory outcomes. Full-Text PDF