Oncology

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Metastatic spinal disease is one of the most common presentations of metastatic bone disease. Associated with carcinomas, adenomas and myelomas, this is a common site for metastatic spread. The typical patient presents to oncological and spinal services rather than to surgical oncologists, and there is a definite debate about who should undergo which intervention. One of the key pieces in the complicated jigsaw of decision making is estimation of survival. If a patient isn’t going to live too long then a kyphoplasty, radiotherapy or a watch-and-wait protocol might be appropriate. On the other hand, if the prognosis is many years the same tumour may be treated with decompression and multilevel instrumentation.

There has been significant difficulty with survival estimation, and in the last edition of 360 we reported on the development of the Boston prognostic score which is designed to estimate the survival of patients presenting with metastatic spinal disease. A research team in Akita (Japan) have reported a small series of 31 patients, all with vertebral metastasis, which perhaps provides food for thought.¹ These authors report on patients with lung cancer and have compared their post-operative prognosis with those with other primary diagnoses following surgical treatment. As perhaps might be expected with a series like this, at the 16-month average follow-up point only 22% of patients were alive. However, the lung cancer metastatic group appeared to derive the same post-operative benefit as those being operated upon for other primary diagnoses.

The authors utilised the revised Tokuhashi score and report that this prognostic tool may well underestimate the survival of lung cancer patients and that, in this series at least, these patients derived the same benefit from surgical intervention as those with vertebral metastasis from other cancer types.

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It is a truism that cost-effectiveness analysis is here to stay. If we cannot prove that expensive treatments are worth doing, in terms of resulting in economic productivity or a reduction in long-term healthcare costs, then the widespread availability of more expensive treatment options will become a thing of the past.

There is little known about the cost effectiveness of bone tumour surgery, with the three competing options being amputation, limb salvage with endoprosthesis, and limb salvage with bulk allograft. With each having an extensive impact on the complication rates and functional outcomes, it is a perfect comparison for the more complex cost-effectiveness analyses. A group in Nashville, Tennessee (USA) have used all of the available data to undertake a Markov cost-effectiveness model.⁵ They used the Medicare reimbursement rates and implant prices to calculate costs, and the Health Utilities Index 3 (HUI-3) survey to calculate health utility. The authors used the widely accepted method of incremental cost-effectiveness ratios (ICER), and less than $100,000 per quality-adjusted life year was considered cost effective.

The results here are actually fairly clear-cut. Osteoarticular allografts, and endoprostheses (but only with around 30% discount applied), were cost effective treatments, with ICERs of $92.59 and $6,114, respectively. In terms of break-even points, discounted endoprostheses were more cost effective than allografts costing over $21 900, assuming the endoprostheses cost less than $51 900.

This interesting study shows the cost effectiveness of allografts versus endoprostheses for knee tumours but the implant companies are going to have to work to ensure endoprostheses continue to be available at a discounted rate.

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Treatment of sarcomatous metastasis can be somewhat tricky. Usually widespread but occasionally solitary, the debate about excision or stabilisation is not quite as straightforward as in other tumours. The use of intramedullary stabilisation is extensive, but in some circumstances excision may be indicated.

To a certain extent, the decision between simple stabilisation and excision and endoprosthesis reconstruction does rely on knowledge of the patient’s longer-term prognosis – those patients with a poorer prognosis who can be treated with a smaller operation without compromise to their longevity clearly should be. The difficulty, particularly in sarcomatous metastasis, is knowing what the longevity actually is. This is where there is a large gap in the published literature; almost nothing is known about the longevity of patients with sarcomatous metastasis.

The recent case series from Nashville, Tennessee (USA) crossed the editorial desks at 360 and is definitely worthy of a mention.⁶ The authors were able to report on the results of 98 sarcomatous metastases in 92 patients. Of these, 40 intramedullary stabilisations were performed in 34 patients and 58 underwent resection over an 18-year period. The selection criteria varied between patients, with the authors choosing intramedullary stabilisation in patients who were at risk of impending fracture from multifocal sarcomatous metastases, and excision for either metaphyseal lesions or solitary metastasis. The authors were able to provide a mean follow-up of 13 months, and during that time there were no metalwork failures. As perhaps would be expected, there were some differences in peri-operative care, and adjuvant chemotherapy or radiotherapy was given as indicated.

The majority (88%) of patients died under observation and surgery was definitive in 85% of patients treated with an intramedullary nail. The most common cause of revision was for local progression, with 12% (n = 4) of patients requiring revision surgery for local progression.

Based on these results, it is clear that patients with widespread metastases from a sarcoma can be managed similarly to those with metastases from any other cancer, and it is fair to expect reasonable results from long bone stabilisation with an intramedullary nail. However, given the 12% revision rate for those where fixation is difficult to achieve or in those with a solitary sarcoma metastasis, this should be treated like a new primary with wide excision and reconstruction.

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Sarcoma are relatively common in childhood and adolescence, and as survivals are improving and children are becoming disease-free adults, the long-term sequelae of adolescent bone tumours are becoming more relevant. In one of the few studies evaluating the long-term effects on family life of childhood sarcoma, a collaborative from Japan report the reproductive and family consequences for survivors of high-grade sarcomas.⁸

The study reports on the outcomes in 38 survivors of childhood, adolescent and young adult high-grade sarcoma. The study team also took the opportunity to assess the long-term quality of life scores in these survivors. Initial diagnoses were of osteosarcoma (n = 28), Ewing’s sarcoma (n = 4), synovial sarcoma (n = 4) and others (n = 2). The study population consisted of 18 males and 20 females and there was a marked difference in terms of marital status and children between males and females (44% vs 75%). Married survivors had better mental health SF-36 scores (although this is reflective of the general population without sarcomas and so may not be a specific finding). There was also a specific finding with regard to ifosfamide which appeared to particularly impact on the likelihood of children in the male survivors.