Oncology

Dedifferentiated chondrosarcoma: a survival analysis

The Surveillance, Epidemiology, and End Results (SEER) database has shed some significant light on a variety of relatively rare bone neoplasias over the past few years, and this paper from Chicago, Illinois (USA) is no different.¹ The authors are able to report on the survival estimates for dedifferentiated chondrosarcoma. This rare malignancy has a range of previously reported survival rates of around 5% to 25%. In the ten-year period of the study (2001 to 2011), centres forming part of the SEER database reported the outcomes of an impressive 159 dedifferentiated chondrosarcomas, and, consequently, a relatively accurate survival estimate with Kaplan–Meier survival analysis is the basis of this important study. The headline result is an 18% five-year overall survival and a 28% disease-specific survival. Unusually for such a rare tumour, there were enough patients here to make a rational attempt to identify covariates associated with survival. The authors established that patients with extremity tumours had a poorer prognosis than those with axial skeleton or chest wall tumours (hazard ratio (HR) 0.6). Patients with stage III+ disease (HR 2.51) and those with tumours larger than 8 cm (HR 2.17) were at higher risk of mortality within the follow-up of the study than those without. In terms of surgically associated prognostic factors, patients treated with amputation (HR 0.43) or limb salvage (HR 0.41) did significantly better than those without surgery, and those with metastatic disease (HR 3.25) at the time of presentation were at high risk of death. This paper paints a rather bleak picture of this unusual bone tumour. The five-year survival rates are arguably poorer results than some of those previously published, and there is still no cure in sight. If no metastases are present at the time of presentation, a complete surgical excision offers the only chance of a cure.

Do orthopaedic oncologists agree on the diagnosis and treatment of cartilage tumours of the appendicular skeleton?

This paper from Santiago (Chile) demonstrates the difficulties of reaching an agreement on appendicular cartilage lesions.² There is a long history of confusion among the pathology world at the more benign end of the cartilage tumour scale, with poor inter- and intra-rater reliabilities when diagnosing either benign enchondroma or low-grade chondrosarcomas. We were somewhat surprised to learn that these concordance exercises have not been undertaken using orthopaedic oncologists. This simple paper therefore set out to determine whether orthopaedic oncologists agree about the diagnosis of cartilaginous neoplasms. The study involved presentation of initial clinical and imaging information with the aims of achieving inter- and intra-observer agreement, establishing the most important clinical and imaging features that guide diagnosis, and determining agreement ratings for proposed treatment plans. A total of 39 patients, all with intramedullary cartilaginous neoplasms of the appendicular skeleton with a cross-section of tumour grades, were presented with their clinical and imaging information to a panel of ten experienced oncologists who classified the neoplasms as benign, low-grade malignant, intermediate-grade malignant, or high-grade malignant. Additionally, the authors collated information on proposed treatment strategies. The inter- and intra-observer reliability were moderate κ = 0.44, and good κ = 0.62, respectively. The panel identified three factors which were helpful in making the diagnosis: cortical involvement in 65% of evaluations; neoplasm size in 51%; and pain in 50%. These results underline the relatively poor concordance among expert panels when attempting to establish the diagnosis of bone tumours.

Survivors of Ewing’s sarcoma

Deltoid-preserving for a primary malignant bone tumour?

Our interest was piqued by this paper in the BJJ this month, asking whether it is safe to preserve the deltoid when undertaking limb salvage procedures in the proximal humerus. There is unquestionably a good reason why patients and surgeons should want to preserve the deltoid; the functional benefits are clear. However, the wisdom of its preservation is the subject of this paper from Paris (France).⁴ This case series aimed to ask whether preservation of the deltoid provides a safe and functional reconstruction or whether en bloc resection of the deltoid and proximal humerus is a more reliable option. These authors undertook a comparative retrospective case review of 45 patients from their institution who had undergone resection of proximal humeral tumours through either a deltoid-sparing or an en bloc approach. There were 29 patients in the deltoid-sparing group and 16 in the deltoid resection group. The authors’ practice was to establish, through analysis of MRI imaging studies, whether there was a complete separation of the tumour from the fat. They undertook a competing risk analysis to establish the risks of tumour recurrence in the two groups. The authors report that there was no significant difference to the probability of survival in either group (7% sparing versus 26% resecting). A deltoid-sparing procedure was more likely if patients presented with a small tumour with less bone involvement, with a continuous fat rim on MRI and if the axillary nerve could be identified. Although interesting, we do take some issue with the conclusions the authors have reached. This paper really suffers from selection bias, and all that the authors have demonstrated is that you can spare the deltoid and get a low local recurrence rate, but only in smaller, less invasive tumours that don’t come near the deltoid. This is really just a report detailing case selection and nothing else.

Does treatment volume affect outcomes in spinal metastatic disease?

Focal ultrasound instead of irradiation for painful bone metastasis?

The traditional treatment for painful bony metastasis that has not fractured, and is not suitable for or has already undergone stabilisation surgery, is the use of localised radiation therapy. Although this has its own potential benefits on the surface of things, there are some disadvantages. Radiation therapy can have local and systemic side effects and, for those intact lesions, definitely results in some difficulty if the patient goes on to fracture, with high rates of infection and wound-healing complications. An alternative approach that has some promise is that of MRI-guided focused ultrasound (MRgFUS), the efficacy of which is reported in this study from Taipei (Taiwan).⁶ The authors undertook a matched-pair analysis of patients presenting with bony metastasis, which compared the therapeutic effects of MRgFUS with conventional radiotherapy. Given the disparity in potential cohort size, the authors used a 1:2 matching process, and matched the groups in terms of age, sex, primary cancer, pre-treatment pain score, and treated site. The authors report a case-matched series of 63 patients (21 MRgFUS and 42 radiotherapy), with outcomes assessed as response for pain control. Both treatments were effective in terms of overall pain control. However, what was perhaps most interesting is that MRgFUS was more efficient than radiotherapy in terms of providing rapid palliation, and there was a significantly higher pain response rate at one week following intervention (71% vs 26%). This is one of the first reports concerning the use of MRgFUS and it establishes the modality as a potentially useful first-line treatment in management of painful bone metastasis. Perhaps most importantly, although there was an overall equivalent response rate, the MRgFUS cohort had much more rapid relief of symptoms, with the majority finding relief within one week.

Quality of life with a spinal metastasis

Following on from the timely paper above, looking at the surgeon outcomes following spinal metastatic surgery, these authors from Shanghai (China) set out to determine the long-term quality of life associated with spinal metastasis with no known primary origin.⁷ They included patients treated between January 2009 and January 2014, all for spinal metastasis of unknown origin. The paper focuses both on these outcomes and on the outcomes of a subgroup analysis, reporting the differences in outcome between those who received surgical treatment and those who received radiotherapy alone. The quality of life in these groups was evaluated using the Functional Assessment of Cancer Therapy-General (FACT-G) measure over a six-month period. In all, the authors report 287 patients, of whom 191 had surgery plus radiotherapy, and 96 had radiation therapy alone. As we might expect, there were some differences in treatment strategies and the authors also explored to a limited extent how this might affect outcomes. Complete follow-up was available for the majority of patients, with 177 patients completing all outcome measures, and 110 deaths during the study surveillance period. The authors are able to report that the surgery group had significantly higher adjusted quality-of-life scores than the radiation therapy group in each domain of the FACT-G questionnaire. It appears that surgery followed by radiotherapy is the most effective way of increasing quality-of-life scores following presentation with spinal metastasis of unknown primary origin. Although the authors evaluated the various potential covariates, the only significant differences appeared to be with the use of a circumferential decompression which, when achieved, resulted in the best quality of life.