Where Are We Now?
The goal of surgery for metastatic bone disease is palliation of symptoms, including pain and functional limitations, although pain and the fear of having pain generally are the two greatest concerns on patients’ minds [1, 2]. Pain and functional limitations can limit a patient’s ability to perform self-care and engage in daily activities. Patients with end-stage cancer, including those with metastatic bone disease, usually are well aware of the impact pain may have on their lives.
A recent study demonstrated that pathologic fractures are associated with pain, depression, and poor quality of life, suggesting that pathologic fracture prevention may minimize or avert these issues [6]. However, there have been no studies which have prospectively evaluated the results of surgery for metastatic bone disease on patient reported outcomes.
Where Do We Need To Go?
While pain and function often are components of quality-of-life surveys, it must be understood that assessing quality of life can be done independently of pain and function. In fact, surveys designed to assess quality of life should be independent of surveys designed to assess pain and function. For example, a patient may have poor function as measured by a survey designed to assess function, yet their quality of life may be quite good for reasons other than their function, and this should be apparent in well-designed quality-of-life survey.
The study by Nooh and colleagues is a good step, but there are still several gaps in our knowledge. First, researchers should define which surveys are best at assessing pain, function, and quality of life in patients with bone metastases. Second, an assessment of the minimal clinical important difference (MCID) should be entertained for each survey that we evaluate. While the patients in the current study were found to have substantial improvement in pain and function, it is unknown whether the patients were satisfied with the results of the treatment. Statistical improvements do not always correlate with a meaningful clinical differences as perceived by patients [5]. Third, researchers should determine which factors are associated with improved quality of life. It may be that yet-unidentified factors, such as histologic subtype, influence quality of life and, if there is preponderance of this histologic subtype in the cohort, may impact the overall assessment of quality of life. Some patients may be more likely to improve than others. It would be useful to know if that were true, and which factors were associated with a stronger likelihood of improvement in quality of life. In addition, it remains unclear which patient-reported outcome measures are most appropriate for patients with bone metastases. There have been studies investigating this issue [3, 4], but we lack a consensus among caregivers.
How Do We Get There?
Prospective longitudinal studies are probably most likely to fill the gaps in our knowledge, as their design can help ensure uniform time points of data collection.
Furthermore, prospective studies designed to assess the MCID are likely to be helpful. There are different methods by which one can assess the MCID. One method utilizes an anchor question whose purpose is to assess the patient’s satisfaction. The response to the anchor question can then be statistically assessed (using receiver-operating characteristics, for example) to develop a threshold value for MCID. This threshold can then be correlated to patient-reported outcome measures (PROMs). Using this method, one can design studies that attempt to discern outcomes that are meaningful to patients.
Furthermore, PROMs are essential for these studies to have a greater impact. In fact, even retrospective analyses of PROMs could be useful in filling the gaps of knowledge that remain. To achieve this, consistent use of outcomes tools in clinical practice will be necessary. These tools are helpful for other reasons, including clinical decision-making, and in time, I believe their regular use will become the norm.
Footnotes
This CORR Insights® is a commentary on the article “Early Improvement in Pain and Functional Outcome but Not Quality of Life After Surgery for Metastatic Long Bone Disease” by Nooh and colleagues available at: DOI: 10.1007/s11999.0000000000000065.
The author certifies that neither he, nor any members of his immediate family, have any commercial associations (such as consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article.
All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request.
The opinions expressed are those of the writers, and do not reflect the opinion or policy of CORR® or The Association of Bone and Joint Surgeons®.
This CORR Insights® comment refers to the article available at DOI: 10.1007/s11999.0000000000000065.
References
- 1.Cleeland CS, O'Mara A, Zagari M, Baas C. Integrating pain metrics into oncology clinical trials. Clin Cancer Res. 2011;17:6646–6650. [DOI] [PubMed] [Google Scholar]
- 2.Engelmann D, Scheffold K, Friedrich M, Hartung TJ, Schulz-Kindermann F, Lordick F, Schilling G, Lo C, Rodin G, Mehnert A. Death-related anxiety in patients with advanced cancer: Validation of the German version of the death and dying distress scale. J Pain Symptom Manage. 2016;52:582–587. [DOI] [PubMed] [Google Scholar]
- 3.Janssen SJ, Paulino Pereira NR, Raskin KA, Ferrone ML, Hornicek FJ, van Dijk CN, Lozano-Calderón SA, Schwab JH. A comparison of questionnaires for assessing physical function in patients with lower extremity bone metastases. J Surg Oncol. 2016;114:691–696. [DOI] [PubMed] [Google Scholar]
- 4.Janssen SJ, van Rein EA, Paulino Pereira NR, Raskin KA, Ferrone ML, Hornicek FJ, Lozano-Calderon SA, Schwab JH. The discrepancy between patient and clinician reported function in extremity bone metastases. Sarcoma. 2016;2016:1014248. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 5.Olsen MF, Bjerre E, Hansen MD, Hilden J, Landler NE, Tendal B, Hróbjartsson A. Pain relief that matters to patients: systematic review of empirical studies assessing the minimum clinically important difference in acute pain. BMC Med. 2017;15:3. [DOI] [PMC free article] [PubMed] [Google Scholar]
- 6.van der Vliet QM, Paulino Pereira NR, Janssen SJ, Hornicek FJ, Ferrone ML, Bramer JA, van Dijk CN, Schwab JH1. What factors are associated with quality of life, pain interference, anxiety, and depression in patients with metastatic bone disease? Clin Orthop Relat Res. 2017;475:498–507. [DOI] [PMC free article] [PubMed] [Google Scholar]