Re: Comparative effectiveness of radical prostatectomy and radiotherapy in prostate cancer: observational study of mortality outcomes
I read Sooriakumaran’s article with interest. As a geriatrician, what strikes me is that the radiotherapy group appear, perhaps unsurprisingly, to be frailer: being older, with more co-morbidities and higher all-cause mortality. The authors have corrected for age and co-morbidities, but one suspects this will not fully address this confounder, as frailty is more complex than simply the presence of other disease states (although this does play a part).
Frailty is a complex condition which currently has no universally accepted definition. However, a widely accepted phenotype is of 3 or more of: unintentional weight loss, self-reported exhaustion, weakness, slow walking speed and low physical activity [1]. One can see from this definition that it shares several similarities with advanced cancer. It is associated with adverse outcomes, including increased mortality [1]. This raises the possibility that some patients may have died from frailty, with incidental localised prostate carcinoma, and have been mis-labelled as a prostate cancer death, as this is a convenient label to give them, in the absence of any other clear diagnosis. It is well established that there are accuracy issues with death certification. Given frailty appears more prevalent in the radiotherapy group this may falsely raise the proportion of deaths attributed to prostate carcinoma.
In metastatic disease, unlike groups 1 to 3, the surgical group had more co-morbidities than the radiotherapy group (ie were probably frailer) and the surgical survival benefit was lost. In addition to this, one suspects that a documented cause of death of prostate carcinoma in someone with known metastatic disease is more likely to be accurate, than in a frail patient with localised disease.
The presence of frailty and possible over-diagnosis of prostate carcinoma as a cause of death is unlikely to fully explain the differences in results between the two groups, as the study examined the possible role of such unknown confounders. However, it does raise the possibility that the advantages of surgery may be slightly overstated in this observational study.
1) Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J, Seeman T, Tracy R, Kop WJ, Burke G, McBurnie MA. Frailty in Older Adults: Evidence of a Phenotype. J Gerentol A Biol Sci Med Sci. 2001 Mar; 56(3): M145-56
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Re: Comparative effectiveness of radical prostatectomy and radiotherapy in prostate cancer: observational study of mortality outcomes
I read Sooriakumaran’s article with interest. As a geriatrician, what strikes me is that the radiotherapy group appear, perhaps unsurprisingly, to be frailer: being older, with more co-morbidities and higher all-cause mortality. The authors have corrected for age and co-morbidities, but one suspects this will not fully address this confounder, as frailty is more complex than simply the presence of other disease states (although this does play a part).
Frailty is a complex condition which currently has no universally accepted definition. However, a widely accepted phenotype is of 3 or more of: unintentional weight loss, self-reported exhaustion, weakness, slow walking speed and low physical activity [1]. One can see from this definition that it shares several similarities with advanced cancer. It is associated with adverse outcomes, including increased mortality [1]. This raises the possibility that some patients may have died from frailty, with incidental localised prostate carcinoma, and have been mis-labelled as a prostate cancer death, as this is a convenient label to give them, in the absence of any other clear diagnosis. It is well established that there are accuracy issues with death certification. Given frailty appears more prevalent in the radiotherapy group this may falsely raise the proportion of deaths attributed to prostate carcinoma.
In metastatic disease, unlike groups 1 to 3, the surgical group had more co-morbidities than the radiotherapy group (ie were probably frailer) and the surgical survival benefit was lost. In addition to this, one suspects that a documented cause of death of prostate carcinoma in someone with known metastatic disease is more likely to be accurate, than in a frail patient with localised disease.
The presence of frailty and possible over-diagnosis of prostate carcinoma as a cause of death is unlikely to fully explain the differences in results between the two groups, as the study examined the possible role of such unknown confounders. However, it does raise the possibility that the advantages of surgery may be slightly overstated in this observational study.
1) Fried LP, Tangen CM, Walston J, Newman AB, Hirsch C, Gottdiener J, Seeman T, Tracy R, Kop WJ, Burke G, McBurnie MA. Frailty in Older Adults: Evidence of a Phenotype. J Gerentol A Biol Sci Med Sci. 2001 Mar; 56(3): M145-56
Competing interests: No competing interests