Thursday, September 8, 2011

Reviewing the historical Journal literature for publications discussing Cancer risk associated with joint/hip implants (4of x)

This is yet another study conducted on  the Swedish population to measure cancer risk in hip replacement patients.  The study I reported on a few posts ago, was conducted on 40,000 patients with metal on metal implants.  This one is conducted on over 100,000 patients but appears to cover all hip implants so no concentration  on metal implants.  While it is interesting to report on the fact that cancer risk is normal when reviewing ALL hip implants ( I would have no reason to question that), I don't quite understand the implication given there doesn't appear to be a claim that all hip implants are associated with cancer.  It appears that the association and preponderance of studies is related to metal implants and specifically metal on metal.
Humm....I guess it is just another data point but not one that is related to measuring the long term effects of meal on metal and cancer.  Just my opinion for whatever its worth.  The study results make complete sense to me.
J Natl Cancer Inst. 2001 Sep 19;93(18):1405-10.

Nationwide study of cancer risk among hip replacement patients in Sweden.


International Epidemiology Institute, Rockville, MD 20850, USA.



Orthopedic implants and their fixatives contain materials with carcinogenic potential. Whether these implants are linked to subsequent cancer development remains unknown, mainly because large-scale, long-term follow-up data are scarce.


We conducted a nationwide cohort study in Sweden to examine cancer incidence among 116,727 patients who underwent hip replacement surgery during the period from 1965 through 1994. Through record linkage to the Swedish Cancer Register, we identified all incident cancers through 1995 in this population (693,954 person-years of observation). For each cancer type, the observed number of cases was divided by that expected in the general Swedish population to produce standardized incidence ratios (SIRs).


Relative to the general population, the cohort had no overall cancer excess (SIR = 1.01; 95% confidence interval [CI] = 0.99 to 1.03). However, we observed elevated SIRs for prostate cancer (SIR = 1.16; 95% CI = 1.11 to 1.22) and melanoma (SIR = 1.15; 95% CI = 1.01 to 1.30) and a reduction in stomach cancer risk (SIR = 0.83; 95% CI = 0.75 to 0.92). Long-term follow-up (>or=15 years) revealed an excess of multiple myeloma (SIR = 1.86; 95% CI = 1.01 to 3.11) and a statistically nonsignificant increase in bladder cancer (SIR = 1.42; 95% CI = 0.98 to 1.99). There was no material increase in risk for bone or connective tissue cancer for either men or women in any follow-up period.


In this, the largest study to date, hip implant patients had similar rates of most types of cancer to those in the general population. Although the excesses of melanoma, multiple myeloma, and prostate and bladder cancers may be due to chance, confounding, or detection bias and should be interpreted cautiously, they warrant further investigation because of the ever-increasing use of hip implants at younger ages.

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