がん診断時の身体機能と悪液質

がん診断時の身体機能：がん悪液質の役割に関する研究を紹介します。

Ana Maria Rodriguez, et al: Physical function at the time of diagnosis: the role of cancer cachexia

198人の進行がん患者を対象に、がん診断時の悪液質はFearonらの国際コンセンサス分類で評価しています。身体機能は2分間歩行テスト、TUG、快適な歩行速度、SF-36の身体機能で評価し、CRPも測定しています。

結果ですが、悪液質の有無に関しては身体機能の有意な予測因子ではありませんでした。TUGと2分間歩行テストは年齢、CRPと関連し、SF-36の身体機能は性別、CRPと関連していました。これより悪液質の有無より全身炎症（CRP陽性）のほうが、がん診断時の身体機能に影響があるという結論です。

Fearonらの国際コンセンサス分類でのがん悪液質診断基準は、6か月で5％以上の体重減少です。健常時体重にもよりますが5％程度の体重減少であれば、身体機能に大きな影響は与えないかもしれません。ただ、がん悪液質の早期発見・介入という点では、身体機能低下の予防が重要です。

また、日頃の運動習慣の有無で差が出るかどうかも知りたいところです。全くの仮説ですが、運動習慣がある方は運動による抗炎症作用もあり、CRPが低く身体機能が高い。一方、運動習慣がない方は運動による抗炎症作用がなく、CRPが陽性で身体機能が低いという可能性もあると思います。

Background and aims: We have recently applied the international consensus classification system for cancer cachexia (Fearon et al. 2011) on people with advanced cancer. Our main objective was to determine the extent to which cachexic state predicted physical function at the time of diagnosis. A second aim was to verify the role of systemic inflammation in predicting physical function.

Methods: One hundred ninety-eight persons with a recent diagnosis of advanced cancer of various origins from the McGill University Health Center and the Jewish General Hospital (JGH) in Montreal, Canada were evaluated prior treatment. Cachexic state was determined by applying the guidelines suggested by Fearon et al. Physical function was measured by the 2-min walk test (2MWT), the Timed-Up and Go (TUG), comfortable gait speed over 5 m, and by the physical function subscale of the SF-36 (PFI). Serum C-reactive protein (CRP) levels were collected and measured. Multiple linear regressions were used to analyze the relationship between the variables.

Results: Cachexic state was not a significant predictor of physical function regardless of how physical function was measured, holding age, gender, primary tumor site, and CRP levels constant. The TUG and 2MWT (R 2 = 0.21 and 0.22) were significantly predicted by age (b = 0.06 ± 0.02 and −0.89 ± 0.33, respectively) and CRP levels (b = 0.02 ± 0.01 and −0.41 ± 0.15, respectively). Age (b = −0.01 ± 0.002) was the only significant predictor of comfortable gait speed (R 2 = 0.28). Sex (b = 11.31 ± 5.15) and CRP levels (b = −0.23 ± 0.09) significantly predicted self-reported PFI (R2 = 0.25).

Conclusions: At the time of diagnosis, systemic inflammation seems to be an important predictor of physical function. Although physical function is on average lower in cachexic and precachexic patients than in normal patients, cachexia in itself does not seem to be a significant predictor of physical function at diagnosis. Physical function levels during the disease progression could however be influenced by cancer cachexia.