副腎皮質がんで中心性サルコペニアと腹腔内脂肪が死亡率と関連

副腎皮質がん患者で中心性サルコペニア（Central Sarcopenia）の悪化と腹腔内脂肪の増加は死亡率悪化と関連する論文を紹介します。

Miller BS, Ignatoski KM, Daignault S, Lindland C, Doherty M, Gauger PG, Hammer GD, Wang SC, Doherty GM; The University of Michigan Analytical Morphomics Group. Worsening Central Sarcopenia and Increasing Intra-Abdominal Fat Correlate with Decreased Survival in Patients with Adrenocortical Carcinoma. World J Surg. 2012 Apr 19. [Epub ahead of print]

リサーチクエスチョンは以下の通りです。

P：副腎皮質がん患者で
E：①体幹の筋肉量が少ないと、②腹腔内脂肪が多いと、
C：①体幹の筋肉量が多い場合と比較して、②腹腔内脂肪が少ない場合と比較して
O：生命予後が悪い（生命予後をより正確に予測できる）
D：後ろ向きコホート研究

体幹の筋肉量は腹部CTで、腸腰筋と腰椎の筋肉の筋面積、腹腔内脂肪、皮下脂肪の量を評価しています。結果ですが、腸腰筋と腰椎の筋肉の筋面積、腹腔内脂肪は生命予後と関連していました。腰椎の筋肉の筋面積が100mm2多いと、死亡率が8％低下しました。

Central Sarcopeniaは中心性サルコペニアという訳でよいですかね。中心性肥満central obesityという言葉もありますので。四肢と体幹の筋肉量評価は、別々に考える必要があるかもしれません。

また、体重測定だけでは筋肉量の増減、腹腔内脂肪の増減は判断できません。筋肉量が多いと生命予後がよく、腹腔内脂肪量が多いと生命予後が悪いということは、体重増減だけで生命予後を予測するにはかなり限度があることになりますね。身体組成評価が重要といえます。

Abstract
BACKGROUND: Accurate prediction of survival from adrenocortical carcinoma (ACC) is difficult and current staging models are unreliable. Central sarcopenia as part of the cachexia syndrome is a marker of frailty and predicts mortality. This study seeks to confirm that psoas muscle density (PMD), lean psoas muscle area (LPMA), lumbar skeletal muscle index (LSMI), and intra-abdominal (IA) or subcutaneous fat (SC) can be used in combination to more accurately predict survival in ACC patients.

METHODS: PMD, LPMA, IA, and SC fat were measured on serial CT scans of patients with ACC. Clinical outcome was correlated with quantitative data from patients with ACC and analyzed. A linear regression model was used to describe the relationship between PMD, LPMA, LSMI, IA, and SC fat, time to recurrence, and length of survival according to tumor stage.

RESULTS: One hundred twenty-five ACC patients (94 females) were treated from 2005 to 2011. Significant morphometric predictors of survival include PMD, LPMA, and IA fat (p ≤ 0.0001, ≤0.0024, <0.0001, respectively) and improve prediction of survival compared to using stage alone. A 100-mm(2) increase in LPMA confers an 8 % lower hazard of death. LSMI does not change significantly between stages (p = 0.3196).

CONCLUSION: Decreased PMD, LPMA, and increased IA fat suggest decreased survival in ACC patients and correlate with traditional staging systems. A more precise prediction of survival may be achieved when staging systems and morphometric measures are used in combination. Serial measurements of morphometric data are possible. The rate of change of these variables over time may be more important than the absolute value.