乳がん術前のBMIと術後のリンパ浮腫発生

乳がん術前のBMIと術後のリンパ浮腫発生の関連をみた報告を紹介します。

Ridner SH, Dietrich MS, Stewart BR, Armer JM: Body mass index and breast cancer treatment-related lymphedema. Support Care Cancer. 2011 Jan 16. [Epub ahead of print]

術前にBMIが30以上の乳がん患者は、BMI30未満の患者と比較してオッズ比で3.6倍（95%信頼区間：1.42-9.04; p = 0.007）、手術6か月後にリンパ浮腫になりやすいという結果です。治療後にBMIが増加した群では、リンパ浮腫の発生増加は認めませんでした。

この論文だけで肥満が術後のリンパ浮腫発生のリスク要因とは断言できませんが、その可能性はあります。肥満はリンパ浮腫治療の阻害因子として明らかに問題ですが、リンパ浮腫発生のリスク要因としても問題かもしれません。

Abstract
PURPOSE: The main purpose was to examine longitudinally the influence of body mass index (BMI) and obesity on the development of breast cancer treatment-related lymphedema. We asked, does elevated BMI increase lymphedema risk?

METHODS: A secondary analysis was conducted on de-identified data collected from 138 newly diagnosed breast cancer survivors who had arm-volume measurements and symptom assessment at pre-treatment baseline and measurements up to 30 months post-surgery in a prospective longitudinal parent study. Arm volume and weight data, part of the information collected during each participant visit, were examined.

RESULTS: Breast cancer survivors whose BMI was ≥30 at the time of breast cancer treatment were approximately 3.6 times more likely to develop lymphedema at 6 months or greater after diagnosis than those with a BMI < 30 at the time of cancer treatment (95% confidence interval, C.I., for odds ratio, O.R., 1.42-9.04; p = 0.007). Those with a general BMI increase or a BMI rise to 30 or greater during their first 30 months of survivorship were not more likely to develop late-onset lymphedema than those who did not have similar changes in BMI.

CONCLUSIONS: Pre-treatment BMI may be a risk factor for lymphedema. Weight gain post-treatment may not be. Further research is warranted.