Myosteatosis as a novel prognostic biomarker after radical cystectomy for bladder cancer

Shimpei Yamashita,Yuya Iwahashi,Nagahide Matsumura,Satoshi Nishizawa,Kazuro Kikkawa,Keizo Hagino,Takashi Iguchi,Yasuo Kohjimoto,Hiroyuki Koike,Haruka Miyai,Isao Hara

doi:10.1038/s41598-020-79340-9

Shimpei Yamashita, Yuya Iwahashi + Show 9 more

Open Access

https://doi.org/10.1038/s41598-020-79340-9

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Abstract

This study aims to evaluate the influence of myosteatosis on survival of patients after radical cystectomy (RC) for bladder cancer. We retrospectively identified 230 patients who underwent RC for bladder cancer at our three institutions between 2009 and 2018. Digitized free-hand outlines of the left and right psoas muscles were made on axial non-contrast computed tomography images at level L3. To assess myosteatosis, average total psoas density (ATPD) in Hounsfield Units (HU) was also calculated as an average of bilateral psoas muscle density. We compared cancer-specific survival (CSS) between high ATPD and low ATPD groups and performed cox regression hazard analyses to identify the predictors of CSS. Median ATPD was 44 HU (quartile: 39–47 Hounsfield Units). Two-year CSS rate in overall patients was 76.6%. Patients with low ATPD (< 44 HU) had significantly lower CSS rate (P = 0.01) than patients with high ATPD (≥ 44 HU). According to multivariate analysis, significant independent predictors of poor CSS were: Eastern Cooperative Oncology Group performance status ≥ 1 (P = 0.03), decreasing ATPD (P = 0.03), non-urothelial carcinoma (P = 0.01), pT ≥ 3 (P < 0.01), and pN positive (P < 0.01). In conclusion, myosteatosis (low ATPD) could be a novel predictor of prognosis after RC for bladder cancer.

Highlights

This study aims to evaluate the influence of myosteatosis on survival of patients after radical cystectomy (RC) for bladder cancer
There were concerns about the possible potential impact of neoadjuvant chemotherapy on the myosteatosis measurements, but in these patients, median average total psoas density (ATPD) difference before and after neoadjuvant chemotherapy was 0 Hounsfield Units (HU) and there was no notable change in ATPD before and after neoadjuvant chemotherapy
We examined low ATPD, namely myosteatosis, as a possible preoperative predictor of prognosis after RC in patients with bladder cancer

Summary

Introduction

This study aims to evaluate the influence of myosteatosis on survival of patients after radical cystectomy (RC) for bladder cancer. Myosteatosis (low ATPD) could be a novel predictor of prognosis after RC for bladder cancer. Sarcopenia, defined as severe wasting of skeletal muscle mass, has been reported in several recent studies to be a preoperative prognostic factor in patients who undergo RC for bladder cancer, and is associated with poor rates of survival after R C7–9. Sarcopenia concerns muscle quantity and can be evaluated on abdominal computed tomography (CT) by the volume of skeletal muscle or psoas muscle[7,8,9]. We evaluate the association between various parameters, including sarcopenia and myosteatosis, and survival after RC in patients with bladder cancer. To assess sarcopenia and myosteatosis, we measured psoas muscle index (PMI) and average total psoas density (ATPD), respectively

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