Background: The measurement of a single abdominal image on computed tomography (CT) can provide an estimate of the total body skeletal muscle. We evaluate the change of the area of the psoas major muscle (PMMA) in a CT which was performed routinely after gastrectomy in gastric cancer. Methods: A total of 119 gastric cancer patients who underwent gastrectomy were enrolled for the study. A CT image at the top of the iliac crest level was obtained at the following times: 3 postoperative months (POM), 6 POM, 1 postoperative year (POY), 2 POY, 3 POY, and 5 POY. We analyzed the change rate of PMMA after gastrectomy and before or after recurrence. Results: PMMA change after gastrectomy was approximately between -8 and -10% over the 5-year observation period. PMMA in the R2 (macroscopic residual tumor)/recurrence group was lower than that in the no recurrence group, and a significant difference was observed at 2 POY (-21.7 ± 3.6% vs. -7.9 ± 2.3%, p < 0.01). PMMA after freshly diagnosed recurrence had decreased significantly by 14.1 ± 1.8% (p < 0.01). Conclusions: Evaluation of PMMA change by CT after gastrectomy could assist in the diagnosis of the progression of cancer state in gastric cancer patients.

Cancer cachexia is defined as a multifactorial syndrome consisting of an ongoing loss of skeletal muscle mass (with or without loss of fat mass) that cannot be fully reversed by conventional nutritional support and leads to progressive functional impairment [1]. It is also recognized as one of the disease states of “sarcopenia,” which was first proposed by Rosenberg [2] in 1989. Loss of skeletal muscle is known to be an incisive indicator of the disease state of cancer patients. However, it is not easy to assess the progression of loss of skeletal muscle in an objective way.

As body imaging techniques for assessment, computed tomography (CT scan), magnetic resonance imaging (MRI), and dual energy X-ray absorptiometry (DXA) have been used for estimating muscle mass or lean body mass. However, MRI requires a long examination time and high cost, and DXA needs a specialized instrument to take X-rays. As a simple method, measurement of a single abdominal image can provide an estimate of total body skeletal muscle, and a significant correlation was shown between single-slice skeletal muscle area at the third lumbar vertebra (L3) and total body skeletal muscle volume in recent studies [3,4,5].

CT is performed routinely after gastrectomy in gastric cancer patients to check for recurrence, which means no other examination is needed to determine skeletal muscle loss.

The purpose of this study was to evaluate the change of the area of the psoas major muscle (PMMA) in a CT image after gastrectomy in gastric cancer patients.

The subjects of the study were 119 gastric cancer patients who underwent gastrectomy during the period from January 2007 to December 2008. Clinicopathological characteristics and surgical procedures of the patients are shown in Table 1. Pathological stage was determined according to the 14th edition of the Japanese classification of gastric cancer [6].

Table 1

Clinicopathological characteristics (n = 119)

Clinicopathological characteristics (n = 119)
Clinicopathological characteristics (n = 119)

We measured PMMA by routine checkup CT after gastrectomy. An axial CT image at the top of the iliac crest level was obtained at the following times: 3 postoperative months (POM), 6 POM, 1 postoperative year (POY), 2 POY, 3 POY, and 5 POY. PMMA was measured in the region of interest by tracing the outline, using image viewer software, “Ziostation” (Ziosoft, Inc., Tokyo; Fig. 1).

Fig. 1

The psoas major muscle area (PMMA) was measured at the top of the iliac crest level by axial CT image.

Fig. 1

The psoas major muscle area (PMMA) was measured at the top of the iliac crest level by axial CT image.

Close modal

We focused on the axial CT image at the top of the iliac crest level, which is easy to detect. The actual slice level was the image in which the iliac crest had just disappeared, which was compatible with the standard measurement site (L3-L4 level). We calculated PMMA change as a decrease ratio of preoperative value.

We analyzed the change rate of PMMA after gastrectomy in gastric cancer patients. We divided them into 2 groups; no recurrence group and R2 (macroscopic residual tumor)/recurrence group, and compared PMMA between them. We also focused on PMMA change after recurrence. (As the recurrence was almost diagnosed by CT, the following time of CT was different from routine checkup periods.) We further divided them into local recurrence and global recurrence groups and evaluated the opportunity of diagnosis, PMMA change, and body weight (BW) change between them. We defined local recurrence as the recurrence of solitary lesion and global recurrence as the recurrence of multiple lesions.

Data are expressed as mean ± SD/SE. The Wilcoxon signed rank test, Student t test, and the log-rank test were used for comparisons between the 2 groups. A p value of <0.05 was considered to be statistically significant.

PMMA change after gastrectomy was approximately between -8 and -10% over the 5-year observation period (Fig. 2). PMMA in the R2/recurrence group was lower than that in the no recurrence group, and a significant difference was observed at 2 POY (-21.7 ± 3.6% vs. -7.9 ± 2.3%, p < 0.01; Fig. 3). The overall survival in the R2/recurrence group was significantly lower than that in the no recurrence group (Fig. 4).

Fig. 2

PMMA change after gastrectomy was approximately between -8 and -10% over the 5-year observation period. The red line showed approximate one. POM, postoperative months; POY, postoperative years; Red, approximate line. The values are shown as mean ± SE.

Fig. 2

PMMA change after gastrectomy was approximately between -8 and -10% over the 5-year observation period. The red line showed approximate one. POM, postoperative months; POY, postoperative years; Red, approximate line. The values are shown as mean ± SE.

Close modal
Fig. 3

PMMA in the R2/recurrence group was lower than that in the no recurrence group, and a significant difference was observed at 2 POY. POM, postoperative months; POY, postoperative years; R2, macroscopic residual tumor. The values are shown as mean ± SE.

Fig. 3

PMMA in the R2/recurrence group was lower than that in the no recurrence group, and a significant difference was observed at 2 POY. POM, postoperative months; POY, postoperative years; R2, macroscopic residual tumor. The values are shown as mean ± SE.

Close modal
Fig. 4

Overall survival in the R2/recurrence group was significantly lower than that in the no recurrence group. MST, median survival time; HR, hazard ratio.

Fig. 4

Overall survival in the R2/recurrence group was significantly lower than that in the no recurrence group. MST, median survival time; HR, hazard ratio.

Close modal

Recurrence after gastrectomy was observed in 30 of 119 cases. The clinical characteristics including recurrence site are shown in Table 2. PMMA after recurrence decreased significantly by 14.1 ± 1.8% (p < 0.01; Fig. 5). The median time interval of CT measurement was 191 (range 58-1,387) days, though there was no correlation between PMMA change and the measurement interval.

Table 2

Clinical characteristics of recurrence cases (n = 30)

Clinical characteristics of recurrence cases (n = 30)
Clinical characteristics of recurrence cases (n = 30)
Fig. 5

PMMA after recurrence decreased significantly by 14.1 ± 1.8%.

Fig. 5

PMMA after recurrence decreased significantly by 14.1 ± 1.8%.

Close modal

We divided recurrence cases into local (n = 6) and global (n = 24) recurrence groups. PMMA change of global group was significantly decreased compared with local group (-14.4 ± 1.2% vs. -1.4 ± 2.3%; p < 0.01). While BW change showed no significant differences, the ratio of marked decrease (less than -10%) of PMMA change was significantly higher than that of the local group (83 vs. 0%; p < 0.01). And the marked decrease cases of PMMA change was frequently observed compared with that of BW change cases (83 vs. 57%; Table 3).

Table 3

PMMA and BW change of recurrence cases

PMMA and BW change of recurrence cases
PMMA and BW change of recurrence cases

Cancer-related sarcopenia is known as secondary sarcopenia, while primary sarcopenia is considered to exist when no cause is evident other than aging. Sarcopenia is one of the elements of the proposed definition of cachexia, which is characterized as a complex metabolic syndrome associated with underlying cancer [7].

It is important to know the progression of sarcopenia precisely for the appropriate treatment of cancer patients, though it is difficult to recognize sarcopenia in an objective quantitative manner. BW change was generally used to evaluate it, but this barometer includes loss of fat tissue and, moreover, in patients with edema and ascites, BW change is not highly reliable as an indicator. In fact, PMMA changed dramatically before and after the global recurrence rather than BW change in this study (Table 3).

Recently, as a method to evaluate sarcopenia (cancer cachexia), the measurement of skeletal muscle mass has attracted attention. Various assessment techniques have been used for evaluation. As well as three imaging techniques (CT, MRI, and DXA), bioimpedance analysis (BIA), and anthropometric measures have been used [7]. Although BIA is a commonly used method as it is easy, noninvasive, repeatable, and of low cost, BIA estimations are subject to uncertainties. First, a large number of empirical prediction equations with a variety of included variables are used by single-frequency BIA and multiple-frequency BIA devices to estimate a certain body compartment; second, different types of devices measure different body parts, for example, lower or upper body or whole body; third, different methods and mathematical approaches are used, and finally the validity of BIA estimation itself has not been unequivocally demonstrated [8]. Therefore, it remains unclear whether accurate evaluation can be performed in patients with cancer and after surgical procedures. Anthropometric measures are susceptible to error and are less reliable as well. Air displacement plethysmography, which is a recognized and scientifically validated densitometric method to measure body composition, is a useful instrument for evaluating the body composition changes during and after chemotherapy in breast cancer patients [9]. However, there are no reports of cancer-related sarcopenia that are analyzed by air displacement plethysmography.

We focused on PMMA at the top of the iliac crest level as an indicator of sarcopenia, the level which was considered to be substituted for the whole skeletal muscle mass, and tried to evaluate the recurrence or progression of cancer after gastrectomy. PMMA after gastrectomy decreased by about 10% from the early period (3 POM) to 5 POY (Fig. 2). PMMA change was worst at 2 POY (-12 ± 2.1%) and recovered thereafter in this study. The reason was presumed to be that many cases died due to recurrence or progression of cancer around 2 POY (Fig. 3). Generally, it is known that patients with advanced gastric cancer frequently die of recurrence during early period after gastrectomy [10,11].

CT has great practical significance due to the widespread use of these images in patient diagnosis and follow-up, thus it is used for clinical accessibility with high precision to quantify specific tissues and to assess whole-body composition [12].

We showed that PMMA after gastrectomy decreased markedly after recurrence. Therefore, PMMA measurement in a CT image taken at routine checkups after gastrectomy has the possibility of an indicator for diagnosing recurrence.

Therefore, it is important to observe PMMA change whenever we took a CT to evaluate the state of cancer.

This report was in accordance with the Helsinki Declaration of 1975, as revised in 2000 and 2008. We gave consideration to the privacy of the patient, and the manuscript does not include any identifying information.

There are no financial or other relations that could lead to a conflict of interest.

1.
Fearon K, Strasser F, Anker SD, Bosaeus I, Bruera E, Fainsinger RL, Jatoi A, Loprinzi C, MacDonald N, Mantovani G, Davis M, Muscaritoli M, Ottery F, Radbruch L, Ravasco P, Walsh D, Wilcock A, Kaasa S: Definition and classification of cancer cachexia: an international consensus. Lancet Oncol 2011;12:489-495.
2.
Rosenberg IH: Summary comments. Am J Clin Nutr 1989;50:1231-1233.
3.
Lieffers JR, Mourtzakis M, Hall KD, McCargar LJ, Prado CM, Baracos VE: A viscerally driven cachexia syndrome in patients with advanced colorectal cancer: contributions of organ and tumor mass to whole-body energy demands. Am J Clin Nutr 2009;89:1173-1179.
4.
Baracos VE, Reiman T, Mourtzakis M, Gioulbasanis I, Antoun S: Body composition in patients with non-small cell lung cancer: a contemporary view of cancer cachexia with the use of computed tomography image analysis. Am J Clin Nutr 2010;91:1133S-1137S.
5.
Martin L, Birdsell L, MacDonald N, Reiman T, Clandinin MT, McCargar LJ, Murphy R, Ghosh S, Sawyer MB, Baracos VE: Cancer cachexia in the age of obesity: skeletal muscle depletion is a powerful prognostic factor, independent of body mass index. J Clin Oncol 2013;31:1539-1547.
6.
Japanese Gastric Cancer Association: Japanese Classification of Gastric Carcinoma. The Ed 14. Tokyo, Kanehara Shuppan Co., 2010.
7.
Cruz-Jentoft AJ, Baeyens JP, Bauer JM, Boirie Y, Cederholm T, Landi F, Martin FC, Michel JP, Rolland Y, Schneider SM, Topinkova E, Vandewoude M, Zamboni M: Sarcopenia: European consensus on definition and diagnosis. Age Ageing 2010;39:412-423.
8.
Haverkort EB, Reijven PLM, Binnekade JM, de van der Schueren MAE, Earthman CP, Gouma DJ, et al: Bioelectrical impedance analysis to estimate body composition in surgical and oncological patients: a systematic review. Eur J Clin Nutr 2015;69:3-13.
9.
Freedman RJ, Aziz N, Albanes D, Hartman T, Danforth D, Hill S, Sebring N, Reynolds JC, Yanovski JA: Weight and body composition changes during and after adjuvant chemotherapy in women with breast cancer. J Clin Endocrinol Metab 2004;89:2248-2253.
10.
Shiraishi N, Inomata M, Osawa N, Yasuda K, Adachi Y, Kitano S: Early and late recurrence after gastrectomy for gastric carcinoma. Univariate and multivariate analyses. Cancer 2000;89:255-261.
11.
Kang WM, Meng QB, Yu JC, Ma ZQ, Li ZT: Factors associated with early recurrence after curative surgery for gastric cancer. World J Gastroenterol 2015;21:5934-5940.
12.
Mourtzakis M, Prado CM, Lieffers JR, Reiman T, McCargar LJ, Baracos VE: A practical and precise approach to quantification of body composition in cancer patients using computed tomography images acquired during routine care. Appl Physiol Nutr Metab 2008;33:997-1006.
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