Effects of physical activity on quality of life and physical function in postoperative patients with gastrointestinal cancer

Abstract

Objectives: This study was to clarify changes in physical function and quality of life (QOL) for postoperative, and to examine the influence of the amount of physical activity on these variables. Methods: This study included 29 patients who underwent gastrointestinal cancer surgery. The QOL measurement was used to the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire for preoperative and 2nd and 4th postoperative weeks. Physical function measured knee extension strength, 4 m walk time, 5 times sit-to-stand test, and 6-minute walk for preoperative and 1st and 2nd postoperative weeks. The amount of physical activity score was based on METs-hours, which is estimated from cumulative physical activity. As basic characteristics were investigated cancer stage, comorbidities and complications, and operative. Statistical analysis was repeated measures analysis of variance was performed to observe postoperative changes in physical function and QOL. Furthermore, stepwise multiple regression analysis was used to the parameters of physical function and QOL affected by the physical activity score were investigated. Results: Physical function decreased postoperatively and generally improved 2nd postoperative week. Though scores on the QOL functional scales improved, some items did not improve sufficiently. Multiple regression analysis showed that physical activity score had an effect on constipation and emotion functioning. Conclusions: Improvement in symptom scales is not sufficient in a short period of time, and they need to be followed up by increasing the amount of physical activity and promoting instantaneous exercise.

Surgical resection, an important treatment for gastrointestinal cancers, involves the use of general anesthesia. Controlled ventilation during surgery affects postoperative respiratory function^1,2). Postoperative pain, analgesia, and immobility also contribute to respiratory function deterioration³⁾. Further, in the case of patients who have undergone gastric cancer surgery, weight loss⁴⁾ and decrease in muscle mass contribute to poor prognosis⁵⁾.

In the Enhanced Recovery After Surgery protocols⁶⁾ (ERAS), perioperative rehabilitation aims to promote early mobilization and increase physical activity. It is generally reported that early mobilization contributes to the prevention of pulmonary complications and improvement of respiratory function^3,7,8). Major abdominal surgery is associated with a reduction in functional capacity with regard to physical function, activities of daily living (ADL), and quality of life (QOL)⁹⁾. It has been reported that improvement of postoperative physical function takes 6 months to achieve⁹⁾. However, while one study indicated improvements in the 4th and 8th postoperative weeks¹⁰⁾, another mentioned only the 4th postoperative week¹¹⁾. Thus, it is evident that the postoperative recovery period is multidimensional and not constant. To improve postoperative physical function, several comparative trials on perioperative rehabilitation protocols^6,12-14) have been conducted, but with inconsistent results.

In terms of physical function and QOL after cancer surgery, older adults have not shown sufficient ADL¹⁵⁾. Additionally, there are indications that in the postoperative stage, patients with gastric cancer present with various long-term symptoms¹⁶⁾ and chronic pain even up to 6 months later¹⁷⁾. A systematic review of post and perioperative rehabilitation programs has shown that exercise improves health-related QOL¹⁸⁾. However, these positive results must be interpreted cautiously¹⁸⁾. Owing to the heterogeneity in exercise programs and measures used to assess health-related QOL, there is a risk of bias in many trials¹⁸⁾. Thus, as studies of postoperative recovery have not presented consistent results, it is important to examine the recovery of physical function and QOL in the as an example of Japan. In addition, while physical activity appears necessary to improve physical function and QOL, the specifics of exercise programs and the optimal amount of exercise they should encompass remain unclear¹⁸⁾.

The objective of this study was to clarify changes in physical function and QOL after a program and to examine the influence of the amount of physical activity on these variables. We hope that the results can facilitate improvements in perioperative rehabilitation programs, leading to more effective treatment.

Methods

Participants

The participants were patients who were hospitalized at the institution to which the authors are affiliated and underwent surgery for gastrointestinal cancers between June 2016 and August 2018. To be included in the study, patients had to be able to: 1) undergo physical function assessment and take a written preoperative survey; 2) undergo physical function assessments during the follow-up period; and 3) take a written survey at and after discharge. Exclusion criteria were patients' conditions that hindered physical function assessment and an inability to take a written survey.

Of the 409 patients who underwent surgery during the study period, only 32 could be investigated preoperatively. Of these, 3 patients were unable to undergo the preoperative follow-up investigation. Thus, this study included 29 patients.

Rehabilitation was performed according to the postoperative rehabilitation protocol (Table 1), which was implemented regardless of the operative procedure or the level of invasiveness. However, therapists adjusted the postoperative rehabilitation program and load according to the patient's condition. In other words, individual activities were adjusted in accordance with patients' pain levels, vital sign status, and cardiopulmonary function. The exercises were selected from criteria the criteria, like walking exercise, the aerobic program, and resistance training.

Table 1.

Postoperative rehabilitation protocol used during the study

○ Time schedule
	Postoperative 1st day;		Early mobilization encouraged
	2nd - 5th day;		Encouragement to continue and prolong out-of-bed activities
			Walking (walking distance 400m)
			Light resistance training, respiratory exercise
	6th - 9th day;		Resistance training, bicycling
			Activity of Dairy Living exercise
	Continue until descharge (postoperative 10th - 14th day)
○ Exercise
	Aerobic exercise
		Type; Bicycling
		Strength; Set target heart rate for karvonen formula within borg scale 13
		Time; 20 - 40 minites
	Resistance training
		Type; Weight and weight load training
		Strength; About 15 repetition maximum
		Part; Lower extremity; Knee extention / Hip flexion / Hip abduction
			Hip extention / Calf raise / Squat
		Upper extremity; Elbow flexion / Shoulder abduction / Shoulder elevation
		Trunka; Abdominal exercise / Bridging

Only physical assessments considered necessary for standard therapy were performed; experimental interventions were excluded. The study complied with the Declaration of Helsinki, and written informed consent was obtained from all participants after explaining the nature of the study to them. This study was approved by the ethics committee of Kanmon Medical Center (approval number: 2016-015). This observational study was conducted according to the STROBE checklist.

Data collection

We investigated disease-specific QOL, physical function, and physical activity. Basic characteristics were obtained from medical records. Disease-specific QOL was measured using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire (EORTC QLQ-C30)¹⁹⁾. The QLQ-C30 was administered thrice: preoperatively, in the 2nd postoperative week (at discharge), and in the 4th postoperative week. Physical function was measured using isometric knee extension strength, 4 m walk time, the 5 times sit-to-stand test, and a 6-minute walk. The knee extension strength, 4 m walk time, and 5 times sit-to-stand test measurements were taken preoperatively and in the 1st and 2nd postoperative weeks. The 6-minute walk was conducted in the 1st and 2nd postoperative weeks. Physical activity score was measured on an average of 3 days from 1st to 2nd postoperative week. Basic characteristics were collected from medical records after discharge.

Physical function measurements

Knee extension strength was measured using a handheld dynamometer (Mobie MT-100W, Sakai Medical Co., Ltd., Tokyo, Japan) based on the method introduced by Kato et al.²⁰⁾. A fixing band was used at the distal lower leg when the lower leg was hanging in the sitting position. The measurement was performed only on the right lower limb, and the average value of 2 measurements was used for analysis. The 4 m walk time measurement and 5 times sit-to-stand test were conducted according to the Short Physical Performance Battery²¹⁾ protocol. The 6-minute walk was measured according to the American Society of Thoracic Surgeons protocol²²⁾. If the patient took a long time to complete the 4 m walk and 5 times sit-to-stand test, the conclusion was that movement was delayed, and the patient's state was poor. If the 6-minute walk was extended, it was interpreted that the patient was in a good condition.

Disease-specific QOL measurement

The QLQ-C30 is a disease-specific QOL survey for patients with cancer that has proven valid and reliable¹⁹⁾. The Japanese version of the survey used in the present study has also been reported to be accurate and reliable²³⁾. This patient-based assessment tool comprises the global health status to measure overall QOL, 5 functional scales to measure activity, and 9 symptom scales that measure physical symptoms. The 5 functional scales are physical functioning, role functioning, emotional functioning, cognitive functioning, and social functioning. The symptom scales include fatigue, nausea and vomiting, pain, dyspnea, insomnia, appetite loss, constipation, diarrhea, and financial difficulties. The tool includes 30 questions scored on a 4-point scale from “Not at all” to “Very much,” with each category scored from 0 to 100. For categories corresponding to global health status and the functional scales, a higher score (close to 100) indicates a better condition. However, for the categories corresponding to the symptom scales, a higher score indicates a more severe condition.

Measurement of physical activity score

Physical activity score was calculated from exercise in rehabilitation and self exercises. We did not include ADL other than exercise during hospitalization. The method of calculation was based on the content of exercise and time spent doing it. Time spent doing rehabilitation was counted as actual time, and self exercises were interviewed. METs values were estimated from the surveyed exercises using Ainsworth et al.'s²⁴⁾ summary of physical activity and a conversion table by the Ministry of Health, Labour and Welfare²⁵⁾. One METs is considered a resting metabolic rate obtained during sitting at rest. Defined by how much more of the subjected activity is against it^24,25). METs-hours were calculated by multiplying the METs value of the exercise content by the time performed. The estimation of METs-hours in physical activity questions has been used in many studies^26-29), with proven reliability^30-32). METs-hour was studied in the three days prior to discharge, approximately the 2nd postoperative week, and the mean value of three days was determined for METs-hour/day. Some study³³⁾ of the postoperative physical activity were of short duration and used METs-hours/day. The calculation of this study was performed by the author alone. The importance of physical activity for cancer patients has been reported^26-29), and self-report measures have been the most common method of surveying the amount of physical activity³⁴⁾. From those results, estimates of METs and METs-hours were calculated. They were mainly performed on patients living at home, and the self-report measures covered all aspects of life. This study investigated only for exercise and these self-report measures were not applicable.

Investigation of basic characteristics

Basic characteristics (patient Attributes, laboratory findings, and treatment data) were investigated. A physician established cancer staging according to the TNM classification recommended by the Union for International Cancer Control³⁵⁾. Comorbidities included cancer, hypertension, hyperlipidemia, diabetes mellitus, cerebrovascular diseases, orthopedic diseases, and medical diseases. Participants with exercise habits were those who performed exercises more than 3 METs at least thrice a week. In terms of blood laboratory findings, albumin and C-reactive protein levels were investigated preoperatively and at discharge. Respiratory function was defined as the percent vital capacity and forced expiratory volume in 1 second/forced vital capacity preoperatively.

Statistical analysis

The report was prepared according to the STROBE checklist. QLQ-C30 scores and physical function decreased significantly immediately after the surgery, with potential for subsequent improvement. We consider it necessary to know the degree of improvement in each aspect to gain a comprehensive understanding. Therefore, the mixed-effects model for repeated measures was used to elucidate postoperative changes in QLQ-C30 scores and physical function evaluation results. Multiple comparisons were performed using the Bonferroni method for items that showed significant differences in the paired t-test.

The comprehensive effect of rehabilitation after gastrointestinal surgery is undetermined^6,12-14). Therefore, we analyzed the influence of physical activity score, including rehabilitation, on QOL and physical function. To analyze the effects of postoperative exercise on QLQ-C30 score and physical function evaluation, stepwise multiple regression analysis was performed. The dependent variable was the physical activity score, while the independent variables were the QLQ-C30 score from the 4th postoperative week and the physical function evaluation from the 2nd postoperative week.

SPSS version 25.0 for Mac (IBM Corporation, Armonk, NY, USA) and R2.8.1 (CRAN, freeware) were used for statistical analysis. P < 0.05 was considered statistically significant.

Results

Participants' basic characteristics

The participant's descriptive statistics are shown in Table 2. Some participants had comorbidities without any serious effects on physical activity. The mean postoperative hospital stay was 15.8 ± 6.4 days. Postoperative rehabilitation was initiated on the first day after surgery and covered the entire postoperative hospital stay. Postoperative complications were found in 5 patients, including anastomotic stricture in 3 cases and anastomotic leakage in 2 cases. Patients with postoperative complications were hospitalized for an average of 26 days, which tended to prolong the overall hospitalization period. However, they had no restriction on activity.

Table 2.

Descriptive statistics for Basic characteristics (basic data, laboratory findings, and treatment data)

Characteristic		Measurements
Units in parentheses. Results are presented as mean ± SD or number of participants. %VC: Percent vital capacity FEV1/FVC: Forced expiratory volume in 1 second/ forced vital capacity CRP: C-reactive protein
	Age (y)	68.2 ± 10.0
	Sex (n)	Men	19
		Women	10
	Body mass index (kg/m2)	22.7 ± 3.1
	Cancer site (n)	Liver	1
		Stomach	20
		Colon	7
		Pancreas	1
	Cancer stage (n)	I	14
		II	6
		III	7
		IV	2
	Preoperative chemotherapy (n)	Yes	2
		No	27
Comorbidity
	Cancer (n)	Yes	3
		No	26
	Hypertension / Hyperlipidemia/ Diabetes mellitus (n)	Yes	15
		No	14
	Cerebrovascular disease (n)	Yes	2
		No	27
	Orthopedic disease (n)	Yes	6
		No	23
	Medical disease (n)	Yes	8
		No	21
	Preoperative %VC (%)	104.1 ± 17.3
	Preoperative FEV1/FVC (%)	74.4 ± 7.8
	Preoperative albumin (g/dl)	4.1 ± 0.5
	Postoperative albumin (g/dl)	3.3 ± 0.6
	Preoperative CRP (mg/dl)	0.8 ± 2.9
	Postoperative CRP (mg/dl)	2.1 ± 2.1
	Exercise habits (n)	Yes	7
		No	22
	working (n)	Yes	11
		No	18
	Operative procedure (n)	Laparoscopic	17
		Laparotomy	12
	Operation time (minutes)	238.5 ± 83.70
	Blood loss (ml)	147.2 ± 204.2
	Postoperative complication (n)	Yes	5
		No	24
	Length of stay (day)	15.8 ± 6.4

Changes in physical function measurements and QOL from the preoperative to the postoperative period

The results of the physical function measurements and QLQ-C30 scores taken preoperatively and postoperatively, as well as the mixed-effects model for repeated measures analysis results, are shown in Table 3.

Table 3.

Preoperative and postoperative changes over time in physical function measurements and EORTC QLQ-C30

Units or details in parentheses. Results are presented as mean ± SD　N.S. are Not Significant　MMRM: Mixed-effects model for repeated measures
			preoperative (pre)	1st postoperative week (po1w)	2nd postoperative week (po2w)	MMRM P value
						pre vs po1w	pre vs po2w	po1w vs po2w
Physical function measurement	Knee extension strength (Nm/kg)		1.11 ± 0.45	0.94 ± 0.45	1.13 ± 0.56	N.S.	N.S.	0.030
	4 m walk time (sec)		3.33 ± 1.53	4.17 ± 1.94	3.76 ± 2.73	0.001	N.S.	N.S.
	5 times sit-to-stand test (sec)		9.57 ± 5.49	13.47 ± 6.92	11.21 ± 5.50	0.000	0.049	0.004
	6-minute walk (m)		–	336.8 ± 113.7	390.6 ± 110.4	–	–	0.000
			preoperative (pre)	2nd postoperative week (po2w)	4th postoperative week (po4w)	MMRM P value
						pre vs po2w	pre vs po4w	po2w vs po4w
EORTC QLQ- C30	Global scales
		Global health status	58.62 ± 25.54	53.45 ± 20.95	54.89 ± 20.84	N.S.	N.S.	N.S.
		Functional scales	81.69 ± 12.84	75.79 ± 13.84	78.93 ± 14.12	N.S.	N.S.	N.S.
		Symptom scales	14.24 ± 11.00	27.06 ± 14.48	24.14 ± 14.05	0.000	0.001	N.S.
	Functional scales
		Physical functioning	87.36 ± 15.36	77.93 ± 18.09	80.92 ± 12.31	0.010	N.S.	N.S.
		Role functioning	85.63 ± 20.76	58.05 ± 30.09	68.97 ± 19.27	0.000	0.009	N.S.
		Emotional functioning	72.70 ± 23.13	80.75 ± 16.68	79.02 ± 23.53	N.S.	N.S.	N.S.
		Cognitive functioning	86.78 ± 15.67	81.61 ± 17.45	86.21 ± 18.4	N.S.	N.S.	N.S.
		Social functioning	76.44 ± 31.03	72.41 ± 28.27	76.44 ± 19.17	N.S.	N.S.	N.S.
	Symptom scales
		Fatigue	20.69 ± 17.50	37.16 ± 23.62	36.40 ± 16.51	0.001	0.001	N.S.
		Nausea and vomiting	4.60 ± 14.01	5.75 ± 11.16	9.20 ± 16.42	N.S.	N.S.	N.S.
		Pain	11.49 ± 18.42	32.76 ± 25.39	26.44 ± 19.68	0.001	0.027	N.S.
		Dyspnea	11.49 ± 20.46	22.99 ± 22.01	20.69 ± 22.56	N.S.	N.S.	N.S.
		Insomnia	16.09 ± 27.63	39.08 ± 32.21	19.54 ± 26.00	0.000	N.S.	0.002
		Appetite loss	12.64 ± 22.56	34.48 ± 32.71	29.89 ± 27.23	0.002	0.019	N.S.
		Constipation	18.39 ± 28.99	29.89 ± 27.23	25.29 ± 24.65	0.025	N.S.	N.S.
		Diarrhoea	8.05 ± 14.52	18.39 ± 21.06	19.54 ± 18.93	N.S.	0.038	N.S.
		Financial difficulties	24.14 ± 34.38	18.39 ± 26.10	18.39 ± 26.10	N.S.	N.S.	N.S.

In terms of physical function measurement results (Table 3), knee extension strength decreased in the 1st postoperative week but tended to increase in the 2nd postoperative week. On the contrary, 4 m walk time and the 5 times sit-to-stand test increased in the 1st postoperative week but tended to decrease in the 2nd postoperative week. Knee extension strength increased significantly between the 1st and 2nd postoperative weeks. The 4 m walk time increased significantly from the preoperative period to the 1st postoperative week. Performance on the 5 times sit-to-stand test increased from the preoperative period to the 1st postoperative week, decreased significantly between the 1st and 2nd postoperative weeks, and overall showed a significant increase from the preoperative period to the 2nd postoperative week. The 6-minute walk also increased significantly between the 1st and 2nd postoperative weeks.

In terms of QLQ-C30 results (Table 3), global health status and functional scale scores decreased in the 2nd postoperative week and somewhat increased in the 4th postoperative week, but the differences were not significant. Symptom scale scores increased significantly in the 2nd postoperative week. In terms of functional scale subscale items, physical and role functioning scores decreased substantially in the 2nd postoperative week. Furthermore, role functioning scores substantially reduced in the 4th postoperative week as compared to the preoperative period. Symptom scale subscale items―fatigue, pain, insomnia, appetite loss, and constipation―significantly worsened from the preoperative period to the 2nd postoperative week. Fatigue, pain, appetite loss, and diarrhea also worsened significantly between the preoperative period and the 4th postoperative week. However, insomnia decreased considerably between the 2nd and 4th postoperative weeks.

Relationship between postoperative physical activity score and postoperative physical function and QLQ-C30 score

The results of postoperative physical activity score are shown in Table 4. The main exercise items were walking, bicycling and resistance training. These activities were converted into METs and averaged over three days, resulting in 2.1 ± 0.7. According to the results of multiple regression analysis (Table 5), constipation and the emotional functioning score of the QLQ-C30 in the 4th postoperative week affected the amount of postoperative exercise. ANOVA results were significant, but the R² was 0.33, indicating a low goodness of fit. The test for normality of residuals was significant.

Table 4.

Postoperative measurement of physical activity score (average of 3 days before discharge)

Physical activity score (METs-hour/day)		02.1 ± 0.7
Units in parentheses. Results are presented as mean ± SD
METs: Metabolic equivalents
Main activities:
	[3.0METs] Walking; 2.5mph, level, firm surface
	[3.5METs] Walking; 2.8 to 3.2 mph, level, moderate pace, firm surface
	[3.5METs] Conditioning exercise; bicycling, stationary, 30-50 watts
	[4.8METs] Conditioning exercise; bicycling, stationary, 51-89 watts
	[3.5METs] Conditioning exercise; resistance (weight) training

Table 5.

Stepwise multiple regression analysis results; 2nd postoperative week physical function and 4th postoperative week QLQ-C30 that affect postoperative physical activity

	Partial regression coefficient	Standard partial regression coefficient	Significant probability	95% Confidence interval
				Lower	Upper
R2 = 0.33, ANOVA p < 0.01 , Durbin-Watson ratio = 1.69
Constipation	-0.02	-0.69	0.00	-0.03	-0.01
Emotional functioning	-0.01	-0.50	0.02	-0.03	-0.01
Constant	-3.75		0.00	-2.61	-4.89

Discussion

The purpose of this study was to examine the impact of physical activity score on postoperative physical function and QOL. Regarding physical function in the 2nd postoperative week and QOL in the 4th postoperative week, there were some items that showed significant improvements, but they were not enough. Although there are many reports^9,10,11,36) on postoperative functional recovery, there is no consensus, and we will present the interpretation of the results of this study. Few reports have examined which parts of the postoperative physical function measurements and QOL subscale are affected by the amount of physical activity. In this study, constipation symptoms tended to decrease with increased physical activity scores. The following is a discussion of changes in physical activity scores and QOL scores, and the effects of the amount of physical activity.

Open and laparoscopic surgeries for gastrointestinal cancer are highly invasive procedures, resulting in increased postoperative protein catabolism³⁷⁾. Protein catabolism degrades the muscle and reduces physical activity³⁷⁾. In addition, suppression of activity because of postoperative pain contributes to a decrease in overall physical activity³⁸⁾. The results of this study also showed reduced activity in the 1st postoperative week compared to preoperative activity levels. Performance on the 5 times sit-to-stand test in the 2nd postoperative week did not improve back to preoperative levels. Post-operative recovery was reported that activity levels were still low at the 4th postoperative week¹⁰⁾. In addition, it was reported to the time for recovery as the physical function was 6 weeks, while ADL took 6 weeks to 3 months to recover⁹⁾. Thus, postoperative recovery requires a medium to long term period of time. In our hospital, most patients are discharged after approximately 2 weeks and return to work and social activities. We believe that this is done in the context of inadequate post-operative recovery. The 5 times sit-to-stand test and 4 m walk time are measured as an examination of the instantaneous element. There have been no reports measuring and examining these as a postoperative assessment of gastrointestinal surgery. Many post-operative exercise programs include aerobics exercise and other^11,12), resulting in an improvement in the 6-minute walk³⁹⁾. The lack of improvement in the 5 times sit-to-stand test in this study indicates that the instantaneous component is slow to improve. The 5 times sit-to-stand test is requiring more of lower limb speed and/or power⁴⁰⁾. Not only that, it is multidimensional, including variables such as sensory-motor, balance, and psychological parameters⁴⁰⁾. We think this is why the improvement differs from knee extension strength, which we consider to be a strong component of the same strength. We think that in the post-operative period, even though muscle power can be exerted, it is difficult to control overall muscular activity and balance, and that agitation due to post-operative anxiety and other emotions can affect performance on the 5 times sit-to-stand test. The 5 times sit-to-stand test is more relevant to the IADLs, which require more complex skills than the ADLs⁴¹⁾. Therefore, improving performance on the 5 times sit-to-stand test, which was inadequately improved at 2 weeks postoperatively, would improve quality of life more. Incorporating spur-of-the-moment activities into the exercise may also lead to that improvement.

In terms of the QLQ-C30, physical and role domain scores decreased in the 2nd postoperative week compared to preoperative scores. Role functioning scores in the 4th postoperative week were still lower than those before surgery; thus, the improvement was not sufficient. Many symptom scale items worsened in the 2nd postoperative week. There were also many symptoms that did not improve in the 4th postoperative week. Antonescu et al.³⁶⁾ reported that QOL after gastrointestinal surgery decreased in the 1st postoperative month but returned to preoperative levels at 2 months after surgery. Therefore, the fact that a certain degree of recovery was achieved at the 4th postoperative week is a satisfactory result and an effect of accelerated activity. Matsushita et al.⁴²⁾ stated that global QOL, physical scale, and appetite scores worsened before discharge, with recovery at 6 months postoperatively. However, they reported that improvements in the physical and cognitive domains and pain are not sufficient for recovery. The social domain, insomnia, and financial difficulties were reported to have improved after discharge. In the present study, the physical domain generally improved at 2nd postoperative week, but the role domain showed a lack of improvement, contrary to Matsushita et al.'s report⁴²⁾. On the contrary, in the symptom scale items, there is a general agreement in terms of insufficient improvement. The role functioning represents the performance of work, daily activities, and leisure time activities⁴³⁾. It is said to indicate the severity of the disease. However, it is also considered important to activate behaviors⁴³⁾, including those that may be beneficial in promoting activities. With respect to symptom scale items, and greater residual fatigue is reported after gastric cancer surgery⁴⁴⁾. We think that the susceptibility to fatigue affects the role functioning and also affects emotional functioning. Although residual fatigue is strongly a result of disease characteristics, it is the exercise therapy that could improve it. Pain, appetite loss and diarrhea on the symptom scale were also not sufficiently improved, but these were more strongly influenced by treatment. These are poorly improved at 4th postoperative week, but they do improve over time^36,42,43). There are no reports of benefit from exercise therapy, and more detailed studies are needed. This may require an instantaneous exercise component, which was not sufficiently improved in this study.

Factors related to the amount of postoperative exercise were constipation and the emotional functioning of the QLQ-C30. In our view, higher physical activity leads to a decrease in constipation and remaining instability in the emotional functioning. In their meta-analysis, Nakano et al.⁴⁵⁾ concluded that exercise is not effective at reducing constipation in patients with cancer. However, in their systematic review, Albrecht et al.⁴⁶⁾ found improvements in constipation. In the present study, exercise had a positive effect on constipation. After gastrointestinal surgery, peristalsis is reduced from the effects of anesthesia⁴⁷⁾. Postoperative ileus occurs in many cases and is believed to resolve spontaneously⁴⁸⁾. However, there are also cases of paralytic ileus, which may last twice as long⁶⁾. Most of the time, medication is the mainstay of treatment, and testing the efficacy of exercise alone is difficult. However, the results of this study suggest that increased physical activity may lead to the suppression of constipation symptoms. In the future, we would like to further examine the importance and effectiveness of physical activity by adjusting for confounding factors. Activity had a positive effect on constipation, while the emotional functioning was rated lower. In the context of mental factors after gastrointestinal surgery, Schag et al.⁴⁹⁾ reported that employed patients have a lower overall QOL; in other words, the more active they are, the lower their QOL. An association between depressive symptoms, QOL, and pain has also been reported in patients with cancer⁵⁰⁾. We believe that patients who are more active are also more likely to have higher goals and experience mental health problems, including anxiety about social activities. Thus, follow-up in the context of rehabilitation as well as self-activity may help mitigate psychological problems. Owing to the nature of cancer, we believe that the association between postoperative activity, exercise, and mental factors should continue to be investigated.

After gastrointestinal surgery, not only does physical function generally deteriorate but also various symptoms of the digestive system remain. Besides, as nutrition intake is challenging, patients often experience a lack of vitality and mental health problems. In this study, various factors related to postoperative physical symptoms were clarified, and we believe that they will contribute to the improvement of future interventions.

Limitations

This study has several limitations. First is the small sample size. The participants constituted only approximately 7% of surgical patients during the study period. Second, cases that meet the inclusion criteria are often cooperative, positive, and active. Therefore, the possibility of selection bias cannot be ruled out. Third, there is a possibility of measurement bias in the measurement of physical activity. In recent years, accelerometers and wearable devices have been increasingly used to measure physical activity and are considered more reliable than self-reported measures. In this study, these terminals could not be used due to cost issues and the possibility of inconvenience in wearing the devices. Fourth, there are limitations related to the analysis. Gastrointestinal cancers can exist at multiple sites, such as the stomach and colon, which may have lowered the study's analytical accuracy. In addition, in the multivariate analysis, only QOL and physical function were used, and other confounding factors were not included. Therefore, it is necessary to adjust for confounding factors as the number of cases increases. For these limitations, the comparative trials are required, and future studies should apply appropriate methodologies to investigate the benefits of rehabilitation.

Conclusions

In this study, changes in physical function and QOL during postoperative rehabilitation were revealed. It is also important to examine whether the amount of physical activity affects physical functioning and QOL, and therefore, how the amount of physical activity affects physical function and QOL. Although physical function and QOL improved after surgery, instantaneous factors and physical symptoms were not seen for the 2nd postoperative or 4th postoperative week was not enough improvement in a short period of time. The amount of physical activity affects constipation and mental health, and we recommend increasing patients' physical activity levels. There is also a need to follow up with rehabilitation. In addition, consideration should be given to incorporating instantaneous programs.

Relevance to clinical practice

There are few reports examining the significance of rehabilitation during hospitalization in patients undergoing surgery for gastrointestinal cancers. In this study, we obtained an interesting result: a greater amount of postoperative exercise resulted in reduced constipation. The opportunity to exercise after gastrointestinal cancer surgery is not limited to rehabilitation. However, in rehabilitation, it is important to develop assessments and protocols and promote exercise in daily care.

Conflict of Interest

There are no conflicts of interest to declare in this study.