Surgery for colorectal cancer (CRC) is followed by a period of recovery which begins in hospital and continues after discharge [
]. Postoperative recovery is a complex process encompassing physical, psychological, and social elements [
]. Clinicians have mainly focused their interest on assessing the in-hospital phases of recovery [
], but from a patient’s perspective recovery is only complete when the patient returns to normal function in day-to-day life [
]. Therefore, recovery might be best estimated with measures of functional status [
Functional status is often evaluated with patient-reported outcomes, for example with physical functioning [
] or activities of daily living [
]. Low physical functioning is associated with disability and a loss of independence [
]. Following a rapid decline after CRC surgery [
], patient physical function scores return to pre-operative values [
]. However, not all individual CRC patients recover to their pre-operative level of physical functioning. In a study among patients over 60 years of age undergoing major abdominal surgery for mixed reasons, less than 50% of patients recovered to baseline levels of functional status at 6 months after surgery [
]. Furthermore, 10% of patients were still unable to perform basic activities of daily living [
]. Recovery depends on clinical factors such as location of the tumor, presence of an ostomy, and patient characteristics (age and physical functioning before surgery) [
Apart from patient and clinical factors, recovery of physical functioning could also be influenced by physical activity. Several studies consistently indicate that physically active older adults [
] and physically active CRC survivors [
] have higher physical functioning. The influence of physical activity on recovery of physical functioning after CRC surgery is unknown. Therefore, the aims of the present study are first to assess the proportion of CRC patients without patient-reported recovery of physical functioning at 6 months post-diagnosis. Second, we examine the association between patient-reported recovery of physical functioning and (a) an increase in moderate-to-vigorous physical activity from pre-to-post surgery and (b) absolute activity levels before and after surgery.
The present study found that at 6 months post-diagnosis about half of CRC patients had not recovered to their pre-operative physical functioning. CRC patients who increased their activity from their levels before surgery were significantly more likely to be recovered compared to patients who had a stable activity level. Furthermore, patients who were physically active after CRC surgery were more likely to recover their physical functioning. In contrast, level of activity before surgery was not associated with recovery of physical functioning.
Few studies have assessed the association between physical activity and recovery of physical functioning after colorectal cancer surgery. Since recovery is defined as return to baseline function, quantification of recovery requires measurement both at baseline and after discharge from the hospital. Those data are not commonly reported. Several studies assessed in-hospital recovery [
], return to work [
], or assessed physical functioning only after surgery [
]. We found that 54% of CRC patients had not recovered their pre-surgery physical functioning at 6-months post-diagnosis. Along with a previous study [
], these data suggest that a substantial proportion of patients have not recovered to preoperative functioning by 5 to 6 months post-surgery.
The main finding in the present study was that CRC patients who increased their physical activity levels above baseline levels were more often recovered from surgery. The magnitude of benefit of increasing activity was similar in patients who had either a high or moderate increase in activity and was independent of pre-surgery physical activity level. Our analyses also demonstrate that CRC patients who were consistently active (at least 150 min/week), but did not increase their activity, did not experience improved recovery. These results are in line with a previous study among cancer survivors, which concluded that it was the change in physical activity since cancer diagnosis that was associated with current physical functioning, rather than the absolute amount of physical activity [
]. However, a possible explanation for this finding is that an increase in physical activity level might be needed in order to regain muscle mass, aerobic capacity, and coordination [
]. Nonetheless, because this is the first study that assessed the impact of absolute levels and relative increases in activity on recovery after CRC surgery, these findings need to be confirmed. Future studies should preferably include multiple assessments of physical activity and physical functioning after surgery to better follow the recovery trajectory.
Furthermore, our results showed that pre-surgery activity was not associated with recovery. Several other studies have examined the effect of pre-surgery activity on recovery of physical functioning among CRC patients. In contrast to our result, one study concluded that a higher pre-operative physical activity level was associated with a faster self-reported recovery after surgery [
]. However, that study measured recovery at 3 and 6 weeks after surgery and only used the single question “to what extent do you feel physically recovered?” to measure recovery among 115 CRC patients. Our results are in line with a recent systematic review that concluded there is no evidence that pre-operative physical activity improves post-operative outcomes such as recovery in CRC patients [
The current study has some limitations that need to be taken into consideration when interpreting the results. First, our measurements were taken at six months post-diagnosis and not at six months post-surgery. However, the number of days since surgery was similar for those patients that did recover versus patients that did not recover at six months post-diagnosis. Furthermore, our results did not seem to be influenced by additional cancer treatment. In sensitivity analyses, in which we included patients treated with only surgical resection, we found a similar association between an increase in physical activity and recovery as in the total study population.
Another limitation is that recovery of physical functioning was measured using questionnaires based on self-report. Generally, the ceiling effect of the physical functioning scale is considered a limitation [
]. Many patients score the maximum of 100 on physical functioning before surgery. As a consequence, patients with the highest possible score cannot be distinguished from each other, while differences in physical functioning are present. Therefore, patients who score the maximum both before and months after surgery (
= 65, 20%) could still have experienced an overall decline in physical functioning, although we were not able to measure this decline. However, for this study we focused on a clinically relevant decline in physical functioning that resulted in a deterioration of the ability to cope independently [
], i.e. patients were considered not recovered from surgery. Ideally, both objective and self-reported measures should have been included to fully capture multiple domains of physical functioning. In a study among older patients undergoing major abdominal surgery, the proportion not recovered indeed varied across different measures [
]. In that study the proportion of patients without recovery was consistently greater with performance-based instruments than with self-reported measures of physical functioning [
]. We found that about half of patients were not recovered to their pre-surgery capacity to perform physical and daily routine activities. We do not expect that more patients would be considered to be recovered if we would have used objective measures of physical functioning.
Physical activity level was measured with self-reported questionnaires. Objective measures, such as accelerometers, are complementary to, rather than a replacement for, self-reported methods in epidemiologic studies. Accelerometers capture short-term measures of physical activity, while questionnaire are designed to give a representative view of habitual long-term physical activity. Physical activity levels of patients around the time of diagnosis may deviate significantly from their regular physical activity behaviour, e.g. because of frequent visits to the hospital. Therefore, accelerometers may be inappropriate to capture habitual physical activity before treatment, while questionnaires are.
Lastly, the response rate of 50% and missing data of some patients on exposure and/or outcome may limit the generalizability of our results. In addition, our study population was quite active; 86% of patients were active at or over the recommended 150 min/week. This is slightly higher than the general Dutch population aged 55+, in which 72% meets the physical activity guideline. However, this activity level was similar to the 91% adherence to the physical activity guideline that was found in another study among Dutch CRC survivors [
]. In contrast, the proportion of CRC patients meeting the activity recommendation in North-America and Australia are generally much lower [
]. The high level of physical activity in our study population might limit the generalizability of our results to other populations of CRC patients. However, our results suggest that the benefit of an increase in physical activity is independent from the pre-surgery level of activity (<150 min/week vs. ≥150 min/week).
This study has several strengths. First, we were able to adjust for many covariates that could potentially confound our associations. Although no data was available about complications that occurred, length of hospital stay was used as an indicator of major complications after surgery. Second, the COLON study provided a unique opportunity to explore recovery after CRC surgery, since we measured physical functioning both before surgery and after discharge from the hospital. Third, we compared CRC patients who increased their activity levels after surgery with patients who had a stable activity level. No comparison was made with regard to patients who decreased their activity levels after CRC surgery, since CRC surgery might result in a prolonged low physical functioning and therefore a reduced ability to be physically active.
The authors would like to thank the co-workers from the following hospitals for their involvement in recruitment for the COLON study: Hospital Gelderse Vallei, Ede; RadboudUMC, Nijmegen; Slingeland Hospital, Doetinchem,; Canisius Wilhelmina Hospital, Nijmegen; Rijnstate Hospital, Arnhem; Gelre Hospitals, Apeldoorn/Zutphen; Hospital Bernhoven, Uden; Isala, Zwolle; ZGT, Almelo; Martini Hospital, Groningen; Admiraal de Ruyter Hospital, Goes/Vlissingen.
The COLON study is sponsored by Wereld Kanker Onderzoek Fonds (WCRF-NL) & World Cancer Research Fund International (WCRF International 2014/1179); Alpe d’Huzes/Dutch Cancer Society (UM 2012-5653, UW 2013-5927); and ERA-NET on Translational Cancer Research (TRANSCAN/Dutch Cancer Society: UW2013-6397, UW2014-6877). Sponsors were not involved in the study design, collection, analysis, interpretation of data, writing of the manuscript or the decision to submit the manuscript.
Availability of data and materials
The datasets analyzed during the current study are available from the corresponding author on reasonable request.
MvZ contributed to data collection, was involved with the conception and design of the study and analyses, performed the statistical analyses and drafted the manuscript. RMW and EK were involved with the conception and design of the cohort as well as with the study and helped to design the analyses. ASvH, PD, HKvH, BMEH, FMK, EJSB, JHWdW, FJBvD, DEGK, RMW, and JJD contributed to data collection. All authors critically read and revised the manuscript and were involved in interpretation of the data. All authors approved the final version of the manuscript.
The authors declare that they have no competing interests.
Consent for publication
Ethics approval and consent to participate
Ethical approval for the study was obtained from the Committee on Research involving Human Subjects, (Commissie Mensgebonden Onderzoek – CMO, region Arnhem-Nijmegen (The Netherlands)), CMO number 2009/349, ABR nr NL30446.091.09. All participants provided a written informed consent.