Treatment interval in curative treatment of colon cancer, does it impact (cancer free) survival? A non-inferiority analysis.

BACKGROUND: In treatment of colon cancer, strict waiting-time targets are enforced, leaving professionals no room to lengthen treatment intervals when advisable, for instance to optimise a patient's health status by means of prehabilitation. Good quality studies supporting these targets are lacking. With this study we aim to establish whether a prolonged treatment interval is associated with a clinically relevant deterioration in overall and cancer free survival. METHODS: This retrospective multicenter non-inferiority study includes all consecutive patients who underwent elective oncological resection of a biopsy-proven primary non-metastatic colon carcinoma between 2010 and 2016 in six hospitals in the Southern Netherlands. Treatment interval was defined as time between diagnosis and surgical treatment. Cut-off points for treatment interval were ≤35 days and ≤49 days. FINDINGS: 3376 patients were included. Cancer recurred in 505 patients (15.0%) For cancer free survival, a treatment interval >35 days and >49 days was non-inferior to a treatment interval ≤35 days. Results for overall survival were inconclusive, but no association was found. CONCLUSION: For cancer free survival, a prolonged treatment interval, even over 49 days, is non-inferior to the currently set waiting-time target of ≤35 days. Therefore, the waiting-time targets set as fundamental objective in current treatment guidelines should become directional instead of strict targets.

A retrospective analysis of the association of effort-independent cardiopulmonary exercise test variables with postoperative complications in patients who underwent elective colorectal surgery.

PURPOSE: This study aimed to investigate the association of effort-independent variables derived from the preoperative cardiopulmonary exercise test (CPET) with 30-day postoperative complications after elective colorectal surgery. METHODS: A multicenter (n=4) retrospective explorative study was performed using data of patients who completed a preoperative CPET and underwent elective colorectal surgery. The preoperative slope of the relation between minute ventilation and carbon dioxide production (VE/VCO2-slope) and the oxygen uptake efficiency slope (OUES), as well as 30-day postoperative complications, were assessed. Multivariable logistic regression analyses and receiver operating characteristic (ROC) curves were used to investigate the prognostic value of the relationship between these preoperative CPET-derived effort-independent variables and postoperative complications. RESULTS: Data from 102 patients (60.1% males) with a median age of 72.0 (interquartile range 67.8-77.4) years were analyzed. Forty-four patients (43.1%) had one or more postoperative complications (of which 52.3% general and 77.3% surgical complications). Merely 10 (9.8%) patients had a general complication only. In multivariate analysis adjusted for surgical approach (open versus minimally invasive surgery), the VE/VCO2-slope (odds ratio (OR) 1.08, confidence interval (CI) 1.02-1.16) and OUES (OR 0.94, CI 0.89-1.00) were statistically significant associated with the occurrence of 30-day postoperative complications. CONCLUSION: The effort-independent VE/VCO2-slope and OUES might be used to assist in future preoperative risk assessment and could especially be of added value in patients who are unable or unwilling to deliver a maximal cardiorespiratory effort. Future research should reveal the predictive value of these variables individually and/or in combination with other prognostic (CPET-derived) variables for postoperative complications. TRIAL REGISTRATION NUMBER: ClinicalTrials.gov NCT05331196.

Influence of different data-averaging methods on mean values of selected variables derived from preoperative cardiopulmonary exercise testing in patients scheduled for colorectal surgery.

INTRODUCTION: Patients with a low cardiorespiratory fitness (CRF) undergoing colorectal cancer surgery have a high risk for postoperative complications. Cardiopulmonary exercise testing (CPET) to assess CRF is the gold standard for preoperative risk assessment. To aid interpretation of raw breath-by-breath data, different methods of data-averaging can be applied. This study aimed to investigate the influence of different data-averaging intervals on CPET variables used for preoperative risk assessment, as well as to evaluate whether different data-averaging intervals influence preoperative risk assessment. METHODS: A total of 21 preoperative CPETs were interpreted by two exercise physiologists using stationary time-based data-averaging intervals of 10, 20, and 30 seconds and rolling average intervals of 3 and 7 breaths. Mean values of CPET variables between different data averaging intervals were compared using repeated measures ANOVA. The variables of interest were oxygen uptake at peak exercise (VO2peak), oxygen uptake at the ventilatory anaerobic threshold (VO2VAT), oxygen uptake efficiency slope (OUES), the ventilatory equivalent for carbon dioxide at the ventilatory anaerobic threshold (VE/VCO2VAT), and the slope of the relationship between the minute ventilation and carbon dioxide production (VE/VCO2-slope). RESULTS: Between data-averaging intervals, no statistically significant differences were found in the mean values of CPET variables except for the ventilatory equivalent for carbon dioxide at the ventilatory anaerobic threshold (P = 0.001). No statistically significant differences were found in the proportion of patients classified as high or low risk regardless of the used data-averaging interval. CONCLUSION: There appears to be no significant or clinically relevant influence of the evaluated data-averaging intervals on the mean values of CPET outcomes used for preoperative risk assessment. Clinicians may choose a data-averaging interval that is appropriate for optimal interpretation and data visualization of the preoperative CPET. Nevertheless, caution should be taken as the chosen data-averaging interval might lead to substantial within-patient variation for individual patients. CLINICAL TRIAL REGISTRATION: Prospectively registered at ClinicalTrials.gov (NCT05353127).

Feasibility of a tele-prehabilitation program in high-risk patients with colon or rectal cancer undergoing elective surgery: a feasibility study.

BACKGROUND: Prehabilitation appears to be an effective strategy to reduce postoperative complications and enhance recovery after colorectal surgery. Although many patients prefer (unsupervised) home-based prehabilitation, adherence can be problematic. Combining home-based prehabilitation with tele-monitoring might demonstrate a higher adherence than unsupervised prehabilitation; however, evidence on its feasibility and effectiveness in patients with colorectal cancer scheduled for elective surgery who are at high risk for postoperative complications is lacking. The aim of this study was to assess the feasibility of a bimodal tele-prehabilitation program in patients with colorectal cancer at high risk for postoperative complications. METHODS: High-risk patients (oxygen uptake at the ventilatory anaerobic threshold ≤11 mL/kg/min or oxygen uptake at peak exercise ≤ 18 mL/kg/min) with colorectal cancer were included in a home-based bimodal tele-prehabilitation program. The program consisted of a personalized tele-monitored moderate to high-intensity interval training intervention and nutritional counseling. Feasibility was measured by participation rate, dropout rate, adherence to the physical exercise training session's frequency, intensity, and time, and retention rate. Patient appreciation was measured by a patient appreciation questionnaire. Changes in preoperative physical fitness as secondary outcomes were quantified by time to exhaustion on a constant work rate (cycle) test, number of repetitions on the 30-s chair-stand test, and walking speed on the 4-m gait speed test. RESULTS: The participation rate was 81%, there were no adverse events, and all participants managed to complete the tele-prehabilitation program (retention rate of 100%). Adherence with regard to the exercise program's frequency, intensity, and time was respectively 91%, 84%, and 100%. All participants appreciated the tele-prehabilitation program. Time to exhaustion on the constant work rate test improved (not statistically significant) from a pre-prehabilitation median score of 317 seconds to a post-prehabilitation median score of 412 seconds (p = 0.24). Median number of repetitions on the 30-s chair-stand test improved from 12 to 16 (p = 0.01). CONCLUSIONS: Tele-prehabilitation seems feasible in high-risk patients with colorectal cancer, but efforts should be made to further improve adherence to physical exercise training intensity. More research is needed to establish the (cost-)effectiveness of tele-prehabilitation regarding preoperative improvements in preoperative aerobic fitness and postoperative reduction of complications. TRIAL REGISTRATION: ISRCTN, ISRCTN64482109 . Registered 09 November 2021 - Retrospectively registered.

Inter-observer agreement of preoperative cardiopulmonary exercise test interpretation in major abdominal surgery.

BACKGROUND: Accurate determination of cardiopulmonary exercise test (CPET) derived parameters is essential to allow for uniform preoperative risk assessment. The objective of this prospective observational study was to evaluate the inter-observer agreement of preoperative CPET-derived variables by comparing a self-preferred approach with a systematic guideline-based approach. METHODS: Twenty-six professionals from multiple centers across the Netherlands interpreted 12 preoperative CPETs of patients scheduled for hepatopancreatobiliary surgery. Outcome parameters of interest were oxygen uptake at the ventilatory anaerobic threshold (V̇O2VAT) and at peak exercise (V̇O2peak), the slope of the relationship between the minute ventilation and carbon dioxide production (V̇E/V̇CO2-slope), and the oxygen uptake efficiency slope (OUES). Inter-observer agreement of the self-preferred approach and the guideline-based approach was quantified by means of the intra-class correlation coefficient. RESULTS: Across the complete cohort, inter-observer agreement intraclass correlation coefficient (ICC) was 0.76 (95% confidence interval (CI) 0.57-0.93) for V̇O2VAT, 0.98 (95% CI 0.95-0.99) for V̇O2peak, and 0.86 (95% CI 0.75-0.95) for the V̇E/V̇CO2-slope when using the self-preferred approach. By using a systematic guideline-based approach, ICCs were 0.88 (95% CI 0.74-0.97) for V̇O2VAT, 0.99 (95% CI 0.99-1.00) for V̇O2peak, 0.97 (95% CI 0.94-0.99) for the V̇E/V̇CO2-slope, and 0.98 (95% CI 0.96-0.99) for the OUES. CONCLUSIONS: Inter-observer agreement of numerical values of CPET-derived parameters can be improved by using a systematic guideline-based approach. Effort-independent variables such as the V̇E/V̇CO2-slope and the OUES might be useful to further improve uniformity in preoperative risk assessment in addition to, or in case V̇O2VAT and V̇O2peak are not determinable.

Moderate-intensity exercise training or high-intensity interval training to improve aerobic fitness during exercise prehabilitation in patients planned for elective abdominal cancer surgery?

Low preoperative aerobic fitness is associated with an increased risk of postoperative complications and delayed recovery in patients with abdominal cancer. Surgical prehabilitation aims to increase aerobic fitness preoperatively to improve patient- and treatment-related outcomes. However, an optimal physical exercise training program that is effective within the short time period available for prehabilitation (<6 weeks) has not yet been established. In this comparative review, studies (n = 8) evaluating the effect of short-term (<6 weeks) moderate-intensity exercise training (MIET) or high-intensity interval training (HIIT) on objectively measured aerobic fitness were summarized. The content of exercise interventions was critically appraised regarding the frequency, intensity, time, type, volume, and - monitoring of - progression (FITT-VP) principles. Three out of four studies evaluating HIIT showed statistically significant improvements in oxygen uptake at peak exercise (VO2peak) by more than 4.9%, the coefficient of variation for VO2peak. None of the two studies investigating short-term MIET showed statistically significant pre-post changes in VO2peak. Although short-term HIIT seems to be a promising intervention, concise description of performed exercise based on the FITT-VP principles was rather inconsistent in studies. Hence, interpretation of the results is challenging, and a translation into practical recommendations is premature. More emphasis should be given to individual responses to physical exercise training. Therefore, adequate risk assessment, personalized physical exercise training prescription using the FITT-VP principles, full reporting of physical exercise training adherence, and objective monitoring of training progression and recovery is needed to ensure for a personalized and effective physical exercise training program within a multimodal prehabilitation program.

The Association Between Treatment Interval and Survival in Patients With Colon or Rectal Cancer: A Systematic Review.

BACKGROUND: Surgery for colon or rectal cancer is associated with a high incidence of complications, especially in patients with a low aerobic fitness. Those patients might benefit from a comprehensive preoperative workup including prehabilitation. However, time between diagnosis and treatment is often limited due to current treatment guidelines. To date, it is unclear whether the treatment interval can be extended without compromising survival. METHODS: A systematic review concerning the association between treatment intervals and survival in patients who underwent elective curative surgery for colon or rectal cancer was performed. A search up to December 2020 was conducted in PubMed, Cinahl and Embase. Original research articles were eligible. Quality assessment was performed using the Downs and Black checklist. RESULTS: Eleven observational studies were included (897 947 patients). In colon cancer, treatment intervals that were statistically significant associated with reduced overall survival or cancer-specific survival ranged between > 30 and > 84 days. In rectal cancer, only one out of four studies showed that treatment intervals > 49 days was associated with reduced cancer-specific survival. CONCLUSIONS: This systematic review identified that studies investigating the association between treatment intervals and survival are heterogeneous with regard to treatment interval definitions, treatment interval time intervals and used outcome measures. These aspects need standardization before a reliable estimate of an optimal treatment interval can be made. In addition, further research should focus on establishing optimal treatment intervals in patients at high risk for postoperative complications, as particularly these patients might benefit from extended diagnosis to treatment intervals permitting comprehensive preoperative preparation.