Longitudinal Dynamic in Weight Loss Impacts Clinical Outcomes for Veterans Undergoing Curative Surgery for Colorectal Cancer
Background: Definitions of malnutrition imperfectly reflect nutritional status or predict perioperative consequences. We sought to identify predictive nutritional trends by examining the effect of preoperative weight on postoperative outcomes in patients with colorectal cancer (CRC).
Methods: This retrospective review examined 148 patients with CRC treated with curative-intent surgery at the Veterans Affairs Ann Arbor Healthcare System in Michigan from January 1, 2015 to December 31, 2019. We evaluated weight dynamics of patients, starting 1 year before cancer diagnosis until 1 year after surgery. We evaluated the association of these weight dynamics with surgical outcomes. Primary outcomes observed were hospital readmission and length of stay (LOS), chemotherapy completion, and delayed recovery defined as abnormal clinical developments.
Results: There were 115 patients in the colon cancer (CC) cohort and 33 in the rectal cancer (RC) cohort. Low preoperative albumin (< 3.5 g/dL) was present in 25 patients with CC (22%) and 11 patients with RC (33%). Six-month preoperative weight loss of at least 3% occurred in 32 patients with CC (36%). Delayed recovery was observed in 35 patients with CC (30%) and 21 patients with RC (64%). Nutrition consultation rates for the CC and RC groups were 15% and 36%, respectively, before the operation; 95% and 100%, respectively, for postoperative inpatients; and 12% and 73%, respectively, for postoperative outpatients. Six-month preoperative weight loss of ≥ 3% was significantly associated with delayed recovery (P < .001) and 60-day readmissions (P = .015) but not increased LOS or chemotherapy noncompletion.
Conclusions: A ≥ 3% weight loss 6 months preceding curative surgery for CRC was associated with adverse outcomes. An intensive nutrition prehabilitation program initiated at the time of cancer diagnosis is needed and may reduce associated complications.
Previous Studies
Our findings are consistent with previous studies that have demonstrated that perioperative weight loss and malnutrition are correlated with delayed recovery and complications, such as wound healing, in patients with GI cancer.2,4,5,8 In a retrospective study of more than 7000 patients with CC, those who were overweight or obese were found to have an improved overall survival compared with other BMI categories, and those who were underweight had an increased 30-day mortality and postoperative complications.16
In another retrospective study of 3799 patients with CC, those who were overweight and obese had an improved 5-year survival rate compared with patients whose weight was normal or underweight. Outcomes were found to be stage dependent.17 In this study cohort, all patients were either overweight or obese and remained in that category even with weight loss. This may have contributed to overall improved outcomes.
Implications and Next Steps
Our study has several implications. One is that BMI criteria < 18.5 may not be a good measure for malnutrition given that about 75% of the patients in our cohort were overweight or obese and none were underweight. We also show a concrete, easily identifiable finding of percent weight change that could be addressed as an automated electronic notification and potentially identify a patient at risk and serve as a trigger for both timely and early nutrition intervention. It seems to be more sensitive than the ASPEN criterion of 10-lb weight loss in 6 months before surgery. Sensitivity is especially appealing given the ease and potential of embedding this tool in an electronic health record and the clinical importance of the consequent intervention. Preoperative as opposed to perioperative nutrition optimization at time of CC diagnosis is essential, as it may help improve postsurgical outcomes as well as oncologic outcomes, including completion of adjuvant chemotherapy. Finally, although our study found that rates of inpatient postoperative nutrition consultation were high, rates of outpatient nutrition consultation in the preoperative period were low. This represents a missed opportunity for intervention before surgery. Similarly, rates of postoperative nutrition follow-up period were low, which points to an area for improvement in longitudinal and holistic care.
We suggest modifications to nutrition intervention protocols, such as ERAS, which should start at the time of GI malignancy diagnosis.18 Other suggestions include standard involvement of nutritionists in inpatient and outpatient settings with longitudinal follow-up in the preoperative and postoperative periods and patient enrollment in a nutrition program with monitoring at time of diagnosis at the VHA. Our findings as well as previous literature suggest that the preoperative period is the most important time to intervene with regard to nutrition optimization and represents an opportunity for intensive prehabilitation. Future areas of research include incorporating other important measures of malnourishment independent of BMI into future study designs, such as sarcopenia and adipose tissue density, to better assess body composition and predict prognostic risk in CC.18,19
Strengths and Limitations
This study is limited by its single-center, retrospective design and small sample sizes, and we acknowledge the limitations of our data set. However, the strength of this VHA-based study is that the single-payer system allows for complete capture of perioperative data as well as the opportunity for focused preoperative interventions to improve outcomes. To our knowledge, there is no currently existing literature on improving nutrition protocols at the VHA for patients with a GI malignancy. These retrospective data will help inform current gaps in quality improvement and supportive oncology as it relates to optimizing malnourishment in veterans undergoing surgical resection for their cancer.
