Weight loss after colon resection is a common observation, especially in cases where a significant portion of the colon has been removed. The mechanism behind this weight change is multifaceted. This article explores the factors influencing weight loss after colon resection, potential complications, dietary management, and long-term health outcomes.
Introduction
Colorectal carcinomas are among the most prevalent carcinomas worldwide, with a significant number of new cases and deaths each year. In the treatment of colorectal carcinoma, multimodal concepts depend on various influencing factors such as patient-specific factors (e.g., age, comorbidities), tumor-specific characteristics (e.g., stage, localization), treatment-associated factors (e.g., type of intervention, neoadjuvant therapy), and postoperative complications.
Background
Colorectal carcinomas are among the most prevalent carcinomas worldwide with an estimated number of new cases of about 1.1 million for colon and about 700,000 for rectal cancer, an estimated number of deaths of about 550,000 for colon, and about 310,000 for rectal cancer. In the treatment of colorectal carcinoma, multimodal concepts depend on various influencing factors such as patient-specific factors (e.g., age, comorbidities), tumor-specific characteristics (e.g., stage, localization), treatment-associated factors (e.g., type of intervention, neoadjuvant therapy), and postoperative complications. In colorectal surgery, risk factors of postoperative complications such as positive tobacco and alcohol anamnesis, age > 65 years, and existing comorbidities with an American Society of Anesthesiologists (ASA) score > III have already been determined. These are associated with higher treatment costs due to longer hospital stays, poorer functional and oncological outcomes, and increased mortality.
However, the influence of BMI is the subject of an ongoing controversial discussion. Also, the influence of unintentional WL in colorectal surgery on the postoperative complication rate is largely unexplored.
Understanding Colon Resection
What is Colon Resection?
Bowel resection surgery, also known as a colectomy or intestinal resection, is a surgical procedure that involves removing a portion of the small or large intestine. A partial colectomy for diverticulitis involves surgically removing the diseased segment of the colon affected by diverticulitis, typically to prevent recurrent episodes or address complications such as perforation or abscess.
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Types of Colon Resection
- Open Surgery: This traditional method involves a large abdominal incision to access the bowel.
- Laparoscopic Surgery: Also called minimally invasive surgery, this type of surgery uses small incisions and a camera (laparoscope) to guide the procedure, reducing the damage to the body.
- Robotic-Assisted Surgery: This advanced technique allows for precise movements using robotic arms controlled by the surgeon.
The decision on which surgical option is best is a collaborative process between the patient and their surgeon, considering factors such as the patient’s condition, the extent of the disease, surgeon expertise, and available medical resources.
Sigmoid Colectomy (Sigmoidectomy)
A sigmoid colectomy, also known as sigmoidectomy, is a surgical procedure involving the removal of the sigmoid colon, which is the S-shaped segment of the large intestine located just before the rectum. This operation is commonly performed to treat diverticulitis, especially in cases where recurrent episodes or complications such as perforation or abscess have occurred. During the procedure, the surgeon removes the diseased portion of the sigmoid colon and reconnects the healthy ends of the bowel, a process called anastomosis. In some cases, a temporary or permanent colostomy may be created to divert stool away from the healing area, allowing for proper recovery.
Colon Bypass Surgery
Colon bypass surgery is a specialized procedure performed in cases where direct removal of diseased colon tissue is not feasible or when preserving as much bowel as possible is necessary. This operation involves creating a bypass around the affected segment, allowing stool to pass without passing through the diseased area. Bypass procedures are often indicated in cases of extensive disease, multiple segments involved, or when the patient is too frail for more extensive resection. They may also be used as a palliative measure in certain cancers or in cases where resection would lead to significant loss of bowel length and function.
Causes of Weight Loss After Colon Resection
Weight loss after colon or bowel resection is a common observation, especially in cases where a significant portion of the colon has been removed. The mechanism behind this weight change is multifaceted. The amount of weight loss after colon resection varies depending on several factors, including the extent of the resection, dietary habits, and individual metabolic responses.
- Decreased Nutrient Absorption: The reduction in the length of the colon can lead to decreased absorption of nutrients, which might result in weight loss over time.
- Dietary Changes: The surgical procedure and subsequent recovery period often involve changes in diet and lifestyle that contribute to weight reduction. Some patients may experience a decrease in appetite or altered bowel habits that lead to lower caloric intake.
- Metabolic Changes: The physical changes in the gastrointestinal tract can influence metabolism and energy expenditure.
Factors Influencing Weight Loss
Several factors can influence the extent of weight loss after colon resection:
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- Extent of Resection: The degree of weight loss depends on the amount of tissue excised, changes in nutrient absorption, and postoperative lifestyle adjustments.
- Preoperative Weight Loss (WL): Unintentional WL as a dynamic variable can be seen as malnutrition. To rule out physiological weight fluctuations, in this study, preoperative WL was considered only if a documented, unintentional WL of at least 3 kg occurred in the last 6 months to achieve a weight loss of 5% according to the statistical average weight.
- Body Mass Index (BMI): Increased preoperative BMI is associated with a higher WI rate.
- BMI as measurement defines the quantitative variable “weight” statistically by relating body mass [kg] to height [m]. It is broken down by the World Health Organization into underweight (BMI < 18.5 kg/m2), normal weight (BMI 18.5-25 kg/m2), overweight (BMI 25-30 kg/m2), and obesity (BMI > 30 kg/m2)
- Neoadjuvant Therapy: Our study demonstrated a significant influence of neoadjuvant therapy for colon carcinoma on preoperative WL (p = 0.004) (Table 2). However, the small number of this subgroup should be taken into account (26/697; 3.7%). In rectal carcinoma, 48% of the patients received neoadjuvant therapy, of which 53.2% presented with preoperative WL. Here, neoadjuvant therapy had no significant influence on preoperative WL (p = 0.33).
- Side of Resection: After 3 years follow-up, left-sided resected survivors of CC had a 5% (p < 0.01) increase in VAT, a 4% (p < 0.001) increase in SAT and a 5% (p < 0.01) increase in TAT
Potential Complications and Side Effects
Removing part of the colon due to diverticulitis can lead to several long-term effects, impacting digestive health, bowel habits, and overall quality of life. Some patients experience changes in bowel movement frequency and consistency, which may include increased or decreased stool passage, urgency, or occasional incontinence. Additionally, the removal of the diseased segment can result in changes to nutrient absorption and gut motility, potentially leading to nutritional deficiencies or altered digestion. Though most patients recover well and continue to enjoy a good quality of life, some may experience complications such as adhesive small bowel obstructions or chronic diarrhea. Psychological impacts are also notable, as adapting to changes in bowel habits and lifestyle may require time and support.
Long-term effects of sigmoid colectomy include potential changes in bowel habits, such as increased frequency or urgency, alterations in nutrient absorption, and risks of complications like adhesions or bowel obstructions.
Other complications include:
- Wound Infections (WI): Increased preoperative BMI is associated with a higher WI rate.
- Anastomotic Leakages (AL): AL rate after colon resection was significantly higher in patients showing preoperative WL.
- In-Hospital Mortality (IHM): Regression analysis demonstrated that Charlson Comorbidity Index, ASA score, UICC stage, age, and emergency surgery are factors exerting a significant influence on IHM. With an increasing ASA score, the risk of IHM rises significantly (p = 0.049). An increase of one score point doubles the risk of IHM (OR 2.008; 95% CI: 1.003-4.021). With an increase in Charlson Comorbidity Index, the risk of IHM rises significantly, namely by 34% per score point (OR 1.340; 95% CI: 1.157-1.553; p = 0.001). Patients with UICC IV also had a significantly increased risk of IHM as compared to stages 0-I (OR 3.228; 95% CI: 1.014-10.283; p = 0.047). Age (OR 1.072; 95% CI: 1.020-1.126; p = 0.006) and emergency surgery (OR 0.126; 95% CI: 0.047-0.334; p = 0.001) were seen to have an increased risk for IHM.
Post-Operative Care and Management
Dietary Management
Post-surgical dietary management plays a crucial role in recovery and long-term health after bowel resection. Immediately after surgery, a liquid or low-fiber diet is typically recommended to minimize stress on the healing bowel. As recovery progresses, patients are gradually introduced to more complex foods, with an emphasis on high-protein, nutrient-dense options to promote tissue repair and strength. Adjustments in fiber intake are often necessary, as some individuals may experience increased bowel movements or diarrhea if fibrous foods are reintroduced too quickly. It is essential to stay well-hydrated and avoid foods that can irritate the bowel, such as spicy or highly processed items. For long-term management, a balanced diet rich in fruits, vegetables, lean proteins, and healthy fats can help maintain optimal digestive health and prevent future complications.
Lifestyle Adjustments
Postoperative life following partial colon removal involves adjustments in diet, lifestyle, and sometimes ongoing medical management. Patients typically need to follow a specific dietary plan during the recovery phase, focusing on easily digestible foods and gradually reintroducing fiber to prevent complications like diarrhea or constipation. Long-term, individuals may experience changes in bowel habits, including increased frequency or urgency, which can require lifestyle adaptations. Regular follow-up with healthcare providers is essential to monitor for potential complications such as adhesions or bowel obstructions. Many patients return to normal activities within a few weeks to months after surgery, and a significant number report a substantial reduction in diverticulitis symptoms. Psychological support may also be beneficial, as adapting to changes in bowel function and lifestyle can be challenging at first.
Ostomy
Whether an ostomy bag is needed depends on the location and extent of the bowel resection. A colostomy is when a section of the colon is brought to the surface of the abdomen to create an opening (stoma), allowing waste to exit the body into a pouch. An ileostomy is similar but involves the small intestine rather than the colon. Some ostomies are temporary and reversed after healing, while others may be permanent depending on the underlying condition.
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Resumption of Bowel Movements
Yes, bowel movements should resume for most patients after surgery. Most patients will not need a stoma or will only need a temporary one to allow the intestines to heal.
Can Diverticulitis Recur After Colon Resection?
While colectomy is highly effective in preventing the recurrence of diverticulitis, it does not guarantee that the disease will never reappear. In most cases, removing the diseased segment of the colon significantly reduces the risk of future diverticulitis episodes, especially if the entire affected area has been excised. However, in some instances, diverticula may develop in other parts of the colon, leading to new episodes of inflammation or infection. Factors influencing recurrence include the extent of resection, the presence of diverticula elsewhere in the colon, and individual health conditions. Patients who have undergone colectomy should continue to maintain a healthy diet, manage risk factors such as obesity and smoking, and adhere to regular medical check-ups to monitor their digestive health.
Colon removal significantly reduces the risk of recurrent diverticulitis in the excised area, but it cannot completely eliminate the possibility of diverticula developing elsewhere in the colon.
Bariatric Surgery After Colon Resection
Bariatric surgery, designed to promote weight loss in individuals with obesity, can be considered after colon surgery, but it requires careful planning and consultation with a multidisciplinary team. The type of colon surgery performed, the patient’s overall health, and the presence of any gastrointestinal complications influence the feasibility of bariatric procedures such as gastric bypass or sleeve gastrectomy. Post-bowel resection patients may have altered anatomy or bowel function, which can affect the choice of bariatric procedure and its outcomes. Additionally, nutritional absorption may be impacted by both surgeries, necessitating close monitoring and nutritional support.
Bariatric surgery can be performed after colon resection, but it requires careful assessment by a healthcare team. The altered anatomy and nutritional status post-resection influence the choice and safety of bariatric procedures.
Recovery Time
Once a patient is discharged from the hospital, it can range from a few days to a week after surgery, depending on the complexity of the procedure and the individual’s conditions. Most patients recovering from a bowel resection return to normal activities within a few months. However, dietary and lifestyle changes may be necessary depending on the underlying condition.
Weight Change After Colectomy for Ulcerative Colitis
Weight change after colectomy for ulcerative colitis is unknown. All patients, underwent a subtotal colectomy, then a proctectomy with J ileal pouch anal anastomosis protected by an ileostomy, and finally an ileostomy closure in the context of ulcerative colitis at the Nancy University Hospital from May 2014 to October 2020, were included. Twenty-six patients were included. The median body mass index of healthy weight was 23.3 kg/m2. Before subtotal colectomy, the median body mass index decreased to 21.3 kg/m2, a reduction of 8.5%. One month after subtotal colectomy, the median body mass index was at its lowest level of 20.8 kg/m2, which represented a 10.7% decrease from the healthy weight. Thereafter a significant increase in body mass index was observed before the proctectomy, reaching the threshold of 22.8 kg/m2, an increase of 8.7% from the lowest level.
Study on Abdominal Adipose Tissue Changes After Colon Cancer Surgery
A historical prospective study of survivors of stage I-III CC, who had undergone intended curative cancer treatment with right-sided colonic resection (right-sided hemicolectomy) or left-sided colonic resection (left-sided hemicolectomy, sigmoid resection) between 2014-2018 at Department of Surgical Gastroenterology at Copenhagen University Hospital - Herlev and Gentofte, Herlev, Denmark. Following cancer surgery some patients, depending on cancer stage, were treated with 3-6 months of adjuvant chemotherapy (FOLFOX (5-fluorouracil (5-FU), leucovorin, and oxaliplatin), CAPOX (capecitabine and oxaliplatin), monotherapy 5-FU or capecitabine).
After 3 years follow-up, left-sided resected survivors of CC had a 5% (p < 0.01) increase in VAT, a 4% (p < 0.001) increase in SAT and a 5% (p < 0.01) increase in TAT. Patients who had undergone right-sided colonic resection had no change in VAT, but a 6% (95% CI: 4-9%, p < 0.001) increase in SAT and a 4% (95% CI: 1-7%, p < 0.01) increase in TAT after 3 years. Stratified by sex, only males undergoing left-sided colonic resection had a significant VAT increase of 6% (95% CI: 2-10%, p < 0.01) after 3 years.