Colorectal cancer is the fourth most diagnosed cancer in Australia and the second-leading cause of cancer-related death. 1,2 An estimated 5% of Australians will develop colorectal cancer by the age of 851.
Whilst the median age at diagnosis is 69 in males and 72 in females, colorectal cancer can occur in individuals under the age of 50.2 Fortunately however, the five year survival has increased for colorectal cancer with a combination of screening and improved treatment modalities.3
The liver is the dominant metastatic site for patients with colorectal cancer, commonly occurring in up to 40-50% of patients. 4 Previously considered palliative, liver metastasis may be amenable to curative resection with overall survival approaching 60%.4
Signs/symptoms
The following symptoms should be investigated further, and test results provided to the patient within one week of testing.5
- Positive FOBT
- Passage of blood with or without mucus in faeces
- Altered bowel habits (diarrhea or constipation)
- Undiagnosed abdominal pain
- Unexplained abdominal or rectal mass
- Unexplained weight loss
- Lethargy
- Unexplained iron-deficiency anaemia
Rarely, patients with colorectal cancer may present incidentally with suspicious radiological findings and are asymptomatic.
Investigations
In the first instance, patients should have:
- Routine blood tests (full blood count [FBC])
- Urea and electrolytes [U&E]
- Liver function tests [LFTs]
- Carcinoembryonic antigen [CEA]
Ultimately however, the diagnosis is confirmed histologically by colonoscopy and staged by a contrast-enhanced CT chest, abdomen, and pelvis. Additional investigations to complete the staging of the primary disease, may include an MRI of the rectum.
If liver metastasis is suspected, an MRI of the liver with primovist is ordered and a PET to determine the precise location, relationship of liver metastasis to critical structures and exclude the presence of extrahepatic disease (disease outside the liver).
A liver biopsy is unnecessary and potentially dangerous for most patients with liver lesions and should only be arranged at the recommendation of a hepatobiliary surgeon following review of the patients imaging. Furthermore, in the presence of metastatic disease, further testing may include molecular analysis of the primary tumor’s genetics to select appropriate systemic agents for treatment.
All newly diagnosed cases of colorectal cancer should be discussed at a multidisciplinary team meeting for the purposes of treatment planning. A multi-disciplinary meeting is a meeting of multiple experts from different specialties who review potential malignancies and formulate a decision that is both patient-centered and evidence-based. In the meeting patients are discussed and, in their absence, imaging and biopsies (if applicable) are reviewed. A consensus is reached, and the treatment plan communicated to the patient by the treating doctor and the patient’s general practitioner.
Treatments recommended are either for curative or palliative intent. The treatment intent depends on patient (age, medical comorbidities, performance status, patient’s wishes) and disease factors (stage of disease, liver function). Furthermore, discussion at a multi-disciplinary team meeting is mandatory for high-risk and complex cases such as patients with pre-operative rectal cancers, metastatic and recurrent disease.
Treatments
As previously mentioned, treatment intent primarily depends on patient and disease factors and is reached by consensus in a multi-disciplinary meeting of specialists which could include surgeons with colorectal, hepatobiliary and pancreatic training, as well as medical oncologists, radiation oncologists, radiologists and pathologists. Importantly however, the outcome of treatment ultimately depends on the individual patient’s tumor biology.
Indicators of poor tumour biology include adverse histological factors of the primary tumour (grade of differentiation, nodal metastasis, perforation, resection margin) and the presence or absence of metastasis (liver, lung, peritoneum). In addition, the number, location, and presence of metastasis in the liver and lung are additional factors often predictive of poor tumour biology.
Curative approach
In the absence of metastatic disease, patients with resectable colorectal cancer are typically offered surgery, depending on patients wishes, age, comorbidities, and performance status. For patients with a resectable rectal cancer, neoadjuvant chemotherapy or radiotherapy precedes surgical treatment. Previously performed entirely by an open approach, colorectal cancer resections has evolved to include multiple minimally invasive techniques with additional patient benefits and preserved surgical and oncological outcomes. Options include either laparoscopy or increasingly robotic surgery. Furthermore, robotic colorectal surgery offers additional advantages over laparoscopy, providing three dimensional magnified views, a stable camera platform, wristed instruments, better ergonomics and decreased surgeon fatigue.
Commonly there are two scenarios in which patients present with colorectal liver metastasis. Patients may present with liver metastasis (synchronous disease) at diagnosis of the colorectal cancer or alternatively are diagnosed with liver metastasis following treatment of their colorectal primary (metachronous disease). For patients with resectable synchronous tumours, the sequence of surgery may include the primary tumour first followed by liver resection, liver resection and primary together (synchronous strategy) or more commonly the liver first followed by resection of the primary disease (liver-first approach). The approach chosen also depends on patient (age, fitness, comorbidities, performance status) and disease factors (location of liver and primary tumour).
Curative treatment strategies for colorectal liver metastasis include resection, resection with ablation or rarely transplantation. Importantly systemic treatment is administered either perioperatively (before and after) or alternatively in the adjuvant setting (after surgery), typically for a period of six months.
Resection is recommended for patients who have an excellent performance status (age, few comorbidities, reasonable liver function) and have technically resectable disease in the absence of unresectable extrahepatic disease. Resection can be performed by an open approach or selectively laparoscopically by a subspecialist surgeon with advanced hepatobiliary training safely and with excellent long-term outcomes. Liver resection may be combined with ablation either intra-operatively or pre-operatively under ultrasound guidance by a radiologist to preserve the volume of liver remaining following resection. Alternatively in patients with a relatively small liver, strategies to increase the volume of liver exist increasing the availability of liver surgery for patients with more extensive disease in both lobes of the liver.
Finally, liver transplantation may be offered selectively for some patients, depending on both patient and disease factors.
Palliative
Palliative treatment includes best supportive care, systemic treatment, and occasionally liver-directed therapy (chemoembolization or radioembolization) or stereotactic beam radiotherapy.
Palliative surgical options to manage the primary include endoscopic stenting, fecal diversion (stoma) and occasionally bowel resection.
Conclusion
Colorectal cancer is a leading cause of cancer-related mortality in Australia. More recently, survival has increased through a combination of screening and improved treatment modalities. Treatment intent depends on patient and disease factors and is decided following mandatory discussion in a multi-disciplinary meeting. Treatment offered is tailored to the patient and offered by subspecialist surgeons with advanced training, in tertiary institutions safely and with excellent long-term outcomes.
Bibliography
- Bowel cancer (Colorectal Cancer) in Australia statistics. (2022, August 31). Retrieved from Australian Government Cancer Australia: https://www.canceraustralia.gov.au/cancer-types/bowel-cancer/statistics
- Bowel Cancer. (2021, September 15). Retrieved from Better Health Channel: https: //www.betterhealth.vic.gov.au/health/conditionsandtreatments/bowel-cancer
- Cancer Council Victoria. (2022, May). Retrieved from Bowel cancer statistics and trends: https://www.cancervic.org.au/research/vcr/cancer-fact-sheets/bowel-cancer.html#
- Cancer Council Victoria and Department of Health Victoria. (2021). Optimal care pathway for people with colorectal cancer. Melbourne: Cancer Council Victoria.
- Koh, C., Freeman, V., Gormly, K., O'Rourke, N., Lee, P., Luck, A., & Yan, T. (n.d.). Management of resectable metastatic colorectal cancer (MNG14). Retrieved from Cancer Council Australia Clinical Guidelines: https://wiki.cancer.org.au/australia/Clinical_question:Management_metastatic_resection
Written by Mr Travis Ackermann Mr Travis Ackermann | St John of God Health Care (sjog.org.au) and Mr Hanu Chouhan Mr Hanu Chouhan | St John of God Health Care (sjog.org.au)
