Liver metastases from colon or rectal cancer: moving from despair to hope

Returning readers would be well aware from my previous posts, how unique our liver is as an organ.

To summarise, 

The liver is the only organ that receives blood from two sources

1. the blood from the digestive tract, pancreas and associated organs enters the liver via the portal vein

2. the oxygenated blood from the general circulatory system enters the liver via the hepatic artery and its branches

Due to its responsibility of trapping, filtering and neutralising toxins, infective agents etc, most of the blood from the digestive tract and allied organs first passes through the liver before being circulated into the rest of the body.

Colon and rectal cancer is among the top 5 by way of incidence and cause of cancer related deaths in India.

In the last couple of decades, improvement in detection methods, availability of safe surgical techniques as well as introduction of better tolerated chemotherapy and targeted therapy have all helped improve survival in patients with cancer in general and colon and rectal cancer in particular.

Many patients with colon and rectal cancer can expect to survive more than 10 years after diagnosis making it a chronic stable disease like others.

The Achille's heel however is that when the cancer has metastasised ie spread to cells or tissues away from the original site, the chance of survival falls precipitously to a few weeks to a few months.

The American Joint Committee for Cancer (AJCC) even in its most recent iteration classifies presence of metastases as Stage IV, the last stage of colon or rectal cancer.

Since most of the blood from the colon or rectum is first carried to the liver via the portal vein, even cancer cells can travel by this route (they can also travel through the entire body by the hepatic artery route). The unique microscopic structure within the liver, traps these cells and they are believed to remain in the liver for at least sometime before they travel onward through the entire body. This property of the liver provides a putative window of opportunity for clinicians to treat the disease before it becomes generalised.

More than 70% patients with a diagnosis of colon or rectal cancer will develop metastases in the liver from time of diagnosis to death.

In about 30% of such patients, liver is the only organ to bear the metstatic burden.

In 10-15% patients, liver metastases are already present when the cancer is first detected. Such metastases are termed synchronous metastases.

In the rest, the metastases appear later and are called metachronous metastases.

As mentioned before, metastatic cells are considered to remain in the liver before spreading elsewhere.

There multiple options to treat metastases in the liver including 

liver surgery (hepatectomy)

liver transplantation

ablation techniques ( radiofrequency etc

Choosing the appropriate liver directed therapy depends on the site, size, number and location of the metastases as well as the patient profile.

Successful liver directed therapies have demonstrated a welcome trend towards  improved cancer free survival  and overall survival in recent studies with certain caveats

1. response to systemic therapy
2. completely resectable / no extrahepatic metastases
3. liver metastases completely resectable (R0)
4. adequate future liver remnant volume after resection

Liver directed therapies are complementary to systemic or targeted therapy and need to be timed and carried out in conjunction with a multidisciplinary team for optimal results.

Presence of metastases in both lobes of the liver present a vexing but not insurmountable challenge.

Combination of techniques concurrently or in a sequential or staged manner can completely rid the liver of all metastases with curative intent with meticulous planning and execution and for the rest liver transplantation does remain an option at least from the Scandinavian experience.

I personally have managed several patients who are surviving more than 5 years despite having been diagnosed with stage IV colon or rectal cancer and are still going strong.

So this is my shout-out to patients who have metastatic colon or rectal cancer, 

the age of despair is over, embrace the era of hope