Colorectal cancer was the third most prevalent cancer in Korea in 2020. Generally, colorectal cancer boasts a high cure and survival rate compared to other cancers. However, the prognosis for stage 4 colorectal cancer with distant metastases remains grim. Approximately 20 percent of patients receive a diagnosis of stage 4 colon cancer with distant metastases at the initial diagnosis, and despite advancements in treatment, the prognosis for stage 4 colon cancer remains unfavorable, with a median survival time of approximately 30 months.

In my practice, I've had patients ask me, “I heard that stage 4 colon cancer can be operated on, so why can't I get surgery?” Here's my answer to that question.

In recent years, multidisciplinary care for patients with metastatic colorectal cancer has gained popularity. A team of specialists, including radiologists, surgeons (colorectal, thoracic, or hepatobiliary, depending on the metastatic disease), radiation oncologists, and medical oncologists, assess each patient's disease status. They determine if resection is currently feasible or if future resection might become possible as the metastases or primary colorectal cancer site improves with chemotherapy.

"For example, let's consider a typical clinic scenario where a patient presents with stage IV colorectal cancer accompanied by liver metastases.

The first step in the assessment, with guidance from the experienced multidisciplinary team, is to determine both the technical resectability and the patient's favorable oncologic prognosis.

In patients with liver metastases from colorectal cancer, resectability isn't solely determined by factors like the number or size of liver tumors or bilateral liver involvement. The key criterion is that at least 30 percent of the liver remains after resection. If a liver metastasis is in a challenging location for surgical removal, complete resection can still be achieved by combining suitable local therapies such as radiofrequency ablation/microwave ablation (RFA/MBA) or stereotactic body radiotherapy (SBRT).

Oncologic criteria encompass prognosis-related factors like the timing of colon cancer metastasis, cancer aggressiveness, and the presence of extrahepatic lesions. For instance, if there are inoperable metastatic lesions in organs other than the liver, more than five metastatic lesions, or disease progression, the prognosis is considered poor even if surgery is performed on the liver metastases.

Of course, the decision to operate depends on more than just whether the tumor is technically removable and can be expected to recur and have a good prognosis; it also depends on the patient's age, general condition, comorbidities, ability to actively seek surgery or other treatments, and the patient's goals and preferences for treatment.

If, after a multidisciplinary evaluation, the patient is deemed surgically accessible and the tumor is considered operable, surgery may proceed without perioperative systemic chemotherapy. However, if there is insufficient residual liver volume or a risk of postoperative liver failure, a viable treatment strategy is to reevaluate the lesion every 2 to 3 months after administering preoperative systemic chemotherapy to determine the optimal timing for surgery.

Advancements in biomarkers and therapeutics for colorectal cancer mean that even if surgery isn't immediately feasible, the option of surgical resection can be reconsidered if there's a favorable response to targeted therapy with anti-EGFR antibodies (e.g., cetuximab) and cytotoxic chemotherapy for RAS wild-type left colon cancer, or anti-VEGF antibody therapy (e.g., bevacizumab) and cytotoxic chemotherapy for RAS-mutated right colon cancer.

However, in clinical practice, there are many more patients with inoperable metastatic colorectal cancer. Often, patients are so frustrated by the inoperability that they don't even want to start treatment. The primary goal of systemic anti-cancer therapy is to control symptoms and prolong survival as comfortably as possible, even if a cure is not possible. Although time constraints in the clinic do not allow me to be as emotionally supportive as I would like to be, I am always happy to see patients who are doing well with their treatment. Furthermore, as an oncologist, I hold onto the hope that innovative treatment methods will continue to emerge, offering improved outcomes for many patients.

Professor Kim graduated from Chonnam National University College of Medicine and trained in internal medicine at Asan Medical Center in Seoul. She is currently an assistant professor of hematology-oncology at Ulsan National University Hospital, where she treats colon and liver cancer. This column was originally published in Korean in Korea Healthlog, the sister publication of Korea Biomedical Review, on Oct. 4. -- Ed