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Detecting lung cancer early and undergoing surgery is not the end of the story. Managing recurrence after surgery can determine survival. While it varies by stage, lung cancer carries a risk of recurrence after surgery of up to 70% (at stage 3).
Compared with other cancers, lung cancer cells divide quickly and the tumors are aggressive in nature. Even after successful surgery, invisible micro-cancer cells can remain and lead to recurrence or metastasis. As a result, lung cancer has held the top spot for cancer mortality for more than 20 years.
Fortunately, many effective new drugs for lung cancer have been developed and are being applied to patients. Recently, for "EGFR-mutated non-small cell lung cancer," which accounts for 30-40% of lung cancers, a treatment strategy that lowers recurrence risk and extends long-term survival by administering targeted therapy after surgery has been drawing attention.
Jung Hyun-ae, a renowned specialist in lung cancer chemotherapy and professor of hematology-oncology at Samsung Medical Center, appeared on Seoul Economic Daily TV's "Now, the Master" at 9 p.m. on the 6th and said, "Lung cancer treatment does not end with simply removing the cancer through surgery," adding, "A strategy of preventing recurrence by administering targeted therapy after surgery determines patients' survival and quality of life."
◇Why lung cancer is fatal
Compared with other solid tumors, lung cancer cells divide quickly, and more than 40% of patients are already diagnosed at stage 4. Professor Jung Hyun-ae explained, "The lungs are an organ where pain is not pronounced, so early detection is not easy based only on common symptoms such as coughing or phlegm."
Symptoms are not the only reason lung cancer is difficult to detect early. Lung nodules often cannot be clearly distinguished as inflammation, infection, or tumor through imaging alone. In addition, lung biopsies are not easily performed because of the risk of complications such as pneumothorax or hemothorax.
Currently, lung cancer screening in Korea mainly targets high-risk smokers. Professor Jung said, "In Asia, there are quite a few non-smoking women with adenocarcinoma, but there is still no national early screening program for them," adding, "Some countries, such as Taiwan, are moving toward including low-dose CT screening for non-smokers who have risk factors such as family history."
Meanwhile, lung cancer is divided into non-small cell lung cancer and small cell lung cancer. Of these, non-small cell lung cancer accounts for 80-85% of all lung cancers. Non-small cell lung cancer is further divided into adenocarcinoma and squamous cell carcinoma, with adenocarcinoma appearing relatively more often in non-smokers and women.
◇Recurrence risk even after surgery… more than half recur at stage 3
Lung cancer treatment strategies differ by stage. From stage 1 to stage 3, surgery is considered first with the goal of a cure. However, being able to operate does not mean the risk of recurrence disappears.
Professor Jung said, "The recurrence rate for stage 1 lung cancer is about 10-20%, stage 2 about 20-30%, and stage 3 about 50-70%," adding, "Lung cancer tumors are aggressive and heterogeneous in nature, and invisible micro-cancer cells can remain, so the risk of recurrence is high."
To prevent recurrence, customized treatment is evolving. This is because, even for the same lung cancer, treatment strategies differ depending on the genetic mutations the cancer cells carry. A representative mutation is "EGFR." Professor Jung explained, "EGFR mutations are commonly reported in Asians, non-smokers, women, and adenocarcinoma patients," adding, "In adenocarcinoma, EGFR mutations are confirmed in up to 40% of cases." EGFR mutations are not hereditary mutations inherited from parents and passed on to children; in most cases, they are mutations acquired by cancer cells later in life. The important point is that the EGFR mutation is a "target that drugs can be used against." Professor Jung said, "An EGFR mutation goes beyond simply meaning the cancer has a different character — it is a mutation whose disease course can be changed through targeted therapy."
◇Post-surgery chemotherapy for lung cancer, a key strategy to prevent recurrence
A major recent change in lung cancer treatment is that post-surgical chemotherapy is actively performed even for early-stage cancer. This strategy suppresses micro-cancer cells that may remain even after visible cancer is removed by surgery, using targeted therapies or immunotherapy to prevent recurrence. In EGFR-mutation-positive non-small cell lung cancer, a targeted therapy with the ingredient osimertinib (brand name: Tagrisso) is representative. After originally proving effective in treating stage 4 EGFR-mutated lung cancer, this drug was also studied for the purpose of preventing recurrence after surgery. Professor Jung Hyun-ae said, "In stage 1 to stage 3 EGFR-mutation-positive non-small cell lung cancer patients, taking osimertinib for three years after surgery was confirmed to significantly lower the risk of recurrence," adding, "In 2023, even an increase in survival rate was proven, with results showing the risk of death was reduced by about 51%." In particular, osimertinib is known as a drug that crosses the blood-brain barrier relatively well. Professor Jung explained, "EGFR-mutated lung cancer carries a high risk of brain metastasis, and osimertinib can also be expected to have an effect in preventing brain metastasis."
However, there are practical issues as well. Osimertinib is covered by health insurance for stage 4 lung cancer, but it is not yet covered for stage 1-3 treatment aimed at preventing recurrence after surgery.
Professor Jung said, "In treating lung cancer, there are times when we hit limits, but as new lung cancer drugs continue to be developed and applied to patients, survival times are increasing and the risk of death is decreasing, so we should have hope."
A miraculous chemotherapy that lowers lung cancer recurrence rates [Jung Hyun-ae, professor of hematology-oncology at Samsung Medical Center]
