One of the most frightening moments after a cancer diagnosis comes when patients are told it is time to begin chemotherapy. Worries arrive first — losing their hair, being unable to eat, having to quit their job.
But as treatments to control side effects have advanced alongside the drugs themselves, a growing number of patients are keeping up their daily routines during chemotherapy.
Kang Seok-yun, a professor of hematology-oncology at Ajou University Hospital, said on the Seoul Economic Daily TV program "Top Doctors Now," which aired at 9:25 p.m. on the 24th, that "chemotherapy is not a process of giving up daily life but a journey toward getting it back." He added that "it is important to continue treatment while consulting closely with the medical team."
Pre- and Post-Surgery Chemotherapy Differ in Purpose
The timing of chemotherapy varies with the type and stage of cancer and the goal of treatment. Chemotherapy before surgery is used to shrink tumors to make an operation possible or to preserve an organ. Chemotherapy after surgery aims to eliminate microscopic cancer cells that cannot be seen and lower the chance of recurrence. In stage 4 cancer that has spread or cannot be removed surgically, chemotherapy is used to shrink tumors, ease symptoms and extend survival.
Early-stage cancer does not automatically rule out chemotherapy. Depending on the cancer type, treatment may be given even at stage 1 if the risk of recurrence is high. Conversely, chemotherapy may be withheld in stage 4 cases if the drugs are not effective or the patient's overall condition is poor.
The effectiveness of chemotherapy is assessed by comparing tumor size and changes before and after treatment through imaging tests such as CT, MRI and PET-CT. Changes in symptoms reported by patients, including pain, bloody stool and diarrhea, are also considered. Response is typically evaluated after about two to three months of treatment, though this varies with the drug and treatment cycle.
Targeted and Immunotherapy Drugs Do Not Work for Everyone
Chemotherapy drugs fall broadly into three categories: conventional cytotoxic agents, targeted therapies and immunotherapies. Cytotoxic drugs attack rapidly dividing cancer cells but can also affect normal cells such as hair follicles and mucous membranes, leading to side effects including hair loss and mucosal damage. Targeted therapies home in on specific proteins or genetic mutations in cancer cells, while immunotherapies help immune cells recognize and attack cancer cells.
Targeted therapies and immunotherapies are not, however, more effective for every patient. They can be used only in patients with particular targets or genetic characteristics. That has made genetic testing important for stage 4 patients to determine whether such drugs are an option.
As important as the choice of drug is proper management of side effects during treatment. Patients should see a doctor if they have diarrhea seven to eight or more times a day accompanied by dehydration and lethargy, or if numbness in the hands and feet becomes severe enough that they repeatedly drop objects and lose sensation. Prompt care is also needed if persistent vomiting makes it difficult to take in water or food, or if blood or bile appears in the vomit. The same applies when a fever of 38 degrees Celsius or higher persists while the white blood cell count is low after chemotherapy. "Side effects are not something to simply grit your teeth and bear," Kang said. "If you have uncomfortable symptoms, you should actively discuss them with your medical team."
For Stage 4 Cancer, Treatment Stops When Side Effects Outweigh Benefits
In stage 4 cancer, the same chemotherapy can continue as long as the patient tolerates it well and the disease stays under control. If the cancer becomes resistant to the drug, treatment moves to the next line of therapy.
When treatment works well and the cancer is sufficiently controlled, patients may take a treatment holiday, pausing chemotherapy for a set period. Stopping treatment may also be considered if side effects outweigh the benefits, or if focusing on symptom relief is judged more helpful to the patient than continuing chemotherapy.
"Stopping treatment does not mean giving up on the patient," Kang said. "If the side effects are greater than the benefits of treatment, not treating can be the better choice."
Beyond established chemotherapy, clinical trials of new drugs can offer another option. Trials evaluate drugs under development or new treatment combinations to see whether they work better than existing therapies. They can give patients early access to new treatments, but because eligibility and treatment conditions differ from trial to trial, thorough consultation with the attending medical team is necessary.
Work, Exercise and Travel Are Possible During Chemotherapy
Undergoing chemotherapy does not mean putting all of daily life on hold. Kang recommends staying on the job if the patient's physical condition allows it and the work is not too demanding.
One of Kang's patients was diagnosed in their early 40s with stage 4 colorectal cancer that had spread to the peritoneum, was treated with immunotherapy, and has had the disease well controlled for more than five to six years while working at a factory.
Exercise helps as well. Walking or light jogging for about 20 to 30 minutes a day, within one's own physical limits, is advisable. Travel is also possible, but patients should avoid periods when their white blood cell count is low and consult their medical team before going.
Adequate protein intake is needed during chemotherapy to support recovery. Patients who struggle to eat meat can change how it is cooked or turn to plant-based proteins and nutritional drinks containing protein.
Raw foods such as sashimi, raw beef and fresh vegetables are not banned outright, but the risk of infection should be weighed when the white blood cell count is low. Vegetables and fruit are best washed thoroughly before eating.
Health supplements with unclear ingredients are best avoided where possible, as they may interact with chemotherapy drugs. One or two weak cups of coffee a day are generally fine absent any particular problem, but alcohol is best avoided.
"Patients undergoing chemotherapy are not alone," Kang said. "If something is hard or uncomfortable, I hope they will not endure it by themselves but continue treatment while talking it through with their medical team."