Cancer treatment can be an important step toward controlling or treating cancer. However, treatments such as chemotherapy, radiation therapy, immunotherapy, targeted therapy and cancer surgery can sometimes cause side effects.
Some side effects may be mild and temporary, while others may require prompt medical attention. This is why patients should report new, worsening or unusual symptoms to their healthcare team rather than waiting for them to become severe.
Importantly, the warning signs and level of urgency can vary depending on the type of cancer treatment, the patient’s health and the advice provided by their treating medical team.
Why Is It Important to Report Side Effects?
Many cancer treatment side effects can be managed more effectively when they are identified early.
Reporting symptoms allows your healthcare team to:
- Determine whether the symptom is related to treatment
- Assess how serious it may be
- Recommend appropriate supportive care
- Adjust treatment when necessary
- Prevent complications from becoming more serious
- Help you continue treatment safely when possible
Do not assume that a symptom is “normal” just because you are receiving cancer treatment.
Your oncology team would rather know about a new symptom early than have you wait until it becomes difficult to manage.
Common Side Effects During Cancer Treatment
Side effects vary widely depending on the treatment.
Some commonly reported symptoms include:
Fatigue
Feeling unusually tired or lacking energy can occur with several cancer treatments.
Rest, nutrition, hydration and appropriate activity may help, but persistent or severe fatigue should be discussed with your healthcare team.
Nausea or Vomiting
Some cancer treatments can cause nausea or vomiting.
Your doctor may prescribe medicines to help control these symptoms.
If vomiting prevents you from drinking fluids or taking prescribed medicines, contact your healthcare team promptly.
Loss of Appetite
Changes in appetite can occur during cancer treatment.
If you are eating significantly less than usual or experiencing unintentional weight loss, tell your doctor.
Mouth Sores
Certain treatments can cause soreness or irritation in the mouth.
Tell your healthcare team if mouth problems make eating, drinking or swallowing difficult.
Diarrhea or Constipation
Changes in bowel movements can occur with some cancer treatments and medicines.
Persistent or severe diarrhea, constipation, abdominal pain or other significant changes should be reported.
Hair Loss
Some cancer treatments can cause temporary or permanent hair changes.
Your healthcare team can explain whether hair loss is expected with your particular treatment.
Warning Symptoms That Should Not Be Ignored
The symptoms that require urgent attention depend on the treatment you are receiving.
However, patients should contact their cancer care team promptly if they develop new, severe, rapidly worsening or unusual symptoms.
Depending on your individual treatment plan, symptoms that may require urgent evaluation can include:
- Fever or chills
- Difficulty breathing
- Chest pain
- Severe or persistent vomiting
- Severe or persistent diarrhea
- Uncontrolled bleeding
- Confusion or sudden changes in alertness
- Severe weakness or dizziness
- Signs of dehydration
- Sudden severe pain
- New neurological symptoms
- Significant swelling or an allergic-type reaction
These symptoms do not necessarily mean that a serious complication has occurred, but they may require prompt assessment.
Follow the specific emergency instructions provided by your oncology team.
Fever During Cancer Treatment
Fever can be particularly important during certain cancer treatments because some treatments can reduce the body’s ability to fight infections.
If your oncology team has given you a specific temperature threshold or instructions about fever, follow those instructions rather than relying on a general number from the internet.
If you develop a fever or chills during cancer treatment, contact your healthcare team according to the instructions they have provided.
What About Infection?
Some cancer treatments can affect the immune system or reduce certain blood cells, potentially increasing the risk of infection.
Possible signs of infection can include:
- Fever
- Chills
- Persistent cough
- Sore throat
- Burning or pain while urinating
- Redness or swelling around a wound
- New or worsening weakness
Your doctor may recommend blood tests or other investigations if an infection is suspected.
Bleeding or Easy Bruising
Certain cancer treatments can affect blood cells involved in clotting.
Contact your healthcare team if you notice unusual bleeding such as:
- Frequent nosebleeds
- Bleeding gums
- Blood in urine
- Blood in stool
- Vomiting blood
- Unusual or rapidly increasing bruising
Your doctor may recommend blood tests to check your blood counts and determine whether further treatment is needed.
When Should You Call Your Cancer Team?
A useful rule is:
If something feels significantly different, new, severe or is getting worse, tell your healthcare team.
Do not wait until your next scheduled appointment if you have been specifically instructed to report certain symptoms immediately.
Your oncology team may provide you with a personalized list of symptoms and emergency contact numbers based on your treatment.
Keep these instructions somewhere easily accessible.
Should You Stop Cancer Treatment Because of Side Effects?
Do not stop, skip or change your cancer treatment on your own.
Some side effects can be managed with supportive medicines, changes in timing or dosage, hydration, nutritional support or other interventions.
If a side effect is significant, your doctor may decide to modify or temporarily pause treatment.
The decision should be made by your treating medical team after assessing your individual situation.
Keep a Record of Your Symptoms
Keeping a simple symptom diary can make it easier to communicate with your healthcare team.
You can record:
- What symptom occurred
- When it started
- How severe it was
- How long it lasted
- What made it better or worse
- Any medicines taken
- Temperature readings, when relevant
- Food and fluid intake if requested by your healthcare team
This information can help your doctor identify patterns and make appropriate treatment decisions.
Questions to Ask Your Doctor Before Starting Treatment
Before beginning cancer treatment, ask your healthcare team:
- What side effects should I expect?
- Which symptoms should I report immediately?
- What temperature should prompt me to call?
- Who should I contact outside clinic hours?
- Which symptoms require emergency care?
- What medicines can I take for common side effects?
- Should I avoid any particular medicines or foods?
- What should I do if I cannot eat or drink normally?
Having these answers beforehand can make it easier to respond if symptoms develop.
Every Patient’s Warning Signs May Be Different
There is no single list of warning symptoms that applies to every cancer patient.
The risk depends on:
- Type of cancer
- Cancer stage
- Treatment being given
- Treatment dose
- Other medicines
- Age
- Existing medical conditions
- Immune system function
- Individual response to treatment
For example, the symptoms that require urgent attention during chemotherapy may differ from those that are particularly important during immunotherapy or after major cancer surgery.
Always follow the instructions given by your own cancer care team.
When Is Emergency Care Needed?
If you experience a potentially life-threatening symptom—such as severe difficulty breathing, severe chest pain, loss of consciousness, major uncontrolled bleeding or another medical emergency—seek immediate emergency medical care.
Do not wait for a routine oncology appointment.
If your treatment team has provided a specific emergency number or hospital contact, use that information.
Book a Consultation With Dr. Sudam Sadangi
Managing cancer involves more than treating the tumor. Recognizing and communicating treatment side effects early is also an important part of safe and effective cancer care.
If you or a loved one has been diagnosed with cancer and needs specialist guidance regarding treatment options, surgery or cancer-related symptoms, timely consultation can help you understand the next steps.
Dr. Sudam Sadangi, Onco Surgeon in Bhubaneswar, provides specialized cancer evaluation, surgical oncology care and personalized treatment guidance.
Call for Appointment: +91 7854841519
Location: IMS & SUM Hospital, Bhubaneswar, Odisha
Email: sudamscb@gmail.com
