Medical Oncologist
CION Cancer Clinics
Blood clots in the leg or lung after surgery | CION Cancer Clinics
A blood clot after surgery usually starts in a deep vein of the calf or thigh, giving one swollen, sore, warm leg. If part of it breaks off and reaches the lungs, it causes sudden breathlessness, chest pain on breathing in, or coughing up blood, and that needs emergency care straight away. This page explains the signs, why surgery raises the risk, and how clots are prevented and treated. CION Cancer Clinics’ surgical oncologists in Hyderabad can talk this through with you.
MM
Medically reviewed by Dr. Muralidhar MuddusettyConsultant Surgical Oncologist · MBBS (AIIMS), MS (Surgery, AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh) · last reviewed September 2026, next review due September 2027
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On this page
- What does a blood clot after surgery look like?
- Which signs point to a clot, and which usually do not?
- What happens if the team thinks you have a clot?
- What do the words on the scan report mean?
- How are clots prevented, and who is prevention not suited to?
- What do families often get wrong about clots?
- Common questions about blood clots after surgery
The short answer
What does a blood clot after surgery look like?
A clot in the leg usually shows as one calf or thigh that becomes swollen, sore, warm and sometimes red or darker than the other leg. A clot that has travelled to the lungs shows as sudden breathlessness, sharp chest pain when you breathe in, a racing heart, or coughing up blood.
What the two names mean
Deep vein thrombosis, or DVT, is a clot in one of the deep veins, most often in the leg. Pulmonary embolism, or PE, happens when a piece of that clot breaks off, passes through the heart and gets stuck in a blood vessel in the lung. Doctors often write the two together as VTE. The lung clot can be life-threatening.
Why cancer surgery raises the chance
The operation makes the blood more ready to clot. Lying in bed slows blood in the leg veins. Cancer itself makes blood stickier. A long operation on the belly or pelvis, older age, a previous clot and some hormone or chemotherapy medicines add to it.
When clots tend to appear
A clot can form on the ward or after you have gone home. The raised risk carries on through the weeks when you are home and moving less.
A clot can form with no warning signs at all. That is why prevention starts in hospital.
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Breathlessness or chest pain after surgery cannot wait
If you, or the person you are caring for, suddenly becomes breathless, has sharp chest pain that is worse on breathing in, coughs up blood, faints, or has a racing heart after an operation, treat it as an emergency. Call 108 or go to the nearest emergency department straight away and say they have recently had cancer surgery. Do not wait to see if it settles, and do not drive yourself there.
Not sure whether this applies to you?
Ask an oncologistSpotting it
Which signs point to a clot, and which usually do not?
You do not have to decide which it is. Your job is to notice and tell the team. Their job is to check.
Signs in the leg
A leg clot nearly always affects one leg more than the other. Compare both legs side by side, in good light.
Look for
- Swelling in one calf or thigh
- Throbbing or cramping pain, worse when standing or walking
- Skin that feels warm to touch
- Red or darker skin over the sore area
Signs in the chest
These can come on within minutes, sometimes with no leg signs before them at all.
Look for
- Sudden breathlessness, even at rest
- Sharp chest or upper back pain on breathing in
- Coughing up blood
- A fast heartbeat, dizziness or fainting
Things that can look similar
Both legs being a little puffy after surgery is common, from the fluids given during the operation, and usually settles. Bruising around the spot where a blood-thinning injection is given is expected. Some breathlessness after a big operation is normal. Tell the ward anyway, and let them decide.
If a clot is suspected
What happens if the team thinks you have a clot?
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You tell someone straight away
On the ward, your nurse. At home, the helpline or the nearest emergency department. Say which leg and when it started.
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An examination and a blood test
The doctor checks both legs, your pulse, breathing and oxygen level. A blood test called D-dimer may be done. After surgery it is often raised anyway, so a scan is usually still needed.
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A scan to find the clot
For the leg, an ultrasound with jelly on the skin, with no radiation. For the lungs, usually a CT scan with dye given into a vein.
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Blood-thinning treatment starts
If the doctor strongly suspects a clot, treatment may start before the scan result. It may be injections such as enoxaparin (Clexane), heparin through a drip, or tablets such as apixaban or rivaroxaban. Your surgeon weighs this against bleeding from the fresh wound.
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A plan for the weeks ahead
How long the medicine continues is set by your doctors. It depends on what caused the clot and on your cancer treatment.
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On your report
What do the words on the scan report mean?
- DVT (deep vein thrombosis)
- A clot in a deep vein, usually in the calf or thigh.
- PE (pulmonary embolism)
- A clot that has lodged in a blood vessel in the lung.
- Doppler ultrasound
- The leg scan. It shows whether blood is flowing freely through the vein or is blocked.
- CTPA
- A CT scan of the chest with dye, used to look for clots in the lung blood vessels.
- Anticoagulant
- A blood-thinning medicine. It stops clots growing and new ones forming while the body slowly breaks down the existing clot.
- Compression stockings
- Tight elastic stockings that squeeze the legs gently so blood does not pool in the veins.
Prevention
How are clots prevented, and who is prevention not suited to?
Most people having major cancer surgery are offered clot prevention from the day of the operation. It is usually a combination of moving, stockings or leg pumps, and a blood-thinning medicine.
Moving early
You will be helped to sit out and walk as soon as it is safe. In bed, pointing and flexing your feet keeps blood moving. Family can remind you.
Stockings and leg pumps
Elastic stockings or inflating calf sleeves are common. They do not suit people with poor circulation in the legs or loss of feeling in the feet from diabetes, so the team checks first.
Blood-thinning injections
A small injection under the skin of the belly is often given on the ward, and sometimes continued at home. A family member may be taught to give it. It may be delayed or avoided in someone who is bleeding, has a low platelet count or has serious kidney problems. Never stop, skip or start one on your own. If a dose is missed, call the team.
What this page cannot tell you
It cannot tell you whether the swelling in your leg is a clot. Only an examination and a scan can. It also cannot tell you how long your own medicine should last.
Commonly believed
What do families often get wrong about clots?
"Walking too soon will pull the stitches, so he should rest in bed."
Lying still is one of the main reasons clots form. The team will tell you how much to move. Gentle walking, little and often, is part of recovery.
"Rubbing the sore calf with oil will ease the cramp."
A painful, swollen calf after surgery needs to be checked, not massaged. If it is a clot, rubbing it does nothing to help. Leave the leg alone and tell the team the same day.
"The injections were only for the hospital. At home we can stop."
The risk stays raised after discharge, which is why many surgeons continue the injections at home. When to stop is your surgeon's decision.
"Breathlessness after a big operation is just weakness."
Some tiredness on exertion is expected. Breathlessness that comes on suddenly, gets worse, or comes with chest pain is a warning sign. It needs emergency care, not rest.
Questions we are asked
Common questions about blood clots after surgery
Can a clot happen after I have gone home?
Yes. The raised risk carries on for weeks after the operation, and many clots are found after discharge. Keep walking a little and often, wear the stockings if you were told to, and keep up any injections exactly as prescribed. Watch both legs and your breathing, and call the helpline if anything changes.
Both my mother's legs are swollen. Is that a clot?
Swelling in both legs after surgery is more often from fluids given during the operation, from sitting with the legs down, or from low protein in the blood. A clot usually affects one leg more. That said, only an examination can tell. Mention it to the team, and go the same day if one leg is clearly worse.
We live in a district and travel home by bus or car. Is that a risk?
Long journeys sitting still add to the risk. Ask the team before discharge whether it is safe to travel. On the way, stop regularly to walk a little, move your feet and ankles while seated, drink water if you are allowed to, and wear stockings if they were prescribed.
Do blood thinners dissolve the clot?
Not directly. They stop the clot from growing and stop new clots forming. The body then breaks the existing clot down slowly on its own. Stronger clot-busting treatment is kept for a small group with a very large lung clot, and used with great caution soon after surgery.
Who gives the injections once we are at home?
Often a family member, or the patient, after being shown on the ward. The injection goes under the skin of the belly and the needle is short. Ask the nurse to watch you give one before you leave.
There is a bruise where the injection goes in. Should I worry?
Small bruises at the injection spot are common and expected. Change the spot each time. Tell the team if bruises are large and spreading, if the wound starts oozing blood, if urine turns pink or stools turn black, or if you have nosebleeds or bleeding gums that will not stop.
Will a clot delay chemotherapy or the next treatment?
It can, for a short while, while the clot is treated and you become stable. Many people carry on with cancer treatment while taking blood thinners, with the doses and timing planned by the oncologist and surgeon together. Make sure every doctor treating you knows you are on a blood thinner.
Is treatment for a clot covered by Aarogyasri or insurance?
When a clot is a complication of approved cancer surgery, its treatment is often covered as part of that care. Rules differ between Aarogyasri, CGHS, ECHS, EHS and cashless insurance policies, and some limit the number of days covered. Call the helpline with your card details and the team will check your own cover.
Meet the Specialists
17+ senior cancer specialists. One panel for your case.
Trained at AIIMS, Tata Memorial, and leading international centres. Combined 150+ years of experience. Every complex case is reviewed by 3+ of them — together.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
Medical Oncologist
Medical Oncologist
Surgical Oncologist
Dr. Muralidhar Muddusetty
MBBS (AIIMS), MS (Surgery) (AIIMS), DNB (Surgical Oncology), MRCS (Edinburgh)
Surgical Oncologist
Surgical Oncologist
Surgical Oncologist
Dr. Vinay Mamidala
MBBS, MS(General Surgery), M.Ch(Surgical Oncology), FMAS, FARIS(Ongoing)
Surgical Oncologist
Radiation Oncologist
Radiation Oncologist
Radiation Oncologist
Hematologist
Surgical Oncologist
Dr. Vajja Sandeep Kumar
MBBS, MS (General Surgery), DrNB (Surgical Oncology), FALS Oncology
Surgical Oncologist
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Sources
- NHS — Deep vein thrombosis (DVT)
- NHS — Pulmonary embolism
- NICE — Venous thromboembolism in over 16s: reducing the risk of hospital-acquired deep vein thrombosis or pulmonary embolism (NG89)
- American Cancer Society — Cancer surgery
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
Keep reading
Related pages
Red Flags After Discharge: When to Come Back TodayEvery sign after an operation that needs same-day helpBleeding After Cancer SurgeryWhat to watch for when you are on blood thinnersMedicines Around Cancer SurgeryHow blood thinners and other medicines are planned around an operationRecovery, Eating and Getting Back to LifeHow to keep moving safely once you are home
Talk to us
Worried about swelling or breathing after an operation?
If it is sudden breathlessness or chest pain, go to the nearest emergency department now. For anything else, call the helpline and we will help you reach the surgical team. One helpline serves every CION centre.