Unresectable Cancer: Reasons and Exceptions

When a tumor cannot be surgically removed

Unresectable cancer is that which cannot be removed completely through surgery. This can be the case for a variety of reasons, including tumor size, stage, and location.

Since surgery often offers the best chance of a cure for many tumors, this may be discouraging news to hear. However, with advances in cancer research, a tumor that was initially deemed inoperable may be able to be operated on after a period of treatment.

This article explains the reasons why surgery may not be offered as a treatment option for your tumor (at least initially). It also discusses treatment alternatives and why, in some cases, there will be exceptions to the rule.

Serious surgeon talking with senior patient lying on bed in hospital ward
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Reasons a Tumor May Be Unresectable

A tumor may be considered unresectable for several reasons. The size, location, and spread of the cancer are all factors. So are any underlying health conditions that increase the risks of surgery.

Tumor Size

In some cases, a tumor may be too large to safely remove through surgery.

In others, surgery cannot be done because the tumor is in an essential organ like the liver or pancreas and removing the cancer would mean taking too much of the organ it has invaded along with it. This would likely rule out surgery as a possible treatment option.

For example, a wedge resection is a procedure often used to treat people with early-stage lung cancer. Once a tumor size reaches 2 centimeters (cm), though, this procedure is no longer considered a good option.

Tumor Location

A tumor may be intertwined with blood vessels and other vital structures in the body. Removing such cancer could pose too much of a risk.

For example, your brainstem works to control breathing, heart function, and other essential operations. A brain tumor in this region, such as a glioma, is serious and may prove fatal. But in many cases, surgery to treat the brain tumor isn't possible because it would interfere with critical functions.

Tumor Spread

Whether a tumor has metastasized, or spread, is a key factor in whether a cancer is unresectable. This is because surgery to remove a primary tumor found in the lung, for example, will not remove cancer that has spread from that area to other parts of the body.

In some cancers, resection is no longer a possibility when cancer has reached specific lymph nodes. As these small structures are part of a network that cycles fluid throughout your body, cancer that invades them can "hitch a ride" and spread more easily.


Keep in mind that an unresectable tumor is still a treatable tumor. And a tumor that cannot be operated on today may, though not always, be resectable after treatment.

Treatments to Manage Cancer

Systemic treatments—i.e., those that treat the whole body—may extend life and improve symptoms for many people living with cancer.

Systemic treatments that may be used in lieu of surgery include:

These may also be used in hopes of making conversion surgery possible down the line.

Radiation therapy, a localized treatment, only treats the area where a tumor is and a small amount of surrounding tissue. It can also be used for these purposes.

When Surgery May Become a Possibility

Radiation treatment that successfully shrinks the size of a tumor can be followed by surgery in some cases. It may become possible to remove more or all of the cancer.

Chemotherapy and other drugs can also change a cancer so that it's no longer unresectable and conversion surgery can be performed.

Multiple studies have suggested some benefits to this approach. Among them is a 2021 study from China that looked at 156 people with metastatic colorectal cancer (CRC). Of them, 76 had initially unresectable cancers, while the others could be treated with surgery from the outset.

People who could not have surgery at the start, but were treated with chemotherapy and targeted therapy drugs that made later resection possible, had a greater chance of prolonged survival times.

Though cancer that has spread may not be treated with surgery, a secondary tumor—one that has formed elsewhere in the body because of spreading cancer cells—may be resectable from the outset.


If your cancer is considered unresectable, that means surgery is not a treatment option. There are factors that may contribute to the reason, such as the size or location of a tumor. Often, though, the reason surgery is not possible is because the cancer has spread from its original site.

In some cases, radiation, chemotherapy and other treatment alternatives may change tumors. For example, if a tumor size is smaller after radiation, then a conversion surgery may be possible. It also may be possible if the cancer has only spread to a few sites.

Advances in cancer care, including the possibility of surgical removal, have led to better outcomes. Still, there are many reasons why a cancer is (and remains) unresectable. Be sure to speak with your healthcare provider about the risks and benefits of surgery and other treatments.

A Word From Verywell

Hearing that a tumor is unresectable can leave you wanting a second opinion. This is absolutely a case in which you should get one.

In fact, most cancer specialists encourage it—not because they aren't sure about their decision making, but because they want you to feel confident about your next steps.

In addition, good practitioners know that they don't know everything there is to know about a field as quickly changing as oncology. Consulting with another provider may bring a different perspective that can help shape the treatment plan you end up moving ahead with.

Frequently Asked Questions

  • What is a secondary cancer?

    Secondary cancer is a tumor that forms because of cancer cells that have spread from the original site elsewhere in the body. For example, liver cancer that forms because of the spread of lung cancer cells is called secondary liver cancer. Some people also use the term for an additional cancer that develops apart from a primary tumor.

  • How does overall health affect decisions about cancer surgery?

    Your underlying health issues may contribute to decisions about whether your cancer is unresectable. For example, people with lung conditions such as asthma may be more at risk when anesthesia is used. Other conditions can put you at risk for blood clots, infections, and other complications of surgery.

8 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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Additional Reading

By Lynne Eldridge, MD
 Lynne Eldrige, MD, is a lung cancer physician, patient advocate, and award-winning author of "Avoiding Cancer One Day at a Time."