Unresectable Cancer - Definition and Explanations

Why Would a Tumor be Unresectable and What are the Options?

team of surgeons in the operating room
What does it mean if your cancer is called unresectable?. Istockphoto.com/Stock Photo©uchar

Definition: Unresectable

An unresectable tumor is defined as one that cannot be removed completely through surgery. Since surgery often offers the best chance for a cure with solid tumors, this can be discouraging news to hear.

Yet just because a tumor is inoperable does not mean it is untreatable  It's also important to note that with advances in cancer research, not all tumors that are initially unresectable will remain inoperable indefinitely. This is discussed in further depth below.

Reasons a Tumor May Be Unresectable

A tumor may be unresectable for several reasons. Some of these include:

  •  The size of the tumor - The tumor may be too large to safely remove, or may require removing too much of an essential organ to remove all of the tumor via surgery.
  •  The location of the tumor - A tumor may be intertwined with blood vessels and other vital structures in the body making safe removal impossible.
  •  Spread of the tumor to distant sites (metastases.)  Since metastatic cancer (usually stage 4 cancer) has spread to regions beyond the tumor, removal of the tumor will not control all of the cancer.  Surgery and radiation therapy are considered local treatments, they treat only the area where a tumor is and a small amount of surrounding tissue.  In contrast, chemotherapy, hormonal therapies, targeted therapy, and immunotherapy are systemic treatments - they treat cancer cells that are located anywhere in the body (an exception is that some chemotherapy and other drugs do not readily pass through the blood-brain barrier making treatment of brain metastases difficult.)
  •  Other health conditions that could raise the risk of surgery - Such as heart disease, lung disease, or severe diabetes that would raise the risk of surgery to unacceptable levels.

Unresectable Tumors ARE Treatable

It's important to keep in mind that just because a tumor is unresectable does not mean it is untreatable.

Systemic treatments - treatments that treat the whole body rather than just the site of cancer - may extend life and improve symptoms for many people living with cancer. While we tend to associate surgery with the ability to "cure" cancer, some of the newer systemic treatments may offer a chance for long-term survival. Examples of this with lung cancer include newer radiation technologies, immunotherapy medications, and targeted therapies with the option of switching to another targeted therapy when a tumor becomes resistant. In fact, the survival rates for many advanced cancers are improving due to these options.

Exceptions to the Rule - Making Unresectable Cancers Resectable

While it was thought at one time that unresectable meant permanently unresectable, this thought is changing. A review of the literature to date reveals many example of solid tumors such as non-small cell lung cancer, colorectal cancer with liver metastases, bladder cancer, exocrine pancreatic cancer, advanced melanoma, and more, in which aggressive treatment with chemotherapy and sometimes radiation therapy (called neoadjuvant therapy or downsizing) reduced the size of a tumor to the point in which surgery was possible; tumors that were unresectable initially became resectable.

The Concept of Oligometastases

Another new and refreshing concept in what was once unresectable cancer is the concept of oligometastases. The term oligo means few, and what this describes is a solid tumor that has one or only a few areas to which it has metastasized. By definition metastatic cancer or stage 4 cancer would be considered inoperable; surgery would be unable to treat all of the tumor. The thought has been that surgery would be an unneeded discomfort and risk if it would not really make a difference in the course of the tumor. (Note, there are some exceptions to this rule, for example in ovarian cancer partial surgery or "debulking surgery" may be considered to lengthen life.)  

An example of treatment using this approach would be treating what was once considered inoperable non-small cell lung cancer in a patient with lung cancer plus one or a few brain metastases. There have now been people who have had surgery for both their lung cancer and to remove one or a few brain metastases who have achieved long-term survival.

Also Known As: inoperable

Examples: Due to the location of John's tumor - being near his heart - the doctor told him his tumor was unresectable, and that combining chemotherapy and radiation would be the best option for his cancer.


Fabre, E. et al. Evolution of induction chemotherapy for non-small cell lung cancer over the last 30 years: A surgical appraisal. Thoracic Cancer. 2015. 6(6):731-40.

Imai, K. et al. Nomogram for prediction of prognosis in patients with initially unresectable colorectal liver metastases. The British Journal of Surgery. 2016 Jan 18. (Epub ahead of print).

Kato, A. et al. Downsizing Chemotherapy for Initially Unresectable Locally Advanced Biliary Tract Cancer Patients Treated with Gemcitabine Plus Cisplatin Combination Therapy Followed by Radical Surgery. Annals of Surgical Oncology. 2015. Suppl 3:1093-9.

Nitsche, U. et al. Resectability After First-Line FOLFIRINOX in Initially Unresectable Locally Advanced Pancreatic Cancer: A Single-Center Experience. Annals of Surgical Oncology. 2015. Suppl 3:1212-20.

Yang, C. et al. Long-Term Outcomes of Lobectomy for Non-Small Cell Lung Cancer After Definitive Radiation Treatment. Annals of Thoracic Surgery. 2015. 99(6):1914-20.

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