Surgery for Cancer
Surgery is the oldest effective cancer therapy. It may be used alone or in combination with other modalities (see also Overview of Cancer Therapy). The size, type, and location of the primary tumor may determine operability and outcome. The presence of metastases may preclude an aggressive surgical approach to the primary tumor.
Factors that increase operative risk in cancer patients include
Debilitation due to cancer
Paraneoplastic syndromes (less common)
Cancer patients often have poor nutrition due to anorexia and the catabolic influences of tumor growth, and these factors may inhibit or slow recovery from surgery. Patients may be neutropenic or thrombocytopenic or may have clotting disorders; these conditions increase the risk of sepsis and hemorrhage. Therefore, preoperative evaluation is paramount.
If a primary tumor has not metastasized, surgery may be curative. Establishing a complete margin of normal tissue around the primary tumor (as in breast cancer surgery) is critical for the success of primary tumor resection and prevention of recurrence. Intraoperative examination of frozen tissue sections by a pathologist may be needed. Immediate resection of additional tissue is done if margins are positive for tumor cells. However, examination of frozen tissue is inferior to examination of processed and stained tissue. Later review of margin tissue may prove the need for wider resection.
Surgical resection for primary tumor with local spread may also require removal of involved regional lymph nodes, resection of an involved adjacent organ, or en bloc resection. Survival rates with surgery alone are listed for selected cancers (see table Median 5-Yr Survival in Various Types of Cancer).
Neoadjuvant chemotherapy or radiation therapy may be done when the primary tumor has spread into adjacent normal tissues extensively. In neoadjuvant therapy, surgery is delayed so that other modalities (eg, chemotherapy, radiation therapy) can be used to reduce the size of the required resection.
When cancer has metastasized to regional lymph nodes, nonsurgical modalities may be the best initial treatments, as in locally advanced lung cancer or head and neck cancer. Single metastases, especially those in the lungs or liver, can sometimes be resected with a reasonable rate of cure.
Patients with a limited number of metastases, particularly to the liver, brain, or lungs, may benefit from surgical resection of both the primary and metastatic tumor. For example, in colon cancer with liver metastases, resection produces 5-yr survival rates of 30 to 40% if < 4 hepatic lesions exist and if adequate tumor margins can be obtained.
Cytoreduction (surgical resection to reduce tumor burden) is often an option when removal of all tumor tissue is impossible, as in most cases of ovarian cancer. Cytoreduction may increase the sensitivity of the remaining tissue to other treatment modalities through mechanisms that are not entirely clear. Primary renal cell carcinomas and ovarian cancers should be resected, if feasible, even in the presence of metastases. Cytoreduction also has yielded favorable results in pediatric solid tumors.
Surgery to relieve symptoms and preserve quality of life may be a reasonable alternative when cure is unlikely or when an attempt at cure produces adverse effects that are unacceptable to the patient. Tumor resection may be indicated to control pain, to reduce the risk of hemorrhage, or to relieve obstruction of a vital organ (eg, intestine, urinary tract). Nutritional supplementation with a feeding gastrostomy or jejunostomy tube may be necessary if proximal obstruction exists.