Surgery remains one of the most important treatment components for solid tumours. Surgery alone can be curative in patients with localized disease, but because many patients (~70%) have evidence of micro-metastases at diagnosis, combining surgery with other treatment modalities is usually necessary to achieve higher response rates. Continuing advances in cancer surgery have improved patient outcomes and permitted more complex operative procedures. These include:
a)improved technical ability to perform complex, radical surgeries, as well as greater understanding about the appropriate applications of radical surgery;
b)improved surgical intensive care units resulting in reduced mortality;
c)new techniques and improved prosthetics to decrease disability and disfigurement caused by radical surgery; and
the use of antibiotic therapy to reduce morbidity secondary to infection.
Principles of Cancer Surgery – A number of principles are used by the surgical oncologist in the management of malignant disease:
- Slow growing cancers are the most amenable to surgical treatment.
- The initial surgery for malignancy is more successful than secondary operations for recurrence. This is the guiding principle behind many radical surgeries.
- A margin of normal tissue must be excised to assure an adequate resection.
- Clinical staging to determine the extent of disease should be completed before definitive surgery, if possible.
- Removal of the tumour with adjacent lymph nodes is preferable to simple tumour excision (if no serious disfigurement results).
- The patient must find the potential impairment resulting from the surgery acceptable.
- Immediate reconstruction and rehabilitation are essential components of cancer surgery and postoperative care.
Staging surgeries are performed to determine the extent of disease. The information obtained helps the oncologist select the surgical procedure and additional therapy most appropriate for that stage of the disease. Exploratory surgery is commonly used to stage disease in patients with Hodgkin’s disease or ovarian cancers. During staging operations, abdominal organs are exposed and palpated for gross evidence of disease. Multiple biopsies are taken from the peritoneal cavity.
In cases of metastatic disease, where surgery alone would not be curative and other treatment modalities will be used, staging surgery permits the determination of the exact extent of the disease. Preparations may also be made for further treatment or observations; for example, implanting radio-opague clips for tumour delineation during staging surgery. This spares the patient morbidity associated with more radical or unnecessary procedures.
Definitive Surgery – The goal of definitive surgery is to excise as much of the tumour as possible. During a curative surgery, the entire tumour, associated lymphatics, margin of surrounding tissue are removed as one specimen. This decreases the possibility of seeding normal tissue with cancer cells. Surgery can be curative for early-stage cervical, breast, GI tract, skin, and vulvar cancers, among others. Ultimately, the selection of the appropriate surgical procedure considers the size of the tumour, its anatomic extent, and the patient’s physiological status.
When patients have large or unresectable tumours, cytoreductive or debulking surgery may be performed. Reducing the tumour mass in certain cancers can increase the effectiveness of subsequent radiation or chemotherapy, both of which are most effective against small numbers of cancer cells. For example, cytoreductive surgery has proven beneficial for ovarian cancer. This approach to treatment is generally beneficial only in cancers where other treatment modalities are effective in controlling residual disease.
Surgery may also be useful to manage metastatic disease in selected patients. When metastasis is confined to solitary lesion or a few nodules — as it may be to the lung, brain or liver — surgical removal of these specific areas is frequently of value.
Two other surgical techniques are used in select clinical situations. Cryosurgery, where malignant cells are destroyed by the application of liquid nitrogen, may be used for cancers of the oral cavity, skin and prostate. Laser surgery is another procedure used for the local excision of laryngeal cancer and in the treatment of cervical dysplasias. It is also used in surgeries where excessive bleeding may be a problem. Laser surgery is more frequently used now than cryosurgery.
Preventive Surgery plays a limited role in the prevention of malignancy. Surgical intervention may be indicated for a patient with a strong family history of cancer, an underlying condition, or congenital predisposition that increases the risk of developing cancer. For example, colectomy may be recommended for a patient with ulcerative colitis or a history of familial polyposis who has an increased risk of developing colon cancer. Occasionally, prophylactic subcutaneous mastectomies are considered for women with a very strong family history of breast cancer and previous fibrocystic disease. Before any prophylactic surgery, patients should be informed of the statistical risks of developing malignancy as well as the risks and benefits of prophylactic surgery.
Reconstruction. Reconstructive surgery is becoming more common to repair anatomical defects and improve function and cosmetic appearance following radical surgery. Reconstructive techniques that minimize deformity and improve the quality of life include: breast reconstruction after mastectomy, restoration of acceptable appearance after head and neck surgery and the use of artificial joints after surgery for sarcoma.
Palliative Surgery can be effective in relieving symptoms in more advanced stages of cancer. For example, when pain cannot be controlled through pharmacologic or behavioral interventions, the nerve pathways can be surgically interrupted. Surgery is also indicated in patients with obstructions related to local expansion of the tumour. Common sites of obstruction are the bowel in colorectal cancer, biliary obstruction in hepatobiliary tumours, and urinary tract obstruction from cancers of the cervix, ovary, bladder, prostate and rectum.
Endoscopic introduction of stents in bile duct or ureter is frequently used to prevent or relieve obstruction.
