Chapter 081. Principles of Cancer Treatment (Part 3)

Staging As noted in Chap. 77, an important component of patient management is defining the extent of disease. Radiographic and other imaging tests can be helpful in defining the clinical stage; however, pathologic staging requires defining the extent of involvement by documenting the histologic presence of tumor in tissue biopsies obtained through a surgical procedure. Axillary lymph node sampling in breast cancer and lymph node sampling at laparotomy for lymphomas and testicular, colon, and other intraabdominal cancers may provide crucialinformation for treatment planning and may determine the extent and nature of primary cancer treatment.TreatmentSurgery is the most effective means...
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Chapter 081. Principles of Cancer Treatment (Part 3) Chapter 081. Principles of Cancer Treatment (Part 3) Staging As noted in Chap. 77, an important component of patient management isdefining the extent of disease. Radiographic and other imaging tests can be helpfulin defining the clinical stage; however, pathologic staging requires defining theextent of involvement by documenting the histologic presence of tumor in tissuebiopsies obtained through a surgical procedure. Axillary lymph node sampling inbreast cancer and lymph node sampling at laparotomy for lymphomas andtesticular, colon, and other intraabdominal cancers may provide crucialinformation for treatment planning and may determine the extent and nature ofprimary cancer treatment. Treatment Surgery is the most effective means of treating cancer. Today about 40% ofcancer patients are cured by surgery. Unfortunately, a large fraction of patientswith solid tumors (perhaps 60%) have metastatic disease that is not accessible forremoval. However, even when the disease is not curable by surgery alone, theremoval of tumor can obtain important benefits, including local control of tumor,preservation of organ function, debulking that permits subsequent therapy to workbetter, and staging information on extent of involvement. Cancer surgery aimingfor cure is usually planned to excise the tumor completely with an adequatemargin of normal tissue (the margin varies with the tumor and the anatomy),touching the tumor as little as possible to prevent vascular and lymphatic spread,and minimizing operative risk. Extending the procedure to resect draining lymphnodes obtains prognostic information, but such resections alone generally do notimprove survival. Increasingly, laparoscopic approaches are being used to address primaryabdominal and pelvic tumors. Lymph node spread may be assessed using thesentinel node approach, in which the first draining lymph node a spreading tumorwould encounter is defined by injecting a dye into the tumor site at operation andthen resecting the first node to turn blue. The sentinel node assessment iscontinuing to undergo clinical evaluation but appears to provide reliableinformation without the risks (lymphedema, lymphangiosarcoma) associated withresection of all the regional nodes. Advances in adjuvant chemotherapy andradiation therapy following surgery have permitted a substantial decrease in theextent of primary surgery necessary to obtain the best outcomes. Thus,lumpectomy with radiation therapy is as effective as modified radical mastectomyfor breast cancer, and limb-sparing surgery followed by adjuvant radiation therapyand chemotherapy has replaced radical primary surgical procedures involvingamputation and disarticulation for childhood rhabdomyosarcomas. More limitedsurgery is also being employed to spare organ function, as in larynx and bladdercancer. The magnitude of operations necessary to optimally control and curecancer has also been diminished by technical advances; for example, the circularanastomotic stapler has allowed narrower (neoadjuvant therapy. Because the sequence of treatment is critical to success andis different from the standard surgery-first approach, coordination among thesurgical oncologist, radiation oncologist, and medical oncologist is crucial. Surgery may be curative in a subset of patients with metastatic disease.Patients with lung metastases from osteosarcoma may be cured by resection of thelung lesions. In patients with colon cancer who have fewer than five livermetastases restricted to one lobe and no extrahepatic metastases, hepaticlobectomy may produce long-term disease-free survival in 25% of selectedpatients. Surgery can also be associated with systemic antitumor effects. In thesetting of hormonally responsive tumors, oophorectomy and/or adrenalectomymay control estrogen production, and orchiectomy may reduce androgenproduction; both have effects on metastatic tumor growth. If resection of theprimary lesion takes place in the presence of metastases, acceleration of metastaticgrowth may occur, perhaps based on the removal of a source of angiogenesisinhibitors and mass-related growth regulators in the tumor. In selecting a surgeon or center for primary cancer treatment, considerationmust be given to the volume of cancer surgeries undertaken by the site. Studies ina variety of cancers have shown that increased annual procedure volume appearsto correlate with outcome. In addition, facilities with extensive support systems—e.g., for joint thoracic and abdominal surgical teams with cardiopulmonary bypass,if needed—may allow resection of certain tumors that would otherwise not bepossible.