What are the risk factors for colon cancer?
How a Treatment Strategy Is Chosen
Among the available options for the treatment of a cancer, the oncologist will choose one to start with (“first-line therapy”), another as a second line therapy when needed, and then others as dictated by the behavior of the cancer. These choices will be guided by several factors:
FACTORS ONCOLOGISTS CONSIDER IN CHOOSING A TREATMENT
The data. Oncologists love data, and the treatment of cancer is guided more by the results of clinical trials than any other field of medicine (this is a good thing, producing orderly and methodical progress). Every year at the main meeting of oncologists run by the American Society of Clinical Oncology, nearly ten thousand new studies are presented from around the world pertaining to the biology, treatment, and prevention of cancer. The American Society of Hematology runs the corresponding meeting for blood disorders. Besides these and many other meetings, the latest cancer research is published in many medical journals. In addition, research leaders in each cancer field meet frequently to discuss the latest findings with other oncologists and to draft guidelines on treating various cancers. Oncologists use a range of data and information when deciding on the best treatment to give a patient. These include: definitive results from large, randomized clinical trials, in which a new treatment is compared to the current standard of care; less certain but “promising” results from smaller studies; the recommendation of a colleague who may have special expertise in treating a particular cancer; and their own experience.
Important biologic properties of the cancer. In addition to the grade and other features described in a standard pathology report (such as the presence of the estrogen receptor and Her2 in breast cancers), additional studies may be performed that guide treatment decisions. These may include specific molecules or genetic alterations that the cancer possesses. For example, if a lung cancer contains a mutation in the DNA code of the EGFR gene, then the pill erlotinib (Tarceva) may be highly effective and used instead of chemotherapy. Or if a colon or rectal cancer contains a mutation in the DNA code of a gene called KRAS, then the medicines cetuximab (Erbitux) and panitumomab (Vectibix) will not be used because they will not add benefit to chemotherapy.
The extent and aggressiveness of the cancer. A rapidly growing, life threatening cancer usually requires more intensive therapy than may be required to control a less threatening cancer.
The age and medical condition of the patient. These factors help guide the oncologist to choose treatments that the patient can tolerate physically without excessive toxicity.
The wishes of the patient. This is paramount in any treatment decision. Given a choice of treatments, oncologists will recommend those most in keeping with the patient’s needs: for example, chemotherapy that spares hair is given when possible to those for whom hair loss is anathema. It is vital that the patient and oncologist have open communication and a good rapport so that the patient can accurately convey how much he or she wants to fight and what type of side effects he or she is willing to tolerate. Good communication ensures that patients feel their doctor understands them and what they are about as people and cancer patients.
The availability of a clinical trial. Cancers that are not routinely curable demand that we try to do better. It is only by conducting research studies that better cancer treatments will be found. The National Institutes of Health and National Cancer Institute are expanding their efforts to make clinical trials available to all cancer patients (www.clinicaltrials.gov). All oncologists need to provide their patients with access to new therapies; cancer patients, for their part, need to consider participating in these studies both for their own benefit and for the greater good.
Once a treatment is chosen, the duration of therapy is decided upon so that the patient knows what to expect. Treatment may be for a specified time (for example, six cycles of chemotherapy) or open-ended: a treatment is continued as long as it is well tolerated and deemed to be working.
Evaluation of the cancer by CT scans or other tests may be performed at regular intervals during treatment (for example, after every two to three cycles) to make certain the treatment is working. On completion of therapy, a break is given in order to allow the patient’s body (and psyche) to recover. Thereafter, regular follow-up examinations and imaging studies may be employed to track the condition of the patient and status of the disease. Treatments are resumed if the cancer regrows; the six factors are again employed to guide the choice of second-line therapy and beyond.
A metastatic cancer may be contained over time through the sequential use of one therapy after another.
The treatment of many forms of metastatic cancer (such as those of the breast, colon, prostate, and lung) has become continuous: treatments are administered at regular intervals (often weekly or every other week) until they are deemed ineffective or the patient needs a break. If treatment is working after several months on therapy but side effects are accumulating or blood counts remain low, then breaks in treatment may be given. If several drugs are being used successfully, the harshest one may be halted for a period of time; this approach is being tested on numerous cancers.
Should the cancer enter a complete remission, treatment may be halted and the patient closely monitored, depending on the comfort levels of both patient and physician. Some patients feel uneasy without treatment, whereas others can’t wait to put therapy out of their minds for awhile. Typically, a patient and his or her oncologist will engage in a give and take regarding the merits and toxicities of continuing treatment beyond a certain point. The oncologist should initiate and guide these discussions. Although I have said that oncologists love data, there is little data regarding stopping points for chronic cancer treatments that are working. Common practice patterns have emerged, with a tendency to continue treatment, as outlined above.
