Curing cancer requires eliminating all cells capable of causing cancer recurrence in a person's lifetime. The major modalities of therapy are
Systemic cancer modalities include
Hormonal therapy (for selected cancers, eg, prostate, breast, endometrium)
Immune therapy Immunotherapy of Cancer A number of immunologic interventions, both passive and active, can be directed against tumor cells. (See also Immunotherapeutics.) In passive cellular immunotherapy, specific effector cells... read more including monoclonal antibodies, interferons, biologic response modifiers, tumor vaccines, and cell therapies (for many different types of cancer)
Differentiating drugs such as retinoids (for acute promyelocytic leukemia Acute Myeloid Leukemia (AML) In acute myeloid leukemia (AML), malignant transformation and uncontrolled proliferation of an abnormally differentiated, long-lived myeloid progenitor cell results in high circulating numbers... read more
) and isocitrate dehydrogenase-2 (IDH2) inhibitors (for acute myeloid leukemia Acute Myeloid Leukemia (AML) In acute myeloid leukemia (AML), malignant transformation and uncontrolled proliferation of an abnormally differentiated, long-lived myeloid progenitor cell results in high circulating numbers... read more )Targeted drugs that exploit the growing knowledge of genomics and cellular and molecular biology (eg, imatinib for chronic myeloid leukemia Chronic Myeloid Leukemia (CML) Chronic myeloid leukemia (CML) occurs when a pluripotent stem cell undergoes malignant transformation and clonal myeloproliferation, leading to a striking overproduction of mature and immature... read more )
Often, modalities are combined to create a treatment program that is appropriate for the patient, based on patient and tumor characteristics as well as patient preferences. These modalities can be combined with the primary treatment at the same time or used before or after. The primary purpose of adjuvant therapy, which is given after, and neoadjuvant therapy, which is given beforehand, is to prevent cancer recurrence and increase survival.
Overall treatment should be coordinated among a radiation oncologist, surgeon, and medical oncologist, where appropriate. Choice of modalities constantly evolves, and numerous controlled research trials continue. When available and appropriate, clinical trial participation should be considered and discussed with patients.
Treatment decisions should weigh the likelihood of adverse effects against the likelihood of benefit; these decisions require frank communication and possibly the involvement of a multidisciplinary cancer team. Patient preferences for how to live out the end of life (see Advance Directives Advance Directives Advance directives are legal documents that extend a person's control over health care decisions in the event that the person becomes incapacitated. They are called advance directives because... read more ) should be established early in the course of cancer treatment despite the difficulties of discussing death at such a sensitive time.
Response to cancer treatment
Various terms are used to describe the response to treatment (see table Defining Response to Cancer Treatment Defining Response to Cancer Treatment 
). Disease-free or progression-free survival often serves as an indicator of cure and varies with cancer type. For example, lung, colon, bladder, large cell lymphomas, and testicular cancers are usually cured after 5 years of disease-free survival. However, breast and prostate cancers may recur long after 5 years, an event indicating tumor dormancy (now a major area of research); a 10-year disease-free interval is more indicative of cure in these cancers.
Survival rates with the different modalities, alone and in combination, are listed for selected cancers (see table 5-Year Survival in Various Types of Cancer 5-Year Survival in Various Types of Cancer ).
