Overview of Cancer Therapy

ByRobert Peter Gale, MD, PhD, DSC(hc), Imperial College London
Reviewed/Revised Aug 2022
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    Curing cancer requires eliminating all cells capable of causing cancer recurrence in a person's lifetime. The major modalities of therapy are

    Surgery is the oldest effective cancer therapy. It can be used alone or in combination with other modalities. The size, type, and location of the cancer may determine operability and outcome. The presence of metastases typically precludes surgery.

    Radiation therapy can cure many cancers, particularly those that are localized or that can be completely encompassed within a radiation field. Radiation therapy plus surgery (for head and neck, laryngeal, or uterine cancer) or combined with chemotherapy and surgery (for sarcomas or breast, esophageal, lung, or rectal cancers) improves cure rates and allows for more limited surgery.

    Systemic cancer modalities include

    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) 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). 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 considered 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).

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