What is meant by cycle in the medical field?

From the Guidelines

In the medical field, a cycle refers to a recurring pattern or sequence of events that occurs at regular intervals, such as a scheduled period of medication administration followed by a rest period, commonly seen in chemotherapy treatments where drugs are given for several days or weeks, followed by a recovery period before the next cycle begins, as described in the context of chemotherapy cycles lasting 21-28 days 1.

Definition of Cycle

The term "cycle" has several specific applications depending on the context.

• In reproductive medicine, it typically describes the menstrual cycle, which is the monthly series of hormonal changes in women that includes ovulation and menstruation, usually lasting about 28 days.
• In pharmacology, a cycle refers to a scheduled period of medication administration followed by a rest period, commonly seen in chemotherapy treatments where drugs are given for several days or weeks, followed by a recovery period before the next cycle begins.
• For example, a typical chemotherapy cycle might involve receiving medication for 1-5 days followed by 2-3 weeks of recovery, as seen in the treatment of invasive breast cancer with TAC chemotherapy, which is cycled every 21 days for 6 cycles 1.

Applications of Cycles

The term can also describe biological rhythms like sleep cycles or circadian rhythms that regulate bodily functions.

• In physical therapy, treatment cycles involve periods of exercise followed by rest to promote healing and strength building.
• These cyclical approaches are designed to maximize therapeutic benefits while minimizing side effects, allowing the body time to recover between treatment phases and working with the body's natural rhythms rather than against them.

Chemotherapy Cycles

In the context of chemotherapy, cycles are used to describe the scheduled periods of treatment, such as the 4-6 cycles of platinum-doublet chemotherapy and bevacizumab, which should be continued until evidence of disease progression or unacceptable toxicity 1.

• The duration of a chemotherapy cycle can vary, but it is typically 21-28 days, as seen in the treatment of non-small cell lung cancer with continuation maintenance therapy 1.
• The use of cycles in chemotherapy allows for the optimization of treatment outcomes, while minimizing the risk of adverse effects, as described in the treatment of myeloma with new agents, where cycles of treatment are used to achieve a sustained response 1.

From the Research

Definition of Cycle in the Medical Field

The term "cycle" in the medical field can refer to different concepts depending on the context.

• In the context of antibiotic resistance, a cycle refers to the scheduled rotation of one class of antibiotics with one or more different classes exhibiting comparable spectra of activity, with the intention of reducing antibiotic resistance rates 2, 3.
• In cancer treatment, a cycle can refer to a course of chemotherapy treatment, where a patient receives a specific regimen of drugs for a set period of time, followed by a rest period before the next cycle begins 4.
• Cyclotherapy is a therapeutic approach that involves alternating between different treatments, such as chemotherapy and a p53 activator, to improve cancer treatment outcomes 5.
• In the context of women's health, a cycle can refer to the menstrual cycle, which is the monthly series of physiological changes that occur in a woman's body in preparation for a potential pregnancy 6.

Key Characteristics of a Cycle

• A cycle typically involves a repetitive pattern of events or treatments, with each cycle building on the previous one.
• The duration of a cycle can vary depending on the context, ranging from a few days to several weeks or months.
• Cycles can be used to achieve a specific therapeutic goal, such as reducing antibiotic resistance or improving cancer treatment outcomes.

Examples of Cycles in Medicine

• Antibiotic cycling: rotating between different classes of antibiotics to reduce resistance rates 2, 3.
• Chemotherapy cycles: administering a specific regimen of drugs for a set period of time, followed by a rest period before the next cycle begins 4.
• Menstrual cycle: the monthly series of physiological changes that occur in a woman's body in preparation for a potential pregnancy 6.