Tiredness happens to everyone -- it's a feeling you expect after certain activities or at the end of the day. Usually, you know why you are tired and a good night's sleep solves the problem.
Fatigue, which is often confused with tiredness, is a daily lack of energy, a whole-body tiredness not relieved by sleep. It can last for a short time (a month or less) or stay around longer (1-6 months or longer). Fatigue can prevent you from functioning normally and gets in the way of things you enjoy or need to do.
Incidence and mortality
Colorectal cancer (CRC) is the third most common malignant neoplasm worldwide  and the second leading cause of cancer deaths (irrespective of gender) in the United States. It is estimated that there will be 142,820 new cases diagnosed in the United States in 2013 and 50,830 deaths due to this disease. Between 2005 and 2009, CRC incidence rates in the United States declined by 4.1% per year among adults aged 50 years and older. For the past...
Cancer-related fatigue is one of the most common side effects of colorectal cancer and its treatment. It is not predictable by tumor type, treatment, or stage of illness. Usually, it comes on suddenly, does not result from activity or exertion, and is not relieved by rest or sleep. It is often described as "paralyzing" and may continue even after treatment is complete.
In addition to fatigue, weight loss and decreased appetite are common in people being treated for colorectal cancer.
What Causes Fatigue With Colorectal Cancer?
The exact reason for colorectal cancer-related fatigue is unknown. It may be related to the disease itself or its treatments.
The following colorectal cancer treatments are commonly associated with fatigue:
Chemotherapy. Any chemotherapy drug or regimen may cause fatigue. Fatigue usually develops after several weeks of chemotherapy. In some, fatigue lasts a few days, while others say the problem persists throughout the course of treatment and even after the treatment is complete.
Radiation therapy. Radiation, commonly used in the treatment of rectal cancer, can cause fatigue that increases over time. This can occur regardless of the treatment site. Fatigue usually lasts from 3 to 4 weeks after treatment stops, but can continue for up to 2 to 3 months.
Combination therapy. More than one cancer treatment at the same time or one after the other increases the chances of developing fatigue.