Cancer Symptoms Overview

This article provides information about cancer symptoms to the general public is to facilitate early recognition and thus timely treatment.  With a few exceptions, almost all cancers are curable if detected early enough.  The most effective “treatment” for a particular cancer would be to focus on prevention by removing factors that are known to contribute to its development.  An example of prevention would be avoiding cigarette smoking as it is a major risk factor for the development of lung cancer.  Another example of prevention measures would be to avoid heavy sun exposure and the use of appropriate skin protective creams to decrease the risk of developing skin cancer.

Unfortunately, prevention measures are limited as the growth of cancer requires several factors including damage to DNA either directly or indirectly, a tolerant immune system to allow a cancer to grow and usually some contributing factors that “assist” in a cancer’s growth.  The biology of cancer is very complicated and hundreds of different growth pathways have been identified.  Even among the same type of tumor such as colon cancer, there are many different types of mutations that lead to a similar outcome.  This helps explain why there is no “silver bullet” for most cancers and why a treatment might work well in one person for colon cancer and would be completely ineffective for another person with a similar tumor.

Since prevention measures are helpful but cannot eliminate cancer, the emphasis on early detection is justified.  There are thousands of different cancers so public health guidelines emphasize screening and early detection for the most common cancers.  According to the Centers for Disease Control and Prevention (CDC) and the National Program of Cancer Registries (NPCR), the most common cancers in the United States are as follows:

The top 10 most common cancers diagnosed in men in the United States from 2003-2007.

The top 10 most common cancers diagnosed in women in the United States from 2003-2007.

The top 10 most common causes of death from cancer in men in the United States from 2003-2007.

The top 10 most common causes of death from cancer in women in the United States from 2003-2007.

From these data it can concluded that the most common types of cancer and causes of cancer death are lung, colon, prostate and breast cancers.  These explain the emphasis placed on public health information and public policies screening for cancer.

Subsequent articles in this series will discuss the importance, usefulness and limitations of recognizing symptoms that may be a sign of cancer.  We will discuss in detail the 20 most common cancers emphasizing the early symptoms that might arise as signals of their presence.

A symptom can be broadly defined as a disturbance or a subjective feeling of disease.  Not all symptoms are painful but could be an unusual sensation such as numbness of the leg or shaking of the hands.  In a strict medical definition, a symptom is purely subjective (i.e. what the patient experiences) and a sign is an objective finding (i.e. what an observer can see).  For example, a purely subjective symptom would be the sudden feeling of numbness of the face (also called parasthesia).  A parasthesia cannot be observed but described by the person who feels it.  An objective sign would be a rash of the face.  For the purposes of subsequent discussions, the term symptom will be used to describe any abnormality a person might discover, experience or be disturbed by.

Symptoms of cancer could be described in several different categories.  For example, one could classify symptoms of a particular cancer as:

  • Early symptoms that might suggest the diagnosis of cancer
  • Symptoms that might suggest the cancer has advanced in the locale where it started
  • Symptoms that might suggest the cancer has spread to other regions of the body
  • Symptoms experienced as a result of treatment of a cancer
  • Symptoms experienced as a result of an unexpected complication from treatment of cancer

The emphasis of subsequent discussions about cancer symptoms will focus mostly on the early symptoms that might suggest the diagnosis of cancer.  In the sections dealing with specific cancer types in detail, some of the other types of symptoms will also be discussed.

A common reason that someone sees their doctor is to find out if a problem they are having is something serious.  The challenge for the doctor is to decide which symptoms require further investigation with some type of imaging, blood work or invasive testing.  It is dangerous, expensive and not practical to perform testing for every symptom that might represent cancer.  A subsequent article will discuss this dilemma in detail by reviewing statistical concepts (e.g. sensitivity, specificity, positive predictive value, etc.) for common symptoms.

A big challenge for evaluation of common symptoms of cancer is that they tend to be very non-specific.  For example, symptoms such as weakness or recurring fevers usually happen with a cancer called lymphoma.  Everyone gets a “fever” now and then or feels a bit weak from time to time and clearly this should not prompt a consideration of lymphoma each time.  Most cancer symptoms are not very specific and require some supporting information to make sense of it.  In the articles reviewing specific cancer types, we will also describe different types of supporting information that is used to help interpret common symptoms.

Early detection of most cancers can make a huge difference in the outcomes of its treatment and awareness of symptoms can play a role in making this happen.  An example of this might be someone who notices some blood in a bowel movement and decides that this is “just hemorrhoids” and ignores it.  Blood passage from the intestines is never normal and can be a sign of intestinal cancer.  Additional goals are to describe the risk of cancer with different symptoms that people commonly worry about such as bloody nipple discharge or breast pain.  The vast majority of women with breast pain do not have breast cancer and 95% of women with bloody nipple discharge do not have breast cancer.  The primary emphasis of these series of articles will be to stress the importance of certain “red flag” symptoms that cannot be ignored and typically require further investigation to understand the cause and to exclude the presence of a cancer.


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  4. This article was originally published on September 3, 2012 and last revision and update was 9/4/2015.