Sandbox:Cancer screening and primary care

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Vishal Devarkonda, M.B.B.S[2]

Overview

Worldwide, cancer is among the leading causes of morbidity and mortality; cancer contributed to approximately 8.2 million deaths in 2012, or an estimated 13% of overall deaths. WHO expects a 70% increase in the number of new cancer cases over the next two decades. The burden of cancer is substantial and increasing worldwide. The incidence, prevalence, and mortality of specific cancers vary widely across countries as a result of variations in lifestyle risk factors (such as tobacco use, physical inactivity, excess body weight, reproductive patterns), the prevalence of carcinogenic infections (e.g., Hepatitis B, Hepatitis C, HPV), genetics, and the availability of health care resources. In 2012, lung, prostate, colorectal, gastric, and liver carcinomas were the most common cancers among men, while breast, colorectal, lung, cervical, and gastric carcinomas were most common among women. In 2014, the Agency for Healthcare Research and Quality estimated the direct medical costs associated with cancer in United States at $87.7 billion dollars. It is estimated that HBV/HCV and HPV are responsible for up to 20% of cancer deaths in low- and middle-income countries. It is also estimated that more than 30% of these cases are preventable. Measures to prevent some types of cancer include effective screening, vaccination, and lifestyle modifications. This page provides information about the epidemiology and primary care aspects of preventing cancer.

Epidemiology

Worldwide, cancer is among the leading causes of morbidity and mortality; cancer contributed to approximately 8.2 million deaths in 2012, or an estimated 13% of overall deaths. The most common type of cancer (excluding non-melanoma skin cancers) is breast cancer; it is estimated that there were more than 249,000 new cases in the United States in 2016. The next most common cancers are lung cancer and prostate cancer. In the United States, to qualify as a common cancer, the estimated annual incidence for 2016 had to be 40,000 cases or more.

The following table presents official estimates of new cases and deaths in the United States for each common cancer type:

American Cancer Society: Cancer Facts & Figures 2016
Cancer Type	Estimated New Cases	Estimated Deaths
Breast	249,200	40,890
Lung (Including Bronchus)	224,390	158,080
Prostate	180,890	26,120
Colon and Rectal (Combined)	134,490	49,190
Bladder	76,960	16,390
Melanoma	76,380	10,130
Non-Hodgkin Lymphoma	72,580	20,150
Thyroid	64,300	1,980
Kidney (Renal Cell and Renal Pelvis) Cancer	62,700	14,240
Leukemia (All Types)	60,140	24,400
Endometrial	60,050	10,470
Pancreatic	53,070	41,780

Adulthood Cancers

Top 10 Cancers by Incidence and Mortality
by Incidence		by Mortality
Cancer type	Incidence	Cancer type	Mortality
Female Breast	123.7	Lung and Bronchus	43.4
Prostate	101.6	Female Breast	20.7
Lung and Bronchus	59.4	Prostate	19.2
Colon and rectum	38.4	Colon and rectum	14.5
Corpus and Uterus	25.9	Pancreas	10.8
Melanomas of the Skin	20.7	Ovary	7.2
Urinary Bladder	20.0	Leukemias	6.7
Non-Hodgkin Lymphoma	18.5	Liver and Intrahepatic Bile duct	6.5
Kidney and Renal Pelvis	16.0	Non-Hodgkin Lymphoma	5.7
Thyroid	14.6	Corpus and Uterus	4.6

* Rates are per 100,000 persons and are age-adjusted to the 2000 U.S. standard population.

Most Common Cancers in the United States by Gender
Male				Female
Most Common (by Occurrence)	Incidence	Most Common (by Mortality)	Mortality	Most Common (by Occurrence)	Incidence	Most Common (by Mortality)	Mortality
Prostate cancer	101.6	Lung cancer	53.9	Breast cancer	123.7	Lung cancer	35.4
Lung cancer	69.8	Prostate cancer	19.2	Lung cancer	51.5	Breast cancer	20.7
Colorectal cancer	44.2	Colorectal cancer	17.3	Colorectal cancer	33.6	Colorectal cancer	12.1

* Rates are per 100,000 persons and are age-adjusted to the 2000 U.S. standard population.

Childhood Cancers

In 2013, the most commonly diagnosed cancers and leading causes of cancer-related death in children aged 0 to 19 years were leukemia and central nervous system cancers.

Childhood Cancers
	Incidence		Mortality
Cancer type	0-14 years	0-19 years	0-14 years	0-19 years
All cancers combined	16.8	18.0	2.1	2.3
Leukemias	4.8	4.3	0.6	0.6
Brain and Central nervous system cancer	3.6	3.2	0.7	0.7

* Rates are per 100,000 persons and are age-adjusted to the 2000 U.S. standard population.

Please click here to know more about the cancer epidemiology

Prevention

Effective measures for cancer prevention include:

• Screening
• Vaccination
• Lifestyle modifications

Screening

Breast Cancer

United States Preventive Services Task Force Recommendations for Breast Cancer Screenings
Population	Recommendation	Grade
Women, 40 Years and Older	The USPSTF concludes that the current evidence is insufficient to assess the additional benefits and harms of clinical breast examination (CBE) beyond screening mammography in women 40 years or older.	I
Women, Age 50-74 Years	The USPSTF recommends biennial screening mammography for women 50-74 years.	B
Women, Before the Age of 50 Years	The decision to start regular, biennial screening mammography before the age of 50 years should be an individual one and take patient context into account, including the patient's values regarding specific benefits and harms.	C
Women, 75 Years and Older	The USPSTF concludes that the current evidence is insufficient to assess the benefits and harms of screening mammography in women 75 years and older.	I

Relevance of Breast Cancer Screening

Studies have reported that, for women of all age groups with an average risk, breast cancer screening was associated with a reduction in breast cancer mortality of approximately 20%, although there was an uncertainty in the quantitative estimates of outcomes for different breast cancer screening strategies in the United States.

Please click here to learn more about Breast cancer screening.

Colon Cancer

United States Preventive Services Task Force Recommendations for Colon Cancer Screening
Population	Recommendation	Grade
Adults aged 50 to 75 years	The USPSTF recommends screening for colorectal cancer starting at age 50 years and continuing until age 75 years.	A
Adults aged 76 to 85 years	The decision to screen for colorectal cancer in adults aged 76 to 85 years should be an individual one, taking into account the patient’s overall health and prior screening history. Adults in this age group who have never been screened for colorectal cancer are more likely to benefit from screenings. Screening would be most appropriate among adults who 1) are healthy enough to undergo treatment if colorectal cancer is detected and 2) do not have co-morbid conditions that would significantly limit their life expectancy.	C

Relevance of Colon Cancer Screenings

Studies have reported a 40% to 60% risk reduction for the incidence o colorectal cancer and mortality from colorectal cancer after screening colonoscopy.

Please click here to know more about Colon cancer screening.

Cervical Cancer

United States Preventive Services Task Force Recommendations for Cervical Cancer Screening
Population	Recommendation	Grade
Women aged 21 to 65 (Pap Smear) or 30-65 (in combo with HPV testing)	The USPSTF recommends screening for cervical cancer in women age 21 to 65 years with cytology (Pap smear) every 3 years or, for women age 30 to 65 years who want to lengthen the screening interval, screening with a combination of cytology and human papillomavirus (HPV) testing every 5 years.	A

Relevance of Cervical Cancer Screening

Studies have shown that, in patients undergoing regular cervical cancer screenings, approximately 70%-80% of cervical cancer deaths can be prevented.

Please click here to learn more about Cervical cancer screening.

Lung Cancer

United States Preventive Services Task Force Recommendations for Lung Cancer Screening
Population	Recommendation	Grade
Adults aged 55-80, with a history of smoking	The USPSTF recommends annual screening for lung cancer with low-dose computed tomography (LDCT) in adults aged 55 to 80 years who have a 30 pack-year smoking history and currently smoke or have quit within the past 15 years. Screening should be discontinued once a person has not smoked for 15 years or develops a health problem that substantially limits life expectancy or the ability or willingness to have curative lung surgery.	B

Lung caner screening relevance

The National Lung Screen Trial (NLST), a randomized controlled trial, involving 50,000 participants as demonstrated a 20% relative lung cancer mortality benefit.

Please click here to learn more about lung cancer screening.

Vaccination

Vaccine	Recommendation
HPV vaccine	Age< 15 years	Two doses of HPV vaccine at least six months apart.
	Age> 15 years	Three doses of HPV vaccine over a span of 24 weeks, with a minimum of 4 weeks interval between the first two doses, and 12 weeks between second and third dose. Young women can get HPV vaccine until they are 27 years old and young men can get HPV vaccine until they are 22 years old.
Hepatitis B vaccine	All infants should receive their first dose of hepatitis B vaccine as soon as possible after birth, preferably within 24 hours, followed by two or three additional doses. The vaccination schedule for children and adults involves 3 intramuscular injections, the second and third doses administered 1 and 6 months after the first.

Relevance of the HPV Vaccine in Cancer Prevention

Studies have reported that the development of the 4vHPV vaccine has decreased the prevalence of HPV 6/11/16/18 cervical/vaginal infections, genital warts, low- and high-grade cytological abnormalities, CIN2, CIN3, and AIS among females in their teens and 20s.

Please click here to learn more about the HPV vaccine.

Relevance of the Hepatits B Vaccine in Cancer Prevention

Strong evidence that hepatocellular cancer (HCC) can be prevented is provided by a cluster randomized controlled trial of the immunization of 75,000 newborns with hepatitis B virus (HBV) vaccine. After a median of about 25 years of follow-up, the incidence ratio of primary liver cancer in the vaccination-at-birth group versus the control group (68% of whom received catch-up vaccinations at ages 10–14 years) was 0.16 (95% confidence interval, 0.03–0.77). These findings suggest that if HBV can be prevented, then much HCC can be prevented.

Please click here to learn more about the Hepatitis B vaccine.

Lifestyle modifications

Lifestyle modifications
Avoiding Tobacco	Cigarette Smoking	Lung cancer is the leading cause of cancer death, and almost all cases can be attributed to cigarette smoking. Compared to nonsmokers, current smokers are about 25 times more likely to die from lung cancer. Smoking causes between 80% and 90% of lung cancer deaths. Smoking also causes cancer of the mouth and throat, esophagus, stomach, colon, rectum, liver, pancreas, voicebox (larynx), trachea, bronchus, kidney and renal pelvis, urinary bladder, and cervix, and causes acute myeloid leukemia.
	Secondhand Smoke	Adults who are exposed to secondhand smoke at home or at work experience an increase their risk of developing lung cancer of 20% to 30%. Concentrations of many cancer-causing and toxic chemicals are higher in secondhand smoke than in the smoke inhaled by smokers. Please click here to know more about smoking cessation Please click here to learn more about lung cancer.
Protecting Your Skin		Skin cancer is the most common kind of cancer in the United States. Exposure to ultraviolet (UV) rays from the sun and tanning beds appears to be the most important environmental factor involved with developing skin cancer. To help prevent skin cancer while still having fun outdoors, protect yourself by seeking shade; applying sunscreen; and wearing sun-protective clothing, a hat, and sunglasses. Please click here to learn more about skin cancer.
Limiting Alcohol Intake		Studies around the world have shown that drinking alcohol regularly increases the risk of getting mouth, voice box, and throat cancers. A large number of studies provide strong evidence that drinking alcohol is a risk factor for primary liver cancer, and more than 100 studies have found an increased risk of breast cancer with increasing alcohol intake. The link between alcohol consumption and colorectal (colon) cancer has been reported in more than 50 studies. Please click here to learn more about alcoholism.
Maintaining a Healthy Weight		Research has shown that being overweight or obese substantially raises a person’s risk of getting endometrial (uterine), breast, prostate, and colorectal cancers. Overweight is defined as a body mass index (BMI) of 25 to 29, and obesity is defined as a BMI of 30 or higher. Please click here to learn more about obesity management.
Getting Tested for Hepatitis C		Hepatitis is inflammation of the liver, which is most often caused by a virus. In the United States, the most common type of viral hepatitis is Hepatitis C. Over time, chronic Hepatitis C can lead to serious liver problems including liver damage, cirrhosis, liver failure, or liver cancer. CDC recommends that anyone who was born between 1945 and 1965 get tested for Hepatitis C. Please click here to learn more about Hepatitis C.

Please click here to learn more about Cancer prevention.