Hpv: Environmental Co-Factors And Prevention In The United States

HPV: Environmental co-factors and prevention in the United States

Introduction

Current uses of medical technologies to prevent Cervical Cancer (CC) have proven inadequate in the further reduction of morbidity. Current medical methods are effective enough to almost completely prevent mortality from CC, but due to the inability of the US Health Care System to implement preventative measures in a timely and thorough manner, an estimated 10,400 woman will be diagnosed with CC and more than 4,000 woman will die from it in 2005. Over 6 billion dollars are spent each year on the evaluation and management of CC and Human Papilloma Virus (HPV) its primary etiological agent. This case study will analyze and describe the role of HPV and other environmental co-factors, specifically Pap testing, smoking and nutrition, in the United States which increase the risk of it’s progression into CC. Current preventative measures will be explained and an evaluation of the HPV Vaccinations effectiveness and financial viability will be analyzed as an appropriate next step to the prevention of Cervical Cancer in the United States.

Cervical cancer is the third leading cause of death from malignancy in women worldwide. CC is multi-causal, and behavioral factors such as sexual practices, smoking, health screening practices and dietary habits all are important determinants of cervical cancer risk. Prevention, thus far, has been limited to Pap testing for abnormal cervical cells caused primarily by HPV, a sexually transmitted disease, which is present in 95% of CC cases. Pap tests have been implemented as a preventative service in most health facilities and Managed Care programs. If changes in cervical cells and HPV infection are identified and dealt with appropriately, CC would become a rare disease. Unfortunately, a significant percentage of the population does not have access to these services due to lack of adequate healthcare coverage, resources and access.

A vaccine against HPV is currently in development, and may be released as soon as 2006. This paper will analyze the health implications of distributing the vaccine on a nation wide scale, the necessity of doing so, the financial feasability as well as who in the US population should be vaccinated. Additionally, guidelines for a nation wide, federally funded cessation program will be discussed as well as interventions for mal-nutrition that makes malignancy for more likely in under-served populations.

Background

HPV

The exact process by which co-factors and HPV lead to cervical cancer is uncertain. Persistent infection with certain types of HPV is the leading cause of CC, but CC is an uncommon consequence of HPV infection. Other co-factors must be present in order for HPV to progress into CC. The CDC estimates that up to 80% of people in the US are currently or have been infected with HPV in the past. About 15% (20 million people) currently have one or more detectable genital HPV infections, with 6.2 million new genital HPV infections occurring each year.

The viral etiology of HPV was suspected in 1920 and cervical tissue changes were observed for the first time through the colposcope in 1930. Around 1950 detection of the virus became a reality and its association with CC was published by Dr. Papanicolaou. In the 1970's wide spread Pap smear testing and treatment of precancerous cells became regular practice. According to the American Cancer Society, the number of deaths from cervical cancer has dropped 74% between 1955 and 1992, mainly due to the increased use of the Pap test (Table 1).

Factors contributing to the incidence of CC and HPV are lifestyle habits (smoking and diet), sexual behaviors, and certain demographics (minority and immigrant populations) which increase the risk of HPV infection and the likelihood of persistent infection and CC. Specific environmental risk factors include, but are not limited to, exposure to DES (synthetic estrogen), depressed immune system (examples include HIV or chemotherapy), sexual habits (multiple sexual partners, intercourse at a young age, history of STD’s), use of oral contraceptives or IUD, cigarette smoking (with a two-to four-fold increased incidence of CC in cigarette smokers), some vitamin/mineral deficiencies (low levels of folic acid serum levels lead to a 7.5 times greater risk of developing cervical dysplasia in a study by Kwasniewska et al), age, race (associated SES), immigrant status, healthcare coverage and the availability Pap and HPV screening.

The Pap Test

The absence of Pap testing is a main predictor of CC incidence. Up to 60% of CC cases occur among women that have never been screened. Disparities exist due to the lack of healthcare and respective lack of screening in certain populations. Eighty-three percent of women report having had a Pap test in the last 3 years. Data from the 2000 national health interview survey (table 2) show that the majority of health insured women (85.8%) had been screened with considerable lower screening rates in women without health insurance (only 62%). Due to the high percentage of the US population without health insurance or access to preventative Pap testing, namely females of low socio-economic standing, recent immigrants, and women of African, Hispanic or Asian origin, the morbidity and mortality in these populations remains disproportionately high. As seen in Table 3, the incidence of CC among African Americans is 1.5 times higher than whites, and Hispanics have a rate of disease 1.5 times that of non-Hispanic (National Program for Cancer Registries and NCI’s SEER Cancer Registries).

Environmental factors found to be most relevant in the progression of cervical abnormalities into CC are prevalence of HPV (with 95% of CC cases being directly related to HPV), lack of preventative screening (in 2005 50% of women with CC had not had a pap smear, and another 30% had them infrequently), and lack of follow-up after abnormal Pap tests.

HPV is especially dangerous because it is sub-clinical, usually undetectable with no signs or symptoms of infection, and with only 1% of infected females exhibiting warts. An estimated 76% of the population have never heard of HPV combined with alarming rates of women not participating in screening it becomes apparent that women unknowingly put themselves at high risk of a deadly and preventable disease.

Reducing the incidence of HPV would have the largest impact on morbidity and mortality of CC in the United States. The use of a vaccine to prevent the most common cancer causing strains of HPV is showing promise in being effective and cost efficient, with greater ease of distribution to the general