Textbook Problem

Cervical Cancer Incidence in HPV-Positive Women

A persistent infection with one of about 10 strains of genital HPV (human papillomavirus) is the main risk factor for cervical cancer. The virus spreads easily by sexual contact, but vaccines that prevent infection have been available since 2006. The vaccines consist of viral proteins that self-assemble into virus-like particles. The particles are not infectious (they contain no viral DNA), but their component proteins trigger an immune response that can prevent HPV infection and the cervical cancer it causes.

In 2003, Michelle Khan and her coworkers published results of their 10-year study correlating HPV status with cervical cancer incidence in women (FIGURE 37.23). All 20,514 participants were free of cervical cancer when the study began.

FIGURE 37.23 Cumulative incidence rate of cervical cancer correlated with HPV status.

● HPV16 positive

○ HPV16 negative and HPV18 positive

▾ All other cancer-causing HPV types combined

▿ No cancer-causing HPV types was detected.

At 110 months into the study, what percentage of women who were not infected with any type of cancer-causing HPV had cervical cancer? What percentage of women who were infected with HPV16 also had cancer?

Summary Introduction

To determine: The percentage of women who were not infected with any type of cancer-causing HPV, but had cervical cancer.

Introduction: The researchers in the given study attempted to make a connection between the presence of various HPV viral infections and the incidence of cervical cancer. Cervical cancer arises from the cervix, which occurs due to the abnormal growth of the cells that have the capability to invade or spread to other body parts.

Explanation of Solution

The given study showed that approximately one percent of the women who had no cancer-causing HPV infections developed cervical cancer. The study shows that the infection with the genital HPV is the main risk factor for cervical cancer. The women who have not been infected with cancer-causing HPV have a small chance of having cervical cancer. HPV is not the only cause of cervical cancer. It can also be caused due to a weakened immune system, long-term mental stress, giving birth at a very young age, several pregnancies, birth control pills, and so on.

Conclusion

In the given study, 1% of women who were not infected with any type of cancer-causing HPV had cervical cancer.

Summary Introduction

To determine: The percentage of the women who were infected with HPV16 had cancer.

Introduction: The researchers in this study attempted to make a connection between the presence of various HPV viral infections and the incidence of cervical cancer. Cervical cancer arises from the cervix, which occurs due to the abnormal growth of the cells that have the capability to invade or spread to other body parts.

Explanation of Solution

At 110 months, 17 percent of the women who tested positive for HPV16 had cervical cancer. Human papillomavirus that spreads easily by sexual contact is a risk factor for cervical cancer. The study indicates that those women who are HPV-positive have a high risk of getting cervical cancer.

The HPV positive women, who have the habit of smoking and have HIV influence, are more likely to develop cervical cancer. If the virus infection is left untreated, the pre-cancerous cells will develop to cancer cells, but it will take 10 to 15 years.

Conclusion

In the given study, 17 percent of the women who were infected with HPV16 had cancer.