However, there’s no shortage of conflicting reports about the efficacy of mammograms to reduce the incidence of invasive breast cancer in women. Late in 2009, the U.S. Preventative Services Task Force (USPSTF) published controversial recommendations for breast cancer screening in the Annals of Internal Medicine. The recommendations included biennial mammograms for women aged 50-74 years, but not for women aged 40-49, who should instead discuss a variety of risk factors with their clinician before deciding on a mammogram. The USPSTF recommendations were based on numerous studies which reported that mammographic screening in this age group did not reduce mortality from breast cancer.

So, why the controversy about the screening efficacy of mammograms in women in the 40-49 age group? Two-words: breast density. Breast tissue is composed of connective tissue (dense), and fatty tissue (non-dense). Women with dense breasts have a higher ratio of connective tissue to fatty tissue. Mammograms can miss tumors, particularly in younger women or women with dense breasts, because on a mammogram, fatty tissue appears as a dark area, while connective tissue appears white. Breast tumors are also dense, and thus appear white on a mammogram. Tumor detection in the presence of dense tissue is a difficult one, and usually requires follow-up ultrasound to rule out a tumor.

In the past many studies were conducted using results from traditional mammograms (where the image is on x-ray film), which rendered the evaluation of breast tissue in dense breasts difficult and subject to high false-positive and false-negative rates. The newer and more advanced digital mammography uses less radiation and produces computerized images which can be enhanced for better analysis. Abnormal areas in breast tissue can be magnified and compared to previous digital mammograms. Recent studies find that digital mammography leads to increased cancer detection rates, especially when performed in conjunction with an ultrasound in women with dense breasts, regardless of age. As traditional mammograms are phased out, future mammographic studies will  include more cohorts of women evaluated with digital mammography. This may decrease the number of conflicting studies and direct breast screening guidelines in the right direction.

References:

http://www.cdc.gov/cancer/breast/statistics/

http://www.cancer.org/docroot/CRI/content/CRI_2_2_1X_How_many_people_get_breast_cancer_5.asp?sitearea=

http://seer.cancer.gov/statfacts/html/breast.html

http://www.imaginis.com/breast-health/ultrasound-images-of-breast-conditions-1

http://www.texmed.org/Template.aspx?id=8323

http://www.sciencedaily.com/releases/2009/08/090803110956.htm

In the fall of 2009, the World Health Organization published a 10 year study which examined the cell phone habits of more than 120,000 people in 13 countries. The study reported a significantly higher risk of developing brain tumors in individuals with 10 years or more of cell phone usage. Similar findings in other studies have added to the growing concern over long-term exposure to cell phone usage.

In 2007, Dr. Lennart Hardell, from Örebro University in Sweden, reported an increased risk of malignant glioma in cell phone users, and that a daily one hour exposure significantly increased the risk for developing a brain tumor after 10 years. Recently, Dr. Ronald B. Herberman, director emeritus of the University of Pittsburgh Cancer Institute delivered a memo to over 3000 staff and faculty members, essentially warning them of the health risks of cell phone use, and specifically stated that children should limit cell phone use to emergencies only.

So why aren’t cell phones packaged with health warning labels in the same way that alcohol and cigarettes are labeled? The jury is out on whether the cell-phone and brain tumor link is convincing enough to warrant major concerns. In fact, the number of studies that render the link inconclusive far outnumber the studies which do (arguably, though, we can exclude studies funded by telecommunication companies). Discrepancy in these findings is due in large part to the inherent bias found in case-control studies, which are designed to examine specific factors that may contribute to a disease process or illness by comparing similarly matched individuals, those with and without the medical condition in question. In this case, the studies essentially rely on the participant’s recall of cell phone usage patterns as far back as 10 years.

Further substantiation of the clinical health risks posed by cell phone usage will need to include cohort studies, where healthy individuals, with and without exposure to cell phones are followed over a period of time and examined for occurrence of brain tumors. This of course means that it will take years to adequately determine the health risk. In the meantime, it may serve us well to heed recommendations to limit exposure to the electromagnetic radiation emitted by cell phones.

References:

http://artpredator.files.wordpress.com/2009/03/cell-phones-on-planes.jpg

http://www.webmd.com/cancer/brain-cancer/news/20091203/cell-phones-and-brain-tumors-no-connection

http://www.ncbi.nlm.nih.gov/pubmed/17409179

http://www.post-gazette.com/downloads/20080722upci_cellphone_memo.pdf

http://www.cancer.gov/cancertopics/factsheet/Risk/cellphones

http://www.medicalnewstoday.com/articles/161960.php

http://www.reuters.com/article/idUSTRE59C5GA20091013

http://www.newser.com/story/69023/report-revives-fears-of-cell-phone-tumor-link.html

http://www.physorg.com/news175853675.html

HPV is not only limited to cervical cancer, but has also been implicated in squamous cell carcinomas of the head and neck regions (HNSCC) and includes oral, tonsillar, and oropharyngeal tumors—which have usually been associated with long term alcohol and tobacco usage. The incidence of HNSCC has risen steadily over the last 20-30 years in younger patients, and about 20% of these carcinomas are HPV positive with HPV type 16 emerging as the most prevalent subtype present in these tumors.

However, unlike the clinical regimen for cervical carcinoma which includes HPV typing of the tumor tissue, there are currently no standard molecular tests utilized as part of the clinical treatment protocols for head and neck cancers. Prognostic factors for survival include molecular diagnostic testing for cytokines, proteomic profiling, and testing for the presence of HPV.

Interestingly, the detection of HPV in  head and neck cancer is a favorable prognostic marker; HPV positive tumors are biologically distinct from HPV negative tumors which are typically associated with long-term tobacco and alcohol use. This favorable prognostic factor in younger patients with HPV positive tumors may be attributed to the lack of p53 mutations found in younger patients, and thus improves chemotherapeutic treatment response in these patients, in part because the efficacy of chemotherapy depends upon a functional p53 gene that mediates apoptosis (programmed cell death) in response to radiation and chemotherapy.

Note: the thumbnail above shows visibly HPV-infected cells