Health Briefs

February 1, 2004

Although the enthusiasm for breast enlargement implants has waned in recent years, thousands of women still undergo this procedure every year.  As these women age, and their risk of breast cancer begins to rise, concerns about the effects of their breast implants on the sensitivity of screening mammograms have been raised.  Several studies have found little evidence of any significant reduction in the sensitivity and overall accuracy of mammograms in women with breast implants.   However, physicians who are routinely involved in breast care remain concerned that the implants, which are “radio opaque” (and, hence may obscure small adjacent tumors at the time of mammography), may disguise small potentially suspicious breast tumors.

A new study in this week’s issue of the Journal of the American Medical Association looked at 137 women with breast implants and 685 women without breast implants.  All of these women had previously been diagnosed with breast cancer between 1995 and 2002.  These two groups of women were then compared to two additional groups of women, without a history of breast cancer, including 10,533 women with breast implants and 974,915 women without breast implants.  The purpose of this ambitious study was to determine whether or not the presence of breast implants impacted upon the accuracy of mammography, and to assess for possible differences in breast cancer features among women with and without breast implants. 

The study determined that the mammograms of asymptomatic women without breast implants detected existing breast tumors 67% of the time, while in asymptomatic women with breast implants, only 45% of existing breast tumors were mammographically detected.  Among women with symptoms suggestive of a possible breast tumor, the mammograms of the women with and without breast implants detected approximately the same percentage of existing breast tumors.  When the authors looked at the biological characteristics of the breast tumors, and the frequency of lymph node involvement outside of the breast, there were no significant differences between the women who had breast implants and those who did not have implants.

Summarizing their results, the authors concluded that the presence of breast implants significantly decreases the ability of mammograms to detect breast tumors in women without any symptoms of breast disease.  This finding is not entirely surprising, as the asymptomatic group of women are much more likely to have very small tumors in their breasts when compared to women who have a palpable lump in their breast, bloody nipple discharge, worrisome skin changes, or other symptoms of possible breast cancer.  In my own practice, as a cancer surgeon, I can certainly attest to the contortions that mammography technicians go through in an attempt to fully image the breasts of women with large radio opaque breast implants.  The good news in this study, however, is that the presence of breast implants does not appear to result in women being diagnosed with more aggressive or otherwise more advanced breast cancers when compared with women who do not have breast implants.

HEART BYPASS SURGERY VOLUME & PATIENT OUTCOMES

Several recent studies have shown that the volume of certain complex surgical procedures performed within a hospital is inversely proportional to the risk of serious complications and death.  Among these complicated procedures are heart bypasses (coronary artery bypass grafting, or CABG), esophagectomy, pulmonary lobectomy and pancreaticoduodenectomy (“Whipple procedure”).  Recent studies have shown that hospitals and surgeons with the highest volume of these index operations tend to have better patient outcomes than extremely low volume facilities and surgeons.  Some surgeons have objected to the findings of such studies, pointing out that there are many hospitals and surgeons with moderate volumes and excellent outcomes.  A recent study published in the Journal of the American Medical Association, has now called into question the premise that high-volume is directly linked to fewer complications and deaths.

The authors reviewed a total of 267,089 CABG procedures, performed at 439 US hospitals.   The average volume of CABG procedures among these hospitals was 253 per year, with 82% of the hospitals performing fewer than 500 CABGs per year.  Among all of the hospitals, the average risk of postoperative death was 2.7%. 

The authors compared the incidence of postoperative death among patients from hospitals with low and high volumes, and determined that there was only a 2% difference in overall patient mortality.  Moreover, this minimal difference in mortality between the highest and lowest volume hospitals was not observed at all in patients younger than 65 years of age.  Following statistical analysis, the authors calculated that the closure of up to 100 of the lowest-volume hospitals (i.e., those performing 150 or fewer CABGs per year) would avert fewer than 1% of all CABG-related deaths.  Thus, this large-scale study appears to show only a minimal correlation between hospital volume of CABG operations and postoperative mortality.  The authors concluded that other discriminators of poor outcomes following CABG surgery should be identified.  I find this study rather fascinating, as it suggests that the surgeons who have disavowed the results of previous studies showing a worse outcome at low-volume centers may not have been entirely incorrect after all.

WHAT MOSQUITOES FIND ATTRACTIVE IN HUMANS…

Mosquitoes spread many diseases, including one of the world’s most virulent infectious diseases, malaria.  Cases of malaria have been reported in at least 100 countries around the world, and this age-old parasitic disease of the blood afflicts an estimated 120 million new victims every year.  At least 300 million people in the world are thought to carry the mosquito-borne parasite in their blood at any one time, and more than 40% of the world’s population lives in areas where malaria is known to be endemic.  In Africa alone, more than 800,000 children die from this disease every year.  In the US, mosquitoes have been associated with the spread of several viral diseases, including West Nile Virus.  Beyond their propensity for carrying harmful diseases, mosquitoes vex humans around the world with their itching, stinging bites.  Past research has suggested that mosquitoes zero in on their human and animal hosts by following a stream of exhaled carbon dioxide as we breath.  Other studies have suggested that the bloodsucking insects are able to detect our body heat with specialized infrared receptors.  A new study in the journal Nature has found yet another mechanism whereby this surprisingly complicated creature is able to track down its prey.  After doing some fancy molecular studies, the Yale University scientists discovered that the mosquito is able to detect a specific chemical component of… human sweat!  They suggest that further study of this finding may lead to improvements in mosquito baits for trapping the winged pests, and the design of improved mosquito repellants.  Meanwhile, I think that I’ll double-up on my antiperspirant!

ERECTILE DYSFUNCTION:  A GENETIC DISORDER…?

As former politicians and football coaches frequently attest to on television these days, erectile dysfunction (ED) is no longer something to be embarrassed about, as there are now several oral medications that are effective in treating this delicate condition.  As men age, a gradual deterioration in their vascular system results in an increasing difficulty in initiating and maintaining erections.  Smoking, diabetes, and a genetic predisposition to early cardiovascular disease are all associated with an increased risk of ED.  Following the entry of Viagra on the market in 1998, this traditionally unspoken ailment became, almost overnight, the source of endless commentary and jokes.  Now, with several new challengers to Viagra on the FDA’s approval list, including one pill (Cialis) that is purported to last as long as 36 hours (thus earning the appellation “Le Weekender” in the French press…), men everywhere now happily and freely discuss their ED, and how these medications have improved their lives. Now that Viagra faces “stiff” competition (sorry…) for market share, the new challengers to the Viagra throne are even directly targeting women in their advertisements, by suggesting that their products can rekindle the fires of emotional—if not physical—intimacy with their partner once again.

An interesting study in the Archives of Internal Medicine looked at the incidence of ED among identical twins and among fraternal twins.  Identical twins are, of course, genetically identical.  Therefore, diseases that arise in identical twins more commonly than in the general population are more likely to have at least some underlying genetic basis.  Conversely, fraternal twins develop from two separate eggs and, thus, are no more closely related to each other than you are to your separately born brothers or sisters.

A total of 890 identical twin pairs and 619 fraternal twin pairs (average age = 50) were studied utilizing specialized health surveys.  Specifically, self-reported difficulty with initiating and maintaining an erection was assessed by this survey.  This study determined that, overall, 23% of these men experienced difficulty in initiating an erection, while 27% experienced difficulty in maintaining an erection.  On the average, twice as many identical twin pairs both experienced ED when compared to the non-identical twin pairs.  When the study’s results were statistically evaluated, using standard genetic tests, the authors determined that there is a 35% predisposition for inheritance of susceptibility towards inadequate initiation of erection.  Likewise, the potential inherited contribution towards a risk of difficulties in maintaining an erection was calculated to be approximately 42%.  In less confusing terms, this study suggests that as men age, the genes that they inherited from one or both parents appear to play a significant role in their risk of developing ED.  Based upon other diseases with similar genetic influences, it is very likely that men who have an underlying genetic propensity to develop ED will be more likely to develop this condition earlier, and in a more advanced state, if they also indulge in modifiable behaviors already linked with the development of ED.  Physicians are rarely able to persuade smokers to give up their tobacco.  However, I occasionally find that younger men, who invariably believe themselves to be invulnerable to life-threatening illnesses, will throw their smokes away when I tell them that smokers have nearly 30 times the risk of developing ED when compared to nonsmokers….

Dr. Robert A. Wascher