New Treatment for Prostate Cancer?; Red Meat, Fiber & Colon Cancer; Malpractice & Errors in Surgery

EXPERIMENTAL NEW TREATMENT FOR PROSTATE CANCER

Prostate cancer, which occurs most commonly in older men, is, in many ways, analogous to breast cancer in women. In the majority of cases, there is an important hormonal link in the development, progression and treatment of both of these cancers. In 2007, an estimated 219,000 new cases of prostate cancer will be diagnosed in the
United States, and more than 27,000 men will die of the disease in the same year.

Currently, there are three primary approaches to the treatment of prostate cancer. This walnut-sized gland that sits at the base of the bladder can be surgically removed, or the prostate gland can “seeded” with radioactive implants to kill tumor cells, or prostate cancer can be treated with a combination of hormonal medications (or castration) and close observation (some urologists are also “freezing” prostate tumors, using an approach termed cryotherapy). All of these therapies have their limitations and associated side effects, with the most notable side effects of surgery and radiation therapy being impotence, urinary incontinence (the inability to control the starting or stopping of the flow of urine), and obstruction to the flow of urine.

A new, non-surgical approach to destroying, or “ablating,” malignant prostate tumors is described in the current issue of the Journal of Urology. This novel therapy, known as high-intensity focused ultrasound (HIFU), is notable because it generally does not require any sort of surgical incision or other invasive interventions. Basically, high-energy sonic beams are guided and focused upon target tumor tissue by a computer-operated rectal probe, and these sound wave beams then heat the target tissues to temperatures around the boiling point of water, causing destruction of tumor cells and a small rim of surrounding, grossly normal prostate tissue. (I want to emphasize the “grossly normal prostate tissue” aspect of this treatment because, unlike surgical prostatectomy, radioactive seed implant therapy, cryotherapy and HIFU do not involve the total removal of the prostate tumor and surrounding prostate gland tissue as part of treatment, and therefore, the microscopic extent of residual, viable prostate cancer cells, if any, cannot be conclusively evaluated at the time of treatment by a pathologist.)

HIFU is already being used to treat benign diseases of the prostate gland, with good results. However, its long term efficacy and side effects profile, when used as a primary treatment for prostate cancer, is not well understood at this time. In this small clinical study, 20 men with prostate cancer underwent treatment of their tumors with transrectal HIFU (one of the patients did not return for follow-up after HIFU treatment). Temporary difficulties in passing urine was noted in only 10% of the patients in this study, and one patient experience an area of thermal injury to the rectal wall due to the ultrasound beams. Following treatment with HIFU, the level of prostate specific antigen (PSA), a prostate cancer marker in the blood, was measured in these study patients. In 42% of this small group of study patients, PSA levels declined to an almost undetectable level, and follow-up needle biopsies of the prostate gland revealed no apparent residual, viable tumor cells.

The application of HIFU as a primary treatment for prostate cancer is, clearly, still in its infancy. Considerably larger clinical research trials will need to be completed, and long-term follow-up will be necessary before HIFU can be recommended as a safe and effective treatment for prostate cancer. Moreover, HIFU will need to be directly compared with other current, validated prostate cancer therapies in a prospective, randomized clinical trial setting, allowing for a side-by-side comparison of HIFU with these more established therapies. (Similar investigation of HIFU is also being conducted for the treatment of breast cancer, and other types of cancer, as well.). However, based, as least, upon preliminary studies such as these, it appears that HIFU may be a potentially effective treatment for selected patients with prostate cancer, and may allow at least some patients with this disease to avoid surgery or the use of radiation treatments.

Importantly, in this very small pilot clinical study, only 42% of the study patients achieved a “chemical” or “pathological” cure of their prostate cancers. Clearly, more work needs to be done with current HIFU technology, and more clinical study will be necessary in order to allow for the identification of those patients who might benefit the most from this exciting new cancer therapy modality.

RED MEAT vs. WHITE MEAT: DNA DAMAGE & COLON CANCER RISK

Among the well-established risk factors for colon and rectal cancer, there is little debate these days but that a diet rich in red meat and processed meat increases the risk of this cancer, which is the third most common cancer killer in both men and women. A great deal of research has already been devoted to understanding the biological links between diet and the risk of developing colorectal cancer (and other cancers as well). A new research study in the journal Carcinogenesis offers tantalizing insights into the mechanisms whereby red meat may cause colorectal cancer and, more importantly, potential dietary interventions that may block the injurious effects of red meat on the DNA of cells that line the colon and rectum.

This Australian study looked at the damage caused in the DNA of the colon following diets rich in red meat (versus white meat) in rats. (Much—but not all—previous research has suggested that white meat, unlike red meat, does not appear to significantly increase the risk of colorectal cancer.) Given that some previous research has suggested a protective effect of dietary fiber against colorectal cancer, some of the rats in this study were also fed an indigestible starch which is also a dietary fiber. Multiple studies of the DNA in the cells lining the rats’ colons was then performed, looking for the types of genetic damage known to be potentially associated with the development of colorectal cancer. These studies showed that both red meat and white meat, when consumed in large quantities, were associated with characteristic DNA damage, although this damage was much more extensive among the rats eating a red meat diet. These adverse DNA changes appeared to be largely prevented in those rats that were also fed the dietary fiber supplement. The fiber supplement also appeared to restore the protective mucus barrier in the colon that has previously been shown to be lost in the presence of large amounts of red meat in the diet, and which has been implicated in the development of colorectal cancer as well.

Taken together this elegant study shows that, at least in rats, red meat appears to be directly associated with the development of DNA damage thought to be involved in colorectal cancer development (and to a much greater extent than white meat), and that a particular form of indigestible fiber (and, once again, at least in rats…) appears to block these forms of worrisome DNA injury. Whether these same phenomena occur in humans is not entirely clear and, indeed, some recent epidemiological studies have called into question the proposed protective effect of dietary fiber with respect to colorectal cancer risk. Additional study, specifically in humans, will need to be conducted, to further establish and validate the findings observed in this particular study. Quite apart from the very important association between red meat and colorectal cancer risk, however, it has been well-established that red meat, with its attendant high content of saturated fats, is a also a risk factor for the development of cardiovascular disease and obesity, as well as a risk factor for cancers other than colorectal cancer. Needless to say, a diet rich in natural sources of fiber, and low in red meat and processed meat, is probably the most prudent approach to a healthy diet.

SURGERY MALPRACTICE CASES: PATTERNS OF ERROR

A review and analysis of 444 surgical malpractice claims, recently published in the Annals of Surgery, found 258 cases in which surgical injuries to patients were identified. In 52% of these cases, patient injuries appeared to involve “technical errors” allegedly committed by the surgeon while in the operating room. Permanent disability occurred in 49% of these cases, and an additional 16% of patient injuries resulted in death. Almost two-thirds (65%) of these “technical errors” were the result of manual errors in the actual performance of the surgical procedure(s), while 26% were due to a combination of manual errors and errors in judgment. Only 9% of these injury cases were determined to have been caused by errors in clinical judgment alone.

Most interesting was the finding that in 73% of these cases, experienced surgeons were involved, and that 84% of these malpractice cases involved routine surgical procedures. Only 16% of the cases involved unusually complex or rare operations, and only 14% of the operating surgeons were judged to have been inexperienced in performing the procedures involved (9% of the cases appeared to involve poorly supervised surgical residents). Other important factors that appeared to be involved in these patient injury cases included emergency cases, difficult or atypical patient anatomy, and a history of the patient having had prior operations in the same anatomic area (altogether, one or more of these patient-related factors occurred in 61% of the malpractice cases). Interestingly, equipment or other “technology-related” systems failures appeared to have been involved in 21% of these surgical malpractice cases.

The findings of this study are both significant and provocative. There is abundant clinical research data showing that preventable surgical errors account for an enormous public health burden in terms of disability and death. Indeed, a tremendous emphasis has recently been placed, for both hospitals and surgeons, on the prevention of seemingly avoidable injuries to surgical patients. Most notably, these include exquisite precautions to avoid performing the wrong operation on a patient, surgery on the wrong side of the body, surgery on the wrong patient (!), and leaving surgical sponges or instruments behind (i.e., inside of the patient). Other areas of intense risk-reduction focus include the avoidance of medication errors inside and outside of the operating room, the aggressive implementation of preventive measures to reduce the risk of life-threatening blood clot formation, and measures to ensure the appropriate use of antibiotics.

More controversial approaches to surgical risk reduction have been proposed by several government and private health insurance agencies, and other public health organizations. As a prime example, there are several large studies that have linked surgeon and hospital experience, training and volume with better outcomes among Medicare patients undergoing selected complex, medium- and high-risk procedures, including coronary artery bypass surgery, and major operations for cancers of the esophagus, stomach, colon, rectum and pancreas. At the same time, numerous retrospective clinical studies from smaller, lower-volume hospitals and surgeons have appeared to show outcomes comparable to specialized centers for these very same cases. Thus, proponents of “regionalization” for certain “index” surgical cases point to the data suggesting that patients will do better in high-volume tertiary referral centers, while smaller community hospitals and medical centers point to data suggesting that they are also capable of providing high quality patient outcomes in these cases, as well. This dynamic also reaches into multiple other areas of increasingly heated debate and controversy in the United States, including issues of selective reimbursement by health insurance entities (and which may deprive community medical centers with excellent patient outcomes of the revenue that they require to remain economically viable), the threat of restrictive credentialing for surgeons who practice outside of regional tertiary specialty medical centers (and who, currently, provide the overwhelming majority of surgical care in this country), and the “town vs. gown” debate over the putative superiority of academic university hospitals vs. private community-based medical centers, to name just a few areas of chronic dispute and concern.

Certainly, the findings of this particular study would appear to lend weight to those who believe that, given the appropriate training and resources, and with the rigorous implementation of proven clinical pathways for the management of complex surgical diseases, excellent patient outcomes can be achieved at smaller community-based medical centers, and by community-based surgeons who are well-trained and highly competent, despite performing smaller volumes of “index” surgical cases than their high-volume referral center colleagues.

The results of this study also suggest that the current risk reductions strategies in place may be inadequate to deal with the causes that appear to underlie the majority of patient injuries suffered during the course of surgical operations. In this study, the majority of technical errors that resulted in a malpractice suit being file arose during the course of routine surgical procedures that were performed by experienced, properly credentialed surgeons.

As the major focus of current risk reduction efforts is increasingly directed towards restricting surgeons who are credentialed to perform high-complexity operations, requiring inexperienced surgeons to obtain additional specialized training, and improving oversight and supervision of surgical residents, the results of this study call into question how effective these strategies will be in reducing preventable surgical injuries to patients. Instead, the results of this study would appear to suggest that more effort should be invested in the areas of improving intra-operative decision-making, and improved surgical performance, especially in patients with aberrant anatomy or a history of prior operations in the same anatomic regions, and for patients undergoing emergency operations.

As a practicing cancer surgeon who routinely performs some of the most complex and high-risk operations possible, I am keenly aware, at all times, of the potential for adverse outcomes in my patients. Unfortunately, although we all wish that it were otherwise, surgery, like all other human endeavors, will never be completely “error-free.” However, studies such as this provide us with useful insights, using a systems-based approach to analyze the potential root causes of errors, into ways that we can all work together to drive down the risk of preventable injury and death in our patients to an absolute minimum. I often tell my medical students and residents that surgery involves the willful, deliberate (and hopefully well-controlled) infliction of severe physical trauma on the body of another human being, in the hope of therapeutic benefit for the patient. In an analogy taken from my now distant days as a private airplane pilot (“There are old pilots and bold pilots, but not many old and bold pilots…”), I tell my young trainees that there is no such thing as a “minor” operation. Even the seemingly simplest surgical procedures, if improperly performed (or if the patient, as a whole, is poorly managed), can result in terrible complications, including the Ultimate Complication.

This entry was posted on Sunday, November 18th, 2007 at 10:17 am and is filed under Family, Health, Technology, Vox Populi. You can follow any responses to this entry through the RSS 2.0 feed. | 268 views | Trackback | Print this page |

Cancer surgeon, professor of surgery & author. Webmaster: http://doctorwascher.com | More from Robert A. Wascher, MD, FACS