International Trial Shows Aspirin Protects Against Colorectal Cancer

A daily dose of aspirin can prevent the occurrence of cancer in people with a genetic predisposition towards Lynch syndrome, a condition which accounts for around five percent of all colon cancers, a scientist told the audience at Europe’s largest cancer congress, ECCO 15 – ESMO 34, the joint 15th European CanCer Organisation (ECCO) and 34th European Society for Medical Oncology (ESMO) Multidisciplinary Congress, September 20 – 24 in Berlin, Germany.

Professor John Burn, from the Institute of Human Genetics, Newcastle University, Newcastle upon Tyne, UK, said that he believed that he and his colleagues might have uncovered a simple way of controlling cancer stem cells, which are essential to the formation of malignant tumors.

The clinical trial, which involved 1071 carriers of the Lynch syndrome mutation in 42 centers worldwide, randomized participants to a daily dose of 600mg aspirin and/or 30g Novelose®, a resistant starch that escapes digestion in the small intestine. “Although there were many reports that aspirin might have a beneficial effect in a range of cancers,” said Prof Burn, “they were from case control and epidemiological studies. We decided that the only way to achieve conclusive proof was to undertake a randomized trial in a high risk population.”

Lynch syndrome, often called hereditary nonpolyposis colorectal cancer (HNPCC), is a rare type type of inherited cancer of the digestive tract that increases a patient’s risk of cancer, particularly the colon and rectum. People with Lynch syndrome have an increased risk of cancers of the stomach, small intestine, liver, gallbladder ducts, upper urinary tract, brain, skin, and prostate. Women carriers also have a high risk of developing endometrial and ovarian cancers.

These patients tend to develop cancer quickly, so the scientists expected to see answers at an early stage. The first results were disappointing, however; at an average of 29 months after randomization the scientists saw no evidence of the benefits of aspirin in the high-risk population studied.

“Our original design allowed for long term post trial follow-up,” noted Prof Burn. “We have managed to track down most of those who completed the trial – around 75% of the original consent cohort – with information extending up to 10 years from randomization. We found that, around four years after randomization, there was a divergence in the incidence of cancers between the aspirin and placebo groups. To date, there have been only six colon cancers in the aspirin group as opposed to 16 who took placebo. There is also a reduction in endometrial cancer. This is a statistically significant result and we are delighted – all the more so because we stopped giving the aspirin after four years, yet the effect is continuing, and is directly correlated with the duration of aspirin use on the trial.”

Although scientists believe that diet is a major factor in the prevention of colorectal cancers, there are no randomized trial data which can prove it, since running proper, controlled trials of diet is extremely difficult. However, there is a strong inverse relationship between colon cancer and how much starch people eat. Resistant starch, after escaping digestion in the upper gut, is fermented in the colon and forms short chain fatty acids, which are powerful anti-cancer agents.

“Our very large colon probably evolved to capture such nutrients from our forefathers’ diets,” explained Prof Burn. “Because we were giving starch as well as aspirin we would also have expected to see a decrease in cancers in the placebo group. However, there could be a number of reasons for this result – perhaps patients didn’t take the starch every day, or that it simply wasn’t resistant enough.”

There were minor problems due to aspirin side effects; out of over 1000 people, 11 in the aspirin group had notable gastro-intestinal bleeds or ulcers as opposed to nine in the placebo group. But this was counter-balanced by fewer strokes and heart attacks in the aspirin group.

The mechanism by which aspirin protects against cancer has yet to be elucidated, but the scientists believe that cancer stem cells are involved. “We do not think that the mechanisms discussed to date are likely to provide an explanation,” said Prof Burn. “For example, the inflammatory enzyme COX2(Cyclooxygenase-2), a protein that acts as an enzyme and specifically catalyzes the production of certain chemical messengers called prostaglandins, is over-expressed in early cancer, but our results suggest an effect that predates the cancer, and may even predate the adenoma which precedes it. We believe that aspirin may have an effect on the survival of aberrant stem cells in the colon. These cancer stem cells are normally resistant to chemotherapy, but if a stem cell mutates but does not reveal its potential until an adenoma is formed, and if aspirin reduced the chances of such cells surviving, this would explain our results.”

The team intends to undertake a further study to see whether a smaller dose of aspirin would have the same beneficial effect or not. “We are planning to ask people with Lynch syndrome to agree to ‘toss a coin’ and take, say, either one or two aspirin tablets per day. Then we can see whether the people on the lower dose have the same protection, with fewer side effects. The problem is that, to have a significant result, this will need about 10 times as many people as we needed for our first trial, but the good news is that everyone gets treated,” said Prof Burn.

For more information:

• Abstract no: 6000, Gastro-intestinal malignancies, colorectal cancer session, Monday 11.00 hrs CEST (Hall 2)

Also read these PubMed abstracts:

• Hua A, Mackenzie GG, Rigas B. The differential cell signaling effects of two positional isomers of the anticancer NO-donating aspirin. Int J Oncol. 2009 Oct;35(4):837-44.
• Barry EL, Sansbury LB, Grau MV, Ali IU, Tsang S, et al. Cyclooxygenase-2 Polymorphisms, Aspirin Treatment, and Risk for Colorectal Adenoma Recurrence--Data from a Randomized Clinical Trial. Cancer Epidemiol Biomarkers Prev. 2009 Sep 15. [Epub ahead of print]
• Lang DL. Aspirin as Colorectal Cancer Adjuvant Therapy. Gastroenterology. 2009 Aug 22. [Epub ahead of print]
• Neugut AI. Aspirin as adjuvant therapy for colorectal cancer: a promising new twist for an old drug. JAMA. 2009 Aug 12;302(6):688-9
• Chan AT, Giovannucci EL, Meyerhardt JA, Schernhammer ES, et al. Aspirin dose and duration of use and risk of colorectal cancer in men. Gastroenterology. 2008 Jan;134(1):21-8. Epub 2007 Sep 26.

Combined Program of Vaccination and Testing for the Human Papilloma Virus Could Eradicate Cervical Cancer

Cervical neoplasia is usually an asymptomatic squamous cell carcinoma caused by human papilloma virus infection (HPV); less often, it is an adenocarcinoma. The recognition that human papilloma virus (HPV) is a cause of cervical cancer has opened new opportunities for the prevention of the disease. Primary prevention is now possible via immunization with highly efficacious HPV vaccines and secondary prevention has gained impetus with the advent of sensitive HPV DNA testing to improve traditional Pap cytology screening programs.

As a result, cervical cancer could be eradicated within the next 50 years. However, according to a cervical cancer screening expert, this can only happen if governments implement national screening programs based on detection of the human papilloma virus (HPV), which causes the disease, together with vaccination programs against the virus.

Professor Jack Cuzick told Europe’s largest cancer congress, ECCO 15 – ESMO 34, (the joint multidisciplinary 15th congress of the European CanCer Organisation and the 34th congress of the European Society for Medical Oncology), meeting in Berlin, Germany (September 20 – 24, 2009) that while the current HPV vaccines protect against two cancer-causing strains of the HPV virus, soon there would be vaccines available that protect against nine types. If vaccination were to be combined with HPV screening (which is much more sensitive than the currently used Pap smear test), then eventually the cancer would disappear in those countries that had successfully implemented national programs. However, this would require political will and effort at both national and European level.

“It’s important to say up front that the HPV is responsible for all cervix cancer,” Cuzick said. “If you can eradicate the virus, the cancer will not appear. So the current vaccine holds the promise of eradicating about 70-75% of cervical cancers (caused by HPV types 16 and 18), and there appears to be some additional cross protection amongst types that are closely related to 16 or 18, in particular 31, 45 and a little bit of 33. There are new vaccines being planned that will vaccinate against nine types. If they are successful, there should be no need to screen women that have been vaccinated at all. That’s the long-term future: vaccination and no screening. After about 50 years, we could see cervical cancer disappearing.”

As the current HPV vaccine only protects against two of the cancer-causing types, vaccinated women will still require screening for the rest of their lives.

“Women vaccinated above the age of about 16 will need to be regularly screened for the rest of their life, because the vaccine is not effective in women who have already been exposed to the virus. Even for girls vaccinated before this age with the current vaccine, there will be a need for some screening to protect from cancers caused by HPV types not in the vaccine, so screening is here to stay for the foreseeable future. However, we need to change to screening for HPV rather than the Pap smear test, and then it will be possible for the tests to be conducted at longer intervals,” said Prof Cuzick, who is the John Snow Professor of Epidemiology and head of department at the Cancer Research UK Centre for Epidemiology, Mathematics and Statistics, Wolfson Institute of Preventive Medicine (London, UK).

The Pap test uses cytology to detect pre-cancerous changes to cells; it relies on subjective assessments by people examining the cells in the smear with a microscope and so is open to human error. Prof Cuzick believes such errors will increase as the proportions of smears with affected cells decline due to increasing numbers of women having been vaccinated. In contrast, the HPV test is almost completely automated, is designed to detect the virus in the smear rather than relying on visual examination, and so is much less likely to be affected by human error.

Prof Cuzick said that countries should be switching to the HPV screening test now. “There’s overwhelming evidence that HPV screening is more effective than the Pap smear test, which misses about a third to a half of all high grade lesions. There are now several available commercial HPV tests and most of these tests show a sensitivity (the proportion of true positives correctly identified) in the order of 95% for high grade lesions, whereas cytology is somewhere between 50-70%. So it would really streamline the service because you could test less frequently, and it’s also been shown that the protection lasts longer so that screening every five to seven years is probably appropriate.”

However, he warned that the European Union and national governments should take the initiative in discussions on implementing screening and vaccination programs, rather than leaving it to pharmaceutical companies to lead the debate.

“The European Commission and Parliament, together with national governments, could be doing more to promote HPV testing. One of the most useful things the EU could do would be to provide a forum for the dissemination of knowledge about the role of HPV both to doctors and to the general public. It could sponsor a major symposium to discuss HPV testing, vaccination and the best strategies for implementing programs in member countries."

“There’s been a lot of concern, particularly with the vaccine, that dissemination of information about HPV has come mainly from the drug companies, and people are, not surprisingly, a little sceptical of pharmaceutical-based education programs. So if the EU was to take this up without pharmaceutical support, I think it would be very appropriate and it would provide a forum that would be extremely legitimate.”

Although current HPV tests are more expensive than cytology tests, Prof Cuzick said the price would go down as the volume of tests increased. In addition, the fact that it’s more accurate and women could be screened at longer intervals meant that switching to HPV testing could save governments money in the long term.

“For younger women we think HPV testing should happen every five years starting at age 25-30; by the time they’re 50, if they’ve been negative, they could probably be screened every eight years. So there’s a lot to be gained, both in terms of better protection and less frequent screening, which will save time and money. If women can go less often and get more protection it makes a lot of sense.”

For more information:

• Oncopolicy session: Drug and lifestyle mediated prevention initiatives in Europe. Thursday 11.15-12.15 hrs CEST (Hall 3)
• Merck Manuals for Healthcare Professionals

Also read these Pubmed Abstracts

• Franceschi S, Cuzick J, Herrero R, Dillner J, Wheeler CM. EUROGIN 2008 roadmap on cervical cancer prevention. Int J Cancer. 2009 Jun 11;125(10):2246-2255. [Epub ahead of print]
• Breitenecker G. [Cervical cancer screening : Past - present - future.] Pathologe. 2009 Sep 16. [Epub ahead of print] German.
• Dinas K, Nasioutziki M, Arvanitidou O, Mavromatidis G, et al. Awareness of human papillomavirus infection, testing and vaccination in midwives and midwifery students in Greece. J Obstet Gynaecol. 2009 Aug;29(6):542-6.
• Lynge E, Antilla A, Arbyn M, Segnan N, Ronco G. What's next? Perspectives and future needs of cervical screening in Europe in the era of molecular testing and vaccination.
  Eur J Cancer. 2009 Oct;45(15):2714-21. Epub 2009 Aug 18.
  Franco EL, Coutlée F, Ferenczy A. Integrating human papillomavirus vaccination in cervical cancer control programmes. Public Health Genomics. 2009;12(5-6):352-61. Epub 2009 Aug 11.
• Ginsberg GM, Edejer TT, Lauer JA, Sepulveda C. Screening, prevention and treatment of cervical cancer-A global and regional generalized cost-effectiveness analysis.
  Vaccine. 2009 Jul 31. [Epub ahead of print]
• Barzon L, Giorgi C, Buonaguro FM, et al, Guidelines of the Italian Society for Virology on HPV testing and vaccination for cervical cancer prevention. Infect Agent Cancer. 2008 Dec 16;3(1):14

Information for your patients:

• Genital HPV Infection - CDC Fact Sheet
• Virus del papiloma humano genital (VPH)
• Center for Young Women's Health
• Merck Manuals (Home Edition) for Patients and Caregivers: Cervical Cancer
• Onco'Zine - The International Cancer Network

Images courtesy American Society of Clinical oncology (ASCO).

FDA approves New Single-Pill Combination of valsartan and aliskiren to Treat High Blood Pressure

The US Food and Drug Administration (FDA) has approved a new single-pill combination of aliskiren and valsartan tablets (Valturna; Novartis AG, Basel, Switzerland), the first and only medicine to target two key points within the renin system, also known as the renin angiotensin aldosterone system or RAAS, an important regulator of blood pressure.

This is the first approval for the single-pill combination of aliskiren and valsartan, which is indicated for the treatment of high blood pressure in patients not adequately controlled on aliskiren or angiotensin receptor blocker (ARB) monotherapy and as initial therapy in patients likely to need multiple drugs to achieve their blood pressure goals.

"This unique combination brings together the powerful blood pressure lowering effects of valsartan and aliskiren," said Joe Jimenez, CEO of the Novartis Pharmaceuticals Division. "It offers an important additional treatment option for physicians and hypertension patients, many of whom are not at their blood pressure goal. Valturna builds upon our strong cardiovascular franchise and is consistent with our long-term commitment to developing effective and innovative therapies. It further strengthens our growing portfolio of single-pill combinations to treat high blood pressure."

The new single-pill combines in a single pill valsartan, the active ingredient in Diovan , the number one selling branded high blood pressure medicine worldwide, and aliskiren, the active ingredient in Tekturna, the only approved direct renin inhibitor (DRI). The combination offers significantly greater blood pressure reduction than either valsartan or aliskiren alone.

"When it comes to diagnosing and treating high blood pressure, there is a real need for innovative therapies that help patients get to a healthier blood pressure range," said John Flack, M.D., Valturna investigator, and Chairman of the Department of Internal Medicine, Wayne State University, Detroit. "Now for the first time, we have a treatment option in one pill that targets two key points of the RAAS, which may be overactive in many hypertensive patients."

This approval was primarily based on a pivotal eight-week randomized, double-blind, placebo-controlled clinical trial in approximately 1,800 patients, which studied aliskiren 150 mg and 300 mg and valsartan 160 mg and 320 mg alone and in combination. The initial doses of aliskiren and valsartan were 150 mg and 160 mg, respectively, and were increased at four weeks to 300 mg and 320 mg, respectively.

Blood pressure reductions with the aliskiren/valsartan combination were significantly greater than with the monotherapies or placebo at the eight-week primary endpoint. Mean systolic and diastolic blood pressure reductions from baseline were 17.2/12.2 mmHg for aliskiren 300 mg/valsartan 320 mg, compared with 12.8/9.7 mmHg for valsartan 320 mg, 13.0/9.0 mmHg for aliskiren 300 mg, and 4.6/4.1 mmHg for placebo (p<0.05>.

For more information, read these PubMed abstracts:

Yamamoto E, Kataoka K, Dong YF, Nakamura T, Fukuda M, et al. Aliskiren enhances the protective effects of valsartan against cardiovascular and renal injury in endothelial nitric oxide synthase-deficient mice. Hypertension. 2009 Sep;54(3):633-8. Epub 2009 Jul 13.

• Geiger H, Barranco E, Gorostidi M, Taylor A, et al. Combination therapy with various combinations of aliskiren, valsartan, and hydrochlorothiazide in hypertensive patients not adequately responsive to hydrochlorothiazide alone. J Clin Hypertens (Greenwich). 2009 Jun;11(6):324-32.
• Yarows SA, Oparil S, Patel S, Fang H, Zhang J. Aliskiren and valsartan in stage 2 hypertension: subgroup analysis of a randomized, double-blind study.
  Adv Ther. 2008 Dec;25(12):1288-302.
• Tato AM, García López F. [Is the combination aliskiren /valsartan as effective and safe as either drug in monotherapy for treating hypertension?] Nefrologia. 2008;28 Suppl 2:10-1. (Spanish).
• Oparil S, Yarows SA, Patel S, Fang H, Zhang J, Satlin A. Efficacy and safety of combined use of aliskiren and valsartan in patients with hypertension: a randomised, double-blind trial. Lancet. 2007 Jul 21;370(9583):221-9
• Chrysant SG, Murray AV, Hoppe UC, Dattani D, Patel S, Hsu H, Zhang J. Long-term safety, tolerability and efficacy of aliskiren in combination with valsartan in patients with hypertension: a 6-month interim analysis. Curr Med Res Opin. 2008 Apr;24(4):1039-47. Epub 2008 Feb 27.