MIT Team Develops Urine Test for Cancer

Scientists at MIT say they have developed a simple, cheap paper test that could be used to improve cancer diagnosis rates and help people get treated earlier. The diagnostic, which works much like a pregnancy test, reportedly could reveal within minutes, based on a urine sample, whether a person has cancer. This approach has helped detect infectious diseases, and the new technology allows noncommunicable diseases to be detected using the same strategy.

The technique, developed by MIT professor and Howard Hughes Medical Institute investigator Sangeeta Bhatia, Ph.D., relies on nanoparticles that interact with tumor proteases, each of which can trigger release of hundreds of biomarkers that are then detectable in a patient's urine.

“When we invented this new class of synthetic biomarker, we used a highly specialized instrument to do the analysis,” said Dr. Bhatia. “For the developing world, we thought it would be exciting to adapt it instead to a paper test that could be performed on unprocessed samples in a rural setting, without the need for any specialized equipment. The simple readout could even be transmitted to a remote caregiver by a picture on a mobile phone.”

Dr. Bhatia, who is also a member of MIT's Koch Institute for Integrative Cancer Research and Institute for Medical Engineering and Science, is the senior author of a paper (“Point-of-care diagnostics for noncommunicable diseases using synthetic urinary biomarkers and paper microfluidics”) describing the particles in Proceedings of the National Academy of Sciences.

In 2012, Dr. Bhatia and colleagues introduced the concept of a synthetic biomarker technology to amplify signals from tumor proteins that would be hard to detect on their own. These proteins, known as matrix metalloproteinases (MMPs), help cancer cells escape their original locations by cutting through proteins of the extracellular matrix, which normally holds cells in place.

The MIT nanoparticles are coated with peptides targeted by different MMPs. These particles congregate at tumor sites, where MMPs cleave hundreds of peptides, which accumulate in the kidneys and are excreted in the urine.

In the original version of the technology, these peptides were detected using a mass spectrometer. However, these instruments are not readily available in the developing world, so the researchers adapted the particles so they could be analyzed on paper, using a lateral flow assay.

“We describe the design of exogenous agents that serve as synthetic biomarkers for NCDs [noncommunicable diseases] by producing urinary signals that can be quantified by a companion paper test. These synthetic biomarkers are composed of nanoparticles conjugated to ligand-encoded reporters via protease-sensitive peptide substrates,” wrote the investigators. “Upon delivery, the nanoparticles passively target diseased sites…where up-regulated proteases cleave the peptide substrates and release reporters that are cleared into urine. The reporters are engineered for detection by sandwich immunoassays, and we demonstrate their quantification directly from unmodified urine.”

In tests in mice, the researchers were able to accurately identify colon tumors as well as blood clots. Dr. Bhatia says these tests represent the first step toward a diagnostic device that could someday be useful in human patients.

• Tomado de genengnews.com

Human Papillomavirus Molecular Detection with Genotyping

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Gold-plated nano-bits find, destroy cancer cells

Comparable to nano-scale Navy Seals, Cornell scientists have merged tiny gold and iron oxide particles to work as a team, then added antibody guides to steer the team through the bloodstream toward colorectal cancer cells. And in a nanosecond, the alloyed allies then kill the bad guys – cancer cells – with absorbed infrared heat.

This scenario is not science fiction – welcome to a medical reality.

“It’s a simple concept. It’s colloidal chemistry. By themselves, gold and iron-oxide alloys are benign and inert, and the infrared light is low-power heating,” said Carl Batt, Cornell’s Liberty Hyde Bailey Professor of Food Science and the senior author on the paper. “But put these inert alloys together, attach an antibody to guide it to the right target, zap it with infrared light and the cancer cells die. The cells only need to be heated up a few degrees to die.”

Batt and his colleagues – Dickson K. Kirui, Ph.D. ’11, a postdoctoral fellow at Houston Methodist Research Institute and the paper’s first author; Ildar Khalidov, radiology, Weill Cornell Medical College; and Yi Wang, biomedical engineering, Cornell – published their study in Nanomedicine (print edition, July 2013).

For cancer therapy, current hyperthermic techniques – applying heat to the whole body – heat up cancer cells and healthy tissue, alike. Thus, healthy tissue tends to get damaged. This study shows that by using gold nanoparticles, which amplify the low energy heat source efficiently, cancer cells can be targeted better and heat damage to healthy tissues can be mitigated. By adding the magnetic iron oxide particles to the gold, doctors watching MRI and CT scanners can follow along the trail of this nano-sized crew to its target.

When a near-infrared laser is used, the light penetrates deep into the tissue, heating the nanoparticle to about 120 degrees Fahrenheit – an ample temperature to kill many targeted cancer cells. This results in a threefold increase in killing cancer cells and a substantial tumor reduction within 30 days, according to Kirui. “It’s not a complete reduction in the tumor, but doctors can employ other aggressive strategies with success. It also reduces the dosage of highly toxic chemicals and radiation – leading to a better quality of life,” he explained.

Tomado de: news.cornell.edu

Study suggests statin use decreases breast cancer mortality

Statin use – both before and after a diagnosis of breast cancer – was associated with up to a 66% reduction in the risk of dying from that cancer, a large database study has concluded.

Investigators reported that the risk reduction was consistent even after controlling for age, tumor stage and morphology, and primary treatment choice, Dr. Teemu Murtola said during an interview at the annual meeting of the American Association for Cancer Research.

"We saw that there was clearly a dose-dependent reduction in the risk of breast cancer mortality among statin users," who comprised 13% of the more than 31,000 women in the study, said Dr. Murtola, an epidemiologist at Johns Hopkins University in Baltimore. "The association held for both localized and metastatic tumors. There really appears to be something going on here, and it’s certainly a reason for further study."

During the follow-up, 6,011 women died; 3,169 deaths were due to breast cancer. The death rate among users was significantly lower than it was among nonusers (7.5% vs. 21%). In the adjusted analysis, statin users were 67% less likely to die than were nonusers with localized disease (hazard ratio, 0.33). Among those with metastatic disease, statins conferred a 48% decreased risk of death (HR, 0.52).

All of the statins investigated in the study cohort were associated with a significantly decreased risk of breast cancer death, including simvastatin (HR, 0.47), atorvastatin (HR, 0.27), fluvastatin (HR, 0.35), and pravastatin (HR, 0.50).

The retrospective study looked at statin use and breast cancer mortality among 31,114 women with breast cancer who were diagnosed in Finland during 1995-2003. All of the patients were included in the Finnish Cancer Registry. The country’s national health database also contained detailed information on statin use and other health indicators. The data on statins included the date of each prescription purchase, the numbers of refills, the dosage, and the number of pills in each refill.

Breast cancer data included the date of diagnosis, stage (local, lymph-node positive or metastatic), morphology, primary treatment choice (surgery, radiation, chemotherapy, hormonal therapy, or other), and the date and cause of death.

Follow-up started at the time of diagnosis and continued until death or the common closing date of Dec. 31, 2003, whichever came first. Median follow-up was about 3 years, but ranged from less than 1 year to 9 years.

Statin users accounted for 13% of the cohort (4,169); the remainder never used the drugs. Women who took the medications were significantly older than nonusers (64 years vs. 58 years), and more likely to have had surgery as a treatment (96% vs. 92%). They were also more likely to have undergone radiation (55% vs. 54%), but significantly less likely to have had chemotherapy (15% vs. 24%) or hormonal therapy (20% vs. 25%). Metastatic cancer was significantly less common among statin users – 4% vs. 7%. These differences may reflect an early identification of breast cancer among users, perhaps because they were visiting a physician more frequently for lipid monitoring, Dr. Murtola said. However, the multivariate analysis controlled for all these differences, including metastatic and local disease.

Dr. Murtola then investigated the mortality effects of both pre- and postdiagnostic statin use.

Compliance was high among women who started the drugs before their breast cancer diagnosis, with 85% continuing until the end of follow-up. Compared with nonusers, women who used statins for up to 490 days were 46% less likely to die of local disease and 30% less likely to die from metastatic disease.

Those who took the drugs for 491 days or more before diagnosis were 66% less likely to die from local disease and 40% less likely to die from metastatic disease.

There was no such clear, dose-dependent relationship between mortality risk and statins taken after diagnosis, Dr. Murtola said. But, he added, low compliance could have masked any benefit. "Only 14% of those who started statins after diagnosis continued to take them until the end of the follow-up period," he said. "When we limited the analysis to those who were compliant until the end of their follow-up, we saw a very similar dose-dependent risk reduction in breast cancer mortality."

In vitro studies suggest that statins could have a direct effect on breast cancer cells, he said. They seem to block the mevalonate pathway – a process involved in the manufacture of cholesterol, and also key to cell metabolism. Cells with abnormally high metabolic rates – like breast cancer cells – could be particularly vulnerable to this action, he said.

"I think that because the drugs target this pathway their impact extends beyond cholesterol. It’s certainly worth further study."

Tomado de oncologypractice.com

Old Biomarker May Have New Role in Lung Ca

Bilirubin, which is considered a useful liver function marker, may also point to smokers at increased risk for lung cancer.

In a large Taiwanese prospective cohort, male smokers with bilirubin in the lowest quartile lowest had a 69% higher risk for developing lung cancer, and a 76% higher rate of lung cancer mortality, compared with male smokers who had the highest bilirubin levels, said Xifeng Wu, MD, of the University of Texas MD Anderson Cancer Center in Houston.

In men who had never smoked, bilirubin levels had no significant effect on health outcomes.

The research showed that serum bilirubin is a potential biomarker for lung cancer risk prediction, Wu told MedPage Today at the annual meeting of the American Association for Cancer Research.

"It was kind of a surprise and very interesting," Wu said. "The biomarker was identified from metabolic profiling and validated by the large, cohort study."

In the Taiwanese cohort of 435,985 individuals, the incidence rate of lung cancer in men with bilirubin levels of 0.68 mg/dL or less was 7.02 per 10,000 person-years irrespective of smoking history. This compared with a rate of 3.73 per 10,000 person-years in men whose bilirubin levels were 1.12 mg/dL or more, again irrespective of smoking history.

Wu said this translated into a 51% increase in the risk for developing lung cancer for low-bilirubin patients.

Also, the lung-cancer specific mortality rate in men with low bilirubin was 4.84 per 10,000 person-years compared with 2.46 per 10,000 person-years in men with high bilirubin.

When only male smokers were analyzed the associations were starker -- a 76% increase in lung cancer mortality.

Wu said she first conducted global, unbiased metabolomic profiling in serum samples from 20 healthy controls, 20 patients in early-stage lung cancer, and 20 patients in late-stage lung cancer. Matching for age and gender, Wu selected three differentially expressed metabolites for validation in two case-control populations. Bilirubin emerged and was validated by the large Taiwanese prospective cohort.

Wu said the study focused on male smokers and was limited by an insufficient amount of female smokers from which to draw conclusions.

But the research does point to the potential benefit of using biomarkers in cancer research, she said.

"We need to identify additional biomarkers, including metabolomic biomarkers," Wu said.

"It's a very large study and brings up interesting findings that to my knowledge haven't been reported before," said Lecia Sequist, MD, of Massachusetts General Hospital in Boston. "This will generate a lot of interesting future research in biologic relations between bilirubin and lung cancer."

Tomado de  medpagetoday.com

Entre un 30 y un 40% de los diagnósticos de cáncer de próstata son innecesarios

Según los expertos reunidos en el I Foro Integral de esta dolencia, el cribado selectivo ha conseguido disminuir la mortalidad por este tumor, aunque muchos pacientes están siendo sobretratados.

“Entre un 30 y un 40% de los diagnósticos de cáncer de próstata son innecesarios”. Así lo ha manifestado el doctor Bernardino Miñana, coordinador del Grupo de Uro Oncología de la Asociación Española de Urología (AEU), en el marco del I Foro integral sobre cáncer de próstata que durante hoy y mañana se celebra en Murcia, y al que acuden cerca de 300 expertos de toda España. Tal y como ha señalado el doctor Miñana, “uno de los retos que se nos plantean actualmente es evitar diagnósticos innecesarios en pacientes con bajo riesgo de desarrollar síntomas, con el objetivo de no comprometer su calidad de vida con tratamientos innecesarios.”
     El cáncer de próstata es un tumor con una incidencia similar al de mama en la mujer. Actualmente en España, según datos del Registro Nacional de Cáncer de Próstata de la AEU, se diagnostican más de 20.000 nuevos casos al año. Con el objetivo de debatir cuál es la situación actual de esta enfermedad, teniendo en cuenta que está directamente asociada a la edad y que se prevé que siga aumentando debido al progresivo envejecimiento de la población, por primera vez se reúnen en este encuentro científico los principales agentes (pacientes, autoridades y profesionales sanitarios, medios de comunicación e industria farmacéutica) involucrados en esta enfermedad.

     “Una reunión”, ha asegurado el doctor Humberto Villavicencio, presidente de la AEU, “que es clave en un momento como el actual, de crisis económica, que obliga a racionalizar recursos para mantener la sostenibilidad del Sistema Nacional de Salud, lo que además va a afectar especialmente a una patología como el tumor de próstata, que constituye un verdadero problema de salud pública”.

PSA y tacto rectal

     Las dos pruebas que ponen al urólogo sobre la pista de un posible tumor prostático son la palpación de la próstata a través de tacto rectal y la determinación del antígeno prostático en sangre, prueba que consiste en un simple análisis de sangre y que es conocida como PSA. Según el doctor Villavicencio, “no cabe cuestionarse la validez del diagnóstico precoz con el PSA porque es innegable que ha cambiado totalmente el pronóstico del cáncer de próstata. Hace 20 años la mayor parte de estos tumores no podían curarse y en la actualidad es posible abordar con éxito la mayoría de ellos. De hecho, nueve de cada diez pacientes se diagnostican en un estadio susceptible de recibir un tratamiento con intención curativa”.

     Sin embargo, el consenso no es tal cuando lo que se plantea es si merece la pena someter a todos los hombres mayores de 50 años a estas pruebas, igual que se hace con las mamografías a las mujeres. La cuestión es si produce realmente un beneficio, dado que no son pocos los afectados que, por la naturaleza de su tumor, de progresión muy lenta, acaban falleciendo con el tumor y no a causa de él. “En estos casos”, explicó el doctor Miñana, “la opción es hacer un seguimiento activo sin hacer uso de la medicación. No obstante, el temor que produce la enfermedad hace que muchos urólogos y los propios pacientes prefieran abordarlo, lo que conlleva un consumo de recursos y una serie de comorbilidades asociadas al tratamiento que podrían evitarse”.
Evitar tratamientos innecesarios en pacientes con bajo riesgo

     La mayoría de los casos de cáncer de próstata se diagnostican en varones de 69-70 años. Para el doctor Miñana, “la tendencia actual de pedir un PSA a todos los varones mayores de 50, 60, 70 y 80 años, tanto por parte de los urólogos como por los médicos de atención primaria, ha generado que entre un 30-40% de los nuevos casos se detecten en pacientes con un riesgo muy bajo de fallecer a causa del tumor. Es decir, con un tumor muy localizado y de una evolución tan lenta que no hubiera merecido la pena detectarlo. El objetivo de cualquier programa de screening es diagnosticar cánceres que vayan a comprometer la vida del paciente, por lo que este 30-40% podría corresponder a pacientes sobrediagnosticados y, quizás, sobretratados”.

     En este grupo de pacientes, que además va en aumento debido al progresivo envejecimiento de la población, los expertos apuntan a que lo más razonable es no recomendar ningún tratamiento si la esperanza de vida es inferior a diez años. “La opción”, explicó el doctor Miñana, “es hacer un seguimiento activo. Es decir, realizar una biopsia periódicamente para ver si en algún momento se produce un cambio de tamaño en el tumor. Si el tumor no se manifiesta, se mantiene indolente, nuestra recomendación es no tratarlo, ya que el paciente probablemente fallezca a causa de otra enfermedad. Este tipo de vigilancia implica la realización de análisis y biopsias periódicas”.

     Otra opción es el tratamiento focal, que consiste en tratar exclusivamente la parte de la próstata enferma sin tener que extirpar toda la glándula. “La aplicación de estos tratamientos”, comentó este experto, “supondría un cambio radical en nuestra forma de diagnosticar y monitorizar el cáncer de próstata, ya que nos basaríamos en la imagen que nos proporciona la resonancia magnética. A estos pacientes habría que hacerles una resonancia multimagnética, que es la única que permite visualizar de alguna forma este tumor, ya que, por ser un cáncer multifocal, resulta complicado verlo con otro tipo de prueba. De esta forma, es posible no quitar la glándula entera y hacer un tratamiento con menos secuelas para el paciente. Evitas así la incontinencia y la disfunción eréctil asociadas a la cirugía radical”.

Tratamiento del cáncer de próstata

     Cuando la enfermedad está localizada, los médicos cuentan con dos opciones terapéuticas: la radioterapia y la cirugía (prostatectomía radical). La intervención quirúrgica permite extraer la glándula prostática y analizarla para determinar con exactitud en qué etapa de crecimiento se encuentra el tumor. Esta operación se puede realizar mediante una intervención tradicional abierta, por vía laparoscópica o asistida por robot, siendo la probabilidad de curación así como los efectos sobre la erección y la continencia similares mediante los tres tipos de cirugía. En el caso de la radioterapia, se puede administrar por vía externa (convencional) o implantando unas semillas radioactivas dentro de la próstata (braquiterapia). También existen otras opciones como la crioterapia y la HIFU (ultrasonidos) que aún es preciso contar más experiencia. “El tratamiento de estos tumores localizados dependerá siempre de la edad del paciente y la agresividad del propio tumor, de tal manera que cabe contemplar en casos muy seleccionados la abstención o demora terapéutica”, aclaró el doctor Miñana.

     La terapia hormonal actúa bloqueando la producción de hormonas masculinas que son las que estimulan el crecimiento del tumor. En estos casos, la indicación se limita a los casos en los que el tumor se encuentra ya diseminado (metástasis) o porque ha habido una recaída tras la cirugía. Asimismo ha demostrado ser útil como adyuvante a radioterapia en pacientes de alto riesgo. Desde hace pocos años, se dispone de quimioterapia que permite un ligero pero significativo incremento en la expectativa de vida de los pacientes con metástasis y que son resistentes al tratamiento hormonal.

     Por otra parte, aunque la cirugía asistida por robot mejora la precisión de la intervención quirúrgica, los costes que implican su implementación dificultan su expansión. “Lo cierto es que en un momento como el actual es importante evaluar el coste-eficacia de las nuevas tecnologías, ya que en muchas casas se empiezan a utilizar técnicas insuficientemente evaluadas y que poco aportan a la utilizada anteriormente. En esta reunión contamos con representantes de la administración sanitaria que precisamente abordarán la importancia de evaluar las nuevas tecnologías, ya que actualmente nuestro SNS no puede permitirse su aplicación a grane escala, como es el caso de la robótica, aunque es indiscutible que el futuro pasa por este tipo de cirugía”, subrayó el doctor Miñana.

Calidad de vida

     Otro de los temas que se debatirán en el I Foro Integral de cáncer de próstata es la calidad del paciente con cáncer de próstata. Los tratamientos locales (cirugía y radioterapia) pueden afectar en la función sexual, a la continencia urinaria y, en el caso de la radioterapia, también al aparato digestivo. Por su parte, las terapias sistémicas, como la quimioterapia, la inmunoterapia y las nuevas moléculas en investigación tampoco están exentas de efectos adversos. “La tendencia es a optar por tratamientos cada vez menos invasivos para el paciente. Por lo que otro de los contenidos que abordaremos será analizar el impacto real de todos los tratamientos y de que forma se pueden prevenir, minimizar o evitar los efectos secundarios”, concluyó este experto.

Cáncer de vejiga y riñón

      Otros de los tumores urológicos que se analizarán en este marco científico son el cáncer de vejiga, en el que España se encuentra entre los países europeos con mayor incidencia y que es uno de los tumores que más recursos sanitarios consume. Así como el de riñón, en el que han aparecido nuevas moléculas efectivas para el tratamiento en su etapa más avanzada.

Tomado de Jano.es

New More-Sensitive Blood Test Catches Recurring Breast Cancer a Year Earlier

 A new blood test is twice as sensitive and can detect breast cancer recurrence a full year earlier than current blood tests, according to a scientist who reported at the 243rd National Meeting & Exposition of the American Chemical Society (ACS) in San Diego on March 29.

Daniel Raftery, Ph.D., who reported on the test, pointed out that breast cancer survivors -- 2.5 million in the U.S. alone -- face about a 1-in-5 chance that the cancer will come back, or recur, within 10 years of treatment. Research shows that early detection of these recurrences and treatment can save lives. However, currently available blood tests are not very sensitive. Perhaps the best known test for a biological "marker" protein, or "biomarker," called CA 27.29, misses many cases of recurrence and detects them late -- often after symptoms, such as difficulty breathing or bone pain, surface.

"We have identified a group of nine biomarkers that signal recurrence of breast cancer," Raftery said. "Our markers detect twice as many recurrences as the CA marker does at the same specificity. They also detect cancer recurrence earlier, about 11-12 months sooner than existing tests. They accomplish this with blood samples, rather than biopsies, with less discomfort to patients."

To find these markers, Raftery's team at Purdue University and Matrix-Bio, Inc., a company he founded, analyzed many hundreds of "metabolites" in the blood of breast cancer survivors. Metabolites are small molecules, biological byproducts formed as the body's cells go about the business of life. Some are released into the bloodstream and urine. The rapidly emerging scientific field called "metabolite profiling" seeks to understand how these metabolites relate to health and disease. Groups of metabolites already have been linked to a range of diseases. Many of Raftery's biomarkers were known to be involved in cancer. But no one knew that this group of metabolites could serve as biomarkers for breast cancer recurrence, he said.

The markers are detected with an instrument called a mass spectrometer, which is common in clinical laboratories. Raftery explained that these markers would be used in combination with results from CA 27.29 blood tests.

"We take both of those results together and roll them into the profile so that the score we generate is a combination of the CA value and our nine metabolites," he said. "If the score indicates that the cancer probably has returned, the patient would then likely undergo imaging tests to locate the tumor."

Raftery hopes that the new test will become available later this year. In the meantime, the researchers are conducting another clinical study with the test. He also said that, in the future, the test might be useful in the early detection of breast cancer, not just recurrences.

The scientists acknowledged partial funding from the National Institutes of Health

American Chemical Society (ACS). "New more-sensitive blood test catches recurring breast cancer a year earlier." ScienceDaily, 28 Mar. 2012. Web. 16 Apr. 2012.

Common medicines may cut cancer drug potency: study

Many patients taking a widely prescribed class of oral cancer drugs are also using a variety of medications that could reduce the effectiveness of the cancer treatment or increase its toxic side effects, according to research by Medco Health Solutions Inc.

For example, 43 percent of patients taking the highly effective leukemia drug Gleevec were also on another medicine that could diminish its efficacy, while 68 percent were taking something that could potentially raise the toxicity level, the study found.

Not surprisingly, the study found that the vast majority of the cancer drugs were prescribed by an oncologist, while the other medicines were typically prescribed by a primary care physician.

"More communication needs to take place across all doctors that are prescribing for the patient," said Medco's Steve Bowlin, who is presenting the study findings on Friday at the American Society for Clinical Pharmacology and Therapeutics meeting in Washington.

The Medco drug interaction study looked at pharmacy claims of about 11,600 patients who had been prescribed any of nine oral drugs known as kinase inhibitors, used to treat a variety of cancers. They include Gleevec and Tasigna from Novartis; Pfizer Inc's Sutent; Nexavar from Onyx Pharmaceuticals Inc and Bayer AG; Tarceva, sold by Roche Holding and Japan's Astellas Pharma Inc; Sprycel from Bristol-Myers Squibb Co; and GlaxoSmithKline Plc's Tykerb.

The medications that could potentially cause such adverse "drug-drug interactions" (DDI) include commonly used heartburn drugs known as proton pump inhibitors (PPIs), such as Nexium and Prevacid; steroids; a class of blood pressure and heart medications known as calcium channel blockers; and some antibiotics and antifungal treatments.

At the high end of the range, 74 percent of patients who were taking Glaxo's kidney cancer drug Votrient were also taking a drug that could increase toxicity, researchers said.

Fifty-seven percent of Tarceva patients were also taking a drug that could weaken effectiveness, more than for any of the other cancer treatments.

Sutent had the lowest incidence of potentially troubling drug interactions, with 23 percent of patients taking a medicine that could decrease its effectiveness and 24 percent on a drug that could increase Sutent's toxicity.

"The fact that one-quarter to 75 percent of patients on these oral drugs may not be getting the full benefit of their treatment or may in fact be putting their health at further risk because of another medication they are taking is concerning," Dr. Milayna Subar of Medco's Oncology Therapeutic Resource Center said in a statement.

The PPI drugs for heartburn and acid reflux were the most likely to alter the effectiveness and toxicity of Gleevec, researchers said. For the lung cancer drug Tarceva, steroids and PPIs were most likely to decrease efficacy, while certain antibiotics were most likely to increase toxicity.

Even though the Tarceva label cautions against using the antibiotic ciprofloxacin when taking that cancer drug, the analysis found that the two were co-prescribed for a significant number of patients.

"There are other therapeutic alternatives that could be prescribed that would not have the same potential for interaction," said study co-author Eric Stanek, who called for increased surveillance of patient prescribing.

The analysis also found that the overlap for patients taking one of the oral cancer drugs and a medicine that could cause problems was rarely for just a day or two.

"In many instances, 30 or 40 percent of the time people were on a cancer drug they were also on a DDI drug," Bowlin said. "On average, it was substantial amount of time."

Medco, a pharmacy benefit manager that is in the process of being acquired by rival Express Scripts Inc, offers a Drug Utilization Review program under which its oncology pharmacists can alert doctors about potentially troubling medication interactions.

Tomado de Reuters.com: Reporting By Bill Berkrot; Editing by Gerald E. McCormick