Login | Register

Deadly Pancreatic Cancer Develops Much More Slowly Than We Thought, Raising Hopes Of Earlier Detection

Scientists who studied the genetics of pancreatic cancer, one of the deadliest cancers with fewer than five per cent of patients still alive five years after diagnosis, found that it takes much longer to grow than we thought, as long as 20 years to become lethal, but the good news is this extends the window of opportunity for earlier detection, especially if a blood or stool test could be developed to pick up some of the early cancer-causing mutations that they found.

You can read a paper on how senior author Dr. Christine Iacobuzio-Donahue, a pathologist at Johns Hopkins University School of Medicine in Baltimore, Maryland in the US, and colleagues arrived at these findings in the 28 October issue of the journal Nature.

Co-leading the study was Dr. Bert Vogelstein, a Howard Hughes Medical Institute investigator at the Johns Hopkins Kimmel Cancer Center. He said in a statement there are two theories for why pancreatic cancer is so deadly.

The first theory is that the tumors are very aggressive right from the start and spread rapidly to other organs. The other theory is that they are not aggressive but spread slowly, with symptoms appearing very late in the process, so that the chances of survival are much diminished.

“We were surprised and pleased to discover that this second theory is correct, at least for a major fraction of tumors,” said Vogelstein.

“It means that there is a window of opportunity for early detection of pancreatic cancer,” he added.

For the study, Iacobuzio-Donahue, Vogelstein and colleagues investigated autopsy tissue from seven patients who died with pancreatic cancer. The samples included tissue from primary tumors in the pancreas, and also from lesions of where it had spread (metastased) to the lungs, liver and other organs.

They sequenced the DNA of all the genes in both types of tissue and compared them to see if there were any genetic differences between primary pancreatic tumors and metastatic lesions.

Across all seven patients, they found 61 cancer-related mutations on average per metastatic lesion, and that 64 per cent of them, on average, were also present in the primary tumor.

Using a technique termed “molecular clock”, and observing the steady rate of growth of cancer cells in lab cultures, they estimated how long it took for each of the mutations to grow in the primary tumors and the metastased lesions.

The results showed that on average, over 20 years elapsed between the appearance of the first mutated pancreatic cancer cell and death:

* It took 11.7 years on average, for a mature primary tumor to form in the pancreas after the first cancer-related mutation appeared in a cell.

* It took an average of another 6.8 years before the primary tumor sent out a metastatic lesion to another organ.

* After that, it was another 2.7 years on average, before the patient died.

Vogelstein said this is similar to what we’ve seen before in colorectal cancers, the tumors take decades to evolve.

However, unlike other cancers, pancreatic cancer usually shows no symptoms until it has spread. The first symptom is usually jaundice, but that only appears after lesions have started growing in the liver.

Vogelstein said these findings raise the chance that a blood or stool test could be developed to look for signs of early cancer-causing mutations.

“It gives us hope that we will eventually be able to reduce morbidity and mortality from pancreatic cancer through earlier detection,” he said, adding that he and his team are already working on such a test for colorectal cancer.

The researchers also made another interesting discovery about how pancreatic tumors evolve. They found that the tumors continue to accumulate genetic mutations after they first appear: when they analyzed the genes of pieces of tumor they found they were made of genetically distinct sub-tumors.

Vogelstein said they found what looked like a “series of generations of tumor clones: fathers, grandfathers, great-grandfathers, you could say,” within the primary tumor.

He said this showed the primary tumor was not a single tumor but an accumulation of several genetically distinct tumors.

They were also able to locate within the primary tumor, the subclone that had given rise to each metastased lesion.

“That’s fascinating from a basic science perspective and gives us some deep insights into how these tumors evolve,” said Vogelstein.


One Response to “Deadly Pancreatic Cancer Develops Much More Slowly Than We Thought, Raising Hopes Of Earlier Detection”

  • […] October 28, 2010: Deadly Pancreatic Cancer Develops Much More Slowly Than We Thought, Raising Hopes … October 27, 2010: Sleepiness Could Be In Our Genes October 26, 2010: Gel Alternative To Contraceptive Pill Shows Promising Results In Small Trial October 25, 2010: Potentially Deadly Superbug Rising In Chicago Hospitals October 25, 2010: Paralyzed Man Brain Damaged After Nurse Accidentally Switches Off His Life Support, UK October 24, 2010: Malaria-Transmitting Mosquito Evolving, NIH Grantees Find October 24, 2010: Research Shows a Phone Call can Improve Diabetic Condition October 23, 2010: Too Many Sisters Affect Male Sexuality October 23, 2010: The Impact Of Chronic Diseases On Patients Also Depends On Their Perception Of The Disease October 23, 2010: Researchers Develop First Implanted Device To Treat Balance Disorder October 22, 2010: Low-Dose Aspirin May Cut Risk Of Developing And Dying From Colon Cancer October 21, 2010: Superior Sedation Method For Children Revealed By Study October 21, 2010: Miniature Solar Cells Might Make Chemotherapy Less Toxic October 21, 2010: Malaria Much Bigger Killer In India Than We Thought October 19, 2010: Real-Time Non-Invasive Blood Monitor Could Cut Transfusions During Surgery October 17, 2010: Need A Study Break To Refresh? Maybe Not, Say Stanford Researchers October 17, 2010: New Research Helps Clinicians Predict Treatment Outcomes For Children With OCD October 16, 2010: Melanin Production Controlled By Molecular Switch, May Allow True Sunless Tanning October 15, 2010: Lay Bystanders Should Do Just Chest Compressions, No Mouth-To-Mouth October 14, 2010: Link Between Vegetable Consumption And Decreased Breast Cancer Risk In African-American Women October 14, 2010: Age-Related Memory Loss In Mice Reversed By Promising Drug Candidate October 12, 2010: Higher Kidney Stone Risk For Postmenopausal Women On Estrogen Therapy October 11, 2010: Common Prostate Cancer Treatment Linked To Bone Decay October 10, 2010: Discovery Could Impact How The Body Receives Medicine October 10, 2010: Thoughts About Time Inspire People To Socialize October 8, 2010: Insoluble Medicines Can Be Made Orally Available If In Nano Crystal October 7, 2010: Hidden In Your Genes There May Be A Thirst For Excitement October 7, 2010: AACN Applauds The New Institute Of Medicine Report Calling For Transformational Change In Nursing Education And Practice October 5, 2010: Human Growth Hormone Shows Promise In Treating Cystic Fibrosis Symptoms October 5, 2010: Researchers Identify First Ever Treatment Effective Against Terminal Cancer In Animals October 1, 2010: 12 Percent Of Workers Would Choose To Quit Or Retire Rather Than Report For Work During A Serious Pandemic […]

Leave a Reply

Your email address will not be published. Required fields are marked *