Screening for colon cancer saves lives because curable precancerous lesions and early curable colon cancers can be detected and treated. By contrast, if one waits until patients with a colon cancer are symptomatic, in most cases the cancer will have spread to lymph nodes or other organs, and the odds of curing the patient are greatly reduced.
We believe that the greatest opportunity for reducing the number of deaths caused by pancreatic cancer lies in early diagnosis, if possible at a precancerous stage. Six problems need to be tackled for the early detection and cure of pancreatic cancer to become a reality.
First, the curable tumors that give rise to advanced, incurable, pancreatic cancers have to be understood. Second, there has to be a practical time-frame to detect these curable tumors. That is, the advancement from a curable tumor to an incurable cancer has to be slow enough that there is a reasonable chance that the localized tumors can be clinically detected and treated. Third, a test has to be created to detect the curable tumors. This is not a trivial problem when it comes to tumors of the pancreas, because the pancreas lies deep in the back of the abdomen. Fourth, because treating tumors in the pancreas can cause complications (any treatment does), there needs to be a method to differentiate between localized tumors with a significant chance of progressing to an advanced cancer, from tumors with a minimal or no risk of progressing. Fifth, the disease being screened for has to be relatively common the population to be screened. This is because mathematically, screening tests that are applied to populations that are unlikely to have the disease that is being screened for are likely to generate a high number of false positive results (false alarms). Finally, research has to be developed which demonstrates that screening actually saves lives.
As a recent paper in Science Translational Medicine (Bettegowda and colleagues, Sci Transl Med. 2014 Feb 19;6(224):224ra24) nicely demonstrates, screening tests based on genetic changes offer great promise. As these technologies improve, so will the opportunities for the early detection of pancreatic tumors grow. Once developed, we sincerely believe that such early detection tests will have a real, palpable, impact on this disease.
Dr. Hruban