Generally speaking, pancreatic ductal adenocarcinoma in early stages doesn't cause any symptoms. Once it causes symptoms, such as dull pain in the upper abdomen which can radiate to the back, weight loss or jaundice, the disease is usually advanced. That means that it has spread locally, e.g. By invading into adjacent tissues such as nerves, lymph nodes etc., or has even metastatically spread.

Furthermore, to my knowledge, there is no specific early clinical marker that could detect the disease

Early stage usually means localized disease. And TNM classification is useful for most of the solid tumors because of demonstrated slow stepwise progression. In most of the solid tumors the primary lesion is enough large to cause symptoms or to be detected clinically/by imaging BEFORE obtaining metastatic potential. This is not the case with pancreatic ductal adenocarcinoma, where metastatic potential is present even in very small and clinically silent or still undetectable by imaging primary tumor. If you look at the survival figures even in stage I pancreatic cancer you will realize that there is something wrong with our current staging – most of the T1N0M0 pts died from distant disease. In these circumstances TNM stages does not seem useful, and more biological markers are needed in order to stratify precisely pts with pancreatic cancer. And I am not sure that there is a clinically working definition for a think like “pancreatic cancer in early stage”.

May be one 15-year old boy and his mesothelin test will change the history of pancreatic cancer management? Who knows. I highly suggest the following information:

http://student.societyforscience.org/article/speedy-cancer-detector

Pancreas lies in the duodenal loop and in front of celiac axis. Even local growth makes it unresectable. Symptoms of pain occur when celiac plexus is compromised and by then it is too late to surgically remove completely. There are risk factors and warming signs but no data available to do ANY kind of testing for early detection like in breast, cervix etc.

I'm not a pancreatic cancer expert by any means, but in terms of early detection by the use of noninvasive imaging techniques, such as Nuclear Medicine, there isn't much to offer other than ultrasound perhaps, and I'm also not sure how early detection would affect outcomes, or what guidelines would be used for patient selection in terms of who to test and how often. As someone already suggested, an identified marker (as in the case of PSA) and a simple blood assay for it would be highly desirable, even if the test was not 100% reliable (false positives or negatives, for example). Even with early detection, what can patients be offered in terms of effective treatment? Not much as far as I know. It seems as though both detection and treatment options need considerable advancement before any significant improvement in patient outcomes would be observed.

If is it true that in many cases PC at early stage is silent, another problem is that, if we exclude few high risk individual, no surveillance programs for an early diagnosis is available.

Only for patients with a family history of pancreatic cancer, or pre-cancerous lesions, as IPMN, a screening and, eventually, preemptive surgery is possible. However, no clear results are available to confirm how much these strategies are cost effective.