It is known that anomalies in the chromosomal content can often be found in many solid carcinomas. Some studies showed a strong correlation between DNA ploidy status and survival and identified DNA ploidy as a potential predictive marker of prognosis in human pancreatic cancer. Most of these studies were retrospective and based on the analysis of paraffin- embedded archival material and therefore provided only limited evidence. The aim of this prospective long-term follow-up study was to evaluate the prognostic impact of the DNA index, which was assessed by DNA image cytometry from fresh tumor samples, on the survival of patients undergoing resection of ductal adenocarcinoma of the pancreatic head.
The results of this study identify DNA index as a strong independent predictive marker of prognosis in patients with invasive ductal pancreatic cancer. DNA index might be useful in the identification of high-risk patients, as it is a reliable predictive factor of survival. Furthermore, the present study was able to show that DNA index does not correlate with histopathological parameters, such as tumor stage or resection margin, and therefore represents an independent marker of tumor biology instead of another histopathological parameter. However, a combination of DNA index with other histopathological parameters (eg, lymph node status) might allow even stronger prediction of survival in patients with pancreatic cancer. In the present study, the patients with low DNA index and negative lymph node status showed a significantly prolonged survival compared to the patients with adverse combinations of these independent predictive factors.
To do that, The DNA index, which is the mean nuclear DNA content of the G0/G1 compartment of the neoplastic cell population divided by the DNA content of the G0/G1 compartment of the similarly processed group of known diploid reference cells, was automatically calculated. DNA ploidy and DNA index were measured in all the patients. Through the DNA image cytometry, 15 tumors were identified as diploid (24.6%) and 46 tumors (75.4%) were identified as nondiploid. The mean ± SD DNA index of the entire cohort was 1.87 ± 0.30.