Practical strategies to screen for cancer remain a high priority for public health. For all types of cancer, early diagnosis gives patients the best chance of positive outcomes. Early diagnosis increases the availability of treatment options, and early-stage tumors typically present as more susceptible to treatment than late-stage, more established tumors.
Esophageal cancer is a prime example of a malignancy where early diagnosis makes a big difference in survival. According to the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) data, the overall five-year survival rate for esophageal cancer is only around 20%. However, five-year survival in patients with localized cases (those confined to the esophageal tissue) is almost 50% and cases with regional spread to the lymph nodes have around 28% odds of five-year survival. Unfortunately, patients diagnosed with late-stage cases where cancer has spread to distant tissues or organs have only about a 5% chance of five-year survival. This data highlights the need to promote reliable and assessable screening strategies for esophageal cancer.
Endoscopy, a technique using a narrow tube to look inside the esophagus and collect tissue samples, is a standard method for esophageal cancer screening for patients diagnosed with Barrett’s esophagus (BE), a premalignant condition of esophageal cancer. The American Gastroenterological Association recommends patients with nondysplastic EB undergo endoscopy every three to five years.
However, endoscopies miss a significant number of esophageal cancer cases, which are then detected at a later point, when the disease has presumably advanced. In fact, so many cases evade detection by endoscopy that we have a specific term to define these cases. When a BE patient receives a negative endoscopy result but receives a cancer diagnosis before the next recommended surveillance time, the resulting malignancy is called "post-endoscopy esophageal adenocarcinoma" (PEEC). Studies suggest between 14% and 21% of all esophageal cancers fall into the PEEC classification.
The inability to accurately detect esophageal cancer in patients undergoing screening presents a substantial clinical challenge. A recent study published in Clinical Gastroenterology and Hepatology highlighted these concerns.
The study found the association between neoplasia detection rate (NDR) and risk of PEEC among BE patients recently diagnosed with esophageal cancer. The researchers used data from over 15,000 patients with BE. Esophageal cancer cases diagnosed between 30 and 365 days from BE diagnosis are classified as PEEC, while those diagnosed more than a year after endoscopy were considered incident esophageal cancer.
The researchers found 198 patients who developed esophageal cancer after endoscopy. These cases included 44 (22.2%) PEEC diagnoses and 118 (59.6%) incident esophageal cancer diagnoses. In addition, 36 patients received an esophageal cancer diagnosis within 30 days of endoscopy. Further statistical analysis showed a notably higher incidence rate for PEEC compared to incident esophageal cancer.
This study shows that over 20% of esophageal cancer cases are detected shortly after a negative endoscopy. The literature shows similar inconsistencies between the efficiency of colonoscopies for detecting colon cancer and the incidence of post-colonoscopy colon cancer. These findings highlight a discrepancy between the detection of cancer during endoscopy and the detection of PEEC, underscoring the urgent need to standardize endoscopy protocols.
Sources: Am J Gestroent, Clin Gastroent Hepatol, Gastroenterol