After endoscopic resection, high-risk T1 colorectal cancer (CRC) may have a tenfold greater risk of recurrence than low-risk disease, based on a meta-analysis involving more than 5,000 patients.
These findings support personalized, histologically based surveillance strategies following endoscopic resection of T1 CRC, reported lead author Hao Dang of Leiden University Medical Center in the Netherlands, and colleagues.
“With the introduction of population-based screening programs, a growing number of early-invasive colorectal cancers (T1 CRCs) are detected and treated with local endoscopic resection,” the investigators wrote in Clinical Gastroenterology and Hepatology.
Success with this approach, however, depends upon accurate risk recurrence data, which have been lacking.
Joseph Feuerstein, MD, of the department of medicine at Harvard Medical School and associate clinical chief of gastroenterology at Beth Israel Deaconess Medical Center, Boston, said, “While attempting complete resection of an early cancer with a colonoscopy is appealing, given the very low morbidity associated with it, this technique is only advisable if the risk of recurrence is extremely low when comparing [it] to surgical resection.”
In addition to patient selection, accurate recurrence data could also inform postoperative surveillance.
“To determine the optimal frequency and method of surveillance, it is important to know how often, and at which moments in follow-up local or distant CRC recurrences exactly occur,” wrote Mr. Dang and colleagues. “However, for endoscopically treated T1 CRC patients, the definite answers to these questions have not yet been provided.”
To find answers, Mr. Dang and colleagues conducted a meta-analysis involving 71 studies and 5,167 patients with endoscopically treated T1 CRC. The primary outcome was cumulative incidence and time pattern of CRC recurrence. Data were further characterized by local and/or distant metastasis and CRC-specific mortality.
The pooled cumulative incidence of CRC recurrence was 3.3%, with local and distant recurrences occurring at similar, respective rates of 1.9% and 1.6%. Most recurrences (95.6%) occurred within 72 months of endoscopic resection.
Risk-based recurrence analysis revealed a distinct pattern, with high-risk T1 CRCs recurring at a rate of 7.0% (95% confidence interval, 4.9%-9.9%; I2 = 48.1%), compared with just 0.7% for low-risk tumors (95%-CI, 0.4%-1.2%; I2 = 0%). Mortality data emphasized the clinical importance of this disparity, as the CRC-related mortality rate was 1.7% across the entire population, versus 40.8% among patients with recurrence.
“Our meta-analysis provides quantitative measures of relevant follow-up outcomes, which can form the basis for evidence-based surveillance recommendations for endoscopically treated T1 CRC patients,” the investigators concluded.
According to Dr. Feuerstein, the findings highlight the importance of surveillance after endoscopic resection of CRC while adding clarity to appropriate timing.
“Current guidelines recommend a colonoscopy following a colon cancer diagnosis at 1 year and then 3 years and then every 5 years,” Dr. Feuerstein said. “Adhering to these guidelines would likely identify most cases of recurrence early on within the 72-month window identified in this study.” He noted that “high-risk T1 CRC should probably be monitored more aggressively.”
Anoop Prabhu, MD, of the department of medicine at the University of Michigan Medical Center and director of endoscopy at Ann Arbor Veterans Affairs Medical Center, drew similar conclusions from the findings, noting that “tumor histology appears to be a powerful risk-stratification tool for subsequent surveillance.”
“One of the most important take-home messages from this paper is that, in those patients with low-risk, endoscopically resected colon cancer, surveillance with a colonoscopy in 1 year (as opposed to more intense endoscopic or radiographic surveillance) is likely more than adequate and can save unnecessary testing,” Dr. Prabhu said.
To build upon these findings, Dr. Prabhu suggested that upcoming studies could directly compare different management pathways.
“A potential area for future research would be a cost-effectiveness analysis of competing surveillance strategies after upfront endoscopic resection, with a particular focus on cancer-specific survival,” he said.
The investigators disclosed relationships with Boston Scientific, Cook Medical, and Medtronics. Dr. Feuerstein and Dr. Prabhu reported no relevant conflicts of interest.