The intensity of posttreatment surveillance of patients with rectal cancer managed by a watch-and-wait approach can be safely reduced if patients achieve and maintain a clinical complete response within the first 3 years of initiation of that approach, a retrospective, multicenter registry study suggests.
“The risk of local regrowth or distant metastases after a clinical complete response to neoadjuvant chemoradiotherapy after nonoperative management of rectal cancer remains an important drawback for the widespread uptake of watch and wait in clinical practice,” Laura Fernandez, MD, Champalimaud Clinical Center, Lisbon, and colleagues observe.
“Conditional survival analysis estimates suggest that patients who sustain a clinical complete response for 3 years have 5% or lower risk of developing a local regrowth and a less than 2% risk of developing systemic recurrence thereafter,” the investigators emphasize.
Achieving a complete clinical recovery and sustaining it for 1 year is the “most relevant protective factor” for patients with rectal cancer and places them in an “excellent prognostic stage,” Fernandez said in a press statement.
The study was published online Dec. 11 in The Lancet Oncology.
A watch-and-wait database
A total of 793 patients were identified from the International Watch and Wait Database, a large registry of patients who experience a clinical complete response after neoadjuvant chemotherapy and who are managed by a watch-and-wait strategy. The registry includes data from 47 clinics in 15 countries.
The main outcome measures were the probability of patients remaining free of local regrowth and distant metastasis for an additional 2 years after sustaining a clinical complete response for 1, 3, and 5 years after the start of watch-and-wait management.
Among patients who had sustained clinical complete response for 1 year, the probability of remaining local regrowth–free for an additional 2 years – in other words, for a total of 3 years – was 88.1%.
Local regrowth–free survival rates were in the high 90 percentages after sustaining a clinical response for 3 years and for 5 years.
“Similar results were observed for distant metastasis–free survival,” Dr. Fernandez and colleagues continue. For example, 2-year conditional distant metastasis–free survival rates among patients who remained free of distant metastasis from the time the decision was made to initiate watch-and-wait management for 1 year was 93.8%; for 3 years, it was 97.8%; and for 5 years, it was 96.6%, the investigators report.
The only risk factors identified in the study for local regrowth over time was baseline clinical tumor stage and total dose of radiotherapy received.
However, after patients have achieved and sustained a complete clinical response for 1 year, known risk factors for local regrowth, such as disease stage before any treatment and the dose of radiation received by the patient, “seem to become irrelevant,” said Dr. Fernandez.
The authors say that after a patient sustains a clinical complete response for more than 3 years, it is unlikely that intensive surveillance for the detection of local regrowth would be required.
Indeed, they suggest that those who have no sign of regrowth or distant metastases at 3 years post treatment could probably be followed in established follow-up programs for rectal cancer patients who are treated with standard therapy, including radical resection.