Author: By Eleanor McDermid, Senior medwireNews Reporter
medwireNews: Intensive surveillance may only be necessary for the first 3 years for rectal cancer patients who maintain a clinical complete response after neoadjuvant chemoradiotherapy, research suggests.
“The risk of local regrowth or distant metastases after a clinical complete response to neoadjuvant chemoradiotherapy after non-operative management of rectal cancer remains an important drawback for the widespread uptake of watch and wait in clinical practice”, write Rodrigo Perez, from Angelita and Joaquim Gama Institute in São Paulo, Brazil, and co-researchers.
But in their conditional survival modelling study of 793 rectal cancer patients from the International Watch & Wait Database who had a clinical complete response after neoadjuvant chemoradiotherapy, the team found that patients had a less than 5% risk for both these outcomes – if they had a sustained clinical complete response for 3 years.
If patients had maintained a clinical complete response for 1 year, then the estimated probability of remaining free of local regrowth for an additional 2 years was 88.1%.
However, after maintaining a clinical complete response for 3 and 5 years, these rates increased to 97.3% and 98.6%, respectively.
Likewise, the estimated probability of remaining free of distant metastases was 93.8% after 1 year of watch and wait, but rose to 97.8% and 96.6% for those who remained in watch and wait after 3 and 5 years, respectively.
“Based on our findings, intensive surveillance of the rectum for the detection of local regrowth after sustaining a clinical complete response for more than 3 years is unlikely to be required”, write the researchers in The Lancet Oncology.
“Patients without any signs of regrowth or distant metastases at 3 years could probably be included in well established follow-up programmes for patients with rectal cancer who undergo standard treatment pathways involving radical resection.”
The known baseline risk factors of cT stage and radiotherapy dose were both significantly associated with local regrowth risk in the first year. Specifically, the estimated probability of remaining free of regrowth was 88.0% versus 80.9% for patients with cT1 or cT2 versus cT3 stage tumours and was 76.8% versus 85.2% for those who received less than 50.4 Gy versus a higher dose.
However, among patients who sustained a clinical complete response for longer than 1 year, these factors had no significant influence on local regrowth risk.
Rodrigo Perez and team say that “these risk factors appear to be less relevant after 1 year of a sustained clinical complete response.”
They conclude: “Ultimately, the biological information provided by a sustained clinical complete response could override these risk factors.”
Fernandez LM, São Julião GP, Figueiredo NL, et al. Conditional recurrence-free survival of clinical complete responders managed by watch and wait after neoadjuvant chemoradiotherapy for rectal cancer in the International Watch & Wait Database: a retrospective, international, multicentre registry study. Lancet Oncol; Advance online publication 11 December 2020. doi:10.1016/S1470-2045(20)30557-X
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