Before they make their decision, the patients are told that if, at any time during the following 24 months, any sign of tumor reappearance (or "regrowth") were to emerge, that would necessarily mean undergoing immediate surgery to remove the tumor in the exact way as initially programmed.
But if the cancer does not regrow during those first 24 months, the patient will then go on to be examined, at least every six months, for three additional years. After that, if it still doesn't reappear, the exams will continue at a rate of once a year.
Is it wise to wait?
Criticism of this protocol has focused, in particular, on the possibility of wasting precious time, during which the tumor could become, if not metastatic, possibly uncontrollable and impossible to remove surgically. It is this deferment of the surgery that the team has now shown to be safe in 97% of cases of tumor regrowth.
The new study involved 385 patients from both centers (83 from the Champalimaud) that were diagnosed between 2005 and 2018 and found to have a complete clinical response following chemoradiotherapy. Of those 385 patients, 89 (23 from Champalimaud) - or around 25% - had tumor regrowth during the first 24 months. And of the patients who experienced regrowth, "97% were rescued, which means operated on as initially programmed", says Figueiredo.
In other words, the W&W period did not compromise the outcome for those patients. The final result was the same they would have obtained if the surgery had been performed immediately.
There were also some patients included in W&W (3%) who were either too frail or too old to sustain a major abdominal operation - or who, experiencing a regrowth after the W&W period, refused to have surgery. These patients were then given the best possible palliative care.
Another line of criticism has to do with the possibility that waiting to see what happens could increase the risk of developing distant metastases, that is, of the initial tumor spreading to other parts of the body, in particular to the liver and lungs. Figueiredo points out that this study was not designed to answer this question.
However, what these researchers have effectively observed is that, compared to historical rectal series in the literature, for which 25% of the patients with rectal cancer go on to develop metastases, this only happened to 8.2% of the patients submitted to the W&W protocol. According to Figueiredo, this could simply reflect the fact that eligible patients for the alternative protocol have a much better prognosis than the general population of rectal cancer patients - and start out with a reduced risk of metastases.
Two next steps, he adds, are already ongoing, namely at the Champalimaud. One is to intensify radiation oncology protocols in order to increase the number of rectal cancer patients who reach a clinical complete response and become eligible for W&W - that is, to contemplate radio and chemotherapy as a standard standalone treatment for these tumours and not just a precursory step for surgery. The other is to improve the diagnostic accuracy of MRI and endoscopy exams in order to reduce the number of "false negatives" - that is, the number of apparently complete responses in which the tumor is actually still there after chemoradiotherapy but fails to be detected.
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