Chemoradiotherapy plus induction or consolidation chemotherapy as total neoadjuvant therapy for locally advanced rectal cancer

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Published: 15 Jul 2019
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Prof Ralf-Dieter Hofheinz - Uniklinik Mannheim, Mannheim, Germany

Prof Ralf-Dieter Hofheinz speaks to ecancer at ESMO 21st World Congress on Gastrointestinal Cancer about the results from a randomised, phase II trial chemoradiotherapy plus induction or consolidation chemotherapy as total neoadjuvant therapy for locally advanced rectal cancer.

He describes the trial design, along with the patient population selected and the main hypothesis of the study which was that the pathological complete response rate (pCR) would increase 25% after total neoadjuvant therapy (TNT).

Prof Hofheinz states that the participants that were administered with chemoradiotherapy first, and later consolidation chemotherapy achieved a pCR of 25 percent - compared to patients who received chemotherapy first, who achieved 17 percent pCR.

He concludes by discussing the upcoming phase III trial, where neoadjuvant chemotherapy will be compared with immediate surgery, in a low-risk patient population.

 

Rectal cancer treatment is dramatically changing these days and we have a division between local risk patients at high and low local risk. What we’ll present tomorrow is a study for high risk local rectal cancer patients where we investigated two different types of total neoadjuvant therapy regimens. We asked the question which one was to pick for the next phase III trial so we had an arm where we first gave chemotherapy, six weeks of FOLFOX, and then another arm where we started with chemoradiotherapy. Basically this was not a comparison between both arms but it was a pick the winner phase II design where we included a total of 306 patients. The question was in which arm the pCR rate could be increased to about 25%, coming from a historical pCR rate of 15%.

So what turned out the results were the winning arm is basically arm where we started with chemoradiotherapy and gave consolidation chemotherapy. We had a 25% complete pathologic response rate. In contrast, the other arm where we started with chemotherapy were 17% only.  So, given that the surgical morbidity and the complication rate is basically identical between both arms we can say we can move on forwards with this regimen in the next phase III trial.

In this phase III trial we plan to include high risk local cancer patients only, T3 and T4 tumours with an infiltration depth of at least 5mm in the perirectal fat in the lower and mid-rectal rectum only. A complementary study will be for the early patients or early T3 which means infiltration below 5mm where the question is not so much of local treatment intensification but in those patients the question is to spare them from radiotherapy. So we will compare neoadjuvant chemotherapy only with immediate surgery in this low risk rectal cancer group.

Basically I think this is one of the questions we all have, what do the patients need at all, how much chemotherapy, how much radiotherapy. Time is over that all patients are treated the same with pre-op chemoradiotherapy and surgery.

Basically, just another question is how can we spare the organs or organ sparing treatment? This would mean complete clinical remission – would you still go for surgery? I told that we had a 25% of complete remissions plus 3-4% of patients with clinical complete remissions who did not undergo surgery, resulting in a total of almost 30% of pCR rate and cCR rate. This is really much in view of the fact that the patients include the high risk patients.

So the last question we have to answer as a community is which patients can be spared from surgery without compromising the overall survival data.