An analysis of a set of randomised trials involving patients in Denmark, Norway and Sweden has been able to provide new insights into the effects of chemotherapy in colorectal cancer, ECCO 12 - the European Cancer Conference heard today (Thursday 25 September).
Prof. Bengt Glimelius, a professor and consultant at the University Hospital in Uppsala and the University Hospital Karolinska Sjukhuset in Stockholm, explained to a news briefing that by collaborating across borders and carrying out a joint analysis the investigators were able to see how adjuvant therapy was likely to work when used as part of routine care for patients with stage II and III colon and rectal cancer.
The analysis, which constituted the largest clinical study to be presented at the ECCO 12 meeting, demonstrated that among 2,223 patients, the 708 patients with colon cancer stage III had a five-year survival of 49% for those treated by surgery alone, but 56% for those given chemotherapy as well. "Although this difference was not statistically significant, it has helped to highlight the need for chemotherapy to be given under optimum conditions and has provided vital evidence about which are the patients most likely to benefit," he said.
For example, one of the Norwegian contributing trials of 425 patients with stage II and III colon and rectum cancer, while showing no overall statistically different survival (68% controls, 72% chemotherapy arm), did show a statistically significant benefit for chemotherapy for patients with stage III colon cancer (48% controls, 65% chemotherapy arm). The investigators concluded that colon cancer patients with lymph nodes metastases should continue to receive chemotherapy as standard treatment.
Prof Glimelius said that the Nordic collaboration differed from previous clinical studies because some of the trials had a very pragmatic design - they assessed the usefulness of a treatment in the 'real world' closer to routine hospital care than generally is the case in clinical trials. "Pragmatic trials may, for instance, have less strict rules about which patients to include or exclude, be more liberal about randomisation and how quickly chemotherapy should be started and for how long it should be given," he said.
"In this study some patients had quite a delay before starting chemotherapy, even though it was stressed how important it is to initiate treatment as soon as possible when there are fewer tumour cells to kill. It is possible that we did not show any clear statistically significant difference overall because of this longer than average delay due to the trial's pragmatic design. Also, several patients had only four months of treatment, and that may be too short. Importantly, the results tell us to look carefully within our trials to see what may be hidden within the overall results - for example, how results may differ between colon or rectal cancer patients, how benefits may differ between different stages of the disease or between men and women."
He said that the Nordic trial was of great general importance. It was big, it was done in 'real world' conditions with less patient selection than generally is the case. It was also running at a time (the 1990s) when there was not always the closest possible collaboration between specialties.
"What this trial has told us that is of key importance is that we must optimise care by ensuring the closest collaboration between specialities and the optimum conditions for patients, and that cross-border international collaborations are the best way to learn these lessons quickly and efficiently. Small differences in survival can translate into many lives saved in common cancers," he concluded.
 Abstract no: 1066. Prof Bengt Glimelius (Thursday 25 September, 09.30 hrs CET, FECS/EJC award presentations session).
 Abstract no: 1084 Professor Olav Dahl (Thursday 25 September, 10.45 CET Colorectal cancer session).
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