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Conversion therapy means giving drugs to shrink secondary tumours that cannot be operated on at first, in the hope that they become small enough to remove. It is a different goal from simply controlling the disease: the treatment is chosen for how hard it shrinks the tumour, and the scans are reviewed by a surgeon every couple of months.
The idea. When colorectal cancer has spread to the liver but is technically unresectable or too numerous to remove, the aim of first-line treatment can be to make surgery possible rather than to hold the disease still. That changes the choice of regimen towards the combinations with the highest response rates, and it changes the follow-up: the scans are reassessed by a surgeon at intervals, not only for progression.
The evidence. CELIM randomised 111 patients with non-resectable liver metastases (technically unresectable or five or more deposits) to cetuximab with FOLFOX6 or with FOLFIRI. A confirmed partial or complete response occurred in 68 and 57 percent of the two arms, and R0 resection followed in 38 and 30 percent. A blinded retrospective surgical review of the imaging found resectability rose from 32 percent at baseline to 60 percent after chemotherapy. Response was strongly dependent on genotype: 70 percent of patients with KRAS wild-type tumours responded against 41 percent of those with KRAS-mutant tumours (Folprecht 2010). That genotype dependence is why RAS and BRAF testing comes before the regimen is chosen (NICE NG151 1.4.1), and why sidedness enters the decision as well.
What the term does not mean. Conversion is not the same as perioperative chemotherapy for metastases that were already removable, which is the EORTC 40983 question, and it is not the same as a clinical complete response on imaging: disappearing metastases on the scan frequently harbour residual disease, so the surgeon still resects where the deposit was. The parent record carries the first-line regimens and their biomarker rules.
In plain words · KRAS is the most commonly mutated cancer gene, called 'undruggable' for 40 years until 2021.
Showing the target this term concerns: KRAS.
Shares Sidedness (left vs right colon), BRAF, EGFR, KRAS and the tags gi, colorectal.
Shares Sidedness (left vs right colon), BRAF, EGFR, KRAS and the tags gi, colorectal.
Shares Peritoneal metastases from bowel cancer, Colon cancer (adenocarcinoma of the colon), Rectal cancer, Colorectal cancer and the tags gi, colorectal.
Shares Peritoneal metastases from bowel cancer, Colon cancer (adenocarcinoma of the colon), Rectal cancer, Colorectal cancer and the tags gi, colorectal.
Shares Sidedness (left vs right colon), Colon cancer (adenocarcinoma of the colon), Rectal cancer, Colorectal cancer and the tags gi, colorectal.
Shares Sidedness (left vs right colon), BRAF, Colon cancer (adenocarcinoma of the colon), Colorectal cancer and the tags gi, colorectal.
Shares Colon cancer (adenocarcinoma of the colon), Rectal cancer, Colorectal cancer and the tags gi, colorectal.
Shares Colon cancer (adenocarcinoma of the colon), Rectal cancer, Colorectal cancer and the tags gi, colorectal.