Patterns of care for synchronous rectal cancer with liver-only metastasis: Results from the South Australian registry of metastatic colorectal cancer.

Abstract

701 Background: Management of rectal cancer with synchronous liver metastasis is not clear. Optimal timing of radiotherapy, chemotherapy, resection of primary and liver metastasis is debated. Methods: The South Australian Registry for metastatic colorectal cancer has entered all patients with mCRC since 1st February 2006. Registry data were analyzed to assess patient characteristics, therapy received and outcomes for patients with liver only metastasis and synchronous rectal or colon primary. KM analysis was used for survival outcomes. Results: 2677 patents had synchronous mCRC. 42% (n = 1125) had liver only metastasis (primary: 275 rectal/850 colon). The main differences between rectal/liver vs. colon/liver were: more males (68.7% v 57.8%, p = 0.001), younger age (65.8 v 73.3 years, p < 0.001) and less poorly differentiated histology (14.2% v 24.1%, p = 0.003). The rate of no surgery on the primary was 21.4% for rectal cancers v. 36% for colon (p ≤ 0.001). Liver surgery rates in both groups was similar (28.4% v 23.0% (p = 0.075). Out of the 275 rectal cancer patients, 100 (36.3%) had rectal surgery, 83 (30%) had chemo-RT and 47 (17%) had chemotherapy +/- targeted therapy as initial treatment, 45 (16%) patients had no treatment. Median OS of rectal cancer patients based on their initial treatment was 33.2m (Chemo-RT) vs. 22.2m (surgery) vs. 19.2m (chemotherapy +/- targeted therapy, p < 0.001). The mOS for rectal group was 22.8m v. 14.8m (p = 0.001) for colon group. For patients who had liver surgery mOS was 60.7m vs. 67.1m respectively. Survival was better if primary was rectum or left colon vs. right colon (mOS 18.3m vs 18.8m vs 10.2m respectively p < 0.001). Resection of the primary occurred first in all patients who had liver resection. Conclusions: Patients with synchronous rectal cancer with liver only metastases have better survival compared to those with colon cancer and liver only metastases. Where surgery is possible, OS is equivalent between the two groups and in our registry population surgery on the rectal primary or chemo-RT were found to be the preferred initial treatment for rectal cancer patients with synchronous liver metastases.