Should we screen for colorectal cancer in liver transplantation?

Incidence and outcome of colorectal cancer in liver transplant recipients: A national, multicentre analysis on 8115 patients

BACKGROUND & AIMS

De novo malignancies after liver transplantation represent one of the leading causes of death in the long-term. It remains unclear whether liver transplant recipients have an increased risk of colorectal cancer and whether this negatively impacts on survival, particularly in those patients affected by primary sclerosing cholangitis and ulcerative colitis.

METHODS

In this national multicentre cohort retrospective study, the incidence of colorectal cancer in 8115 evaluable adult patients undergoing a liver transplantation between 1 January 1990 and 31 December 2010 was compared to the incidence in the general population through standardised incidence ratios.

RESULTS

Fifty-two (0.6%) cases of colorectal cancer were identified at a median of 5.6 years postliver transplantation, predominantly grade 2 (76.9%) and stage T3 (50%) at diagnosis. The incidence rate of colorectal cancer in the whole liver transplant population was similar to the general UK population (SIR: 0.92), but significantly higher (SIR: 7.0) in the group of patients affected by primary sclerosing cholangitis/ulcerative colitis. One-, five- and ten-year survival rates from colorectal cancer diagnosis were 71%, 48% and 31%, respectively, and the majority of colorectal cancer patients died of cancer-specific causes.

CONCLUSIONS

Liver transplantation alone is not associated with an increased risk of colorectal cancer development. The primary sclerosing cholangitis/ulcerative colitis liver transplant population showed a significantly higher risk of colorectal cancer development than the general population, with a high proportion of advanced stage at diagnosis and a reduced patient survival.

MHC-mismatched mice liver transplantation promotes tumor growth in liver graft

Liver transplantation is a final therapeutic option for treatment of hepatic malignancies, but local recurrence remains high after surgery. However, the underlying mechanisms of local tumor recurrence are still unknown. We speculated that immunological status of transplanted liver may contribute to the progress of tumor development. CT-26 tumor cells are injected into graft after allogeneic or syngeneic liver transplantation. The growth pattern of tumor and the co-relationship of regulatory T cell and effector T cells in liver graft were observed and investigated at 3d, 6d, 9d and 15d post-transplantation. The Hepatic Replacement Area of tumor in allogeneic grafts was significantly larger than that in syngeneic grafts. The activation of tumor growth in allografts was due to the dysfunction of effector T cells mediated by regulatory T cells in liver graft. Using nude mice model, we further confirmed that regulatory T cells from allograft significantly weaken the function of effector T cells in vivo. Our data has showed that MHC-mismatched mice liver transplantation can promote tumor growth in liver graft. For the first time, we demonstrated that susceptibility to tumor development in liver graft is due to the down-regulation of effector T cells' function mediated by the regulatory T cells.

Early and late de novo tumors after liver transplantation in adults: the late onset of bladder tumors in men

Background

De novo tumors (DNT) after liver transplantation (LT) represent a growing concern.

Patients and Methods

We analyzed the incidence of DNT, type, time of onset, risk factors and mortality (as of 2010) in 494 adult patients transplanted in the last 26 years (1983–2009).

Results

DNT occurred in 41 (8.3%) of the patients. The Standardized Incidence Ratio (SIR) compared with the Italian population was 1.8. There was a higher incidence in males (SIR 2.0), an expected extremely high rate of Kaposi’s sarcoma (SIR 127.95) and unexpected higher rates of tumors of the bladder in males (SIR 3.3). The incidence of DNT was higher within the first two years of LT (SIR 2.7) for Kaposi’s sarcoma (SIR 393.3) and after 10 years (SIR 1.7) for bladder tumors (SIR 10.6). Multivariate analysis identified alcoholic cirrhosis (HR = 3.0, 95% CI = 1.2–7.8) and sclerosing cholangitis (HR = 3.5, 95% CI = 1.1–11.3) in the recipient as main risk factors for the occurrence of DNT.

Conclusions

Surveillance protocols for DNT must be specifically oriented to patients transplanted for alcoholic cirrhosis and sclerosing cholangitis. They should focus on early detection of Kaposi’s sarcomas, and more remarkably, on late development bladder tumors in men after LT.

Screening of de novo tumors after liver transplantation

De novo malignancies are frequent complications after liver transplantation. They are one of the leading causes of late death. Some authors have reported promising results following implementation of extensive cancer surveillance programs. Screening protocols might benefit patients by providing a diagnosis at an earlier stage when tumors may be cured. These protocols should be based on the specific risk factors of every patient. Unfortunately, the scientific evidence supporting screening protocols is still very weak both in the general population and in the transplant patients. On this basis, there is not enough evidence to recommend routine screening for all liver transplant recipients, apart from the recommendations accepted for the general population. Multicenter studies in selected groups of patients at high risk for malignancy may be the only way of defining the potential benefit of screening programs post-transplantation.

Colorectal cancer in post-liver transplant recipients

PURPOSE

Several malignancies have been reported to occur more often after liver transplantation. Whether this is also true for colorectal carcinoma is controversial. Our aims were 1) to compare the observed rate of colorectal carcinoma in a post-liver transplantation cohort with incidence data from the general Dutch population, and 2) to stratify for patients with and without primary sclerosing cholangitis, because primary sclerosing cholangitis is well established as a risk factor for colorectal carcinoma.

METHODS

We searched the medical records of liver transplantation patients who had a liver transplantation in our center between 1986 and 2007 with a follow-up of at least 3 months. Incidence data from the general population were retrieved from the Dutch Comprehensive Cancer Registry. Outcome measures were defined as standardized incidence ratio and incidence rate per 100,000 person-years.

RESULTS

Three hundred ninety-four patients (58% men; mean age at liver transplantation, 46.6 y) were included in the 1986 to 2007 period. Bowel investigation before liver transplantation had been performed in 73% of patients. Median follow-up was 5.1 years (range, 0.25-20 y). The mean age at the end of follow-up was 52 years (SD, 13 y). Colorectal carcinoma was diagnosed in four patients (1%) during follow-up. The overall standardized incidence ratio for colorectal carcinoma in post-liver transplant recipients was 2.16 (95% CI: 0.81-5.76) compared with the general population and 1.26 (95% CI: 0.31-5.03) for nonprimary sclerosing cholangitis post-liver transplant recipients.

CONCLUSION

This study suggests that the incidence of colorectal carcinoma is not increased in non-primary sclerosing cholangitis post-liver transplantation compared with the general population. A more intense colorectal carcinoma surveillance program based on this result remains controversial in nonprimary sclerosing cholangitis post-liver transplant recipients.

JC virus infection in colorectal neoplasia that develops after liver transplantation

PURPOSE

Liver transplant recepients (LTRs) have an increased risk of colorectal neoplasia. The mechanism responsible for this is unknown. JCV encodes for TAg and has been implicated in colorectal carcinogenesis. We hypothesized that the use of immunosuppression in LTRs facilitates activation of JCV and is responsible for the increased risk of neoplasia.

EXPERIMENTAL DESIGN

JCV TAg DNA and protein expression were determined in normal colonic epithelium (n = 15) and adenomatous polyps (n = 26) from LTRs and compared with tissue samples from control patients (normal colon, n = 21; adenomas, n = 40). Apoptosis and proliferation were determined by M30 and Ki-67 immunoreactivity, respectively.

RESULTS

JCV TAg DNA was found in 10 of 15 (67%) of normal colonic mucosa from LTRs compared with 5 of 21 (24%) of control normal mucosa (P = 0.025). JCV TAg DNA was detected in 16 of 26 (62%) of the adenomas from LTRs and in 20 of 40 (50%) of control adenomas. JCV TAg protein was expressed in 13 of 26 (50%) adenomas from LTRs versus 2 of 40 (5%) of adenomas from controls (P < 0.001). In adenomas from LTRs, the mean proliferative activity was higher compared with controls (60.3 +/- 3.2% versus 42.7 +/- 2.8%, P < 0.001), whereas mean apoptotic indices were lower in LTRs (0.29 +/- 0.08% versus 0.39 +/- 0.06%, P = 0.05).

CONCLUSIONS

The presence of JCV in the colorectal mucosa and adenomas from LTRs, in concert with the use of immunosuppressive agents, suggests that JCV may undergo reactivation, and the subsequent TAg protein expression might explain the increased risk of colorectal neoplasia in LTRs.