Cancer mortality among solid organ transplant recipients: A systematic review and meta-analysis

OBJECTIVES

To evaluate the cancer mortality risk among solid organ transplant recipients through a systematic review and meta-analysis.

METHODS

Systematic searches were conducted in PubMed (starting from 1965), ISI Web of Science (starting from 1900), MEDLINE (starting from 1976), and Scopus (starting from 1968) from the inception of each database until July 15, 2024. Studies published in English reporting at least one type of cancer mortality risk among recipients of any type of solid organ transplantation were included. The main outcomes were the standardized mortality ratio (SMR) for cancer mortality in transplant recipients compared to the general population, and the hazard ratio (HR) for cancer mortality in transplant recipients versus cancer patients without prior transplantation.

RESULTS

Solid organ transplant recipients had a 2.06-fold increased cancer mortality risk (SMR, 2.06 [95 % CI, 1.56-2.71]) than the general population. Risks were higher in kidney (SMR 1.92 [95 % CI: 1.30-2.84]), liver (SMR 3.07 [95 % CI: 1.80-5.24]), and lung/heart (SMR 4.87 [95 % CI: 3.33-7.12]) transplant recipients. Cancer patients with prior transplantation had a 1.47-fold increased cancer mortality risk (HR 1.47 [95 % CI: 1.29-1.68]) than those without. East Asia female transplant recipients exhibited higher mortality risks from breast, ovarian, cervix and uterus cancers than those from other regions (SMR 3.13 [95 % CI: 1.93-5.07] vs. 1.16 [95 % CI: 0.88-1.53], P < 0.01).

CONCLUSIONS

Solid organ transplant recipients face significantly higher cancer mortality risks than the general population, highlighting the need for targeted cancer screening and interventions, especially for female solid organ transplant recipients from East Asia.

Tumorigenic role of tacrolimus through mTORC1/C2 activation in post-transplant renal cell carcinomas

BACKGROUND

Kidney transplant recipients (KTRs) face an increased risk of renal cell carcinoma (RCC), in which the immunosuppressive regimen plays an important role. This study aimed to identify intracellular signalling alterations associated with post-transplant (post-tx) tumour formation.

METHODS

Expression of mTOR-related proteins were analysed in kidneys obtained from end-stage renal disease (ESRD) patients and RCCs developed in KTRs or non-transplant patients. The effects of tacrolimus (TAC) and rapamycin (RAPA) on mTOR activity, proliferation, and tumour growth were investigated through different in vitro and in vivo experiments.

RESULTS

Elevated mTORC1/C2 activity was observed in post-tx RCCs and in kidneys of TAC-treated ESRD patients. In vitro experiments demonstrated that TAC increases mTOR activity in a normal tubular epithelial cell line and in the investigated RCC cell lines, moreover, promotes the proliferation of some RCC cell line. In vivo, TAC elevated mTORC1/C2 activity in ischaemic kidneys of mice and enhanced tumour growth in xenograft model.

CONCLUSIONS

We observed significantly increased mTOR activity in ischaemic kidneys and post-tx RCCs, which highlights involvement of mTOR pathway both in the healing or fibrotic processes of kidney and in tumorigenesis. TAC-treatment further augmented the already elevated mTOR activity of injured kidney, potentially contributing to tumorigenesis during immunosuppression.

Current status of glucocorticoid usage in solid organ transplantation

Glucocorticoids (GCs) have been the mainstay of immunosuppressive therapy in solid organ transplantation (SOT) for decades, due to their potent effects on innate immunity and tissue protective effects. However, some SOT centers are reluctant to administer GCs long-term because of the various related side effects. This review summarizes the advantages and disadvantages of GCs in SOT. PubMed and Scopus databases were searched from 2011 to April 2021 using search syntaxes covering “transplantation” and “glucocorticoids”. GCs are used in transplant recipients, transplant donors, and organ perfusate solution to improve transplant outcomes. In SOT recipients, GCs are administered as induction and maintenance immunosuppressive therapy. GCs are also the cornerstone to treat acute antibody- and T-cell-mediated rejections. Addition of GCs to organ perfusate solution and pretreatment of transplant donors with GCs are recommended by some guidelines and protocols, to reduce ischemia-reperfusion injury peri-transplant. GCs with low bioavailability and high potency for GC receptors, such as budesonide, nanoparticle-mediated targeted delivery of GCs to specific organs, and combination use of dexamethasone with inducers of immune-regulatory cells, are new methods of GC application in SOT patients to reduce side effects or induce immune-tolerance instead of immunosuppression. Various side effects involving different non-targeted organs/tissues, such as bone, cardiovascular, neuromuscular, skin and gastrointestinal tract, have been noted for GCs. There are also potential drug-drug interactions for GCs in SOT patients.

Risk of Anal High-grade Squamous Intraepithelial Lesions Among Renal Transplant Recipients Compared With Immunocompetent Controls

BACKGROUND

Renal transplant recipients (RTRs) have increased risk of human papillomavirus (HPV)-related cancers, including anal cancer. We investigated the prevalence of anal high-grade intraepithelial lesions (HSILs) in RTRs compared with immunocompetent controls and risk factors for anal HSIL in RTRs.

METHODS

We included 247 RTRs and 248 controls in this cross-sectional study. We obtained anal samples for HPV testing with INNO-LiPA and performed high-resolution anoscopy on all participants. The participants completed a questionnaire on lifestyle and sexual habits. We used logistic regression to estimate odds ratios (ORs) of histologically confirmed anal HSIL in RTRs vs controls and risk factors for anal HSIL in RTRs, stratified by sex and anal high-risk (hr) HPV status, adjusting for age, smoking, lifetime sexual partners, and receptive anal sex.

RESULTS

RTRs had higher anal HSIL prevalence than controls, both among men (6.5% vs 0.8%; adjusted OR [aOR], 11.21 [95% confidence interval {CI}, 1.46-291.17]) and women (15.4% vs 4.0%; aOR, 6.41 [95% CI, 2.14-24.10]). Among those with anal hrHPV, RTRs had higher anal HSIL prevalence than controls (33.8% vs 9.5%; aOR, 6.06 [95% CI, 2.16-20.27]). Having had receptive anal sex (aOR, 6.23 [95% CI, 2.23-19.08]) or genital warts (aOR, 4.21 [95% CI, 1.53-11.48]) were risk factors for anal HSIL in RTRs. All HSIL cases occurred in individuals with anal hrHPV.

CONCLUSIONS

RTRs had increased risk of anal HSIL compared with immunocompetent controls, with particularly high prevalence in female RTRs. Receptive anal sex, previous genital warts, and anal hrHPV infection were risk factors for anal HSIL in RTRs. Screening for anal HSIL in RTRs should be considered.

CLINICAL TRIALS REGISTRATION

NCT03018927.

Association between kidney function and the risk of cancer: Results from the China Health and Retirement longitudinal study (CHARLS)

Objective: Increased cancer risk after dialysis or transplantation has been recognized, but studies of cancer in pre-dialysis chronic kidney disease (CKD) are extremely limited. Therefore, we aim to investigate the risk of cancer in individuals with reduced kidney function.

Methods: This study was based on China Health and Retirement Longitudinal Study (CHARLS), a nationally representative population aged ≥ 45 years old. We included 11 508 (5364 male) individuals with measurement of serum creatinine and without history of cancer at baseline. Incident cancer cases were documented in the biennial questionnaire.

Results: The mean age was 58.7 ± 9.8 years. Participants with estimated glomerular filtration rate (eGFR) ≥ 90 ml/min/1.73m², 60 to 89 ml/min/1.73m², and eGFR < 60 ml/min/1.73m² accounted for 62.9%, 33.7% and 3.4%, respectively. During 42 895 person-years' follow-up, 217 new cases of cancer were recorded. In participants with eGFR < 90 ml/min/1.73m², cubic spline showed linear relationship between the risk of cancer and eGFR, while remained stable and no association in participants with eGFR > 90 ml/min/1.73m². Compared to participants with eGFR ≥ 90 ml/min/1.73m², those with eGFR < 60 ml/min/1.73m² was associated with the increased risk of cancer in the fully adjusted model (hazard ratio 2.08; 95% confidence interval 1.22-3.53); and the risk for kidney and lung cancers was higher among those with eGFR < 60 ml/min/1.73m².

Conclusion: Reduced kidney function is associated with a higher risk of cancer and should be integrated into risk-stratification of cancer screening and management.

Risk of genital warts in renal transplant recipients-A registry-based, prospective cohort study

Genital warts (GWs) are a risk factor for subsequent human papillomavirus (HPV)-related anogenital cancers. In this register-based, prospective cohort study, we estimated the risk of GWs in renal transplant recipients (RTRs) compared with a nontransplanted cohort. In a nationwide database, we identified first-time RTRs in Denmark during 1996 to 2015. For each RTR, 50 age- and sex-matched nontransplanted individuals were selected from the population registry. Information on GWs, sociodemographic characteristics, HPV vaccination, and other causes of immunosuppression was retrieved from registries. We estimated the cumulative incidence of GWs and used Cox regression to estimate hazard ratios (HR) of GWs in RTRs vs non-RTRs. We included 3268 RTRs and 162 910 non-RTRs without GWs 1 year before baseline. RTRs had higher hazard of GWs than non-RTRs (HR = 3.30; 95% confidence interval, 2.76-3.93, adjusted for sex, age, education, and income). The increased hazard of GWs compared with non-RTRs was more pronounced in female than in male RTRs. Although not statistically significant, the hazard tended to be higher in RTRs with functioning grafts compared with RTRs on dialysis after graft failure. The hazard of GWs was increased <1 year after transplantation and remained increased during ≥10 years. In conclusion, RTRs had substantially higher risk of GWs than non-RTRs.

Recipient rs1045642 Polymorphism Is Associated With Office Blood Pressure at 1-Year Post Kidney Transplantation: A Single Center Pharmacogenetic Cohort Pilot Study

Background: Corticosteroids are associated with reduced bone mineral density (BMD), as well as water and salt retention, leading to hypertension. They are substrates for P-glycoprotein, a protein coded by the highly polymorphic ABCB1 gene. We hypothesized that one ABCB1 polymorphism, rs1045642, is associated with blood pressure and BMD parameters at 1-year post kidney transplantation (KT).

Methods: Rs1045642 was genotyped using pyrosequencing in 40 KT recipients. Both dominant (CC vs. CT + TT) and codominant (CC vs. CT vs. TT) genetic models (analysis of variance from linear regressions) were adjusted for confounding variables (age, sex, type of nephropathy, glomerular filtration rate, and corticosteroid use at 1 year).

Results: Rs1045642 genotypes were significantly associated with systolic (SBP) and diastolic (DBP) blood pressure 1-year post-transplantation, independent of the genetic model used (adjusted codominant model: SBP p-value = 0.015, DBP p-value = 0.038; adjusted dominant model: SBP p-value = 0.003, DBP p-value = 0.011). A non-statistically significant trend was observed for an association between rs1045642 and BMD change at 1-year post-KT.

Conclusions: Rs1045642 is significantly associated with higher BP 1 year after KT. Further investigations are necessary to confirm the role of rs1045642 in corticosteroid-related adverse effects.