Survival among solid organ transplant recipients diagnosed with cancer compared to nontransplanted cancer patients—A nationwide study

Abstract

Solid organ transplant recipients (OTRs) have an increased cancer risk but their survival once diagnosed with cancer has seldom been assessed. We therefore investigated cancer‐specific survival among OTRs with a wide range of cancer forms nationally in Sweden. The study included 2,143 OTRs with cancer, and 946,089 nontransplanted cancer patients diagnosed 1992–2013. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox regression models adjusted for age, sex and calendar year. Median follow‐up was 3.1 (range 0–22) years. Overall, OTRs diagnosed with any cancer had a 35% higher rate of cancer death compared to nontransplanted cancer patients (HR: 1.35, 95% CI: 1.24–1.47). Specifically, higher rates of cancer‐specific death were observed among OTRs diagnosed with Hodgkin lymphoma (HR: 15.0, 95% CI: 5.56–40.6), high‐grade non‐Hodgkin lymphoma (HR: 2.68, 95% CI: 1.90–3.77), malignant melanoma (HR: 2.80, 95% CI: 1.74–4.52) and urothelial (HR: 2.56, 95% CI: 1.65–3.97), breast (HR: 2.12, 95% CI: 1.38–3.25), head/neck (HR: 1.55, 95% CI: 1.02–2.36) and colorectal (HR: 1.42, 95% CI: 1.07–1.88) cancer. The worse outcomes were not explained by differences in distribution of cancer stage or histologic subtypes. For other common cancer forms such as prostate, lung and kidney cancer, the prognosis was similar to that in nontransplanted cancer patients. In conclusion, several but not all types of posttransplantation cancer diagnoses are associated with worse outcomes than in the general population. Reasons for this should be further explored to optimize posttransplantation cancer management.

Elevated incidence of head and neck cancer in solid organ transplant recipients

“…Prior studies have demonstrated increased rates of cancer‐related mortality in solid organ transplant recipients, as would be expected, including for head and neck cancers, but again most studies have been hampered by the lack of a control group, making survival comparisons difficult . However, two recent studies have utilized cancer databases to compare cancer patients with transplants to those without: each found a higher rate of cancer‐specific mortality for transplant recipient with certain head and neck cancers . The largest study found increased cancer‐specific mortality in oral cavity/pharynx, but not for thyroid; in the present study, we found significantly worse survival in thyroid patients, but we assessed OS, not cancer‐specific mortality, making comparison of findings challenging .…”

“…The most common posttransplant malignancies include skin cancers, lymphoproliferative disorders, and lung cancer . Several studies have also demonstrated increased risk of head and neck cancers; in particular, oral cavity, oropharynx, and thyroid cancers have been shown to be associated with prior solid organ transplant . While kidneys are the most commonly transplanted—and correspondingly, studied—solid organ, an increased rate of head and neck cancers has also been shown in heart, lung, and liver transplantations …”

“…Additionally, as previous studies have primarily assessed only transplant patients without comparators, the effects of solid organ transplant on head and neck cancer survival is uncertain. A few studies have demonstrated that transplant patients with cancer have worse survival compared with other cancer patients, but research is limited …”

“…4,[7][8][9][10][11][12][13][14][15][16][17][18] While kidneys are the most commonly transplanted-and correspondingly, studied-solid organ, an increased rate of head and neck cancers has also been shown in heart, lung, and liver transplantations. [14][15][16][17][18][19] Though a link between solid organ transplant and subsequent head and neck cancers has been established, the extent of increased risk is unclear. While several robust studies of cancer risk in transplant patients have been conducted, such studies typically have only included cohorts of transplant recipients and lacked a control group: thus, estimates of risk are based on population data.…”

“…A few studies have demonstrated that transplant patients with cancer have worse survival compared with other cancer patients, but research is limited. 6,16,21,22 Ultimately, few studies have assessed transplant and nontransplant patients in tandem, which is important to provide a meaningful comparison group for analysis of cancer risk and survival outcomes in solid organ transplant recipients. The present study aimed to address this gap in the literature by examining a large cohort of patients with and without solid organ transplant, and with and without head and neck cancer, to provide a determination of the risk of head and neck cancer in transplant recipients compared with other patients.…”