Elevated Risks of NHL, Lung Cancer Increase Mortality in Recipients of Organ Transplant

People who receive organ transplants have an elevated risk of developing cancer, particularly lung cancer and non-Hodgkin lymphoma (NHL), according to a study published in Cancer.

Past research has already shown that recipients of solid organ transplants have an increased risk of cancer, and the number of people who have received solid organ transplants has doubled since the late 1980s. While the benefit of organ transplant is quantified in terms of life-years gained, the adverse effect of cancer after organ transplant is quantified by life-years lost (LYL) due to cancer, the authors explained.

“The LYL due to cancer in the population are calculated as the difference between the average actual lifetime with cancer and what would have been experienced in the population without cancer,” they wrote. “In other words, LYL estimate the extent to which the average lifespan is shortened by cancer.”

They evaluated LYL due to cancer in the first 10 years post transplant for various subgroups, including for common types of cancer, in order to understand which cancers are causing premature deaths.

The study included 221,962 solid organ transplant recipients, 61% of whom were male and 61% of whom were non-Hispanic White. Kidneys were the most frequently transplanted organ (62%), followed by liver (18%), heart (10%), and lung (5%). The patients were followed for 1,118,284 person-years within 10 years of transplant during which 5.9% developed cancer.

A total of 35,371 life-years were lost due to cancer for a mean LYL of 0.16 per transplant recipient and 2.7 years per cancer. The cancers with the greatest LYL were lung cancer and NHL.

In addition, the authors found:

• Cancers of infectious etiology, including NHL, were associated with 0.43% of total expected life-years and 23% of all LYL due to cancer.
• Patients with lung or liver cancer had the highest LYL due to their cancer.
• Prostate cancer was not statistically significantly associated with LYL.
• Lung recipients had the highest mean LYL per person, and although lung recipients accounted for 5% of the cohort, they were 8.1% of the total LYL.

LYL due to cancer increased with age during the 10 years after transplant. While “the oldest group comprised 46% of the cohort but 76% of the total LYL. This pattern was consistent for all organs,” the authors noted.

Older lung recipients had the highest proportion of LYL due to cancer, with 31% of LYL due to lung cancer and 11% due to NHL.

Overall, lung cancer and NHL were responsible for 39% of the total LYL due to cancer, and organ recipients who developed either lung cancer or NHL lost an average of almost 5 life-years.

Among organ recipients 35 years and younger, NHL was the largest contributor to LYL due to cancer. “Although this group had the smallest proportion of LYL due to cancer in the 10 years after transplant (0.5% of expected life-years), NHL was a large contributor,” the authors explained.

While the large size of the study is a strength, the researchers noted that a limitation was that cancer registries do not collect information on nonmelanoma skin cancers, which are common and cause morbidity among organ transplant recipients. Another limitation is that the study only followed patients up for 10 years and LYL due to cancer would be much larger if there was a longer follow-up period.

“There are opportunities to reduce cancer mortality and extend the lives of transplant recipients through prevention and screening,” the authors concluded. “Because large proportions of LYL are caused to NHL and lung cancer, these cancers should be a priority.”

Reference

Noone A-M, Pfeiffer RM, Schaubel DE, et al. Life-years lost due to cancer among solid organ transplant recipients in the United States, 1987 to 2014. Cancer. Published online September 20, 2021. doi:10.1002/cncr.33877