AM23: Deferrals of Blood Donors with a History of Cancer

The Food and Drug Administration (FDA) has maintained oversight of blood centers since 1972 but has no regulations governing the eligibility of blood donors with a history of cancer. Most blood centers use the Donor History Questionnaire (DHQ) developed by AABB and approved by the FDA for donor screening. One of the questions on the DHQ is “Have you ever had any type of cancer, including leukemia?” How positive responses are handled—whether donors with a history of cancer are deferred—is left to the medical director’s discretion.

In a Monday afternoon session, “The Science… or Not Behind Deferrals of Blood Donors with a History of Cancer,” Courtney Hopkins, DO, discussed the results of a 2022 survey that studied medical directors’ responses to benign and malignant solid tumors, hematological malignancies, elevated white blood cell counts and the presence of cancer but with no active treatment. The study also addressed post-donation reports of cancer, look-back and donor re-entry strategies.

The survey was developed by a working of group of America’s Blood Centers’ (ABC) Scientific, Medical and Technical Committee. It was sent in June 2022 to representatives of 47 ABC blood center members in the US and Canada. The response rate was 79% (37 respondents, 36 in the US, one in Canada). This represented half of the blood centers.

The survey focused on blood center deferral time periods and look-back policies for donors with a history of cancer, or pre-cancerous lesions, or out-of-range hematologic laboratory values reported by the blood center doing the testing. Recipients were asked, regarding specific cancers, about their deferral periods from the time:

• the lesion was removed, healed and treatment completed
• the cancer/solid tumor was removed and/or treatment completed
• remission was achieved
• the diagnosis was made or remission achieved, if treated

The results were discussed and showed that the deferral time-period ranges included no deferral, up to a one year deferral, a five-year deferral or a permanent deferral.

Also asked were:

• “Once the donor has completed treatment and is now on hormonal period, do you accept the donor?” The majority of the respondents said they would accept the donor.
• “What is your policy for a donor who presents with a history of cancer or lesion, but has no active treatment planned?” The deferral time period ranged from no deferral to a permanent deferral.   
• “If a donor’s white cell count is determined to be out of normal range, at what point would you notify the donor?” Notification varied from no notification to notifying at various white cell thresholds.
• “Do you defer a donor with a white cell count out of range?” The deferral time-period range was from no deferral to a permanent deferral.              
• “If you defer the donor, do you perform look-back on previous donations?” The majority said no.
• “Approximately what percentage of all donors were deferred for cancer at your center in 2021?” Twenty respondents indicated the data were not available. Seventeen respondents estimated the prevalence of cancer referrals to be 1-5%.
• “Does your center have a recruitment re-entry strategy for any cancer/tumor deferred donors after they have completed the deferral period that your center imposed?” Among the respondents, 57% said no, 27% said that donors were contacted around the time the deferral expired and 16% gave other actions, including donors automatically being made eligible after the deferral period lapsed.

Gagan Mathur, MD, MBA, discussed the theoretical risk of donor-transmitted cancer (DTC), examining several studies that looked at precancerous blood donors, evidence from organ and tissue transplants and cancer in transfusion recipients.

Several observational studies suggested an increased incidence of non-Hodgkin lymphoma (NHL) and liver cancer in transfusion recipients, while a pooled analysis suggested no conclusive association between blood transfusion and NHL risk.

In the 1940s, researchers actually attempted to transmit leukemia through blood transfusions to terminally ill patients; none of the 67 recipients evaluated showed any evidence of DTC. Further studies in the 1960s-1980s had granulocytes collected from donors with chronic myelogenous leukemia and given to leukopenic patients with acute leukemia or aplastic anemia. There was no evidence of CML transmission reported.

Despite the prevalence of cancer in up to 8% of blood donors, there are actually no documented cases of DTC, which suggest that the current screening and safety measures are effective. Mathur, however, noted that potential mechanisms for transfusion and cancer association exist, including oncogenic virus transmission, unidentified carcinogenic agents (in blood bags, for example) and immunomodulation.

He noted that cancer deferral policies vary widely among blood centers in North America, not based on evidence but precautionary principles. While adopting evidence-based policies to ensure the safety of both donors and recipients is clearly important, it may be worthwhile to contemplate less restrictive donor policies for post-treatment donors.