Anemia Strikes Two-Thirds of Late-Stage Cancer Patients, Yet Most Go Untreated

Anemia is one of the most common and most overlooked complications of advanced cancer, and a new large-scale study from Beijing now puts hard numbers on just how widespread the problem is. In a retrospective cross-sectional analysis of 1,546 patients with advanced malignancies who had progressed to third-line or later anti-cancer treatment, researchers found that 1,006 — a striking 65.1 percent — were anemic. The work, conducted across nine tertiary hospitals in the Beijing area between June 2018 and June 2023, offers one of the most detailed snapshots to date of cancer-related anemia in patients whose disease has already exhausted standard first- and second-line therapies.

Cancer-related anemia, often abbreviated CRA, arises from a tangle of mechanisms: the tumor itself can suppress red blood cell production through inflammatory cytokines, chemotherapy and radiotherapy damage the bone marrow, nutritional iron deficiency can develop, and bleeding or kidney dysfunction can compound the deficit. The result is a reduced hemoglobin concentration, which starves tissues of oxygen and manifests clinically as fatigue, breathlessness, dizziness, and diminished quality of life. In late-stage disease, where patients are often receiving their third or subsequent lines of treatment, the cumulative toxicity of repeated regimens makes the problem especially acute.

The Beijing study quantified the severity of anemia using standard hemoglobin thresholds. Among the 1,006 anemic patients, the average hemoglobin level was 96.85 grams per liter, with a standard deviation of 14.32. Mild anemia accounted for just over half of cases at 51.3 percent, moderate anemia for 35.8 percent, severe anemia for 10.2 percent, and extremely severe anemia for 2.7 percent. In other words, roughly one in eight anemic patients had fallen into a range serious enough to threaten daily functioning and potentially require urgent intervention.

Red blood cell morphology added another layer of diagnostic insight. Normocytic anemia — red cells of normal size — predominated at 75.3 percent of cases, a pattern consistent with the anemia of chronic disease and marrow suppression rather than classic iron deficiency. Macrocytic anemia, in which red cells are abnormally large, followed at 20.7 percent, a finding that can reflect chemotherapy effects on DNA synthesis, folate or vitamin B12 disturbances, or certain targeted therapies. Microcytic anemia, typically associated with absolute iron deficiency, was the least common at just 4.0 percent, suggesting that straightforward iron replacement alone would address only a small fraction of the problem in this population.

The distribution of severity varied meaningfully by tumor type. Advanced lung cancer and gastrointestinal tumors had the highest proportions of mild anemia, at 56.2 percent and 55.4 percent respectively, meaning most of their anemic patients remained in the least severe category. Gynecologic tumors told a different story: 18.2 percent of anemic patients with these cancers had severe anemia, a rate significantly higher than the 6.3 percent seen in advanced lung cancer and the 6.0 percent in breast cancer. The authors suggest this may reflect the biology and treatment of gynecologic malignancies, including the potential for tumor-related and treatment-related blood loss, though the retrospective design cannot pin down the exact mechanisms.

Perhaps the most sobering finding concerns treatment. Despite the availability of established therapies for cancer-related anemia — iron supplementation, erythropoiesis-stimulating agents, and red blood cell transfusion — only 22.4 percent of the 1,006 anemic patients received any anti-anemia therapy. The treatment gap tracked severity closely: just 10.1 percent of patients with mild anemia were treated, compared with 59.2 percent of those with severe anemia and 96.3 percent of those with very severe anemia. The pattern suggests that clinicians often wait until anemia becomes debilitating before intervening, a reactive approach that the study’s authors argue should give way to earlier, standardized management.

To identify who is most at risk of severe anemia, the researchers performed multivariate logistic regression, a statistical technique that isolates the independent effect of each factor while controlling for the others. The results were revealing. A Karnofsky Performance Status score of 60 or higher — a measure of a patient’s functional ability, where higher scores indicate better day-to-day functioning — was associated with an approximately 62 percent reduction in the odds of severe anemia, with an odds ratio of 0.38. This suggests that a patient’s overall physical condition, and the biological reserve it represents, plays a protective role against the steepest hemoglobin declines.

Tumor type emerged as another independent determinant. Compared with lung cancer, gynecologic tumors carried roughly 3.3 times the risk of severe anemia, with an odds ratio of 3.33, while gastrointestinal tumors carried 1.83 times the risk. A prior history of blood transfusion was also linked to a 76 percent increase in the risk of severe anemia, with an odds ratio of 1.76 — a finding that likely marks patients whose anemia has already proven refractory or recurrent, rather than transfusion itself causing the problem. Notably, age, gender, history of prior tumors, the specific third-line regimen, stage IV disease at initial diagnosis, liver metastasis, and lung metastasis showed no independent association with severe anemia, indicating that these commonly monitored variables are less predictive than performance status and tumor origin.

The study joins a lineage of large surveys, including the European Cancer Anaemia Survey, that have documented the high prevalence and undertreatment of anemia in oncology. What distinguishes the new work is its focus on a heavily pretreated population — patients on third-line or later therapy — a group that is often underrepresented in clinical trials yet increasingly common as cancer survival extends and treatment sequences lengthen. With an incidence of 65.1 percent in this setting, anemia is not a marginal side effect but a central feature of advanced disease management, with direct consequences for treatment tolerance, dosing intensity, and quality of life.

The authors conclude that greater attention and standardized management of anemia should be implemented among cancer patients, and the data point to concrete priorities: routine hemoglobin monitoring and earlier intervention for patients with gynecologic and gastrointestinal tumors, proactive anemia assessment for those with poor performance status, and a lower threshold for treatment before hemoglobin levels fall into the severe range. As cancer care continues to extend lives through successive lines of therapy, the study serves as a reminder that the blood counts of these patients deserve the same systematic attention as their tumors.

Subject of Research: Cancer-related anemia in advanced cancer patients receiving third-line or higher anti-cancer treatment

Article Title: A survey of the current status of cancer-related anemia in 1006 advanced cancer patients undergoing third-line or higher anti-cancer treatment: a multicenter retrospective study in nine tertiary hospitals in Beijing area

Article References: Xu, J., Zhang, Q., Kang, N., Yan, D., Feng, Y., Yin, Y., Liu, J., Jiang, J., Yuan, J., Liu, Z., Han, X., Li, X., & Hou, L. (2026). A survey of the current status of cancer-related anemia in 1006 advanced cancer patients undergoing third-line or higher anti-cancer treatment: a multicenter retrospective study in nine tertiary hospitals in Beijing area. BMC Cancer. https://doi.org/10.1186/s12885-026-17100-0

Image Credits: AI Generated

DOI: 10.1186/s12885-026-17100-0

Keywords: cancer-related anemia, advanced cancer, hemoglobin, chemotherapy, gynecologic tumors, gastrointestinal tumors, lung cancer, performance status, blood transfusion, retrospective study, anemia treatment, oncology