ASCO has published an updated guideline describing the latest evidence on using hematopoietic colony-stimulating factor (CSF) to support anticancer treatment, namely chemotherapy and stem cell transplantation.1
“We wanted to update these guidelines both to include the newer evidence as well as cost, access, and equity considerations that are important for shared decision-making,” said Expert Panel Co-Chair Bishal Gyawali, MD, PhD, FASCO, of Queen’s University, Kingston, Canada.
Recommendations for and Against Using CSFs
CSFs play a vital supportive role for patients with solid tumors and hematologic malignancies. These cytokine-based therapeutics help patients undergoing cytotoxic chemotherapy reduce the duration and severity of neutropenia. CSFs are also critical for mobilizing stem cells and speeding up the recovery of white blood cells in patients who undergo stem cell transplantation.2
Bishal Gyawali, MD, PhD, FASCO
CSFs work by stimulating bone marrow progenitor cells, promoting the maturation of blood cells, and activating fully mature blood cells.3 Their ability to help prevent or mitigate febrile neutropenia is crucial. Febrile neutropenia is a serious and burdensome complication of chemotherapy that is associated with increased hospitalizations, longer hospital stays, and greater risk of death.4
A flurry of research activity over the past decade has resulted in a robust research base for CSFs in oncology. Since the previous guideline update in 2015, more than 30 randomized controlled trials and 16 systematic reviews on CSFs in cancer populations have been published.5
According to Dr. Gyawali, these studies feature new data on the timing and duration of the use of CSFs, investigations into two novel drugs (eflapegrastim and efbemalenograstim), and additional data on filgrastim and pegfilgrastim biosimilars.
Dr. Gyawali and his colleague Tessa Cigler, MD, MPH, of the Breast Center at Weill Cornell Medicine, led the Panel that reviewed the evidence and made recommendations for the guideline update. Panel members included oncologists specializing in various cancers, experts in infectious disease and pharmacology, as well as a patient advocate.
Tessa Cigler, MD, MPH
The changes in this newest guideline are not trivial, said Dr. Gyawali, who noted that “even clinicians who are familiar with the 2015 guidelines will find several novel points to incorporate into their practice.”
One recommendation is that clinicians should offer patients primary CSF prophylaxis if the risk of febrile neutropenia from chemotherapy exceeds 20% and if an alternate chemotherapy with comparable efficacy and safety is unavailable.
However, the guideline update recommends against the routine use of CSFs in the following cases:
- For patients with neutropenia but no fever
- As adjunctive treatment with antibiotic therapy for patients with fever and neutropenia
- For patients receiving concomitant chemotherapy and radiation or radiotherapy alone
“We also offer a conditional recommendation on using CSFs for patients who have experienced a neutropenic complication from a previous cycle of chemotherapy without prophylaxis. Dose modification could be a reasonable alternative in these situations,” said Dr. Gyawali.
Patient-Centric Considerations
The inclusion of new guidance on how to leverage biosimilar products reflects oncology’s growing focus on equitable, patient-centered care.6 Specifically, these agents represent a lower-cost pathway to treatment access for individuals who cannot afford the high price of branded CSF agents.7
A new conditional recommendation is included on the use of antibiotic prophylaxis in settings where CSF agents are not available or when a patient cannot afford one. Additionally, in this latest guideline, the Panel offers direction on how to select short-acting vs long-acting CSFs for patients living in rural areas with transportation challenges.
“We also address self-administration of these products, the need for refrigeration, cost issues, alternative therapies, and the evidence for de-escalation of treatment. All of these issues are extremely relevant to patient outcomes and must be factored into shared decision-making,” he said.
These and other patient-centric considerations are present throughout the updated guideline.
Future Research Needs
Dr. Gyawali explained that he hopes the updated guideline will not only inform clinical care but also influence patient outcomes by shaping future research efforts.
For example, he said, the Panel realized that more research is required to identify factors that predict the risk of febrile neutropenia and how those risk factors might affect treatment decision-making and outcomes. Biomarkers are also needed to help clinicians better understand which patients can benefit from CSF prophylaxis and which can be spared.
“And more de-escalation research is needed to discover the most optimal dose, frequency, and duration of CSF use,” he said.
Given the extensive review and discussion that went into addressing a broad scope of issues related to CSFs, Dr. Gyawali expressed hope that oncologists will review the entire text and not just the top-line recommendations.
“We worked hard to incorporate the latest evidence and interpret it contextually,” he said. “The discussion of de-escalation, patient considerations, cost implications, and more have been written with careful thought and are worth oncologists’ time.”
REFERENCES
1. Gyawali B, Bohlke K, Dickter JK, et al: White blood cell growth factors: ASCO Guideline update. J Clin Oncol. Published online February 25, 2026.
2. Bendall LJ, Bradstock KF: G-CSF: From granulopoietic stimulant to bone marrow stem cell mobilizing agent. Cytokine Growth Factor Rev 25(4):355-367, 2015.
3. Czyżykowski R, Chilczuk P, Iskierka-Jażdżewska E, et al: Granulocyte colony-stimulating factor in supportive treatment in oncology and hematology. Oncol Clin Practice. Published online October 20, 2025.
4. Makhani SS, Abro C, Ketineni S, et al: Inpatient burden and clinical outcomes of febrile neutropenia in cancer patients: a national inpatient sample database analysis. Blood 140 (Suppl 1):5154-5155, 2015.
5. Smith TJ, Bohlke K, Lyman GH, et al: American Society of Clinical Oncology. Recommendations for the use of WBC growth factors: ASCO Clinical practice guideline update. J Clin Oncol 33:3199-3212, 2015.
6. Marion S, Ghazal L, Roth T, et al: Prioritizing patient-centered care in a world of increasingly advanced technologies and disconnected care. Semin Radiat Oncol 34:452-462, 2015.
7. Humphreys SZ, Geller RB, Walden P: Pegfilgrastim biosimilars in US supportive oncology: A narrative review of administration options and economic considerations to maximize patient benefit. Oncol Ther 10:351-361, 2022.
Originally published in ASCO Daily News. © American Society of Clinical Oncology. ASCO Daily News, February 26, 2026. All rights reserved.
