Cancer remains a significant global health challenge, with its incidence rising from 10.1 million cases in 2000 to 19 million in 2020, with 5.7% of new diagnoses occurring in Africa [1] . Despite this increasing burden, cancer-related mortality has been declining, a trend attributed to improved early diagnostic methods and therapeutic advancements, particularly chemotherapy [2] . However, the use of cytotoxic agents is frequently associated with hematological toxicities, of which neutropenia is the most common and severe [3] - [5] .

Chemotherapy-induced neutropenia (CIN) is defined by a decrease in circulating neutrophil count and is graded for severity by the National Cancer Institute’s Common Terminology Criteria for Adverse Events (CTCAE) [6] . Grades 3 (<1,000/mm³) and 4 (<500/mm³) are particularly critical due to the increased risk of infection, which can progress to febrile neutropenia (FN), a life-threatening complication [7] [8] . Episodes of severe CIN often necessitate treatment delays, dose reductions, or discontinuation, thereby compromising the overall efficacy of the therapeutic regimen [9] [10] .

Numerous risk factors for CIN have been identified, including patient-related factors (age, comorbidities), disease-related factors (cancer type and stage), and treatment-related factors (chemotherapy protocol) [11] . To mitigate CIN, current guidelines from organizations like the American Society of Clinical Oncology (ASCO) and the European Society for Medical Oncology (ESMO) recommend the prophylactic use of G-CSFs such as filgrastim or pegfilgrastim [12] [13] . These agents have demonstrated efficacy in reducing the incidence of severe CIN and FN [14] [15] .

However, the implementation of these guidelines varies significantly, particularly in resource-limited settings. A previous study in Cameroon focused on the prevalence and incidence of severe CIN but did not delve into the specific sociodemographic, clinical, and therapeutic characteristics of affected patients [16] . A deeper understanding of these factors is crucial for tailoring preventive measures and management strategies to improve patient outcomes, reduce hospitalizations, and lower associated costs.

The main objective of this study is to describe the sociodemographic, clinical, therapeutic, and evolutionary characteristics of patients with chemotherapy-induced grade 3 and 4 neutropenia at the Yaoundé General Hospital.

A total of 93 patients were recruited, accounting for 157 episodes of chemotherapy-induced grade 3 and 4 neutropenia.

This study characterized the sociodemographic, clinical, therapeutic, and evolutionary profiles of patients with CIN at the Yaoundé General Hospital.

The mean age of 48.42 years is consistent with data from other studies [17] , reflecting that cancer patients are often in the 35-49 age group. The strong female predominance (82%) is explained by the high prevalence of breast cancer, which accounted for 53.8% of cases in our cohort, in line with national data from Globocan 2020 [18] .

The metastatic stage, found in 50.5% of patients, is also similar to findings from other sub-Saharan African studies [19] [20] , reflecting a pattern of late diagnosis.

The involvement of the AC 60 protocol in the majority of CIN cases (54.7%) is consistent with prior research [21] [22] . This regimen, combining anthracyclines and alkylating agents, is known for its high myelosuppressive potential [23] .

The incidental diagnosis of neutropenia (59.2%) highlights the importance of routine hematological monitoring. When present, clinical signs were primarily gastrointestinal, which differs from some studies reporting a predominance of respiratory or cutaneous signs [24] [25] . This discrepancy might be due to differences in study populations, particularly those focused on febrile neutropenia in more severely ill patients.

A WHO performance status of 1 in 80% of patients is a crucial finding, as a good initial general condition is generally considered a protective factor against severe complications [26] [27] . It is also noteworthy that the majority of patients had a normal BMI, although obesity is often cited as a risk factor [28] . However, ASCO guidelines do not establish a direct link between obesity and increased myelosuppression [29] .

The systematic postponement of chemotherapy in 100% of cases of grade 3 and 4 CIN is a common practice, but can be detrimental to treatment efficacy. Delays can promote tumor resistance and negatively impact long-term outcomes [9] . This high rate of treatment deferral stands in stark contrast to the low rate of filgrastim use (24.2%), which was not observed in other countries like Ethiopia [30] . The inability to systematically administer G-CSFs for prophylaxis or treatment forces clinicians to delay treatment to allow for hematological recovery, which ultimately compromises the optimal delivery and intensity of the therapeutic regimen. This low rate could be linked to financial constraints and limited access to G-CSFs, which pose a major barrier in this context. In this resource-limited setting, G-CSFs (Filgrastim/Pegfilgrastim) are typically an out-of-pocket expense for the patient, as they are generally not covered or are only partially covered by local or national health insurance schemes, making them prohibitive for many patients.

The favorable outcome, with 86% of episodes resolving within 7 days, is encouraging. However, the lack of daily CBC monitoring made it impossible to precisely evaluate the duration of neutropenia, a limitation that reflects the logistical and financial challenges of resource-limited settings.

The main limitation of this study is its retrospective nature, which introduced a selection bias due to incomplete medical records and difficulties in standardizing data collection. The small sample size also limits the generalizability of our findings.

Chemotherapy-induced grade 3 and 4 neutropenia remains a significant complication in cancer patients at the Yaoundé General Hospital, frequently leading to systemic chemotherapy deferral (100% of episodes) and suboptimal utilization of Granulocyte Colony-Stimulating Factors (24.2%). The high prevalence of breast cancer, the predominant use of the myelosuppressive AC 60 protocol, and the late diagnosis stage of cancer contribute to this complication burden.

These findings highlight the critical importance of improving the management of CIN to ensure the maintenance of treatment intensity and efficacy. To this end, we recommend developing and implementing local risk-assessment protocols for the systematic use of prophylactic G-CSFs in patients receiving high-risk chemotherapy regimens (like AC 60) or presenting with patient-specific risk factors and advocating for the inclusion of G-CSFs in essential oncology medication lists with subsidies or full coverage by national health schemes to remove the primary financial barrier to access.