The use of cabazitaxel has clear contraindications and requires dose adjustments in patients with different physiological or pathological conditions.

I. Absolute Contraindications

1. Severe Neutropenia

(1) Cabazitaxel is strictly prohibited if the baseline absolute neutrophil count (ANC) is ≤1,500/mm³ before administration.

(2) The drug itself can exacerbate myelosuppression, increasing the risk of infection and death.

(3) Regular blood count monitoring is required during treatment. If persistent severe neutropenia occurs, treatment should be delayed or dose‑reduced, rather than continuing the original regimen.

2. Severe Hypersensitivity History

(1) Patients with a history of severe hypersensitivity reactions to cabazitaxel or its excipients (e.g., polysorbate 80) must not receive the drug.

(2) Hypersensitivity reactions may present as generalised rash, hypotension, or bronchospasm, and can be potentially fatal; strict screening is mandatory.

3. Severe Hepatic Impairment

(1) Patients with total bilirubin >3 times the upper limit of normal (ULN) are contraindicated.

(2) There are no safety data for this population, and use should not be attempted.

II. Dose Adjustments in Special Populations

1. Patients with Hepatic Impairment

(1) Mild hepatic impairment (total bilirubin >1 to ≤1.5×ULN, or AST >1.5×ULN): dose should be reduced to 20 mg/m², with close monitoring of liver function and adverse events.

(2) Moderate hepatic impairment (total bilirubin >1.5 to ≤3×ULN, AST any level): dose further reduced to 15 mg/m², but efficacy becomes more uncertain; risk‑benefit assessment is required.

(3) Severe hepatic impairment (total bilirubin >3×ULN): absolute contraindication, do not administer.

2. Elderly Patients (≥65 years)

(1) No routine starting‑dose adjustment is needed, but elderly patients have a higher risk of severe neutropenia, febrile neutropenia, and infection‑related events.

(2) More frequent monitoring of blood counts and vital signs is recommended during therapy, with prophylactic G‑CSF support considered when necessary.

3. Patients with Renal Impairment

(1) No dose adjustment is required for mild‑to‑moderate renal impairment (not dialysis‑dependent), as renal excretion accounts for a very small fraction (<4%) of the drug.

(2) For end‑stage renal disease (creatinine clearance<15 mL/min/1.73 m²), adequate data are lacking; use should be individualised under close supervision.

4. Paediatric Patients

Safety and efficacy have not been established; use in children is not recommended.

III. Contraindications Related to Fertility, Pregnancy, and Contraception

1. Pregnancy Risk in Females

(1) Cabazitaxel has shown embryolethality and foetal toxicity in animal studies; no safety data exist in pregnant women, so it should not be used during pregnancy.

(2) Women of childbearing potential should avoid becoming pregnant and must use reliable contraception during treatment.

2. Contraceptive Requirements for Male Patients

(1) Male patients with female partners of childbearing potential should use effective contraception during treatment and for at least 4 months after the last dose.

(2) Because the drug may affect spermatogenesis and embryo development, fathering a child is not advised during this period.

3. Potential Impact on Fertility

(1) Animal studies suggest that cabazitaxel may impair male reproductive organs, leading to testicular atrophy or impaired spermatogenesis.

(2) Patients with future fertility wishes should consult a reproductive medicine specialist before treatment and consider sperm banking.