Chemotherapy does increase the risk of infection, primarily because it affects the body’s immune system by damaging not only cancer cells but also healthy cells that are crucial for fighting infections. One of the main targets of chemotherapy drugs is rapidly dividing cells, and this includes bone marrow cells that produce white blood cells. White blood cells, especially neutrophils, are essential components of the immune system responsible for defending against bacteria, viruses, and fungi. When chemotherapy reduces their numbers—a condition called neutropenia—the body’s ability to combat infections is significantly weakened.
The bone marrow suppression caused by chemotherapy leads to a drop in neutrophils (neutropenia), red blood cells (anemia), and platelets (thrombocytopenia). Neutropenia is particularly important because it leaves patients vulnerable to bacterial and fungal infections that a healthy immune system would normally control. This vulnerability can result in serious complications such as fever with neutropenia, which requires urgent medical attention.
Moreover, chemotherapy drugs damage other rapidly dividing healthy tissues like those lining the digestive tract. This damage can cause mucositis—painful inflammation and ulceration—which creates openings through which bacteria can enter the bloodstream more easily. The combination of fewer circulating white blood cells and damaged physical barriers increases infection risk further.
Some newer cancer treatments related to or combined with chemotherapy—such as bispecific antibodies used in multiple myeloma—also impair immune defenses by targeting specific antigens on B-cells or engaging T-cells in ways that disrupt normal immunity. These therapies may require additional preventive measures like antiviral or antibacterial prophylaxis to reduce infection risks.
Because infections during chemotherapy can be life-threatening due to compromised immunity, healthcare providers often implement strategies such as:
– Monitoring blood counts closely throughout treatment cycles.
– Using prophylactic antibiotics or antifungals when patients become severely neutropenic.
– Administering growth factors like G-CSF (granulocyte colony-stimulating factor) to stimulate white cell production.
– Advising strict hygiene practices and avoiding exposure to infectious agents.
– Promptly treating any signs of infection with appropriate antimicrobial therapy.
In summary, while chemotherapy is effective at killing cancerous cells by targeting their rapid division mechanisms—including causing DNA damage—it unfortunately also harms critical components of the immune system responsible for protecting against infections. This immunosuppression explains why patients undergoing chemotherapy have an increased susceptibility to various infections until their immune systems recover after treatment cycles end. Managing this risk involves careful monitoring and preventive care tailored specifically for each patient’s situation during their cancer therapy journey.