Invasive fungal infections or IFI are alarmingly prevalent among cancer patients, particularly those undergoing intensive chemotherapy. According to studies, the overall incidence of IFI in patients with acute myeloid leukemia undergoing chemotherapy is 26.5 per cent, with an incidence of proven IFI at 8.5 per cent. This high prevalence underscores the need for vigilant monitoring and early intervention.

A meta-analysis of 49 studies revealed invasive aspergillosis risk of 4 per cent with antifungal prophylaxis, though real-world data report incidences ranging from 1.7-12 per cent despite prophylactic measures. Studies have further reported that most IFIs occur in the lungs and sinuses, consistent with other findings. Notably, the incidence of IFI was significantly lower with the use of Posaconazole compared to different antifungal drugs.

However, even with Posaconazole, the incidence of proven/probable IFI remains high at 6 per cent, likely due to increased risks associated with treatment in non-HEPA filtered rooms and ongoing construction activities in hospitals.

Certain cancers are associated with a higher risk of IFI due to their interaction with microbial species. Microbial infections are estimated to be responsible for initiating 2.2 million new cancer cases, accounting for around 16% of overall cancer incidences. It highlights the dual role of microbial infections in promoting cancer risk and complicating its treatment.

IFIs are linked to high mortality and morbidity rates in cancer patients. Despite advancements in diagnostics and therapeutics over the past two decades, the mortality rate for IFIs has sustained a 35.7 per cent growth. The most common fungal genera and species involved in cancers include Candida and Fusarium, among others.

These fungi are associated with various cancers, including esophageal, gastric, gallbladder, colorectal, lung, prostate, cervical, skin, breast, and ovarian.

Cancer patients are particularly vulnerable to invasive fungal infections ) due to multiple interrelated factors that weaken their immune system and disrupt natural protective barriers. Intravenous broad-spectrum antibiotics can eliminate normal bacterial flora, leading to fungal colonization. Direct vascular access via central venous catheters or total parenteral nutrition allows fungi to colonize plastic surfaces and provides a direct route to the bloodstream. Nasogastric tubes and gastric acid suppressants can suppress local gastric immune mechanisms, further facilitating fungal growth.

Conditions like diabetes and prolonged ICU stays contribute to immunosuppression and fungal colonization, particularly by Candida. Procedures like intubation and abdominal surgery disrupt local defence mechanisms and anatomical barriers, increasing the risk of fungal translocation into the bloodstream. Chemotherapy, radiation therapy, and the use of corticosteroids or other immunosuppressive agents severely weaken cellular immunity and cause gastrointestinal mucositis, which disrupts anatomical barriers.

Hematopoietic stem cell transplantation, especially with graft-versus-host disease, leads to heavy immunosuppression and mucositis. Additionally, elderly patients often face compounded immunosuppression and co-morbidities, making them more susceptible to IFI.