Which type of cancer is most commonly associated with infective endocarditis?

Cancer Types Associated with Infective Endocarditis

Colorectal cancer is the most strongly associated malignancy with infective endocarditis, particularly when caused by Streptococcus bovis/gallolyticus. 1

Relationship Between Cancer and Infective Endocarditis

Infective endocarditis (IE) can be both a marker for occult cancer and a complication in patients with established cancer. The association varies by cancer type:

Primary Cancer Associations

1. Gastrointestinal Cancers

   • Colorectal cancer has the strongest documented relationship, particularly with S. bovis/gallolyticus IE 1
   • The incidence of IE around colorectal cancer diagnosis (19.8 cases per 100,000 person-months) is substantially higher than other common cancers 2

2. Hematological Malignancies

   • Both abdominal and hematological cancers show elevated risk within the first 3 months after IE diagnosis 1
   • The risk for abdominal cancer remains elevated even during long-term follow-up (>12 months) 1

3. Other Cancers

   • Lung cancer: 5.7 cases per 100,000 person-months 2
   • Prostate cancer: 4.1 cases per 100,000 person-months 2
   • Breast cancer: 1.9 cases per 100,000 person-months 2

Mechanisms and Risk Factors

Cancer patients are predisposed to IE through several mechanisms:

• Immunocompromised state
• Need for invasive procedures
• Hypercoagulability
• Presence of indwelling catheters 3

Non-Bacterial Thrombotic Endocarditis (NBTE)

NBTE (marantic endocarditis) is a non-infectious form of endocarditis characterized by sterile vegetations on heart valves. It is strongly associated with:

• Cancer (particularly adenocarcinomas)
• Autoimmune disorders
• Hypercoagulable states 1

NBTE can mimic infectious endocarditis and is a life-threatening source of thromboembolism 1.

Microbiology Patterns in Cancer Patients with IE

The microbial profile in cancer patients with IE differs from non-cancer patients:

• Staphylococcus species are the most common pathogens in cancer patients with IE 4
• Streptococcus bovis/gallolyticus has a well-documented relationship with colorectal neoplasia 1
• Nosocomial IE is more common in cancer patients 4

Clinical Implications and Management

Screening Recommendations

• For patients with S. bovis/gallolyticus IE, rule out occult colon cancer during hospitalization 1
• In the absence of tumor detection, annual colonoscopy follow-up is suggested 1
• Consider FDG PET/CT to detect gastrointestinal pathology, though negative results don't rule out colonic pathology 1

Prognosis

• IE in cancer patients is associated with poorer outcomes
• In-hospital mortality is significantly higher in cancer patients with IE (34.4% vs. 12.4% in non-cancer patients) 4
• Two-year overall survival for stage I-III colorectal cancer patients with concomitant IE is 46.4% compared to 73.1% for those without IE 2
• S. aureus endocarditis in cancer patients is associated with significantly worse survival 3

Important Clinical Considerations

1. Diagnostic Challenges

   • Differentiate between true IE and NBTE, which can have similar presentations
   • Consider IE in cancer patients with unexplained fever or embolic phenomena
   • Valve involvement patterns: mitral and aortic valves are most commonly affected 3

2. Preventive Measures

   • Consider antibiotic prophylaxis before non-dental invasive procedures in cancer patients, though current guidelines don't specifically identify cancer patients as high-risk for IE 4

3. Treatment Approach

   • Multidisciplinary management involving infectious disease specialists, cardiologists, and oncologists is recommended (Endocarditis Team) 1
   • IE often leads to discontinuation of antitumor therapy, affecting cancer treatment outcomes 4

For patients with S. bovis/gallolyticus IE, thorough gastrointestinal evaluation is essential as this may represent the first indication of an underlying colorectal malignancy.