What do systematic reviews say?

Heparin prophylaxis vs no prophylaxis

Heparin prophylaxis showed no clear difference in major bleeding compared with no prophylaxis (moderate certainty).

• Parenteral anticoagulation in ambulatory patients with cancer 2017 · Cochrane Headline outcomes only
  RR 1.3 [0.94, 1.79]
  18 studies · 9592 participants
  Moderate

Low molecular weight heparin vs vitamin K antagonist secondary prophylaxis

Low molecular weight heparin secondary prophylaxis showed no clear difference in major bleeding (main analysis ‐ active cancer) compared with vitamin K antagonist secondary prophylaxis (low certainty).

• Anticoagulation for the long‐term treatment of venous thromboembolism in people with cancer 2018 · Cochrane Headline outcomes only
  RR 1.09 [0.55, 2.12]
  4 studies · 1712 participants
  Low

Unfractionated heparin vs no thromboprophylaxis

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Low molecular weight heparin vs no thromboprophylaxis

Low‐molecular‐weight heparin probably leads to higher major bleeding compared with no thromboprophylaxis (moderate certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1.63 [1.12, 2.35]
  15 studies · 7282 participants
  Moderate

Low molecular weight heparin vs no prophylaxis

Low‐molecular‐weight heparin showed no clear difference in major bleeding ( compared with no prophylaxis (moderate certainty).

• Interventions for preventing venous thromboembolism in adults undergoing knee arthroscopy 2022 · Cochrane Headline outcomes only
  RR 0.98 [0.06, 15.72]
  1 study · 1451 participants
  Moderate

Low molecular weight heparin vs active control

The review found no eligible studies for this question.

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found
• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 0.14 [0.01, 2.76]
  2 studies · 781 participants
  Low
• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  no estimate extracted
  Studies not reported
  No studies found

Ultra‐low‐molecular‐weight heparin vs placebo

Ultra‐low‐molecular‐weight heparin showed no clear difference in major bleeding compared with placebo (moderate certainty).

• Primary prophylaxis for venous thromboembolism in ambulatory cancer patients receiving chemotherapy 2020 · Cochrane Headline outcomes only
  RR 1.05 [0.55, 2]
  1 study · 3172 participants
  Moderate

Combined NMES and low‐dose heparin vs no prophylaxis

• Neuromuscular electrical stimulation for the prevention of venous thromboembolism 2017 · Cochrane Headline outcomes only
  no estimate extracted
  1 study · 32 participants
  GRADE not reported

Low molecular weight heparin vs vitamin K antagonist (VKA)

It is very uncertain whether low‐molecular‐weight heparin (LMWH) changes major bleeding (up to 3 months) compared with vitamin K antagonist (VKA) (very low certainty).

• Anticoagulation for people with cancer and central venous catheters 2018 · Cochrane Headline outcomes only
  RR 3.11 [0.13, 73.11]
  2 studies · 289 participants
  Very low

Low molecular weight heparin vs no LMWH

It is very uncertain whether low‐molecular‐weight heparin (LMWH) changes major bleeding (up to 3 months) compared with no LMWH (very low certainty).

• Anticoagulation for people with cancer and central venous catheters 2018 · Cochrane Headline outcomes only
  RR 1.49 [0.06, 36.28]
  4 studies · 1018 participants
  Very low

Low molecular weight heparin vs no prophylaxis

Low‐molecular‐weight heparin showed no clear difference in all adverse effects, including allergies at injection site, minor… compared with no prophylaxis (moderate certainty).

• Interventions for preventing venous thromboembolism in adults undergoing knee arthroscopy 2022 · Cochrane Headline outcomes only
  RR 1.85 [0.95, 3.59]
  5 studies · 1978 participants
  Moderate