The endpoint is to investigate if the addition of low molecular heparin - enoxaparin, will result in a significant increase of overall survival in patients with small cell lung cancer, receiving standard chemotherapy.

Chemotherapy will be given in accordance with local or regional guidelines but shall include a platinum drug + any topoisomerase inhibitor. Within these limits the study will accept different local variants as long as each centre remains consistent to its declared standard chemotherapy regimen. The recommended regimen is carboplatin or cisplatin plus etoposide q3 weeks for 4 cycles but up to 6 cycles is allowed. Local dosages and dose reduction schedules will be used.

Inclusion Criteria:

1. Histologically or cytologically verified SCLC, all stages
2. WHO performance status 0, 1, 2 or 3
3. Age 18 years or older
4. Intention and feasibility to treat with chemotherapy consisting of platinum + topoisomerase inhibitor.
5. Platelets >100 x109 /L
6. Signed informed consent
7. PK (prothrombin complex) INR and APTT within normal ranges.

Exclusion Criteria:

1. Prior systemic chemotherapy for lung cancer.
2. Concomitant anticoagulation treatment, except for ASA or clopidogrel
3. Active overt bleeding of clinical importance or at high risk (e.g. earlier observed haemorrhage in a brain metastasis, severe coagulopathy as haemophilia, severe liver dysfunction with impaired coagulation, acute peptic ulcer, and within the last 3 months suffered from intracranial haemorrhage, or surgery in the central nervous system).
4. Any other known contraindication for enoxaparine ( e.g. Hypersensitivity against enoxaparine and its derivatives).
5. Pregnancy or breast-feeding
6. Fertile women not using effective contraceptives or men who do not agree to use effective contraception during the treatment period.
7. Treatment with any other investigational agent, or participation in any other clinical trial.