Lung metastases

Key points

CT chest is the investigation of choice for detection of lung metastases

It is sometimes not possible to determine if a small nodule is benign or malignant from a single scan

Re-imaging should be performed after chemotherapy rounds to assess response to treatment

Persistent or enlarging lung metastases from most tumours can be resected, provided the patient is a) fit for surgery, and b) the MDT, patient and family are in agreement that it is in their best interest

Pulmonary metastasectomy is typically performed through a thoracotomy - multiple approaches have been described:

• Posterolateral (both muscle sparing and cutting)

• Median sternotomy

• Clamshell

Thoracoscopic approaches are also acceptable, as long as the lesion can be easily identified and resected

Multiple bilateral metastasectomies are possible, this aggressive approach is advocated in osteosarcoma, as comparison with historical controls sucggests a possible survival benefit

In the case of other tumour metastases, for example Wilms, metastasectomy is sometimes advocated to spare the patient from the long term sequelae of pulmonary irradiation

Ablation technques are also described, such as cryo- and microwave ablation, however there is not yet sufficent evidence of the efficacy of these techniques in children. In future they may offer a less invasive approach to metastasis control

References

Boam T et al. Do Children With Osteosarcoma Benefit From Pulmonary Metastasectomy?: A Systematic Review of Published Studies and "Real World" Outcomes. Ann Surg. 2024 Aug 1;280(2):235-240. doi: 10.1097/SLA.0000000000006239. Epub 2024 Feb 20. PMID: 38375639.