Lung metastectomy in osteosarcoma: thoracotomy or VATS?

Osteosarcoma, which presents with metastatic lung disease in 15-20% of cases, is one of the few malignancies (along with non-rhabdo soft tissue sarcoma and hepatoblastoma) where resection of metastatic disease to the lung can improve survival.

Although lung metastectomy has been shown to be beneficial in this group, the optimal modality of resection, whether by open thoracotomy or VATS, is not clear. The argument for the use of an open thoracotomy in the management of lung mets has to do with the ability to palpate lesions, whereas VATS relies on imaging for detection of lung nodules. Studies have shown that a CT scan that detects a nodule(s) in the lung can miss additional palpable ones in 50% of patients, approximately half of which contain viable malignant tissue. So, in essence, VATS would likely miss additional malignant nodules, and thus leave behind otherwise palpable malignant lesions, in 25% of patients.

So it seems obvious that an open thoracotomy is the way to go, except that we don’t really know if a VATS followed by close monitoring to detect the 25% of patients with missed nodules that can be salvaged by a second VATS (and thus spare a number of kids a thoracotomy) changes the outcome in terms of long term survival when compared to primary resection of all the palpable nodules with an open thoracotomy.

Reference:
1. St Jude Oncology Review Course
2. Kayton ML et al. Computed tomographic scan of the chest underestimates
the number of metastatic lesions in osteosarcoma (2006);41:200