Tumor growth in lung vessels and the effect on lung cancer outcome

The authors aimed to determine how microscopic vessel invasion affects lung cancer patient outcome. 

The visceral pleura are the membranes surrounding the lungs. In lung cancer,  the presence of tumors in the visceral pleura (known as visceral pleural invasion – VPI), is a factor used in standard classification systems to determine how advanced the cancer is in a patient.

Tiny vessels function within and around the lungs carrying blood and oxygen. Tumor growth within these vessels (known as microscopic vessel invasion – MVI) can lead to a poor outcome in patients with lung cancer, as it can facilitate spread of cancer cells to the rest of the body.

The aim of this study was to determine the effect of MVI on lung cancer outcome.

2,657 patients were used in this study with a follow-up time of 5 years. More than 90% of patients underwent surgery on both lungs. 30.9% experienced cancer recurrence, where 344 patients experienced local cancer recurrence (at the same site as initial tumor) and 478 patients experienced cancer recurrence in different parts of the body.

The 5-year overall survival rate (patients who did not die from lung cancer) in patients with MVI was 57.2% and was significantly lower than that for patients without MVI. Any patient with MVI was more likely to experience cancer spread and had an overall 5-year recurrence-free rate (patients who did not experience cancer recurrence after treatment) of 52.6%, which was significantly lower than that for patients without any MVI (87.5%).

MVI and VPI were identified as the strongest risk factors for experiencing cancer recurrence. Patients with MVI had nearly 3 times the risk of experiencing recurrence compared to patients without MVI and this was considered a significant independent risk factor for recurrence. Patients with VPI had nearly double the risk of experiencing recurrence compared to patients without VPI. 

Patients who did not have either MVI or VPI had a 5-year recurrence-free rate of 91.7% compared to patients who had VPI alone (82.2%), MPI alone (77.4%) or both VPI and MVI (60.3%). Patients experienced worse recurrence-free rates as tumor size increased where patients with small, less advanced tumors (tumors no bigger than 3cm and still confined to the lung) had a recurrence-free rate of 92.2% compared to 32.4% in  patients with larger, more advanced tumors (tumors of any size that have spread from the lungs into other parts of the body).

The authors conclude that MVI was a significant independent risk factor in lung cancer recurrence.

Further studies are required for results to be applied widely. 

If you have microscopic vessel invasion or visceral pleural invasion in your lung cancer, please consult your doctor for the best treatment options available.