A meta-analysis of the diverse invasion and migration responses of lung cancer cells to photon irradiation

Abstract

Objective

To systematically review the relevant literature on the effects of photons on the invasion and migration of lung cancer cells through a meta-analysis, in order to quantitatively evaluate the effects of radiation-related factors and cellular biological factors on the invasion and migration responses.

Methods

The type of radiation, energy, dose, and subtype of lung cancer cells were recorded, as well as biological endpoints, such as invasion and migration. Quantitative comparisons of various studies were conducted through the inclusion of effect size (ES) indicators. The influence of various physical and biological factors on the response to radiation-induced metastasis was clarified by subgroup analysis and One-way analysis of variance.

Results

In terms of radiation types, the promotion effect induced by γ-rays can reach as high as 90%, while X-rays exhibited both promotion (33%) and inhibition effects (55%). For X-rays, the probability of inhibition gradually increased with the increase in dose, ranging from 10% at low doses (0< D ​≤ ​0.5 ​Gy), to 52​% at medium doses (0.5 ​Gy ​< ​D ​≤ ​6 ​Gy), and to 70% at high doses (6 ​Gy ​< ​D ​< ​20 ​Gy). Additionally, from low energy (100–250 ​kV) to high energy (4–10 ​MV), the inhibition rate decreased from 58% to 48%, while the probability of promotion slightly increased from 27% to 31%. Low-energy X-rays with high linear energy transfer (LET) and high relative biological effectiveness (RBE) exhibited a higher proportion of their inhibitory effect than high-energy X-rays.

Conclusion

The γ-rays exhibited more consistent effects than X-rays, especially the promoting effects. However, X-rays showed diverse effects, such as inhibitory effects and promoting effects. Furthermore, for X-rays, the probability of inhibition was related to the dose and energy. These research findings indicated that the quantities related to radiation type, energy and dose, such as LET and RBE, may play a significant role in influencing the different responses of lung cancer cells to photons. This work can enhance the understanding of the impact of photons on cancer metastasis.