  Radiotherapy plays a vital role in cancer treatment, for which accurate
prognosis is important for guiding sequential treatment and improving the
curative effect for patients. An issue of great significance in radiotherapy is
to assess tumor radiosensitivity for devising the optimal treatment strategy.
Previous studies focused on gene expression in cells closely associated with
radiosensitivity, but factors such as the response of a cancer patient to
irradiation and the patient survival time are largely ignored. For clinical
cancer treatment, a specific pre-treatment indicator taking into account cancer
cell type and patient radiosensitivity is of great value but it has been
missing. Here, we propose an effective indicator for radiosensitivity:
radiosensitive gene group centrality (RSGGC), which characterizes the
importance of the group of genes that are radiosensitive in the whole gene
correlation network. We demonstrate, using both clinical patient data and
experimental cancer cell lines, which RSGGC can provide a quantitative estimate
of the effect of radiotherapy, with factors such as the patient survival time
and the survived fraction of cancer cell lines under radiotherapy fully taken
into account. Our main finding is that, for patients with a higher RSGGC score
before radiotherapy, cancer treatment tends to be more effective. The RSGGC can
have significant applications in clinical prognosis, serving as a key measure
to classifying radiosensitive and radioresistant patients.
