The impact of overall radiotherapy treatment time and delay in initiation of radiotherapy on local control and distant metastases in gastric cancer

OBJECTIVES: To study the impact of time factors on local and distant metastases in stomach cancer. METHODS: 67 patients with gastric cancer who received adjuvant treatment were reviewed for the time to initiation of radiotherapy, overall duration of RT and the events of first local recurrence or distant metastasis. RESULTS: The risk probability of local recurrence is increased by 10% (HR = 1.1, p = 0.0009) in association with each additional day of radiotherapy and by 3.8% (HR = 1.038, p = 0.13) per increased day of waiting time before the initiation of RT. The risk probability of distant recurrence was associated with an increase of 7.4% (HR = 1.074 p = 0.0031) with each additional day of RT time and by 2.3% (HR = 1.023, p = 0.0598) following the increase of a day of waiting time. Each day of prolongation of RT beyond 36 days was associated with an increased risk of local recurrence by 10% (OR = 1.1, p = 0.015). Prolongation of waiting time prior to initiation of irradiation retained significance in multivariate analysis. CONCLUSION: There is an association between total treatment time and, to some extent, the time between the surgery and the initiation of radiation on local control and distant metastases.