Skeletal metastatic lesions in colorectal cancer significantly lower quality of life in patients, which requires the choice of optimal treatment procedures, including various radiotherapy options that can reduce patient distress and improve local control of bone lesions.
OBJECTIVE
To study the clinical features and efficiency of radiotherapy for colorectal skeletal metastases.
MATERIAL AND METHODS
The 3-stage study included 810 radiotherapy cycles in patients with bone metastases at various primary sites. Twenty-seven patients were treated for symptomatic and/or complicated colorectal skeletal metastases. The efficiency of radiotherapy was evaluated according to the following criteria: the likelihood of achieving a complete and general analgesic effect, the relative magnitude of pain reduction and the rate of pain syndrome relapses. Irradiation was performed according to a wide-field irradiation technique, using various photon beam radiotherapy options. According to the study protocol, the single focal dose was 6.5 Gy; there were 2 to 4 fractions; the total focal dose was 13—26 Gy.
RESULTS
The average follow-up was 5 (1 to 19) months. Metastases were located in the spine (55.6%) and pelvic bones (25.9%). The frequency of isolated sacral lesions in colorectal cancer was significantly higher than that of breast tumors (p=0.007). There were no cases of metastases to the long bones. The initial pain intensity and the incidence of pathologic fractures in metastases from colorectal cancer did not differ significantly from the average values for all primary sites. The lesion extension was significantly higher than that of bone metastases from lung cancer (p=0.001) and kidney cancer (p=0.004). The overall efficiency of radiotherapy was 96.3%. The rate of pain syndrome relapses was 3.7%. The probability of achieving complete pain relief in bone metastases from colorectal cancer was one of the lowest probabilities among all primary sites and accounted for 33.3% versus 62.9% (p=0.008) in breast cancer metastases. The relative pain reduction (the percentage of pain reduction compared to the baseline level) was also significantly lower than that in breast and prostate cancer metastases: 67.3% vs. 82.3% (p=0.0017) and 81.3% (p=0.012), respectively.
CONCLUSION
Colorectal bone metastases are relatively radioresistant lesions. At the same time, the high overall efficiency of irradiation at a dose of 26 Gy as four fractions of 6.5-Gy, which amounted to more than 95%, with a probability of pain syndrome relapse less than 5% of cases throughout the follow-up period, makes it possible to recommend this radiotherapy option to be used in wide clinical practice.
