In a nutshell
This article investigated the risk of new primary (cancer that does not originate in another organ) cancers after treatment with carbon ion radiotherapy (CIRT), photon radiotherapy (PRT) or surgery for localized prostate cancer (PC).
The authors concluded that CIRT is associated with a lower risk of new primary cancers vs PRT.
Localized PC is cancer that is confined to the prostate gland. The current treatment includes radiation therapy (RT; uses high doses of radiation to kill cancer cells and shrink tumors) or surgery (removal of the prostate). RT has been associated with an increased risk of second primary cancers.
There are several types of RT. Photon RT (PRT) is the most common. Carbon ion RT (CIRT) has a stronger radiation effect on the tumor cells compared with PRT. What treatment method is associated with the lowest risk for second primary cancer in patients with localized PC is still under investigation.
Methods & findings
The study involved 9386 male patients with localized PC. 1455 received CIRT, 1983 received PRT and 5948 received surgery. Follow up for CIRT was 7.9 years, 5.7 years for PRT and 6 years for those who received surgery. The occurrence of second primary cancers was measured.
In the group that received CIRT, 15% of patients developed at least one second primary cancer. Increased age and smoking were associated with an increased risk of developing new cancers in this group. The most common cancers were stomach, bladder, colon, and lung.
After 9.9 years, the risk of developing a second cancer was 16.1% in the CIRT group, 24% in the PRT group and 18.7% in the prostate surgery group. The CIRT group were 19% less likely to develop new cancers compared with the PRT group, and 20% less likely compared with the surgery group. The PRT group was 18% more likely to develop new cancers compared with the surgery group.
The bottom line
The authors concluded that CIRT is associated with a lower risk of new primary cancers in patients with localized PC.
The fine print
This study did not take into account information about the doses of RT used in PRT. This might influence the results.
Published By :
The Lancet. Oncology
Mar 15, 2019
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