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More dose=more toxicity in prostate cancer
- Thread starter Chartreuse Wombat
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It's hard to analyze these pre igrt/pre fiducial studies when they allowed up to 1cm margins into the rectum (per protocol).
No one treats patients this way anymore. I follow my patients and don't see late toxicity rates as high as this
No one treats patients this way anymore. I follow my patients and don't see late toxicity rates as high as this
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Median f/u 8.4 years is not enough for survival outcomes in prostate cancer, especially intermediate risk. Improvements in distant metastasis free rate with dose escalation and 10-15% difference in biochemical free survival.
Those are all good things.
However, high-dose will likely cause some percentage increase in toxicity. They unfortunately didn't separate it out by 3D-CRT and IMRT like their previous publication:
Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial - ScienceDirect
491 patients in the high-dose arm received 3D-CRT, with only 257 receiving IMRT. Maybe that's why the toxicity numbers are so different? Use of IMRT showed improvement in acute toxicity rates.
Those are all good things.
However, high-dose will likely cause some percentage increase in toxicity. They unfortunately didn't separate it out by 3D-CRT and IMRT like their previous publication:
Preliminary Toxicity Analysis of 3-Dimensional Conformal Radiation Therapy Versus Intensity Modulated Radiation Therapy on the High-Dose Arm of the Radiation Therapy Oncology Group 0126 Prostate Cancer Trial - ScienceDirect
491 patients in the high-dose arm received 3D-CRT, with only 257 receiving IMRT. Maybe that's why the toxicity numbers are so different? Use of IMRT showed improvement in acute toxicity rates.
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This patterns was seen in all dose-escalation studies for prostate cancer. When you strive for a higher dose with a higher local control you are going to get more toxicity.
It was largerly grade II toxicity in the earlier trials that went up and not grade III, so that didn't keep people from dose-escalating, but the pattern was there.
The GETUG 06 trial (70 vs. 80 Gy) showed 14% vs. 19.5% GI and 10% vs. 17.5% GU °II-°III toxicity
PMID 21147514
The RTOG 95-09 reported no additional °III toxicity with dose escalation to (70.2 Gy vs. 79.2 Gy), but if you look closely at the °II toxicity rates, you will see the pattern there too...
13% °II GI toxicity with 70.2 Gy vs. 24% °II GI toxicity with 79.2 Gy, that almost twice as common...
PMID 20124169
Surely modern techniques are going to help lower the absolute rates of toxicity, yet you are still bound to see some. Not only men tolerate 78-80 Gy on the anterior wall of the rectum well.
It was largerly grade II toxicity in the earlier trials that went up and not grade III, so that didn't keep people from dose-escalating, but the pattern was there.
The GETUG 06 trial (70 vs. 80 Gy) showed 14% vs. 19.5% GI and 10% vs. 17.5% GU °II-°III toxicity
PMID 21147514
The RTOG 95-09 reported no additional °III toxicity with dose escalation to (70.2 Gy vs. 79.2 Gy), but if you look closely at the °II toxicity rates, you will see the pattern there too...
13% °II GI toxicity with 70.2 Gy vs. 24% °II GI toxicity with 79.2 Gy, that almost twice as common...
PMID 20124169
Surely modern techniques are going to help lower the absolute rates of toxicity, yet you are still bound to see some. Not only men tolerate 78-80 Gy on the anterior wall of the rectum well.
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