How does the recent publication of RTOG 0813 affect your management of centrally located lung tumors?

RTOG 0813 s a very valuable data set. This was the first trial using the TITER method performed within NRG Oncology (formerly RTOG). When 0813 was written, we fully expected there to be more toxicity events than were actually experienced. Please remember that we did not limit dose to central structures on this trial. The dose was prescribed to the PTV and the OARs could receive the prescribed dose (up to 12Gy x 5) as long as the hot-spot within the OAR was <105%. What we found was that basically the local control and toxicity rates for the 11, 11.5, and 12Gy per fraction cohorts were the same. The objective of the trial was to find the MTD, and that was 12Gy per fraction. Thirty patients received 12Gy on this trial, so that's good, but its ...

The publication of RTOG 0813 in which the toxicity was acceptable (less than 10% >Grade 3) makes me more comfortable with a 5 fraction regimen for centrally located tumors. But, as stated by @Dr. First Last, the study was not designed to allow us to make a final "recommended dose". The toxicity was acceptable at 60 Gy in 5 fractions but since there are many centrally located normal structures, each with its own tolerance (possibly), I have kept my prescribed dose to no more than 55 Gy in 5 fractions for centrally located tumors. If I have a problem with keeping the normal tissue constraints to ones used in 0813 (which can be difficult), I wouldn't hesitate to use a bit more fractionation, 55-60 Gy in 7-10 fractions. I know there isn't as mu...

I have treated central lung tumors <4cm with 50Gy in 5 fractions for many years and rarely had any issues, and with excellent local control. There is also substantial data from Japanese investigators that dose-fractionation schemes of 50Gy in 5 or 48Gy in 4 were well tolerated when treating central tumors. Larger tumors can be much more problematic, particularly because significant dose goes further into the mediastinum, esophagus and chest wall, as well as the proximal bronchial tree and hilar vessels. In these cases I usually use 60Gy in 8 fractions, or occasionally ever conventional fractionation if tumors are >~7cm. I always make a point in my discussions with patients that toxicities can be higher with larger tumors/doses so they can b...

Referring to the table below:

• 54 Gy 3 fx BED10 = 151 Gy BED3 = 378 Gy
• 60 Gy 5 fx BED10 = 132 Gy BED3 = 300 Gy
• 55 Gy 5 fx BED10 = 115 Gy BED3 = 256 Gy
• 48 Gy 4 fx BED10 = 105 Gy BED3 = 240 Gy
• 50 Gy 5 fx BED10 = 100 Gy BED3 = 216 Gy

Given the theoretical limitations of BED for large fractions, it is noteworthy that RTOG 0813 has clinically demonstrated the safety of fractions up to 12 Gy for central tumors. However, you could argue that since the trial has shown 12 Gy x 5 fx = 60 Gy to be safe, RTOG 0813 also shows that 12 Gy x 4 fx = 48 Gy should be at least as safe if not safer.

My question for the luminaries on this question thread is this: 1) since this trial showed that 5 fx of 12 Gy is safe but did not answer whether escalating pas...