The results for early vocal
cord cancers are the same for surgery or radiation (see review by Mendenhall
and review).
The usual dose of radiation is to use 200cGy a day and treat to 6600cGy - 7000cGy for T1
and 7000cGy for T2 or T3 (the NCCN has been increasing their dose.) For more advanced
cases hyperfractionation (twice a day) is common and for T3 and T4 chemoradiation is
generally used (if a laryngectomy is not performed.)
The recent RTOG trial for T2 lesions (RTOG 95-12)
compared the following: Standard
Fractionation (Arm 1) Treatment to the primary site will be given at 2 Gy per fraction,
once a day, five days a week to a total dose of 70 Gy in 35 fractions in seven weeks.
Boost fields will begin at 50 Gy so that the target volume (primary site plus at least 1.0
cm dosimetric margin) will receive at least 90% of maximum dose.Hyperfractionation (Arm 2)
Treatment to the primary site will be given at 1.2 Gy per
fraction, twice a day with a minimum of a 6 hour interval, five days a week to a total
dose of 79.2 Gy in 66 Fractions in 6-1/2 weeks. Boost fields will begin at 60
Gy so that the target volume (primary site plus at least 1.0 cm dosimetric margin) will
receive at least 90% of maximum protocol dose (Studies show that T2 lesions probably need
either hyperfractionation or daily doses over 200cGy. The results from MDA with this
protcol where better with hyperfractionation see graph.) |
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