How many PTVs and what doses do you utilize for a cT3N0M0 squamous cell carcinoma of the larynx receiving definitive concurrent chemoradiation?

Additionally, what lymph node levels do you typically treat?

1 Answer

Mednet MemberInvited Expert

Radiation Oncology · University of Texas MD Anderson Cancer Center

Answered on

I typically think of 2 targets - a clinical target and a subclinical target. Whether one wants to divide the subclinical target into 2 targets - an intermediate and lower risk target is an option, but whether it is an absolute is a matter for debate.

Traditional treatment was large fields followed by boost - conceptually 2 targets. With the advent of IMRT 10 -15 yrs ago the 3 target concept came about with an intermediate target for "higher risk" subclinical disease and has been ingrained in the radonc culture.

Whether this "higher risk-subclinical target" is additional margin on CTV1, or/and the nodes most commonly involved from a specific cancer are ways this intermediate target has been used. Whether these targets really need the 6 -7 Gy they are prescribed is unclear.

Personally, for T3N0 larynx I feel comfortable with 2 targets. gross disease with 1-2 cm margin (though except for rare cases the entire larynx is in this target with extralaryngeal margin as dictated by the tumor location/extent) and a subclinical target including levels 2, 3, 4 and 6 (delphian and paratracheal nodes)