RT Book, Section
A1 Bratman, Scott V.
A1 Koritzinsky, Marianne
A2 Harrington, Lea A.
A2 Tannock, Ian F.
A2 Hill, Richard P.
A2 Cescon, David W.
SR Print(0)
ID 1179325152
T1 Tumor and Normal Tissue Response to Radiotherapy
T2 The Basic Science of Oncology, 6e
YR 2021
FD 2021
PB McGraw-Hill Education
PP New York, NY
SN 9781259862076
LK hemonc.mhmedical.com/content.aspx?aid=1179325152
RD 2024/04/20
AB The  purpose  of  clinical  radiotherapy  for  cancer  is  to  control  tumor  growth,  the  likelihood  of  which  depends  on  the  dose  of  radiation  delivered.  However,  this  dose  is  limited  by  the  damage  caused  to  surrounding  normal  tissues  and  the  consequent  risk  of  complications.  Whether  a  certain  risk  of  developing  complications  is  regarded  as  acceptable  depends  both  on  the  function  of  the  tissue(s)  and  the  severity  of  the  damage  involved.  This  risk  must  be  compared  to  the  probability  of  benefit  (ie,  eradicating  the  tumor)  to  determine  the  overall  gain  from  the  treatment.  This  gain  can  be  estimated  for  an  average  group  of  patients,  but  it  may  vary  for  individual  patients,  depending  on  the  particular  characteristics  of  their  tumors  and  the  normal  tissues  at  risk.  The  balance  between  the  probabilities  for  tumor  control  and  normal  tissue  complications  gives  a  measure  of  the  therapeutic  ratio  of  a  treatment  (see  Sec.  16.5.8).  The  therapeutic  ratio  can  be  improved  either  by  increasing  the  effective  radiation  dose  delivered  to  the  tumor  relative  to  that  given  to  surrounding  normal  tissues,  or  by  increasing  the  biologic  response  of  the  tumor  relative  to  that  of  the  surrounding  normal  tissues.