Major innovations in radiotherapy (RT) delivery (3D conformal RT, intensity modulated RT) now permit RT dose escalation to be tested as a means of improving disease control in many tumour sites. With delivery innovations, life-threatening toxicity occurs rarely, but significant clinical toxicity is common. In previous work the investigators have studied a cohort of 98 prostate patients who received dose-escalated 3D-CRT and have obtained evidence of genetic and dosimetric factors underlying rectal/bladder toxicity. They posit that the late radiation toxicity disease state has significant genetic determinants in other malignancies. These determinants are neither understood nor accounted for in selection of treatment, and the investigators propose to study additional well-characterized cohorts, who are clinically well from a disease control perspective, given that comprehensive dosimetric and outcome information is available on all.