Hyperthermia and its effect on tissues are topics of great interest to
scientists working in the area of radiation biology and medicine, It
has been shown by many workers, that blood now in malignant tissue dis
plays a different response to heating than that in normal tissue. Init
ially, the blood flow in tumour tissue is greater than that in normal
tissue, and when heat is applied there is an increase in blood flow. T
he extent of the increase in now with increasing temperature is greate
r in normal tissue than in tumour tissue. In our laboratory we studied
the effect of temperature on skin blood flow. The skin overlying tumo
ur tissue was compared with skin with no underlying abnormality in can
cer patients, and with the skin in healthy control subjects. The instr
ument used was a Laser Doppler Perfusion Monitor, Pf3 (Perimed, Stockh
olm, Sweden). We found that the skin overlying tumour tissue showed hi
gher basal perfusion than the skin at the contralateral site with no u
nderlying abnormality. The skin above tumour tissue showed a reduced p
erfusion response to an increase in temperature (vascular sluggishness
) compared to skin at the contralateral site and skin in healthy contr
ols. The reduction in thermal response depends on the size of the tumo
ur.