Effect of timing of surgery on survival after preoperative hyperfractionated accelerated radiotherapy (HART) for locally advanced rectal cancer (LARC): Is it a matter of days?

Abstract

Bouzourene (2006) Effect of timing of surgery on survival after preoperative hyperfractionated accelerated radiotherapy (HART) for locally advanced rectal cancer (LARC): Is it a matter of days?,

Rectal cancer irradiation. Long course, short course or something else?

“…In an experimental study, the tumour cell kill was similar using 5 )/5 Gy and 10 )/3 Gy (2 daily fractions 6 hours apart) in 5 days, and superior to 10 )/3 Gy in 10 days [23]. Two of the clinical trials are published in this issue of Acta Oncologica [24,25]. These studies build upon the limited knowledge of the relations between fraction size, total dose and treatment time on the one hand and acute (tumour and normal tissue) and late toxicity on the other, as expressed in the so called 'biological models'.…”

“…In yet another study, 25 Gy was given during 5 days with a daily dose of 5 Gy, however, split into two doses of 2.5 Gy [31]. This schedule, although still hypofractionated, will also reduce late normal tissue complication probability (NTCP) compared to 5 )/5 Gy, but also TCP, A Swiss group [25,32] has between 1993 and 2002 treated 279 patients (250 assessable) preoperatively with 41.6 Gy in 2.5 weeks at two daily fractions of 1.6 Gy.…”

“…The concerns for the late adverse effects of the high 5 Gy fractions, even if 'only' 5 fractions are given resulting in a comparably low total dose of 25 Gy, have resulted in attempts to modify the schedule, at the same time keeping the total treatment time short (one or two weeks). Then multiple smaller daily fractions are necessary.…”

“…This schedule, although still hypofractionated, will also reduce late normal tissue complication probability (NTCP) compared to 5 )/5 Gy, but also TCP, A Swiss group [25,32] has between 1993 and 2002 treated 279 patients (250 assessable) preoperatively with 41.6 Gy in 2.5 weeks at two daily fractions of 1.6 Gy. This hyperfractionated accelerated schedule (HART) is similar to the one we tried in the mid 1980s.…”

“…The patients received 25 Gy in 15 fractions of 1.67 Gy in 5 days, i.e. the same total dose, daily dose and number of treatment days as in the 5 )/5 Gy schedule.…”