A tumor control probability model for anal squamous cell carcinoma

Abstract

The published data are broadly consistent with a linear quadratic dose-response model. Dose-individualization in anal cancer should be further investigated in the context of clinical trials.

Early stage anal margin cancer: towards evidence‐based management

“…Due to the lack of high quality evidence, a consensus view was developed by the PLATO TMG (listed under Acknowledgements) where we defined an involved margin as microscopic carcinoma present ≤ 1 mm at the lateral or deep margin. To address the concern that conventional post‐excision CRT is associated with considerable morbidity, there is a rationale for the use of lower dose radiotherapy underpinned by previous published studies and modelling of treatment doses lower than those conventionally used.…”

Anal cancer chemoradiotherapy outcome prediction using 18F-fluorodeoxyglucose positron emission tomography and clinicopathological factors

“…One reason for including local hot spots in the ZMP metric was in the context of radiotherapy. Increasing the radiation dose during primary radiotherapy may give a higher local control rate, 42,43 but may also result in unacceptable normal tissue toxicity. Local dose intensification (dose painting) guided by molecular imaging is an organ sparing approach where only the most aggressive part of the tumor is given increased radiation dose and is being explored for squamous cell carcinomas of the head and neck 44,45 and lung.…”

The impact of contour variation on tumour control probability in anal cancer

“…For the linear quadratic model where n is the number of fractions and D’ is the total dose, an α/β ratio of 10Gy, α of 0.196 and N 0 (number of initial clonogens) of 34,900 were used [ 19 ]. A sensitivity analysis investigated the effect on TCP of increasing N 0 and decreasing prescription dose.…”

“…For the logitEUD model where v i is a voxel, γ 50 is the slope of the dose response curve at D 50 and D i is the total dose delivered to each voxel, D 50 values (dose required for a 50% probability of tumor control at 2 years) for gross and microscopic disease were 42Gy and 30Gy, respectively [ 19 ]. Given these values were taken from curves fit to patients treated with CRT, the effect of concurrent chemotherapy was implicitly incorporated.…”