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Session: Therapy General ePoster Viewing [Return to Session]

The Use of the Normal Tissue Non-Complication Probability (NTCP0) in the Safety Evaluations as a New Alternative of Assessing the Side-Effects of the Radiation Oncology Treatments

T Frometa-Castillo1, A Pyakuryal2, G Narayanasamy3*, A Mesbahi4, (1) Owner at Statistical models project LLC, Chicago, IL, (2) University of District of Columbia, Division of Science and Mathematics, (3) Department of Radiation Oncology, University of Arkansas for Medical Sciences, Little Rock, AA, (4) Tabriz University of Medical Sciences, Briz, ,IR


PO-GePV-T-448 (Sunday, 7/10/2022)   [Eastern Time (GMT-4)]

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Purpose: To encourage the use of the normal tissue non-complication probability (NTCP0) for evaluating safety as alternative to assessing side-effects of radiation therapy (SE-RT); and use of “NTCP0cal” methodology that calculates NTCP0.

Methods: A MATLAB-based application “NTCP0cal” was developed that provides 3 options to calculate NTCP0. One of them employs phenomenological model SMp NTCP0(D). The relationship with sum total NTCP(xi), where i>0 ie., of all complications (TNTCP) where NTCP0=100%-TNTCP is used in the second option. The third option uses an assumed NTCP(xi) discrete probability based on binomial distribution based on target locations and clinical end-points.

Results: Many studies relate use of NTCP in evaluations of SE-RT. QUANTEC studies infer that a majority NTCP models are DVH-based, clinical toxicity is evaluated from SE-RT and NTCP are used mainly for evaluations of principal end-point. The “NTCP0cal” provides 3 calculation options.

Conclusion: As a new radiobiological concept, NTCP0 can be used for correcting the current complication-free cure (P+) and uncomplicated TCP (UTCP) concepts; also allows evaluating SE-RT; and its phenomenological model function of prescription dose (D=n*d) allows estimation of NTCP0 for a range of dose per fraction (d) for specific number of fractions (n) or vice-versa, without DVH information. NTCP0 is calculated as ratio of the number of patients without acute/late complications to the sum total. When this is unknown, NTCP0 can be obtained using the “NTCP0cal” application.


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