Encouraging Results Published on Use of TomoTherapy in Lung Cancer Treatment

MADISON, Wis. – April 9, 2009 – TomoTherapy Incorporated (NASDAQ: TOMO) today cited recently published encouraging preliminary results of an ongoing Phase I clinical trial on the use of intensity-modulated (IMRT) and image-guided radiation therapy (IGRT) focusing on the concept of accelerated hypofractionation to overcome tumor repopulation, one of the well-known mechanisms of radiation resistance, using TomoTherapySM for non-small cell lung cancer (NSCLC).

The paper, published in Technology in Cancer Research and Treatment (Technol Cancer Res Treat. 2008 Dec;7(6):441-8.) titled, “Dose Escalated, Hypofractionated Radiotherapy Using Helical Tomotherapy for Inoperable Non-Small Cell Lung Cancer: Preliminary Results of a Risk-Stratified Phase I Dose Escalation Study,” evaluates a study devised to test the safety of escalating the biologically-effective tumor dose via hypofractionated treatment regimens using 25 fractions over five weeks. Traditionally, radiotherapy is delivered over six to seven weeks, or even longer (sometimes up to 10-11 weeks) if dose-escalation is the goal. A downside to dose escalation in this manner is that tumor repopulation occurs during the prolonged delivery time. Shorter dose-escalated schedules have historically been avoided because of the expectation of severe toxicities. The University of Wisconsin (UW) School of Medicine and Public Health investigators hypothesized that the conformal dose-delivery abilities of TomoTherapy, with helical IMRT and IGRT, would permit safe dose-escalation with shorter schedules, thereby limiting accelerated repopulation, and possibly improving tumor control.

source: Tomotherapy