Marcia Lemkin Foundation Index

Thoracic Radiation Oncology Service
at Massachusetts General Hospital

Thoracic Radiation Oncology Service at Massachusetts General Hospital has the following major research projects: (A) translational research, and (B) clinical research.

A. Translational Research

Translational research means a translation of promising imaging methods/treatments proven in basic science research into clinical research in humans. Molecular imaging is a new and promising method with which biochemical processes in cancer cells as well as living normal can be measured.

All living cells have hexokinase, an enzyme essential for sugar metabolism. Cancer cells have this enzyme 6 to 10 times higher than the surrounding normal cells. Since cancer cells have such a high level of hexokinase activity, this difference in the level of hexokinase can be exploited in making a diagnosis and also monitoring tumor response to radiation or radiation and chemotherapy.

The goals of the current research are:

1. Determine Biomarker/surrogate marker (glucose metabolic rate) representing the probability of tumor control (TCP) at 95% or higher,

2. Develop 3-dimensional isodose map for targeted intensity modulated (IM) RT or IM proton,

3. Develop 3-D molecular imaging map for targeted therapy using IM RT, chemotherapy, biological agents aiming for cTCP ??95%.

A. FDG PET image showing a lung cancer with a high level of FDG uptake.

B. FDG PET image after 42 Gy of radiation and chemotherapy shows a dramatic decrease in FDG uptake representing complete tumor response.

B. Clinical Research

Major clinical research includes:(1) Radiation dose escalation study, (2) 4-dimensional RT planning, and (3) optimized radiation therapy according to normal tissue tolerance. Both basic science research and clinical research are closely related. The findings from the basic science research are tested and verified in the clinical research. The results of the translational research are to be applied to:(1) Radiation dose escalation study, (2) 4-dimensional RT planning, and (3) optimized radiation therapy according to normal tissue tolerance.

A. CT scan of the chest showing a marked obstruction of the left bronchus by a large tumor. The extent of tumor is not well defined.

B. A fused image of CT scan and FDG PET that shows a well delineated region of metabolically active tumor (bright and yellow region).

Radiation therapy guided by molecular imaging consists of deformable image registration of FDG PET image (B) into the chest CT image (A)
for 3-dimensional radiation therapy and also for monitoring tumor response to radiation and chemoradiotherapy.

Conclusion

Our study deals with quantitative correlation between FDG uptake measured with FDG PET 10-12 days after completion of radiation therapy and subsequent local tumor control at 12 months. From this correlation, we can determine the threshold value of FDG uptake below which local recurrence is less than 5%. Such threshold value of FDG uptake representing more than 95% of local tumor control at 12 months is a critical information for individualized and optimized radiation therapy in terms of radiation dose and target volume. There is a real promise that this research in molecular imaging will greatly help improve the results of the current treatment for lung Cancer.

Noah C. Choi, M.D.

Distinguished Scholar in Thoracic Oncology
Massachusetts General Hospital Cancer Center
Head, Thoracic Oncology Unit
Department of Radiation Oncology
Associate Professor of Radiation Oncology
Harvard Medical School