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Squamous cell carcinoma of the eyelids
155
Proceedings of the 1st Annual ASTRO Meeting
study (79-16) of radiation therapy with or without the administration of misonidazole in the treatment First, a Cox regression model was used to identify the pretreatment of brain metastases patients. characteristics defining a group which has a high likelihood of surviving at least 200 days. This group is characterized by a Karnofsky performance status (KPS) of 70-100, an absent/controlled primary tumor, Patients with all four favorable factors, age < 60 years, and metastatic spread only to the brain. have a predicted 200 day survival of 52%. Progrepresenting 11% of the evaluable study population, nostically favorable subgroups can be defined as having at least three of these four favorable factors. These patients have predicted probabilities of surviving at least 200 days between 34 and 52%. Conversely, A second statistical model unfavorable subgroups are classified by having two or less favorable factors. (logistic model) confirmed that the odds of surviving at least 200 days depend on the effects of KPS, The prognostically favorable groups chosen by status of primary tumor, age, and metastatic extent. Subsequent verification means of the logistic model agree with those obtained by the regression model. of these results by a second data set is warranted and will be performed with the data from a previous Patients with prognostically favorable characteristics will be selected RTOG brain metastases study. for future RTOG studies testing radiation therapy in patients with brain metastases.
1017 GLAUCOMA
FOLLOWING
WM Saunders, University
HELIUM
GTY Chen,
ION RADIOTHERAPY
D Char, JR Castro,
of California,
San Francisco
FOR MELANOMA
OF THE EYE
M Austin-Seymour,
and Lawrence
M. Collier
Berkeley
and SR Zink, M. Kohler*
Laboratory,
Northern
California
Oncology
Group*
Glaucoma caused by neovascular proliferation extending into the angle of the anterior chamber of the eye and obstructing drainage of aqueous humor through the canal of Schlemm is a recognized complication of irradiating the eye. We have observed this complication in 18 of 128 patients receiving helium ion radiotherapy for uveal melanoma, and with an average of 19 months followup (3 to 62 months). There is a strong dependence of this complication upon the radiation dose delivered to the tumor. Our unit of dose is the Gray Equivalent, or GyE. One GyE delivered with a helium ion beam is expected to kill the same fraction of oxygenated cells as 1 Gray delivered with a cobalt 60 beam. To date, the incidence of neovascular glaucoma is as follows: 0 of 7 patients receiving 50 GyE, O/32 receiving 60 GyE, O/19 receiving 70 GyE, and 18/69 receiving 80 GyE or higher. We are currently analyzing our date in an attempt to determine if other factors such as the area of retina irradiated, the position of the tumor within the eye or the % volume of the eye irradiated are associated with glaucoma. This is part of an ongoing program by our group to investigate the radiation tolerance of an organ as a function of the fraction of the total organ irradiated. We have found dose-volume histograms derived from 3 dimensional treatment plans to be of great value, both to investigate radiation tolerance, and to optimize the treatment plan before delivering the treatment. This concept will be discussed, using the treatment of eye melanomas as an example.
1018 SQUAMOUS
CELL CARCINOMA
P.J. Fitzpatrick, The Princess
A.M.
Margaret
OF THE EYELIDS Drysdale,
Hospital,
W.M.
Easterbrook
Toronto
Eyelid tumors are relatively comnon but because of their special site present a challenge in Between 1965 The ratio of squamous cell carcinoma to basal cell carcinoma is 1:lO. treatment. and 1980 104 patients with squamous cell carcinoma of the eyelids were treated by irradiation. One-third of the tumors were The median age was 68 years and the male to female ratio 2.3:1. Doses ranged from 2000 cGy in a single exposure to 6000 cGy in greater than 2 cm in diameter. The most comnon schedule was 3500 cGy in five daily exposures. 30 exposures in six weeks. The three-year local control rate was 90.4% and the three-year relapse-free survival 85%. Eleven (10.6%) developed regional metastases and eight (7.6%) had tumor related deaths. Significant changes due to irradiation were reported in 12 (11.5%) patients: these problems mainly occurred with large tumors that had destroyed normal tissues. Among the 104 patients 15 were identified with tumors that might be called acute epithelioma. These all had a phase of rapid growth and nine were larger than 2 cm. Although 14/15 primary lesions were controlled by radiotherapy five patients developed regional metastases and three died from their disease. This appears to be a distinct clinical entity and a paradox because all of the histologies were reported as well differentiated squamuus cell carcinoma,
Proceedings of the 1st Annual ASTRO Meeting
study (79-16) of radiation therapy with or without the administration of misonidazole in the treatment First, a Cox regression model was used to identify the pretreatment of brain metastases patients. characteristics defining a group which has a high likelihood of surviving at least 200 days. This group is characterized by a Karnofsky performance status (KPS) of 70-100, an absent/controlled primary tumor, Patients with all four favorable factors, age < 60 years, and metastatic spread only to the brain. have a predicted 200 day survival of 52%. Progrepresenting 11% of the evaluable study population, nostically favorable subgroups can be defined as having at least three of these four favorable factors. These patients have predicted probabilities of surviving at least 200 days between 34 and 52%. Conversely, A second statistical model unfavorable subgroups are classified by having two or less favorable factors. (logistic model) confirmed that the odds of surviving at least 200 days depend on the effects of KPS, The prognostically favorable groups chosen by status of primary tumor, age, and metastatic extent. Subsequent verification means of the logistic model agree with those obtained by the regression model. of these results by a second data set is warranted and will be performed with the data from a previous Patients with prognostically favorable characteristics will be selected RTOG brain metastases study. for future RTOG studies testing radiation therapy in patients with brain metastases.
1017 GLAUCOMA
FOLLOWING
WM Saunders, University
HELIUM
GTY Chen,
ION RADIOTHERAPY
D Char, JR Castro,
of California,
San Francisco
FOR MELANOMA
OF THE EYE
M Austin-Seymour,
and Lawrence
M. Collier
Berkeley
and SR Zink, M. Kohler*
Laboratory,
Northern
California
Oncology
Group*
Glaucoma caused by neovascular proliferation extending into the angle of the anterior chamber of the eye and obstructing drainage of aqueous humor through the canal of Schlemm is a recognized complication of irradiating the eye. We have observed this complication in 18 of 128 patients receiving helium ion radiotherapy for uveal melanoma, and with an average of 19 months followup (3 to 62 months). There is a strong dependence of this complication upon the radiation dose delivered to the tumor. Our unit of dose is the Gray Equivalent, or GyE. One GyE delivered with a helium ion beam is expected to kill the same fraction of oxygenated cells as 1 Gray delivered with a cobalt 60 beam. To date, the incidence of neovascular glaucoma is as follows: 0 of 7 patients receiving 50 GyE, O/32 receiving 60 GyE, O/19 receiving 70 GyE, and 18/69 receiving 80 GyE or higher. We are currently analyzing our date in an attempt to determine if other factors such as the area of retina irradiated, the position of the tumor within the eye or the % volume of the eye irradiated are associated with glaucoma. This is part of an ongoing program by our group to investigate the radiation tolerance of an organ as a function of the fraction of the total organ irradiated. We have found dose-volume histograms derived from 3 dimensional treatment plans to be of great value, both to investigate radiation tolerance, and to optimize the treatment plan before delivering the treatment. This concept will be discussed, using the treatment of eye melanomas as an example.
1018 SQUAMOUS
CELL CARCINOMA
P.J. Fitzpatrick, The Princess
A.M.
Margaret
OF THE EYELIDS Drysdale,
Hospital,
W.M.
Easterbrook
Toronto
Eyelid tumors are relatively comnon but because of their special site present a challenge in Between 1965 The ratio of squamous cell carcinoma to basal cell carcinoma is 1:lO. treatment. and 1980 104 patients with squamous cell carcinoma of the eyelids were treated by irradiation. One-third of the tumors were The median age was 68 years and the male to female ratio 2.3:1. Doses ranged from 2000 cGy in a single exposure to 6000 cGy in greater than 2 cm in diameter. The most comnon schedule was 3500 cGy in five daily exposures. 30 exposures in six weeks. The three-year local control rate was 90.4% and the three-year relapse-free survival 85%. Eleven (10.6%) developed regional metastases and eight (7.6%) had tumor related deaths. Significant changes due to irradiation were reported in 12 (11.5%) patients: these problems mainly occurred with large tumors that had destroyed normal tissues. Among the 104 patients 15 were identified with tumors that might be called acute epithelioma. These all had a phase of rapid growth and nine were larger than 2 cm. Although 14/15 primary lesions were controlled by radiotherapy five patients developed regional metastases and three died from their disease. This appears to be a distinct clinical entity and a paradox because all of the histologies were reported as well differentiated squamuus cell carcinoma,