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Skin fibroblasts in vitro radiosensitivity can predict for late complications following AVM radiosurgery
Radiotherapy and Oncology 64 (2002) 153–156 www.elsevier.com/locate/radonline
Skin fibroblasts in vitro radiosensitivity can predict for late complications following AVM radiosurgery Gijsbert Peter Raaphorst*, Shawn Malone, Ghazi Alsbeih, Louis Souhani, Eva Szumacher, Andre Girard Ottawa Regional Cancer Centre, 503 Smyth Road, Ottawa, Ontario K1H 1C4, Canada Received 27 June 2001; received in revised form 18 February 2002; accepted 8 April 2002
Abstract Background and purpose: A small proportion of patients undergoing radiotherapy display heightened normal tissue reactions. We have set out to determine whether this sensitivity is genetic in nature and can be assessed using an in vitro skin fibroblast assay in order to predict and avoid excessive normal tissue complications. Patients and methods: In this study we compared five arteriovenous malformation (AVM) patients who were treated with radiotherapy and showed severe normal tissue reactions (necrosis) to two AVM patients who showed normal reactions. Fibroblasts taken from patients were cultured in vitro and irradiated. Results: The results showed that the fibroblasts from the sensitive patients were also more radiosensitive in vitro than the cells from the normally responding patients. Conclusions: The results suggest underlying genetic radiosensitivity and that such an assay may be used for prediction of severe radiosensitivity in AVM patients. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Skin fibroblasts in vitro radiosensitivity; Late complications; Arteriovenous malformation radiosurgery
1. Introduction While radiosurgery is an effective modality for the treatment of intercranial arteriovenous malformations (AVMs) with obliteration rates ranging from 60 to 90% [8– 10,15,16,24,25] there is also a risk of severe normal tissue complications in this patient group. It has been reported that the obliteration rates of AVM depend on the minimum dose to the lesion, which follows a sigmoidal dose response relationship [13]. Approximately 5–10% of patients experience different levels of delayed radiation induced neurologic sequelae, with a 3% risk of brain necrosis. A number of models have been proposed to predict the risk of necrosis which include the volume isoeffect line of Kjellberg [14,23], location and 12 Gy volume [11,12], average dose to 20 cm 3 volume and prior radiation history [22]. While the risk models for AVM treatment take into account a number of factors, they do not account for the possibility of a variation of intrinsic radiosensitivity, which may have a genetic basis. Since such variation has been reported in the literature [2–5,7,17–21] although not all studies agree [27,29]
* Corresponding author.
it is reasonable to expect that such a factor may also play a role in AVM treatment. In fact we [6,28] and others [1,30] have already shown that in vitro skin fibroblasts radiosensitivity correlated with severe late reaction in radiotherapy patients. Thus, the prediction of radiation sensitivity of an AVM patient may help avoid serious normal tissue complications after radiosurgery. We have studied seven AVM patients (five with severe complications, two without complications) as well as additional normally responding controls in order to determine whether the severe reactions were predictable through a fibroblast assay.
2. Materials and methods Five AVM patients (AVM Sens 1, 3, 4, 5, 6) suffering symptomatic radiation necrosis following radiosurgery (evaluated by MRI) and two patients with no symptoms nor necrosis (AVM 2, 7) from three institutions with longstanding radiosurgery experience in Canada were evaluated. The characteristics of the AVMs and details regarding radiosurgery treatment are shown in Table 1. All seven AVM patients had suffered brain hemorrhage prior to diagnosis. Patients were evaluated at each institution by a radiosurgery
0167-8140/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0167-814 0(02)00076-2
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G.P. Raaphorst et al. / Radiotherapy and Oncology 64 (2002) 153–156
Table 1 Patient and cell survival data a Cell line
AVM1 AVM2 AVM3 AVM4 AVM5 AVM6 AVM7 ORF2 ORF8 OMB9 a
AVM location
Thalamus Occipital Corpus callosum Thalamus Occipital Occipital Occipital Cancer Cancer Cancer
AVM size (mm)
25 25 15 40 25 25 20
Dose (Gy)
20 18 20 16 15 20 20
Measured data Immediate plating
Delayed plating
0.20 (0.02) 0.41 (0.06) 0.15 (0.018) 0.22 (0.016) 0.18 (0.02) 0.16 (0.02) 0.30 (0.011) 0.35 (0.50) 0.36 (0.05) 0.38 (0.05)
0.42 (0.055) 0.46 (0.046) 0.33 (0.05) 0.41 (0.45) 0.50 (0.03) 0.38 (0.015) 0.65 (0.09) 0.53 (0.06) 0.54 (0.08)
The numbers in parentheses represent the standard error of the mean.
team that included neurosurgeons, invasive neuro-radiologists, radiation oncologists and physicists. The heightened post-irradiation response in the sensitive patients could not be correlated to AVM volume and hence radiation volume. Following informed consent a 5 mm punch skin biopsy was taken from the medial forearm from each patient, placed in culture media type DMEM/F-12, maintained at 4 8C and supplemented with antibiotic (15%: penicillin, streptomycin and amphotericin B) without serum. After mincing into fragments and after the biopsy was inoculated into tissue culture flasks, 1 ml of fresh media supplemented with 20% fetal bovine serum (FBS) and 1% antibiotic was added, the flasks were incubated at 37 8C in 95% air and 5% CO2, and the volume of media was increased to 5 ml over the following 5 weeks. The out growing fibroblasts were then trypsinized and replated without antibiotic. Radiosensitivity measurements were carried out after the third passage. Clonogenicity was assessed using a fixed number of seeded cells (test 1 feeder) of 1000 cells/cm 2. Plating efficiencies ranged from 15 to 30%. Cells were irradiated in plateau phase by graded single doses of 1–12 Gy. Plateau phase cell cultures were used in order to avoid cell cycle redistribution and to more closely mimic tissue cell density. Irradiation was performed using 250 kVp X-rays (1 mm A1 filter) at a dose rate of 1.42 Gy/min. Cells were trypsinized either immediately (immediate plating: IP) or after 24 h (delayed plating: DP). After treatment cells were plated and incubated at 37 8C in a humidified atmosphere with 5% CO2 for 2 weeks, then fixed and stained with Crystal Violet and surviving colonies were counted. Three petri dishes containing up to 60 colonies were obtained per dose and per experiment. Two to four independent experiments were carried out for each cell line. Curves were fitted using the LQ radiation survival curve model.
3. Results The data presented in Fig. 1 show radiation responses of fibroblasts plated immediately after irradiation (Fig. 1a) or 24
h after irradiation to allow time for repair of potentially lethal damage (Fig. 1b). The AVM 2 and 7 cells derived from a normally responding patient show a more resistant radiation response, equivalent to three other cell strains (ORF2, ORF8 and OMB9) derived from normally responding radiotherapy cancer patients. The other AVM cell strains show a greater radiosensitivity which is mainly reflected in a reduction of the shoulder of the radiation survival curve. Based on this observation and the existing analysis in the literature we further assessed differences at the 2 Gy dose level and the results are shown in Table 1; the IP results clearly show a difference between AVM 2 and 7 compared to the five derived from patients exhibiting heightened normal tissue response. The results in Fig. 1b show that delayed plating resulted in recovery of radiation damage in the sensitive cell strains indicating that potentially lethal damage deficiency is not responsible for the increased sensitivity. In fact differences between AVM 2, 7 and AVM 1, 3, 4, 5, 6 decreased for DP (Table 1) indicating that perhaps the sensitive strains can repair potentially lethal damage to a greater extent. The results at 2 Gy were assessed using Student’s t-test and showed that AVM normals were not different from cancer normals (P ¼ 0:7), AVM sensitive were not different from cancer sensitive (P ¼ 0:82), and AVM normal were different from AVM sensitive (P ¼ 0:005).
4. Discussion The results of this study show that in patients receiving curative treatment for AVM and developing complications these may be related to the genetic radiosensitivity of the patient. Earlier studies have shown that complications are related to such factors as dose, volume and location of the irradiated tissue [11]. In this report we show that intrinsic radiosensitivity is an additional indicator of clinical outcome and these results agree with our previous report on two sensitive AVM cases [26]. The data show that the heightened clinical complication rate was correlated with
G.P. Raaphorst et al. / Radiotherapy and Oncology 64 (2002) 153–156
155
impaired in their ability to repair potentially lethal damage. Because the main difference appears to be in the shoulder of the survival curve the assay may possibly be improved by giving multiple 2 Gy doses in vitro. Finally, as for cancer patients this heightened sensitivity in AVM patients appears to occur in about 1–3% of the treated population. We speculate that it may well be a genetically related radiosensitive subgroup and further molecular analysis may be indicated to assess this possibility. References
Fig. 1. (a) The radiation survival is shown for human fibroblasts irradiated in plateau phase and then plated immediately after irradiation for the colony survival assay. The AVM 2 and 7 and ORF 2 and 8 are cells from normally responding radiotherapy patients while the rest are from patients that exhibited a radiosensitive response to AVM radiotherapy. (b) Survival of cells plated immediately after irradiation is compared to cells plated 24 h after irradiation for the colony survival assay.
heightened in vitro fibroblast radiosensitivity implicating a genetically linked radiosensitivity. Since treatment for AVM can be delayed (since it is not a progressive disease like cancer) the in vitro fibroblast assay which takes about 6–8 weeks could be used as a predictor of radiation response and help avoid severe normal tissue complication. The in vitro fibroblast responses indicated that the sensitive cell strains were characterized by a reduced survival curve shoulder indicating reduced ability for accumulation of sublethal damage. However, these cells were not
[1] Abadir RM, Hakami N. Ataxia telangiectasia with cancer. An indication for reduced radiotherapy and chemotherapy doses. Br J Radiat 1983;56:343–345. [2] Alsbeih G, Malone S, Lochrin C, Gray R, Fertil B, Raaphorst GP. Correlation between normal tissue complications and in-vitro radiosensitivity of skin fibroblasts derived from radiotherapy patients treated for a variety of tumours. Int J Radiat Oncol Biol Phys 2000;46(1):143–152. [3] Alsbeih G, Malone S, Raaphorst GP. Intrinsic radiosensitivity as a predictive assay in radiotherapy: rationale for multifraction approach. Cah Radiobiol 1997;5:13–16. [4] Brock WA, Tucker SL, Geara FB, et al. Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer. Int J Radiat Oncol Biol Phys 1995;32:1371–1379. [5] Brown RC, Ng CE, Raaphorst GP. A comparison of high dose rate, low dose rate and fractionation for optimizing differences in radiosensitivities in vitro. Radiat Oncol Invest 1998;6:209–215. [6] Brown RC, Raaphorst GP, Danjoux CE, Drouin P. Multi-organ fatal chronic complications following radiation treatment for cancer of the cervix: results of fibroblast assay. Gynecol Oncol 1996;61:116–121. [7] Burnet NB, Warm R, Peacock JH. Low dose-rate fibroblast radiosensitivity and the prediction of patient response to radiotherapy. Int J Radiat Biol 1996;70:289–300. [8] Coffey R, Nichols D, Shaw E. Stereotactic radiosurgical treatment of cerebral arteriovenous malformations. Gamma Unit Radiosurgery Study Group. Mayo Clin Proc 1995;70(3):214–222. [9] Colombo F, Pozza F, Chierego G, et al. Linear accelerator radiosurgery for cerebral arteriovenous malformations. An update. Neurosurgery 1994;34(1):14–21. [10] Engenhart R, Wowra B, Debus J, et al. The role of high dose singlefraction irradiation in small and large intracranial arteriovenous malformations. Int J Radiat Oncol Biol Phys 1994;30(1):521–529. [11] Flickinger JC, Kondziolka D, Lunsford LD, Liscak R, Pollock B. Development of a model to predict permanent symptomatic post radiosurgery injury for arteriovenous malformation patients. Int J Radiat Oncol Biol Phys 2000;45:1143–1148. [12] Flickinger JC, Kondziolka D, Maitz AH, et al. Analysis of neurological sequelae from radiosurgery of arteriovenous malformations: how location affects outcome. Int J Radiat Oncol Biol Phys 1998;40(2):273–278. [13] Flickinger JC, Pollick BE, Kondziolka D, Lunsford LD. A doseresponse analysis of arteriovenous malformation obliteration after radiosurgery. Int J Radiat Oncol Biol Phys 1996;36(4):873–879. [14] Flickinger J, Schell M, Larson D. Estimation of complications for linear accelerator radiosurgery with the integrated logistic formula. Int J Radiat Oncol Biol Phys 1990;19:143–148. [15] Friedman W, Bova F, Mendenhall W. Linear accelerator radiosurgery for arteriovenous malformations: the relationship of size to outcome. J Neurosurg 1995;82(2):180–189. [16] Friedman W, Bova F. Linear accelerator radiosurgery for arteriovenous malformations. J Neurosurg 1992;77(6):832–841.
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[17] Geara FB, Peters LJ, Ang KK, Wike JL, Brock WA. Prospective comparison of in vitro normal cell radiosensitivity and normal tissue reactions in radiotherapy patients. Int J Radiat Oncol Biol Phys 1993;27:1173–1179. [18] Geara FB, Peters LJ, Ang KK, Wike JL, Brock WA. Radiosensitivity measurement of keratinocytes and fibroblasts from radiotherapy patients. Int J Radiat Oncol Biol Phys 1992;24:287–293. [19] Geara FB, Peters LJ, Ang KK, et al. Intrinsic radiosensitivity of normal human fibroblasts and lymphocytes after high- and lowdose-rate irradiation. Cancer Res 1992;52:6348–6352. [20] Johansen J, Bentzen SM, Overgaard J, Overgaard M. Evidence for a positive correlation between in vitro radiosensitivity of normal human skin fibroblasts and the occurrence of subcutaneous fibrosis after radiotherapy. Int J Radiat Biol 1994;66:407–412. [21] Johansen J, Bentzen SM, Overgaard J, Overgaard M. Relationship between the in vitro radiosensitivity of skin fibroblasts and the expression of subcutaneous fibrosis, telangiectasia and skin erythema after radiotherapy. Radiother Oncol 1996;40:101–109. [22] Karlsson B, Lax I, Soderman M. Factors influencing the risk for complications following gamma knife radiosurgery of cerebral arteriovenous malformations. Radiother Oncol 1997;43:275–280. [23] Kjellberg R, Hanamura T, Davis J, et al. Bragg-peak proton-beam therapy for arteriovenous malformations of the brain. N Engl J Med 1983;390:269. [24] Kondziolka D, Lunsford L, Kanal E, et al. Stereotactic magnetic
[25]
[26]
[27]
[28]
[29]
[30]
resonance angiography for targeting in arteriovenous malformation radiosurgery. Neurosurgery 1994;35(4):585–590. Kondziolka D, Lunsford L, Flickinger J. Gamma knife stereotactic radiosurgery for cerebral vascular malformation. In: Loeffler JL, Alexander III E, Lunsford L, editors. Stereotactic radiosurgery, New York: McGraw-Hill, 1993. pp. 136–146. Malone S, Raaphorst GP, Gray R, Girard A, Alsbeih G. Enhanced in vitro radiosensitivity of skin fibroblast in two patients developing brain necrosis following AVM radiosurgery: a new factor with potential for a predictive assay. Int J Radiat Oncol Biol Phys 2000;47:185– 190. Peacock J, Ashton A, Bliss J, et al. Cellular radiosensitivity and complication risk after curative radiotherapy. Radiother Oncol 2000;55:173–178. Raaphorst GP, Malone S, Szanto J, Gray R. Severe normal tissue complication correlates with increased in vitro fibroblast radiosensitivity in radical prostate radiotherapy: a case report. Int J Cancer 2000;90(6):336–342. Russell NS, Grummels A, Hart AAM, et al. Low predictive value of intrinsic fibroblast radiosensitivity for fibrosis development following radiotherapy for breast cancer. Int J Radiat Biol 1998;73:661–670. Woods GW, Tyrne TD, Kim TH. Sensitivity of cultured cells to gamma radiation in a patient exhibiting marked in vivo radiation sensitivity. Cancer 1988;62:2341–2345.
Skin fibroblasts in vitro radiosensitivity can predict for late complications following AVM radiosurgery Gijsbert Peter Raaphorst*, Shawn Malone, Ghazi Alsbeih, Louis Souhani, Eva Szumacher, Andre Girard Ottawa Regional Cancer Centre, 503 Smyth Road, Ottawa, Ontario K1H 1C4, Canada Received 27 June 2001; received in revised form 18 February 2002; accepted 8 April 2002
Abstract Background and purpose: A small proportion of patients undergoing radiotherapy display heightened normal tissue reactions. We have set out to determine whether this sensitivity is genetic in nature and can be assessed using an in vitro skin fibroblast assay in order to predict and avoid excessive normal tissue complications. Patients and methods: In this study we compared five arteriovenous malformation (AVM) patients who were treated with radiotherapy and showed severe normal tissue reactions (necrosis) to two AVM patients who showed normal reactions. Fibroblasts taken from patients were cultured in vitro and irradiated. Results: The results showed that the fibroblasts from the sensitive patients were also more radiosensitive in vitro than the cells from the normally responding patients. Conclusions: The results suggest underlying genetic radiosensitivity and that such an assay may be used for prediction of severe radiosensitivity in AVM patients. q 2002 Elsevier Science Ireland Ltd. All rights reserved. Keywords: Skin fibroblasts in vitro radiosensitivity; Late complications; Arteriovenous malformation radiosurgery
1. Introduction While radiosurgery is an effective modality for the treatment of intercranial arteriovenous malformations (AVMs) with obliteration rates ranging from 60 to 90% [8– 10,15,16,24,25] there is also a risk of severe normal tissue complications in this patient group. It has been reported that the obliteration rates of AVM depend on the minimum dose to the lesion, which follows a sigmoidal dose response relationship [13]. Approximately 5–10% of patients experience different levels of delayed radiation induced neurologic sequelae, with a 3% risk of brain necrosis. A number of models have been proposed to predict the risk of necrosis which include the volume isoeffect line of Kjellberg [14,23], location and 12 Gy volume [11,12], average dose to 20 cm 3 volume and prior radiation history [22]. While the risk models for AVM treatment take into account a number of factors, they do not account for the possibility of a variation of intrinsic radiosensitivity, which may have a genetic basis. Since such variation has been reported in the literature [2–5,7,17–21] although not all studies agree [27,29]
* Corresponding author.
it is reasonable to expect that such a factor may also play a role in AVM treatment. In fact we [6,28] and others [1,30] have already shown that in vitro skin fibroblasts radiosensitivity correlated with severe late reaction in radiotherapy patients. Thus, the prediction of radiation sensitivity of an AVM patient may help avoid serious normal tissue complications after radiosurgery. We have studied seven AVM patients (five with severe complications, two without complications) as well as additional normally responding controls in order to determine whether the severe reactions were predictable through a fibroblast assay.
2. Materials and methods Five AVM patients (AVM Sens 1, 3, 4, 5, 6) suffering symptomatic radiation necrosis following radiosurgery (evaluated by MRI) and two patients with no symptoms nor necrosis (AVM 2, 7) from three institutions with longstanding radiosurgery experience in Canada were evaluated. The characteristics of the AVMs and details regarding radiosurgery treatment are shown in Table 1. All seven AVM patients had suffered brain hemorrhage prior to diagnosis. Patients were evaluated at each institution by a radiosurgery
0167-8140/02/$ - see front matter q 2002 Elsevier Science Ireland Ltd. All rights reserved. PII: S 0167-814 0(02)00076-2
154
G.P. Raaphorst et al. / Radiotherapy and Oncology 64 (2002) 153–156
Table 1 Patient and cell survival data a Cell line
AVM1 AVM2 AVM3 AVM4 AVM5 AVM6 AVM7 ORF2 ORF8 OMB9 a
AVM location
Thalamus Occipital Corpus callosum Thalamus Occipital Occipital Occipital Cancer Cancer Cancer
AVM size (mm)
25 25 15 40 25 25 20
Dose (Gy)
20 18 20 16 15 20 20
Measured data Immediate plating
Delayed plating
0.20 (0.02) 0.41 (0.06) 0.15 (0.018) 0.22 (0.016) 0.18 (0.02) 0.16 (0.02) 0.30 (0.011) 0.35 (0.50) 0.36 (0.05) 0.38 (0.05)
0.42 (0.055) 0.46 (0.046) 0.33 (0.05) 0.41 (0.45) 0.50 (0.03) 0.38 (0.015) 0.65 (0.09) 0.53 (0.06) 0.54 (0.08)
The numbers in parentheses represent the standard error of the mean.
team that included neurosurgeons, invasive neuro-radiologists, radiation oncologists and physicists. The heightened post-irradiation response in the sensitive patients could not be correlated to AVM volume and hence radiation volume. Following informed consent a 5 mm punch skin biopsy was taken from the medial forearm from each patient, placed in culture media type DMEM/F-12, maintained at 4 8C and supplemented with antibiotic (15%: penicillin, streptomycin and amphotericin B) without serum. After mincing into fragments and after the biopsy was inoculated into tissue culture flasks, 1 ml of fresh media supplemented with 20% fetal bovine serum (FBS) and 1% antibiotic was added, the flasks were incubated at 37 8C in 95% air and 5% CO2, and the volume of media was increased to 5 ml over the following 5 weeks. The out growing fibroblasts were then trypsinized and replated without antibiotic. Radiosensitivity measurements were carried out after the third passage. Clonogenicity was assessed using a fixed number of seeded cells (test 1 feeder) of 1000 cells/cm 2. Plating efficiencies ranged from 15 to 30%. Cells were irradiated in plateau phase by graded single doses of 1–12 Gy. Plateau phase cell cultures were used in order to avoid cell cycle redistribution and to more closely mimic tissue cell density. Irradiation was performed using 250 kVp X-rays (1 mm A1 filter) at a dose rate of 1.42 Gy/min. Cells were trypsinized either immediately (immediate plating: IP) or after 24 h (delayed plating: DP). After treatment cells were plated and incubated at 37 8C in a humidified atmosphere with 5% CO2 for 2 weeks, then fixed and stained with Crystal Violet and surviving colonies were counted. Three petri dishes containing up to 60 colonies were obtained per dose and per experiment. Two to four independent experiments were carried out for each cell line. Curves were fitted using the LQ radiation survival curve model.
3. Results The data presented in Fig. 1 show radiation responses of fibroblasts plated immediately after irradiation (Fig. 1a) or 24
h after irradiation to allow time for repair of potentially lethal damage (Fig. 1b). The AVM 2 and 7 cells derived from a normally responding patient show a more resistant radiation response, equivalent to three other cell strains (ORF2, ORF8 and OMB9) derived from normally responding radiotherapy cancer patients. The other AVM cell strains show a greater radiosensitivity which is mainly reflected in a reduction of the shoulder of the radiation survival curve. Based on this observation and the existing analysis in the literature we further assessed differences at the 2 Gy dose level and the results are shown in Table 1; the IP results clearly show a difference between AVM 2 and 7 compared to the five derived from patients exhibiting heightened normal tissue response. The results in Fig. 1b show that delayed plating resulted in recovery of radiation damage in the sensitive cell strains indicating that potentially lethal damage deficiency is not responsible for the increased sensitivity. In fact differences between AVM 2, 7 and AVM 1, 3, 4, 5, 6 decreased for DP (Table 1) indicating that perhaps the sensitive strains can repair potentially lethal damage to a greater extent. The results at 2 Gy were assessed using Student’s t-test and showed that AVM normals were not different from cancer normals (P ¼ 0:7), AVM sensitive were not different from cancer sensitive (P ¼ 0:82), and AVM normal were different from AVM sensitive (P ¼ 0:005).
4. Discussion The results of this study show that in patients receiving curative treatment for AVM and developing complications these may be related to the genetic radiosensitivity of the patient. Earlier studies have shown that complications are related to such factors as dose, volume and location of the irradiated tissue [11]. In this report we show that intrinsic radiosensitivity is an additional indicator of clinical outcome and these results agree with our previous report on two sensitive AVM cases [26]. The data show that the heightened clinical complication rate was correlated with
G.P. Raaphorst et al. / Radiotherapy and Oncology 64 (2002) 153–156
155
impaired in their ability to repair potentially lethal damage. Because the main difference appears to be in the shoulder of the survival curve the assay may possibly be improved by giving multiple 2 Gy doses in vitro. Finally, as for cancer patients this heightened sensitivity in AVM patients appears to occur in about 1–3% of the treated population. We speculate that it may well be a genetically related radiosensitive subgroup and further molecular analysis may be indicated to assess this possibility. References
Fig. 1. (a) The radiation survival is shown for human fibroblasts irradiated in plateau phase and then plated immediately after irradiation for the colony survival assay. The AVM 2 and 7 and ORF 2 and 8 are cells from normally responding radiotherapy patients while the rest are from patients that exhibited a radiosensitive response to AVM radiotherapy. (b) Survival of cells plated immediately after irradiation is compared to cells plated 24 h after irradiation for the colony survival assay.
heightened in vitro fibroblast radiosensitivity implicating a genetically linked radiosensitivity. Since treatment for AVM can be delayed (since it is not a progressive disease like cancer) the in vitro fibroblast assay which takes about 6–8 weeks could be used as a predictor of radiation response and help avoid severe normal tissue complication. The in vitro fibroblast responses indicated that the sensitive cell strains were characterized by a reduced survival curve shoulder indicating reduced ability for accumulation of sublethal damage. However, these cells were not
[1] Abadir RM, Hakami N. Ataxia telangiectasia with cancer. An indication for reduced radiotherapy and chemotherapy doses. Br J Radiat 1983;56:343–345. [2] Alsbeih G, Malone S, Lochrin C, Gray R, Fertil B, Raaphorst GP. Correlation between normal tissue complications and in-vitro radiosensitivity of skin fibroblasts derived from radiotherapy patients treated for a variety of tumours. Int J Radiat Oncol Biol Phys 2000;46(1):143–152. [3] Alsbeih G, Malone S, Raaphorst GP. Intrinsic radiosensitivity as a predictive assay in radiotherapy: rationale for multifraction approach. Cah Radiobiol 1997;5:13–16. [4] Brock WA, Tucker SL, Geara FB, et al. Fibroblast radiosensitivity versus acute and late normal skin responses in patients treated for breast cancer. Int J Radiat Oncol Biol Phys 1995;32:1371–1379. [5] Brown RC, Ng CE, Raaphorst GP. A comparison of high dose rate, low dose rate and fractionation for optimizing differences in radiosensitivities in vitro. Radiat Oncol Invest 1998;6:209–215. [6] Brown RC, Raaphorst GP, Danjoux CE, Drouin P. Multi-organ fatal chronic complications following radiation treatment for cancer of the cervix: results of fibroblast assay. Gynecol Oncol 1996;61:116–121. [7] Burnet NB, Warm R, Peacock JH. Low dose-rate fibroblast radiosensitivity and the prediction of patient response to radiotherapy. Int J Radiat Biol 1996;70:289–300. [8] Coffey R, Nichols D, Shaw E. Stereotactic radiosurgical treatment of cerebral arteriovenous malformations. Gamma Unit Radiosurgery Study Group. Mayo Clin Proc 1995;70(3):214–222. [9] Colombo F, Pozza F, Chierego G, et al. Linear accelerator radiosurgery for cerebral arteriovenous malformations. An update. Neurosurgery 1994;34(1):14–21. [10] Engenhart R, Wowra B, Debus J, et al. The role of high dose singlefraction irradiation in small and large intracranial arteriovenous malformations. Int J Radiat Oncol Biol Phys 1994;30(1):521–529. [11] Flickinger JC, Kondziolka D, Lunsford LD, Liscak R, Pollock B. Development of a model to predict permanent symptomatic post radiosurgery injury for arteriovenous malformation patients. Int J Radiat Oncol Biol Phys 2000;45:1143–1148. [12] Flickinger JC, Kondziolka D, Maitz AH, et al. Analysis of neurological sequelae from radiosurgery of arteriovenous malformations: how location affects outcome. Int J Radiat Oncol Biol Phys 1998;40(2):273–278. [13] Flickinger JC, Pollick BE, Kondziolka D, Lunsford LD. A doseresponse analysis of arteriovenous malformation obliteration after radiosurgery. Int J Radiat Oncol Biol Phys 1996;36(4):873–879. [14] Flickinger J, Schell M, Larson D. Estimation of complications for linear accelerator radiosurgery with the integrated logistic formula. Int J Radiat Oncol Biol Phys 1990;19:143–148. [15] Friedman W, Bova F, Mendenhall W. Linear accelerator radiosurgery for arteriovenous malformations: the relationship of size to outcome. J Neurosurg 1995;82(2):180–189. [16] Friedman W, Bova F. Linear accelerator radiosurgery for arteriovenous malformations. J Neurosurg 1992;77(6):832–841.
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G.P. Raaphorst et al. / Radiotherapy and Oncology 64 (2002) 153–156
[17] Geara FB, Peters LJ, Ang KK, Wike JL, Brock WA. Prospective comparison of in vitro normal cell radiosensitivity and normal tissue reactions in radiotherapy patients. Int J Radiat Oncol Biol Phys 1993;27:1173–1179. [18] Geara FB, Peters LJ, Ang KK, Wike JL, Brock WA. Radiosensitivity measurement of keratinocytes and fibroblasts from radiotherapy patients. Int J Radiat Oncol Biol Phys 1992;24:287–293. [19] Geara FB, Peters LJ, Ang KK, et al. Intrinsic radiosensitivity of normal human fibroblasts and lymphocytes after high- and lowdose-rate irradiation. Cancer Res 1992;52:6348–6352. [20] Johansen J, Bentzen SM, Overgaard J, Overgaard M. Evidence for a positive correlation between in vitro radiosensitivity of normal human skin fibroblasts and the occurrence of subcutaneous fibrosis after radiotherapy. Int J Radiat Biol 1994;66:407–412. [21] Johansen J, Bentzen SM, Overgaard J, Overgaard M. Relationship between the in vitro radiosensitivity of skin fibroblasts and the expression of subcutaneous fibrosis, telangiectasia and skin erythema after radiotherapy. Radiother Oncol 1996;40:101–109. [22] Karlsson B, Lax I, Soderman M. Factors influencing the risk for complications following gamma knife radiosurgery of cerebral arteriovenous malformations. Radiother Oncol 1997;43:275–280. [23] Kjellberg R, Hanamura T, Davis J, et al. Bragg-peak proton-beam therapy for arteriovenous malformations of the brain. N Engl J Med 1983;390:269. [24] Kondziolka D, Lunsford L, Kanal E, et al. Stereotactic magnetic
[25]
[26]
[27]
[28]
[29]
[30]
resonance angiography for targeting in arteriovenous malformation radiosurgery. Neurosurgery 1994;35(4):585–590. Kondziolka D, Lunsford L, Flickinger J. Gamma knife stereotactic radiosurgery for cerebral vascular malformation. In: Loeffler JL, Alexander III E, Lunsford L, editors. Stereotactic radiosurgery, New York: McGraw-Hill, 1993. pp. 136–146. Malone S, Raaphorst GP, Gray R, Girard A, Alsbeih G. Enhanced in vitro radiosensitivity of skin fibroblast in two patients developing brain necrosis following AVM radiosurgery: a new factor with potential for a predictive assay. Int J Radiat Oncol Biol Phys 2000;47:185– 190. Peacock J, Ashton A, Bliss J, et al. Cellular radiosensitivity and complication risk after curative radiotherapy. Radiother Oncol 2000;55:173–178. Raaphorst GP, Malone S, Szanto J, Gray R. Severe normal tissue complication correlates with increased in vitro fibroblast radiosensitivity in radical prostate radiotherapy: a case report. Int J Cancer 2000;90(6):336–342. Russell NS, Grummels A, Hart AAM, et al. Low predictive value of intrinsic fibroblast radiosensitivity for fibrosis development following radiotherapy for breast cancer. Int J Radiat Biol 1998;73:661–670. Woods GW, Tyrne TD, Kim TH. Sensitivity of cultured cells to gamma radiation in a patient exhibiting marked in vivo radiation sensitivity. Cancer 1988;62:2341–2345.