T. Aihara1, 2, N. Morita2, N. Kamitani3, H. Kumada1, K. Oonishi1, M. Suzuki4, J. Hiratsuka3, H. Sakurai1. 1Proton Medical Research Centre, University of Tsukuba, Tsukuba, Japan2Departments of Otolaryngology Head and Neck Surgery, and 3Radiation Oncology, Kawasaki Medical School, Kurashiki, Japan4Radiation Oncology Research Laboratory, Research Reactor Institute, Kyoto University, Osaka, Japan

A simple strategy to decrease the incidence of fatal carotid blowout syndrome after BNCT for head and neck cancers

Purpose

• Carotid blowout syndrome (CBS) is a life-threatening complication of BNCT for head and neck cancers

• Determination of the risk factors for CBS is important for the safe use of BNCT

• This study reviews cases of CBS after BNCT at our institution

Indications for BNCT

• Recurrent Head and Neck Cancer (HNC) or newly diagnosed T3/T4 HNC

• Maximum depth of tumor within 5-cm from the skin surface

• T/N ratio of more than 2.5 • Consent to perform BNCT from the patient and their

family• Approval for BNCT by Medical Ethics Committee

Treatment procedure• Intravenous administration of BPA(500mg/kg) as a BPA-Fructose

complex in solution

•Attachment of TLDs and gold wires to the skin surface involved in the irradiation field

•Fixation of the patient on the treatment table

•Neutron flux measurement using gold wire 10 minutes after the start of irradiation

•Blood sampling at the finish of the BPA infusion, and just before and after irradiation

•Dose prediction based on the measured blood boron concentration and neutron flux

•Tumor dose ≧ 20 Gy-EqNormal skin dose ≦ 15 Gy-Eq

•Determination of neutron irradiation period

Patient characteristicsOctober 2003 - December 2011

Patients 33male 21

female 12Age 31-83 (median:67)

Rec/NewRecurrence 24 (after irradiation:23)

New 9

PathologySCC 11MM 10

Other 12Radiation

fieldNeck 18 (carotid lesion:11)

Other 15T/N 2.5-5 (median:2.7)

Patient characteristicsOctober 2003 - December 2011

Patients 33male 21

female 12Age 31-83 (median:67)

Rec/NewRecurrence 24 (after irradiation:23)

New 9

PathologySCC 11MM 10

Other 12Radiation

fieldNeck 18 (carotid lesion:11)

Other 15T/N 2.5-5 (median:2.7)

Criteria of involvement grade (IG)

High grade >2/3

Low grade ≤ 1/3 　　　　　　　　

　　　　

Middle grade ≤ 2/3

No involvement 　　　　　　　　

　　　　

Results (n=18)

IGSkin defect

RT(+) CBSTime to

CBS onset

Not involved

7(+) 3 3(-) 4 3

Low 4(+) 1 1(-) 3 1

Middle 4(+) 1 1 Yes

2 months

(-) 3 2

High 3(+) 1 1 Yes

3 months

(-) 2 2IG : involvement gradeRT : RadiotherapyCBS : carotid blowout syndrome

Results (n=18)

IGSkin defect

RT(+) CBSTime to

CBS onset

Not involved

7(+) 3 3(-) 4 3

Low 4(+) 1 1(-) 3 1

Middle 4(+) 1 1 Yes

2 months

(-) 3 2

High 3(+) 1 1 Yes

3 months

(-) 2 2IG : involvement gradeRT : RadiotherapyCBS : carotid blowout syndrome

A case of CBS

Case No.6

before irradiation 28 days later

Discussion

• Incidence rates of CBS after radiotherapyNewly diagnosed cancer: 2-5% [LingYan Zheng. et al. 2013]

Recurrent cancer: 10-20% [Cengiz M. et al. 2011]

• Incidence rates of CBS after BNCT

4.8% [M, Suzuki. et al. 2013].• CBS developed in two patients after BNCT• These two patients had:

1) Skin defects due to tumor invasion.

2) Recurrence close to the carotid artery after irradiation

Discussion

• Incidence rates of CBS after radiotherapyNewly diagnosed cancer: 2-5% [LingYan Zheng. et al. 2013]

Recurrent cancer: 10-20% [Cengiz M. et al. 2011]

• Incidence rates of CBS after BNCT4.8% [M, Suzuki. et al. 2013]

• CBS developed in two patients after BNCT• These two patients had:

1) Skin defects due to tumor invasion

2) Recurrence close to the carotid artery after irradiation

Conclusion

• Two of 18 patients bled from the carotid artery after BNCT

• These two patients had skin defects from tumor invasion and recurrence close to the carotid artery after irradiation

• This protocol for BNCT in recurrent and advanced head and neck cancer may decrease the incidence of fatal CBS