Dose Constraints for Organs at Risk in Reirradiation for Esophageal Carcinoma

Key Principles for Reirradiation Planning

The National Comprehensive Cancer Network recommends that radiation plans must be based on accurate reconstruction of the previous RT dose distribution, taking into account expected morbidity of additional radiation 1, 2
The American College of Radiology suggests that dose constraints for organs at risk are not clearly established, and the degree of recovery from initial radiation is difficult to estimate 1, 2

The National Comprehensive Cancer Network recommends that maximum spinal cord dose should be limited to 50 Gy with conventional fractionation (1.8-2 Gy per fraction) for initial treatment 3
The American Society for Radiation Oncology suggests that mean lung dose (MLD) should be ≤20 Gy 3
The National Comprehensive Cancer Network recommends that mean esophageal dose (MED) should be <34 Gy for initial treatment 3
The American Heart Association suggests that heart dose constraints: 60 Gy to <1/3 of volume, 45 Gy to <2/3 of volume, 40 Gy to <100% of volume 3
The National Comprehensive Cancer Network recommends that particular caution is warranted when reirradiating the carotid artery, as severe life-threatening complications such as carotid blowout syndrome have been reported in head and neck cancer reirradiation 1, 2

The National Comprehensive Cancer Network recommends that if high-dose RT (≥50 Gy) can be delivered without exceeding estimated OAR dose constraints → proceed with curative-intent reirradiation 1, 2
The American College of Radiology suggests that if adequate target coverage cannot be achieved without exceeding OAR constraints → consider other treatment modalities or palliative-intent low-dose RT only if negligible toxicity risk 1, 2

The National Comprehensive Cancer Network recommends that one should not assume complete recovery of normal tissue tolerance—the degree of recovery from initial radiation is difficult to estimate and varies by organ 1, 2
The American Society for Radiation Oncology suggests that one should not use standard OAR constraints without accounting for previous radiation exposure 1, 2
The National Comprehensive Cancer Network recommends that one should not proceed with reirradiation if accurate reconstruction of previous dose distribution is impossible 1, 2