Table 1.
Characteristics of included studies, with summary statistics of reported hypothyroidism incidence displayed by subgroup.
| Factor | Count (%) N = 111 |
Estimated Hypothyroidism Incidence (%), Reported as Median (IQR) |
|---|---|---|
| Publication Year | ||
| 2000 and prior | 19 (17) | 34 (21–43) |
| 2001–2005 | 8 (7) | 44 (40–47) |
| 2006–2010 | 15 (14) | 31.6 (20.8–45.3) |
| 2011–2015 | 22 (20) | 33.3 (22.8–45) |
| 2016–2020 | 32 (29) | 42.3 (25–46.2) |
| 2021–2022 | 15 (14) | 42 (30.4–54.3) |
| Design | ||
| Prospective | 31 (28) | 37 (27.4–47) |
| Retrospective | 80 (72) | 36.1 (24–46) |
| Interventional | ||
| Yes | 4 (4) | - |
| No | 97 (96) | - |
| Mean/Median Follow Up (months) | ||
| Min | 6 | - |
| First Quartile | 21 | - |
| Median | 32 | - |
| Third Quartile | 50.2 | - |
| Max | 120 | - |
| Unspecified/NA | 24 | - |
| Sample size | Median 102 (62–184.75) | - |
| Participant Type | ||
| Patients | 99 (98) | - |
| Physicians | 2 (2) | - |
| Cancer Site | ||
| General Head and Neck | 64 (58) | 36.7 (26–44.7) |
| Nasopharynx | 28 (25) | 35 (23–46.2) |
| Oropharynx | 6 (5) | 57.5 (35.3–62.5) |
| Larynx/Hypopharynx | 10 (9) | 39.5 (28.7–48.7) |
| Oral Cavity | 3 (3) | 17.9 (16.1–19.7) |
| Radiation Therapy Modality | ||
| Photons | 87 (78) | - |
| Photons/Electrons | 2 (2) | - |
| Particle Therapy | 0 | - |
| Unspecified | 22 (20) | - |
| Radiation Therapy Technique | ||
| IMRT | 36 (32) | 42 (27.4–49.1) |
| Non-IMRT (2D or 3DCRT) | 38 (34) | 35 (21.8–41.6) |
| IMRT and 3DCRT | 10 (9) | 46.5 (27.5–50.8) |
| MRI-guided radiotherapy | 0 | - |
| Unspecified/NA | 27 (24) | 35 (23.9–48.2) |
| Multimodality Therapy | ||
| All therapies allowed | 89 (80) | 36.4 (24.8–45.7) |
| Surgery excluded | 13 (12) | 38.8 (30–47) |
| Surgery required | 4 (4) | 38.6 (26.2–50.5) |
| Unspecified/NA | 5 (5) | 36.4 (25.4–48.2) |
| Thyroid Evaluation | ||
| Biochemical | 73 (66) | 38.8 (26.7–46.2) |
| Clinical | 2 (2) | 4.9 |
| Biochemical and Clinical | 32 (29) | 31.1 (23.9–49.5) |
| Biochemical and Radiographic | 2 (2) | 42 |
| Unspecified/NA * | 2 (2) | - |
Abbreviations: 2D and 3DCRT; two-dimensional and three-dimensional conformal radiation therapy, IMRT; intensity-modulated radiation therapy * Refers to studies investigating physician practices regarding screening for hypothyroidism and thus were considered Unspecified/NA.