Table 1.
Primary tumor volumetric changes in HNSCC or NPC during curative RT or CRT
| Study | Sample Size (n) | Re-Scan Timing | Mean Primary Tumor Volume Reduction (Range) by Fraction (Fx) 10 | Mean Primary Tumor Volume Reduction (Range) by Fx 20 | Mean Primary Tumor Volume Reduction (Range) by End of Treatment |
|---|---|---|---|---|---|
| Bhide IJROBP 2010 [8] | 20 (10 OPC, 6 Laryng or Hypoph, 4 NPC) | Weeks 2, 3, 4, 5 | 3.2% CTV1, where CTV1 was gross disease + 1.5 cm margin (0.74–5.6%) | – | – |
| Liu IJROBP 2018 [9] | 18 (16 OPC, 1 NPC, 1 UP) | Fx 10 and 22 | 16.4% GTV, 15.4% CTV1 where CTV1 was GTV + 0.5 cm margin (GTV − 2.1 to 37.1%, CTV1 0.7 to 30.5%) | – | 32.6% GTV, 28.2% CTV1 by fraction 22 (GTV 9.8 to 56.3%, CTV1 12.0 to 44.8%) |
| Capelle Clin Oncol 2012 [10] | 20 (17 HNSCC, 3 NPC) | Fx 15 | – | 28.8% GTV, 16% PTV60/66 where PTV60 was a 0.5 cm expansion on CTV60 (involved postop regions) for adjuvant patients and PTV66 was a 0.5 cm expansion on the GTV for definitive patients (GTV 1.6 to 60%, PTV 0 to 45%) | – |
| Chitapanarux J Radiat Res 2015 [11] | 17 (17 NPC) | Fx 17 | – | 18.4% GTV, − 7.4% CTV70 by fraction 17 where CTV70 was GTV + 0.5 cm margin (range NS) | – |
| Dewan Asian Pac J 2016 [12] | 30 (15 OPC, 10 OC, 5 Hypoph) | Fx 20 | – | 47.62% GTV, 43.76% CTV where CTV was GTV + 0.5–2 cm margin, 49.69% PTV where PTV was 0.2–0.5 cm margin by fraction 20 (range NS) | – |
| Lee Cancer Res Treat 2016 (13) | 159 (159 NPC) | Fx 15 | – | 43.4% GTV (− 3.8 to 93.5%) | – |
| Lu Chin Med J 2012 [14] | 43 (43 NPC) | Fx 20 | – | 30.1% GTV by Fraction 20 (0.6 to 77.2%) | – |
| Mahmoud Technol Cancer Res Treat 2017 [15] | 22 (11 OPC, 7 OC, 2 Laryng, 1 Hypoph, 1 NPC) | Fx 15, 27 | – | 7.2% CTV-HR for definitive (− 3 to 18%) 7.8% CTV-HR for postoperative (0 to 18%) where CTV-HR “included the regions and/or subjacent lymph node chains within 2 to 3 cm of gross disease” | 12.8% CTV-HR for definitive (−7 to 29%) 10.9% CTV-HR for postoperative (3 to 20%) |
| Surucu Technol Cancer Res Treat 2016 [16] | 48 (28 OPC, 7 NPC, 5 Hypoph, 8 OC) | Week 4 (median; rescans done at a median dose of 37.8Gy with range of 14.4–51.5 Gy) | – | 26.8% GTV (range NS) | – |
| Surucu Technol Cancer Res Treat 2017 [27] | 34 (20 OPC, 6 OC, 5 NPC, 3 Hypoph) | Week 4 (median; rescans done at a median dose of 37.8Gy with range of 27.0–48.6 Gy) | – | – | 35.2% GTV (−18.8 to 79.6%) |
| Castelli Radiat Oncol 2015 [3] | 15 (11 OPC, 2 OC, 1 Laryng, 1 Hypoph) | Weekly | – | – | 31% CTV70 where CTV70 was GTV + 0.5 cm margin (−13 to 73%) |
| Loo Clin Oncol 2011 [17] | 5 (3 OPC, 1 OC, 1 Laryng) | Weekly | – | – | 5.8% CTV68 where CTV68 “encompassed the GTV and high-risk regions” (range NS) |
| Beltran J Appl Clin Med 2012 [18] | 16 (7 OPC, 5 OC, 1 Hypoph, 1 NPC, 2 NS) | Fx 15, 25 | – | – | 13.25% PTV2 where PTV2 was the CTV2 (GTV + high-risk regions) + 0.5 cm margin (range NS) |
| Fung Med Dosim 2012 [19] | 10 (10 NPC) | Fx 21, 31 approx. | – | – | 53.95% CTV, 36.19% PTV where PTV was the CTV + 0.3 cm (range NS) |
| Jin Radiat Oncol 2013 [20] | 9 (9 NPC) | Fx 23 | – | – | 9.4% GTV by fraction 23 (range NS) (non-sig reduction) |
| Schwartz Radiother Oncol 2013 [21] | 22 (22 OPC) | Daily scans, Weekly recalc | – | 5% CTV where CTV was the GTV + high-risk regions (−21 to 13%) | 8% CTV (−6 to 19%) |
| Tan Onco Targets Ther 2013 [22] | 20 (20 NPC) | Weekly | – | – | 55.3% GTV (range NS) |
| Fung J Radiat Res 2014 [23] | 30 (30 NPC) | Every 2 Fx | – | – | 35.7% GTV (range NS) |
| Huang Radiat Oncol 2015 [24] | 19 (19 NPC) | Every 5 Fx | – | – | 65.6% GTV (range NS) |
| Kataria Br J Radiol [25] | 36 (21 OPC, 5 Laryng, 10 Hypoph) | Fx 23 | – | – | 34.0% GTV (range NS) |
| Zhang Radiother Oncol 2016 [26] | 13 (13 OPC) | Weekly | – | – | 24.43% CTV70 where CTV70 was GTV + 0.5 cm margin (−12.6 to 62.1%) |
| Range of median tumor volume (GTV / CTV / PTV) reductions of the included studies | 3 to 16% | 7 to 48% | 6 to 66% | ||
Most studies reported a reduction in the primary target volume over the course of radiotherapy. However, the studies varied in the definition of the target volume reported, with some reporting the GTV, some the high risk CTV (with varying margins), and some the high risk PTV (also with varying margins), making comparisons across studies difficult. Note that for studies that included a wide range of fractions reported at time of re-scan, the median fraction was used for categorizing into the above columns (by Fx 10, Fx 20, etc). In regards to Bhide IJROBP 2010 (8) some patients had induction chemotherapy prior to definitive CRT, which may account for some of the variation seen between the volumetric changes reported by this author and by Liu IJROBP 2018 (9). Overall, the trend seen in these series was for increasing tumor volume reduction throughout therapy with median reductions reported as 3 to 16% by fraction 10, 7 to 48% by fraction 20, and 6 to 66% by end of treatment
“- “information was either not available or was not directly comparable to other volumetric/dosimetric data reported and thus not included
GTV Gross Tumor Volume, CTV Clinical Target Volume, PTV Planned Target Volume, HNSCC Head and Neck Squamous Cell Carcinoma, OPC Oropharyngeal Cancer, OC Oral Cavity Cancer, NPC Nasopharyngeal Cancer, Laryng Laryngeal Cancer, Hypoph Hyopharyngeal Cancer, NS Head and Neck Squamous Cell Carcinoma, Site Not Specified, SN Sinonasal Cancer, UP Head and Neck Squamous Cell Carcinoma of Unknown Primary, Range NS Range not stated