Table 1.
Clinical and treatment characteristics of groups based on fractionation
| Parameter | Daily (n = 46) | QOD/other (n = 46) | P |
|---|---|---|---|
| Median age at diagnosis (y) (range) | 73 (50–94) | 72 (51–95) | .810 |
| Ethnicity | .406 | ||
| Caucasian | 35 (76) | 44 (96) | |
| African American | 3 (7) | 1 (2) | |
| Other | 1 (2) | 1 (2) | |
| Unknown | 7 (15) | 0 (0) | |
| Sex | .999 | ||
| Male | 31 (67) | 32 (68) | |
| Female | 15 (33) | 14 (32) | |
| Median smoking history (pack-years) (range) | 65 (0–168) | 50 (0–160) | .153 |
| History of prior malignancy* | .139 | ||
| None | 35 (76) | 29 (63) | |
| NSCLC (early-stage) | 9 (20) | 5 (11) | |
| Head and neck | 1 (2) | 3 (7) | |
| Gastrointestinal | 0 (0) | 4 (9) | |
| Breast | 1 (2) | 2 (4) | |
| Bladder | 0 (0) | 2 (4) | |
| Skin | 1 (2) | 1 (2) | |
| Prostate | 0 (0) | 2 (4) | |
| Other | 0 (0) | 6 (13) | |
| Prior thoracic irradiation | .999 | ||
| Yes | 3 (7) | 2 (4) | |
| No | 43 (93) | 44 (95) | |
| Indication for SBRT | .412 | ||
| Medically inoperable | 42 (91) | 44 (92) | |
| Refused surgery | 4 (9) | 2 (4) | |
| Lobe of lung | .727 | ||
| Right upper | 11 (24) | 16 (35) | |
| Left lower | 13 (28) | 10 (22) | |
| Right lower | 10 (22) | 8 (17) | |
| Left upper | 10 (22) | 8 (17) | |
| Right middle | 2 (4) | 4 (9) | |
| Location | .817 | ||
| Peripheral | 34 (74) | 32 (72) | |
| Central | 12 (26) | 14 (28) | |
| Lesion size | .689 | ||
| Median (cm) (range) | 5.4 (5.0–7.5) | 5.5 (5.0–7.5) | |
| Histology | .399 | ||
| Squamous cell carcinoma | 19 (41) | 26 (57) | |
| Adenocarcinoma | 13 (28) | 15 (33) | |
| NSCLC, not otherwise specified | 6 (13) | 2 (4) | |
| Large cell carcinoma | 1 (2) | 1 (1) | |
| Mixed adenosquamous | 1 (2) | 0 (0) | |
| No biopsy | 6 (13) | 2 (4) | |
| AJCC clinical T stage | .841 | ||
| T2a | 5 (11) | 5 (11) | |
| T2b | 40 (87) | 39 (86) | |
| T3 | 1 (2) | 2 (4) | |
| Median SUVmax on pre-SBRT PET (range) | 11.5 (2.0–29.6) | 9.4 (3.0–20.3) | .078 |
| Mediastinal nodal sampling | .065 | ||
| Performed | 21 (46) | 11 (24) | |
| Not performed | 25 (54) | 34 (74) | |
| Unknown | 0 (0) | 1 (2) | |
| ECOG performance status at diagnosis | .815 | ||
| 0 | 6 (13) | 4 (9) | |
| 1 | 25 (54) | 24 (52) | |
| 2 | 13 (28) | 15 (33) | |
| 3 | 2 (4) | 2 (4) | |
| Unknown | 0 (0) | 1 (2) | |
| SBRT dose and fractionation | .003† | ||
| 50 Gy in 5 fractions | 28 (61) | 15 (33) | |
| 48 Gy in 4 fractions | 4 (9) | 17 (37) | |
| 54 Gy in 3 fractions | 3 (7) | 8 (17) | |
| 60 Gy in 5 fractions | 5 (11) | 2 (4) | |
| 55 Gy in 5 fractions | 2 (4) | 1 (2) | |
| Other | 4 (9) | 3 (7) | |
| Total SBRT dose | .066 | ||
| Median (Gy) (range) | 50 (40–60) | 50 (36–60)‡ | |
| Biologically effective dose§ | .211 | ||
| Median (Gy) (range) | 100 (72–151.2) | 105.6 (72–151.2) | |
| SBRT technique | .149 | ||
| Fixed-beam 3D | 13 (28) | 21 (46) | |
| Fixed-beam IMRT | 11 (24) | 14 (30) | |
| Dynamic arcs | 3 (7) | 0 (0) | |
| VMAT | 14 (30) | 11 (24) | |
| Unknown | 5 (11) | 0 (0) | |
| Image guidance | .145 | ||
| Kilovoltage (cone-beam) CT | 37 (80) | 30 (65) | |
| Orthogonal X rays | 9 (20) | 9 (20) | |
| Megavoltage CT | 0 (0) | 7 (8) | |
| Receipt of chemotherapy | .612 | ||
| Yes | 1 (2) | 3 (7) | |
| No | 45 (98) | 43 (93) | |
| Primary tumor responseǁ | .407 | ||
| Complete response | 1 (2) | 2 (4) | |
| Partial response | 25 (54) | 25 (54) | |
| Stable | 16 (35) | 10 (22) | |
| Progression | 1 (2) | 1 (2) | |
| Unknown | 3 (7) | 8 (17) |
Abbreviations: AJCC = American Joint Committee on Cancer; CT = computed tomography; ECOG = Eastern Cooperative Oncology Group; IMRT = intensity modulated radiation therapy; NSCLC = non-small cell lung cancer; PET = positron emission tomography; QOD = every other day; SBRT = stereotactic body radiation therapy; SUV = standard uptake value; VMAT = volumetric modulated arc therapy.
Values are number (percentage) unless otherwise noted.
Values do not add up to 100% because of patients with synchronous/metachronous neoplasms.
Statistically significant P value.
36 Gy was delivered to a patient of a planned 48 Gy; the patient did not complete treatment.
Assuming α/β ratio of 10.
As per Response Evaluation Criteria in Solid Tumors.