Table 1
Biologic effective dose (BED) comparison for standard 3-dimensional conformal radiotherapy (3D CRT) and intensity modulated radioation therapy with simultaneous boost (IMRT-SIB) as experimental fractionation
| Treatment | Pelvis TD/d/BED (Gy) | Tumour T≤3 TD/d/BED (Gy) | Tumour T4 TD/d/BED (Gy) |
|---|---|---|---|
| 3D CRT | 45 / 1.8 / 37.5 | 50.4 / 1.8 / 40.9 | 54 / 1.8 / 43.9 |
| IMRT-SIB | 41.8 / 1.9 / 35.9 | 46.2 / 2.1 / 42.1 | 48.4 / 2.2 / 45.2 |
[i] BED is calculated as BED = TD x (d + α/β) / (2 + α/β) - (T - t) x Dprolif in which TD is the total dose, d dose (Gy) per fraction, α/β is the common linear-quadratic quotient (set to 10 Gy), Dprolif is the dose recovered due to proliferation (set to 0.6 Gy/day), T = total treatment time and t = initial delay time (days, set to 7 days)data from 36 prospective studies, 7 retrospective studies and 17 other articles were used. A total of 131 scientific articles are included, involving 25 351 patients. The results were compared with those of a similar overview from 1996 including 15 042 patients. The conclusions reached can be summarized thus: The results after rectal cancer surgery have improved during the past decade. It is likely that local failure rates after 5 years of follow-up at hospitals adopting the TME-concept (TME = total mesorectal excision.20 Standard fractionation for preoperative rectal cancer treatment with 3D CRT consists of 45 Gy in 25 fractions to the tumour and regional lymph nodes (pelvis) and additional boost 3 x 1.8 Gy (TD 50.4 Gy) in T ≤3 and 5 x 1.8 Gy (TD 54 Gy) in T4 tumour.
Figure 1
Intensity modulated radiation therapy plan met the planning goals
Figure 2
Distribution of patients through the trial.
CRT = radiochemotherapy; RT = radiotherapy
Table 2
Influence of potential prognostic factors on overall survival (OS) and disease free survival (DFS)
| Prognostic factor | OS | DFS |
|---|---|---|
| Age | ns | ns |
| Gender | ns | ns |
| WHO PS | ns | ns |
| Tumour grade | ns | ns |
| cTumour stagea | ns | ns |
| cNodal stagea | ns | ns |
| TRG | ns | ns |
| TRG prognostic group | ns | ns |
| pTumour staged | ns | ns |
| pNodal staged | p = 0.005 | p = 0.039 |
| pCRf | ||
| Adjuvant chemotherapyg | ns | ns |
| 5-6 vs. ≤4 cycles* | p = 0.009 | p = 0.012 |
TRG = tumour regression grade23; WHO PS = WHO performance status
a according the AJCC, 7th edition22
a according the AJCC, 7th edition22
Figure 3
Prognostic significance of pathologic nodal stage (pN) on 2-year disease-free survivala, overall survivalb, prognostic significance of the received number of adjuvant chemotherapy cycles in patients without pCR on 2-year disease-free survivalc, and overall survivald in rectal cancer after preoperative radiochemotherapy and surgery.
Table 3
Comparison of tumour regression grade in patients with R0 resection
| IMRT-SIB But-Hadzic et al.16 N = 46 | 3D CRT Focas et al.32 N = 385 | IMRT-SIB But-Hadzic et al.16 N = 46 | IMRT-SIB Li et al.10 N = 58 | |||
|---|---|---|---|---|---|---|
| p | p | |||||
| TRG 4 | 12 (26%) | 40 (10%) | 0.004 | 12 (26 %) | 19 (33 %) | 0.302 |
| TRG 2–3 | 29 (63%) | 254 (66%) | 0.404 | 29 (63 %) | 20 (35 %) | 0.003 |
| TRG 0–1 | 5 (11%) | 91 (24%) | 0.031 | 5 (11 %) | 19 (32 %) | 0.007 |
[i] 3D CRT = 3D conformal radiotherapy; IMRT-SIB = intensity modulated radiation therapy with simultaneous boost; TRG = tumour regression grading23