Table 1.
Model parameters*
| Parameters | Estimates base case | Values (in 2010 US$) | Estimates range (%) | Sources |
| Proportion of patients with KRAS mutations | 28% | – | 25–60 | (49, 50) |
| Proportion of patients with BRAF mutations | 4% | – | 3–10 | (49, 50) |
| Proportion of patients with initially resectable metastases | 20% | – | 10–25 | (4, 9) |
| Proportions of patients with metachronous/ synchronous/synchronous abdominal-peritoneal metastases | 30%/20%/50% | – | † | (4, 10, 33, 34, 51-54) |
| Median number of cycles of conversion therapy | 22 cycles | – | † | (13) |
| Gap between treatment with bevacizumab and resection of metastases (because bevacizumab increases the risk of bleeding and hinders wound healing) | 6 weeks | – | † | (4) |
| Interaction of KRAS mutation on chemotherapiesʹ effectiveness | No effect‡ | – | 4–21 decrease | (22, 55) |
| Effect of cetuximab when KRAS mutation is present | No effect | – | † | (41) |
| Probability of conversion (to resectable) with:ChemotherapyCetuximab and chemotherapy | 14%25% | – | 14-3020-30 | (13, 45, 56, 57) |
| Probability of conversion (to resectable) with bevacizumab | 14% | – | 20 | Interpolation; (4) |
| Maximum overall survival under palliative care | 28 months | – | † | (30) |
| Probability of 1-, 3-, 5-, 10-year survival following hepatic resection | 85%, 39%, 25%, and 11% | – | † | (32-35) |
| Recurrence after hepatic resection | 46% within 12 months | – | † | (36) |
| Repeat hepatic resection rates | 13%–53% | – | † | (38) |
| Third hepatic resections | 16% of the patients who experienced recurrence had third hepatectomy 3–32 mo between second and third hepatectomy with a median of 13–15 mo | – | † | (32, 37, 38) |
| Costs | ||||
| Chemotherapy Rx costs per week(Costs proportioned according to the usage of FOLFOX, FOLFIRI and CapeOX) | – | 451 | +50 | (46) |
| Cetuximab Rx costs per week (regular) | – | 4180‡ | +50 | (46) |
| Cetuximab Rx costs per week (initial) | – | 6653‡ | +50 | (46) |
| Bevacizumab + 5-FU Rx average costs per week | – | 1278 | +50 | (46) |
| Physician costs of administering treatment per cycle | – | 189 | +50 | (58) |
| Monitoring costsCarcinoembryonic antigen (every 3 mo or 2 y; 6 mo for 3-5 y)Chest, abdominal, and/or pelvic CT scan (every 3–6 mo for 2 y; 6–12 mo up to a total of 5 y)Colonoscopy at 1, 3, and then every 5 y | – | 771160706 | +50 | (58, 59) |
| KRAS screening costs | – | 224 | ±50 | (58) |
| KRAS + BRAF screening costs | – | 303 | ±50 | (58) |
| Hepatic surgery costsHospital and professional costsMortality costs (in 5% cases)Morbidity costs (in 30% cases) | – | 40 30020 65712 394 | +50 | (48) |
* FOLFOX = Leucovorin Calcium, Fluorouracil and Oxaliplatin; FOLFIRI = Leucovorin Calcium, Fluorouracil and Irinotecan Hydrochloride; CapeOX = Capecitabine and Oxaliplatin; Rx = Treatment; CT = Computed Tomography; – = not applicable.
† A blank cell in the “estimates range” column indicates that we used only the base case estimate of the variable in the analysis.
‡ Cetuximab is given in combination with chemotherapies, so there is at least the “standard” treatment effect of the chemotherapies given in combination. In this case, we used the cost of a cetuximab regimen, which includes irinotecan, every 2 weeks (4).