Abstract 412P
Background
The treatment of lung metastases in Colorectal Cancer (CRC) has been recognised over the last years. Most evidence supports surgery as the most effective treatment option. Stereotactic Ablative Body Radiotherapy (SABR) has been increasingly used and provides high local control with a relative lack of side effects. We aimed to identify clinicopathological and molecular features associated with survival and toxicity.
Methods
We underwent a retrospective, observational study with 69 CRC patients from Hospital de Sant Pau (Barcelona) with 105 lung metastases treated with surgery (73) or SABR (32) between May 2011 and March 2021. The treatment with SABR was prescribed with a total dose that ranged from 45 to 60 Gy, administered in 3 to 10 sessions, with a Bioequivalent Dose >100 in 96% of the treatments, assuming an αβ=10.
Results
Patient and tumour characteristics regarding each treatment are summarized in the table. For the overall population, local median recurrence free survival (LRFS) was 44.3 months (14-74.7), with 80% of the patients free from local recurrence at 12 months; and median Overall Survival (OS) was 67.6 months (95% CI 42.8-92.3). Among patients whose first local treatment was SABR, median LRFS was 17.6 months (95% CI 13.8-21.5) with 76% of 1-year local control rate; and median OS from first treatment was 35.6 months (95% CI 18.6-52.5). RAS/BRAF wild type patients had a longer OS than RAS/BRAF mutant (35.5m vs. 17.6m, p=0.034). Amongst the 73 lung metastases treated with surgery, 15 excisions were made using VATS technique. Median LRFS was not reached; the LRFS rate was 82% at 1-year and 61% at 3-years. The median OS was 77.7 months (95% CI 57.0-98.4), without significant differences regarding RAS/BRAF mutations. Table: 412P
| Surgery | SABR | p-value | |||
| n | % | n | % | ||
| Age | |||||
| median | 65.4 | 74.5 | |||
| range | 45-79 | 56-86 | |||
| <70 | 33 | 62.3 | 6 | 37.5 | 0.080 |
| ≥70 | 20 | 37.7 | 10 | 62.5 | |
| Sex | |||||
| Male | 36 | 67.9 | 10 | 62.5 | 0.690 |
| Female | 17 | 32.1 | 6 | 37.5 | |
| Performance status ECOG | |||||
| 0 | 23 | 43.5 | 2 | 12.5 | 0.048 |
| 1 | 24 | 45.3 | 11 | 68.8 | |
| ≥ 2 | 6 | 11.3 | 3 | 18.7 | |
| Primary tumor | |||||
| Right colon | 3 | 5.7 | 4 | 25.0 | 0.057 |
| Left colon | 28 | 52.8 | 5 | 31.3 | |
| Rectum | 22 | 41.5 | 7 | 43.8 | |
| Lung metastasis | |||||
| Synchronic | 14 | 26.4 | 3 | 18.8 | 0.533 |
| Methacronic | 39 | 73.6 | 13 | 81.3 | |
| Molecular profile | |||||
| KRAS mut | 28 | 47.2 | 6 | 37.5 | 0.282 |
| NRAS mut | 1 | 1.9 | 0 | 0 | |
| BRAF mut | 1 | 1.9 | 2 | 12.5 | 0.068 |
| RAS/BRAF wild type | 18 | 34.0 | 5 | 31.3 | 0.909 |
| Others (PIK3CA, p53, ERBB2, KIT, AKT1) | |||||
| N/A | 4 | 7.5 | 3 | 18.8 | |
| Number Lung Metastases | |||||
| 1 | 37 | 69.8 | 12 | 75 | 0.688 |
| 2 | 11 | 20.8 | 6 | 37.5 | |
| ≥3 | 5 | 9.4 | |||
| Metastatic sites | |||||
| 1 | 46 | 86.8 | 10 | 62.5 | 0.049 |
| ≥2 | 7 | 13.2 | 6 | 37.5 |
Conclusions
This study shows long OS and high local control in patients with lung metastases treated with surgery or SABR, even in elderly population. Multidisciplinary tumour boards are crucial in this setting in order to decide the best treatment.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
All authors have declared no conflicts of interest.