RESUMO
Aim: Stereotactic ablative radiotherapy (SABR) showed increasing survival in oligometastatic patients. Few studies actually depicted oligometastatic disease (OMD) evolution and which patient will remain disease-free and which will rapidly develop a polymetastatic disease (PMD) after SABR. Therefore, apart from the number of active metastases, there are no clues on which proven factor should be considered for prescribing local treatment in OMD. The study aims to identify predictive factors of polymetastatic evolution in lung oligometastatic colorectal cancer patients. Methods: This international Ethical Committee approved trial (Prot. Negrar 2019-ZT) involved 23 Centers and 450 lung oligometastatic patients. Primary end-point was time to the polymetastatic conversion (tPMC). Additionally, oligometastases number and cumulative gross tumor volume (cumGTV) were used as combined predictive factors of tPMC. Oligometastases number was stratified as 1, 2-3, and 4-5; cumGTV was dichotomized to the value of 10 cc. Results: The median tPMC in the overall population was 26 months. Population was classified in the following tPMC risk classes: low-risk (1-3 oligometastases and cumGTV ≤ 10 cc) with median tPMC of 35.1 months; intermediate-risk (1-3 oligometastases and cumGTV > 10 cc), with median tPMC of 13.9 months, and high-risk (4-5 oligometastases, any cumGTV) with median tPMC of 9.4 months (p = 0.000). Conclusion: The present study identified predictive factors of polymetastatic evolution after SABR in lung oligometastatic colorectal cancer. The results demonstrated that the sole metastases number is not sufficient to define the OMD since patients defined oligometastatic from a numerical point of view might rapidly progress to PMD when the cumulative tumor volume is high. A tailored approach in SABR prescription should be pursued considering the expected disease evolution after SABR, with the aim to avoid unnecessary treatment and toxicity in those at high risk of polymetastatic spread, and maximize local treatment in those with a favorable disease evolution.
RESUMO
PURPOSE: One of the rarest gastrointestinal neoplasm is small bowel cancer. Experience with its treatment modalities is limited. Stereotactic ablative radiation therapy (SABR) has improved, with image-guided radiation therapy becoming a curative option in many tumors. Especially when surgery cannot be performed due to comorbidities, SABR provides a good toxicity profile and an excellent tumor control rate owing to its specific schedule: high dose on a limited and well-defined area. METHODS: An 83-year-old man had arterial hypertension and congestive cardiomyopathy, with recent history of upper abdominal pain, weight loss over 10 kg, and progressive severe fatigue. The patient underwent endoscopy that showed a large mass partially obstructing the second part of the duodenum; a biopsy revealed a moderately differentiated adenocarcinoma. A staging CT scan confirmed localized disease. Due to the patient's age and comorbidities, a SABR was proposed as the preferred treatment. In order to localize the tumor during radiotherapy sessions, surgical clips were placed endoscopically next to the lesion as fiducial markers. The patient received 25 Gy in 5 fractions on alternate days. RESULTS: Resolution of duodenal obstruction and bleeding lasted for 14 months. The patient died of myocardial infarction. CONCLUSIONS: This case suggests that SABR could have a role in the palliative treatment of small bowel cancers, with good toxicity profile, particularly in patients for whom surgical treatment is not a viable option.
