Table 1.

Grading of Recommendations Assessment, Development and Evaluation (GRADE^*) [19, 20]

Endpoint	Conclusion	Literature review	GRADE level
Overall survival	RFA (± PH) + chemotherapy is superior to chemotherapy alone	1 RCT (downgraded; serious imprecision)a	Moderate
	RFA + chemotherapy is superior to chemotherapy alone	1 RCT (downgraded 2x; serious indirectnessb and serious imprecision)a	Low
	RFA (for unresectable CRLM) + PH is equivalent to PH alone	Observational comparative studies	Very low
	RFA alone (for unresectable CRLM) is inferior to PH alone	Observational comparative studies	Very low
	MWA is equivalent to PH	1 RCT (downgraded; very serious risk of bias)	Very low
	MWA (for unresectable CRLM) + PH is equivalent to PH alone	One observational comparative study	Very low
Complications	RFA alone (for unresectable CRLM) is superior to PH	Observational comparative studies	Very low
	Studies on RFA (for unresectable CRLM) + PH versus PH alone show conflicting results	Observational comparative studies	–
	MWA alone is equivalent to PH	1 RCT (downgraded; very serious risk of bias)	Very low
Quality of life	There are no comparative studies on the effect of RFA or MWA	–	–

^*GRADE definitions: high quality—further research is very unlikely to change our confidence in the estimate of effect (randomized controlled trials); moderate quality—further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate (controlled trials, no randomization), low quality—further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate (observational studies); very low quality—any estimate of effect is very uncertain (any other type)

^aserious imprecision: in case of low optimal information size (OIS; number of included patients did not meet sample size), dichotomous outcomes, low number of events, wide confidence intervals with uncertainty about magnitude of effect, or when there is a lot of variation in the effects among the participants in continious measures

^bserious indirectness: very important differences in populations, interventions, outcome measures, or indirect comparisons