Table 1.

Characteristics of the included studies (N=15).

Type of cancer and study			Country		Study type		Treatment		Sample size							Algorithms			Input features (total number of features)			Outcome
									Training		Testing		Validating
All cancer
	Sena et al [38]	Brazil		1b		All		543		N/Aa		N/A		DTb, ANNc, and NBd			Comorbidity and PROe for physical and mental status assessments (9)			180-day death
	Parikh et al [39]	United States		2a		All		18,567		7958		N/A		GBTf and RFg			Demographic, clinicopathologic, laboratory, comorbidity, and electrocardiogram data (599)			180-day death
	Manz et al [37]	United States		4		All		N/A		N/A		24,582		GBT			Same as Parikh et al [39]			180-day death
	Bertsimas et al [50]	United States		2a		All		14,427		9556		N/A		DT, regularized LRh, and GBT			Demographic, clinicopathologic, gene mutations, prior treatment, comorbidity, use of health care resources, vital signs, and laboratory data (401)			180-day death
	Elfiky et al [43]	United States		2b		All		17,832		9114		N/A		GBT			Demographic, clinicopathologic, prescription, comorbidity, laboratory, vital sign, and use of health care resources data and physician notes (5390)			180-day death
Non–small cell lung cancer
	Hanai et al [44]	Japan		2b		Curative resection		125		48		N/A		ANN			Demographic, clinicopathologic, and tumor entity data (17)			1-year death
Gastric cancer
	Nilsaz-Dezfouli et al [45]	Iran		1b		Surgery		452		N/A		N/A		ANN			Demographic, clinicopathologic, tumor entity, and prior treatment (20)			1-year death
Colon and rectum cancer
	Arostegui et al [46]	Spain		2a		Curative or palliative surgery		981		964		N/A		DT and regularized LR			Demographic, clinicopathologic, tumor entity, comorbidity, ASAi prior treatment, laboratory, operational data, postoperational complication, and use of health care resources data (32)			1-year death
Stomach cancer
	Biglarian et al [47]	Iran		2a		Surgery		300		136		N/A		ANN			Demographic, clinicopathologic, and symptom data (NRj)			1-year death
Bladder cancer
	Klén et al [48]	Turkey		2a		Radical cystectomy		733		366		N/A		Regularized LR			Demographic, clinicopathologic, ASA, comorbidity, laboratory, prior treatment, tomography, and operational data (NR)			90-day death
Hepatocellular carcinoma
	Chiu et al [49]	Taiwan		2a		Liver resection		347		87		N/A		ANN			Demographic, clinicopathologic, tumor entity, comorbidity, ASA, laboratory, operational, and postoperational data (21)			1-year death
	Zhang et al [40]	China		2a		Liver transplant		230		60		N/A		ANN			Donor demographic data and recipient laboratory, clinicopathologic, and image data (14)			1-year death
Spinal metastatic
	Karhade et al [41]	United States		2a		Surgery		1432		358		N/A		ANN, SVMk, DT, and BPMl			Demographic, clinicopathologic, tumor entity, ASA, laboratory, and operational data (23)			30-day death
	Karhade et al [42]	United States		2a		Surgery		587		145		N/A		SGBm, RF, ANN, SVM, and regularized LR			Demographic, clinicopathologic, tumor entity, laboratory, operational, ECOGn, ASIAo, and prior treatment data (29)			90-day death
	Karhade et al [36]	United States		4		Curative surgery		N/A		N/A		176		SGB			ECOG, demographic, clinicopathologic, tumor entity, laboratory, prior treatment, and ASIA data (23)			1-year death

^aN/A: not applicable.

^bDT: decision tree.

^cANN: artificial neural network.

^dNB: naive Bayes.

^ePRO: patient-reported outcome.

^fGBT: gradient-boosted tree.

^gRF: random forest.

^hLR: logistic regression.

ⁱASA: American Sociological Association.

^jNR: not reported.

^kSVM: support vector machine.

^lBPM: Bayes point machine.

^mSGB: stochastic gradient boosting.

ⁿECOG: Eastern Cooperative Oncology Group.

^oASIA: American Spinal Injury Association.