The Time of the Insult/Triggering Event in Primary Osteosarcoma and Ewing’s Sarcoma of Bone as Determined by Incubation Period Modeling and Age Distribution of Such Malignancies

Table 3

Incubation period modeling results for osteosarcoma and Ewing’s sarcoma of bone.

Type of malignancy		Average age (yrs)	Pearson IV distribution			Log normal distribution
				99%	99.9%		99%	99.9%
Conventional osteosarcoma
Long bone	3142	23.1 ± 17.4	0.977	2.2	0.45	0.971	2.95	0.3
Short bone	98	33.2 ± 22.5	0.41			0.32
Mandible	179	40.6 ± 20.0	—			0.39
Pelvis	316	43.1 ± 23.3	—			0.39
RSTCl	89	37.5 ± 22.7	—			0.32
Skull	215	39.2 ± 20.5	0.38			0.36
Vertebral	98	44.0 ± 23.2	—			—
Parosteal long bone osteosarcoma	200	27.7 ± 12.5	0.77	8.6	7.65	0.77	8.6	7.65
Ewing’s sarcoma of bone	1832	18.4 ± 11.4	0.985	0.4	−0.7	0.946	ND	ND

RSTCl: rib, sternum, clavicle.
(time of insult or causative triggering] event) is when all are >99 and 99.9%, respectively, for the distribution function, or when is only 1 or 0.1%, respectively.
ND: function not definable, since < 0 is required.