Table 3.

Standardised incidence ratios (SIR) for any metachronous second malignant neoplasm (SMN) diagnosed in Finland between 1992-2021 by follow-up interval and age at first primary cancer (FPC).

Follow-up interval	Age at FPC	Men					Women
		Observed SMNs	Expected SMNs	PYRS	SIR	95% CI	Observed SMNs	Expected SMNs	PYRS	SIR	95% CI
0.5–5 years	20–39	80	24.72	37,884.73	3.24	2.58-4.00	175	75.25	59,420.39	2.33	2.00-2.69
> 5 years	20–39	287	136.07	71,663.84	2.11	1.87-2.36	603	407.64	118,404.86	1.48	1.36-1.60
All	20–39	367	160.79	109,548.57	2.28	2.06-2.52	778	482.89	177,825.25	1.61	1.50-1.73
0.5–5 years	40–59	1,606	1,064.65	185,783.99	1.51	1.44-1.58	2107	1,932.10	329,456.25	1.09	1.04-1.14
> 5 years	40–59	4,355	3,469.12	267,609.15	1.26	1.22-1.29	6075	5,871.76	603,382.19	1.03	1.01-1.06
All	40–59	5,961	4,533.76	453,393.14	1.31	1.28-1.35	8182	7,803.87	932,838.44	1.05	1.03-1.07
0.5–5 years	60–79	11,258	11,818.31	528,047.72	0.95	0.94-0.97	5868	5,569.95	439,822.52	1.05	1.03-1.08
> 5 years	60–79	12,558	13,319.69	465,984.22	0.94	0.93-0.96	8409	7,644.52	483,755.58	1.10	1.08-1.12
All	60–79	23,816	25,138.00	994,031.93	0.95	0.94-0.96	14277	13,214.47	923,578.10	1.08	1.06-1.10
0.5–5 years	80+	2,949	3,312.96	92,387.55	0.89	0.86-0.92	2169	2,101.83	109,319.59	1.03	0.99-1.08
> 5 years	80+	1,003	1,097.98	30,237.46	0.91	0.86-0.97	962	916.30	44,628.81	1.05	0.98-1.12
All	80+	3,952	4,410.94	122,625.00	0.90	0.87-0.92	3131	3,018.13	153,948.41	1.04	1.00-1.07
0.5–5 years	All	15,893	16,220.63	844,104.99	0.98	0.96-1.00	10319	9,679.14	938,018.75	1.07	1.05-1.09
> 5 years	All	18,203	18,022.86	835,494.67	1.01	1.00-1.02	16049	14,840.22	1,250,171.45	1.08	1.06-1.10
All	All	34,096	34,243.49	1,679,598.65	1.00	0.99-1.01	26368	24,519.36	2,188,190.20	1.08	1.06-1.09

CI: confidence interval; Exp: expected; FPC: first primary cancer; Obs: observed; PYRS: person-years at risk; SIR: standardised incidence ratio; SMN: second malignant neoplasm.