Table 2.

Risk for squamous-cell carcinoma (SCC) according to acute and chronic GVHD and duration of immunosuppressive therapy for GVHD

Risk factors	Case patients, no.	Control patients, no.	RR	95% CI	P
Model 1: acute, chronic GVHD*
No acute, no chronic	11	52	1.00	Reference	-
Acute but no chronic	5	22	0.91	0.29-2.87	.87
Any chronic GVHD	42	80	2.79	1.28-6.06	.01
Chronic but no acute†	21	49	2.30	0.95-5.57	.07
Acute and chronic†	21	31	3.33	1.41-7.87	.006
Unknown acute or chronic	0	1	-	-	-
Model 2: total duration of immunosuppression prophylaxis, acute and chronic GVHD therapy, mo‡
None, less than 6	15	51	1.00	Reference	-
6-11	6	37	0.58	0.17-1.89	.36
12-23	11	40	1.37	0.50-3.77	.54
24 or greater	26	25	5.60	2.07-15.19	<.001
24-47§	11	13	4.75	1.27-17.78	.02
48 or greater§	15	12	6.20	1.97-19.50	.002
Unknown	0	2	-	-	-
Model 3: duration of chronic GVHD therapy, mo‡∥
None	21	84	1.00	Reference	-
1-11	6	26	1.00	0.35-2.85	.99
12-23	8	27	1.37	0.50-3.72	.54
24 or greater	23	16	8.44	3.17-22.47	<.001
24-47¶	10	6	22.57	2.63-193.6	.005
48 or greater¶	13	10	6.26	2.16-18.16	<.001
Unknown	0	2	-	-	-

There were 58 case patients and 155 control patients.

^*Acute GVHD includes grades 2-4 acute GVHD

^†Includes the same variables as in the rest of model 1, with the variable any chronic GVHD separated into chronic but no acute and acute and chronic GVHD categories

^‡Total duration (model 2) and duration of chronic GVHD drug therapy (model 3) include months of therapy with immunosuppressive drugs

^§Model includes the same variables as in model 2, with duration 24 or greater separated into 24-47 and 48 or greater

^∥The reference group of model 3 includes 16 case patients and 74 control patients with no chronic GVHD and 5 case patients and 10 control patients who acquired chronic GVHD that did not require therapy

^¶Model includes the same variables as in model 3, with duration variables 24 or greater separated into 24-47 and 48 or greater