Gynecologic oncologists involvement on ovarian cancer standard of care receipt and survival

Table 1 Characteristics of ovarian cancer patients who received any initial surgical procedure by physician specialty (n = 6714)

Characteristic	Surgeon specialty1
	GO	Non-GO
		OBGYN	General surgeon	Other2
No. of patients	2254	3088	914	419
Mean age at diagnosis (stddev)	74.6 (5.9)	74.8 (6.1)	77.0 (6.8)	75.5 (6.2)
Race n (%)
White	1995 (88.5)	2844 (92.1)	827 (90.5)	379 (90.5)
African American	121 (5.4)	104 (3.4)	49 (5.4)	26 (6.2)
Hispanic	35 (1.6)	31 (1.0)	3	3
Asian	53 (2.4)	66 (2.1)	3	3
Other4	47 (2.1)	37 (1.2)	3	3
Marital status
Married	1052 (46.7)	1424 (46.1)	327 (35.8)	170 (40.6)
Single	159 (7.1)	221 (7.2)	53 (5.8)	31 (7.4)
Divorced	148 (6.6)	166 (5.4)	58 (6.3)	29 (6.9)
Widowed	799 (35.4)	1168 (37.8)	458 (50.1)	176 (42.0)
Separated/unknown	96 (4.2)	109 (3.5)	3	3
Charlson-Klabunde comorbidity score
0	1521 (67.5)	2133 (69.1)	605 (66.2)	266 (63.5)
1	498 (22.1)	644 (20.9)	188 (20.6)	93 (22.2)
2	175 (7.8)	189 (6.1)	78 (8.5)	38 (9.1)
3	45 (2.0)	80 (2.6)	29 (3.2)	3
4 or more	3	42 (1.4)	3	3
FIGO treatment stage
IA/IB	200 (8.9)	383 (12.4)	66 (7.2)	43 (10.3)
IC/II	276 (12.2)	516 (16.7)	90 (9.8)	40 (9.5)
IIIA/IIIB	119 (5.3)	179 (5.8)	59 (6.5)	3
IIIC/IV	1580 (70.1)	1898 (61.5)	660 (72.2)	308 (73.5)
Unstaged/NOS	79 (3.5)	112 (3.7)	39 (4.2)	3
Histology
Serous	1460 (64.8)	1897 (61.4)	554 (60.6)	254 (60.6)
Endometrioid	238 (10.6)	381 (12.3)	73 (8.0)	46 (11.0)
Mucinous	129 (5.7)	235 (7.6)	79 (8.6)	25 (6.0)
Clear cell	84 (3.7)	127 (4.1)	3	3
Adenocarcinoma	275 (12.2)	344 (11.1)	175 (19.1)	66 (15.8)
Other5	68 (3.1)	104 (3.3)	20 (2.2)	3

¹Surgeon specialty was categorized according to the most specialized care received during the course of the treatment window;

²39 women received a surgery procedure code during the treatment window (defined as a period of two months prior and one year after a patient’s diagnosis date in which procedures were performed) but surgeon specialty could not be identified;

³Denotes cell size suppression of less than 20;

⁴Other race includes designation of “Other” or Native American;

⁵Other histology includes Transitional. GO: Gynecologic oncologists; FIGO: International Federation of Gynecologists and Obstetricians; NOS: Not otherwise specified.

Table 2 Predictors of receipt of minimum surgical and chemotherapeutic standard of care¹

	Surgical standard of care2		Chemotherapeutic standard of care2
	Odds ratio (95%CI)	P value	Odds ratio (95%CI)	P value
Physician specialty3
Gynecologic oncologist	2.35 (2.03-2.71)	< 0.01	1.25 (1.07-1.47)	0.006
Non-gynecologic oncologist	1.00		1.00
Age at diagnosis
66-69	1.00		1.00
70-74	0.80 (0.67-0.96)	0.017	0.93 (0.78-1.09)	0.393
75-79	0.83 (0.69-1.0)	0.053	0.79 (0.66-0.94)	0.008
80-84	0.58 (0.47-0.71)	< 0.01	0.61 (0.48-75)	< 0.001
≥ 85	0.40 (0.31-0.51)	< 0.01	0.31 (0.21-0.48)	< 0.001
Race4
White	1.00
African American	0.67 (0.50-0.91)	0.01	-
Other	0.83 (0.62-1.10)	0.208	-
Treatment stage5
IA/IB	0.08 (0.07-0.10)	< 0.01	NA	NA
IC/II	0.08 (0.07-0.10)	< 0.01	3.46 (2.86-4.18)	< 0.001
IIIA/IIIB	0.05 (0.04-0.07)	< 0.01	0.83 (0.64-1.09)	0.182
IIIC/IV	1.00		1.00
Charlson-Klabunde comorbidity score
0	1.00		1.00
1	0.84 (0.72-0.98)	0.029	0.84 (0.71-0.99)	0.029
2	0.81 (0.63-1.02)	0.084	0.78 (0.60-1.03)	0.078
3	0.65 (0.44-0.97)	0.039	0.49 (0.31-0.80)	0.005
4 or more	1.09 (0.60-1.97)	0.771	0.63 (0.29-1.37)	0.247
Histology
Serous	1.00		1.00
Endometrioid	1.10 (0.90-1.35)	0.356	0.70 (0.56-0.89)	0.003
Mucinous	0.95 (0.74-1.35)	0.67	0.49 (0.34-0.70)	< 0.001
Clear cell	1.29 (0.93-1.78)	0.13	0.62 (0.41-0.93)	0.026
Transitional	0.70 (0.27-1.79)	0.454	0.76 (0.30-1.97)	0.572
Adenocarcinoma (NOS)	0.44 (0.37-0.54)	< 0.001	1.04 (0.86-1.27)	0.695
Other	1.05 (0.70-1.56)	0.813	0.74 (0.47-1.13)	0.168
Marital status
Married	1.00		1.00
Not married	0.83 (0.72-0.95)	0.007	0.75 (0.66-0.86)	< 0.001
Unknown	1.03 (0.69-1.52)	0.87	0.73 (0.48-1.09)	0.127
Year of diagnosis
1993-1997	0.62 (0.52-0.73)	< 0.01	0.28 (0.23-0.33)	< 0.001
1998-2002	0.79 (0.68-0.92)	0.003	1.09 (0.94-1.26)	0.261
2003-2006	1.00		1.00
SEER region4
Northeast	-		1.00
Midwest	-		0.76 (0.62-0.93)	0.009
South	-		1.09 (0.88-1.37)	0.424
West	-		0.93 (0.78-1.10)	0.391

¹Minimum SOC treatment was based on patients receiving surgery prior to chemotherapy (n = 6714);

²Surgery SOC (n = 4434) and chemotherapy SOC (n = 2595);

³Physician specialty was categorized according to the most specialized care received during the course of the treatment window; there were 39 and 177 cases where physician specialty could not be identified for surgery or chemotherapy procedures, respectively (results for this group not shown);

⁴Race was not entered into the chemotherapy SOC model based on forward selection entry criteria (P≤ 0.10); Region was not entered into the surgery SOC model based on forward selection entry criteria (P≤ 0.10);

⁵Stage I NOS, Stage IA/IB (for chemotherapy SOC) and unknown/unstaged were removed from the analysis since current guidelines recommend early stage patients not receive chemotherapy treatment. NOS: Not otherwise specified; SOC: Standard of care; SEER: Surveillance, Epidemiology, and End Result; NA: Not applicable.

Table 3 Cox proportional hazard model of time-to-death among ovarian cancer patients

Predictor	Model 11		Model 21
	Hazard ratio (95%CI)	P value	Hazard ratio (95%CI)	P value
Received surgery SOC2
Yes	1.00		1.00
No	1.22 (1.12-1.33)	< 0.01	1.21 (1.11-1.31)	< 0.01
Received chemotherapy SOC2			4
Yes	1.00		4
No, but received some chemotherapy	0.95 (0.89-1.02)	0.18	4
Received no chemotherapy	1.29 (1.14-1.46)	< 0.01	4
Age at diagnosis
66-69	1.00		1.00
70-74	1.07 (0.98-1.17)	0.13	1.05 (0.97-1.15)	0.24
75-79	1.23 (1.12-1.34)	< 0.01	1.21 (1.10-1.32)	< 0.01
80-84	1.52 (1.37-1.69)	< 0.01	1.48 (1.33-1.65)	< 0.01
≥ 85	1.96 (1.70-2.26)	< 0.01	1.92 (1.67-2.21)	< 0.01
Race
White	1.00		1.00
African American	1.11 (0.95-1.29)	0.18	1.13 (0.97-1.32)	0.12
Other	0.90 (0.78-1.05)	0.17	0.88 (0.75-1.02)	0.09
Year of diagnosis
1993-1997	1.27 (1.17-1.38)	< 0.01	1.24 (1.14-1.35)	< 0.01
1998-2002	1.18 (1.09-1.27)	< 0.01	1.17 (1.08-1.27)	< 0.01
2003-2006	1.00		1.00
Treatment stage
IA/IB	0.20 (0.18-0.23)	< 0.01	0.17 (0.15-0.20)	< 0.01
IC/II	0.35 (0.32-0.40)	< 0.01	0.36 (0.32-0.40)	< 0.01
IIIA/IIIB	0.61 (0.53-0.71)	< 0.01	0.62 (0.54-0.71)	< 0.01
IIIC/IV	1.00		1.00
Charlson-Klabunde comorbidity score
0	1.00		1.00
1	1.28 (1.18-1.38)	< 0.01	1.26 (1.17-1.36)	< 0.01
2	1.38 (1.22-1.56)	< 0.01	1.37 (1.21-1.55)	< 0.01
3	1.64 (1.34-2.00)	< 0.01	1.64 (1.34-2.01)	< 0.01
≥ 4	2.33 (1.73-3.15)	< 0.01	2.27 (1.67-3.09)	< 0.01
Histology
Serous	1.00		1.00
Endometrioid	0.76 (0.68-0.85)	< 0.01	0.75 (0.68-0.84)	< 0.01
Mucinous	1.22 (1.06-1.41)	< 0.01	1.22 (1.06-1.41)	< 0.01
Clear cell	0.83 (0.69-1.00)	0.05	0.83 (0.69-1.00)	0.05
Transitional	0.79 (0.47-1.31)	0.36	0.79 (0.48-1.32)	0.37
Adenocarcinoma (NOS)	1.07 (0.98-1.18)	0.14	1.07 (0.97-1.17)	0.2
Other	1.02 (0.82-1.28)	0.85	1.02 (0.82-1.28)	0.85
Marital status
Married	1.00		1.00
Not Married	1.07 (1.00-1.14)	0.05	1.07 (1.00-1.14)	0.05
Unknown	1.00 (0.82-1.23)	0.97	0.99 (0.80-1.21)	0.89
Surgeon specialty3
Non-GO	1.00		1.00
GO	0.90 (0.84-0.96)	< 0.01	0.90 (0.84-0.97)	< 0.01
Chemotherapy specialty3
Non-GO	4		1.00
GO	4		0.98 (0.89-1.08)	0.68
Did not receive chemotherapy	4		1.33 (1.19-1.47)	< 0.01

¹Model 1 and Model 2: Includes OC patients who did not have an unknown FIGO stage at diagnosis, and survived at least 4.5 mo after diagnosis;

²Minimum SOC procedure codes for surgery;

³Missing surgeon and physician specialty excluded from analysis;

⁴Excluded from the model based inclusion criteria. Chemotherapy SOC and chemotherapy physician specialty cannot be included in the same model because the common level of “did not receive chemotherapy” would introduce a singularity and prevent model convergence. OC: Ovarian cancer; SOC: Standard of care; GO: Gynecologic oncologist; FIGO: International Federation of Gynecologists and Obstetricians; NOS: Not otherwise specified.