Does regular quality control improve the quality of surgery in Slovenian breast cancer screening program?

Quality indicators of diagnostic surgical procedures split by the year of surgery

	Recommendation	All	2016	2017	2018	p-value
1 QI: waiting time - Median (days) - Proportion of patients with waiting time less than 15 working days	Not more than 15 working days ≥ 90%	41 10.3%	44.5 2.6%	42 6.2%	34 21.5%	< 0.001
2 QI: weight of the excised specimen from the breast - Mean ± S.D. (g) - Proportion of specimens with weight ≤ 30g	Proportion of specimen with weigh less than 30g ≥ 90%	37.3 ± 23.4 47.8%	40.3 ± 25.8 46.2%	32.6 ± 22.1 60.6%	38.2 ± 22.1 38.8%	0.131

The variability of QIs within the institution for each studying year and altogether

		All	2016	2017	2018
	Number of procedures: least active surgeon - most active surgeon	1–166	1–45	6–62	1–67
	Proportion of mastectomies: surgeon with lowest proportion - surgeon with highest proportion	17.8%–100.0%	10.0%–100.0%	12.5%–44.4%	0.0%–100.0%
	Median waiting time ( in days): surgeon with lowest - surgeonwith highest waiting time	28.0–45.0	24.0–45.0	27.0–41.0	23.0–136.0
Therapeutic procedures	Single (breast) operation for the primary tumour (excluding reconstruction): surgeon with lowest - surgeon with highest proportion	83.1%–100.0%	73.3%–100.0%	71.4%–100.0%	75.0%–100.0%
	Invasive breast cancer not greater than 3 cm who underwent BCT: surgeon with lowest - surgeon with highest proportion	0.0%–92.6%	0.0%–94.4%	40.0%–100.0%	77.8%–100.0%
	Weight (g) of the excised specimen from surgeon with lowest mean - surgeon with the breast: surgeon with lowest mean - surgeon with highest highest mean	35.5–89.0	33.5–104.5	28.0–94.0	37.0–81.5
	Patients with invasive cancer and axillary clearance performed with at least 10 LN examined: surgeon with lowest - surgeon with highest proportion	71.4%–100.0%	50.0%–100.0%	80.0%–100.0%	50.0%–100.0%
	Number active surgeon of procedures: least active surgeon - most	3–30	1–12	1–11	1 -12
Diagnostic procedures	Median waiting time ( in days): surgeon with lowest - surgeon with highest waiting time	25.5–45.0	24.0–59.0	28.5–76.0	20.0–71.0
	Weight (g) of the excised specimen from the breast: surgeon with lowest mean - surgeon with highest mean	18.0–70.0	22.0–73.0	15.0–55.0	18.0–94.0

Characteristics of therapeutic procedures performed between 2016 and 2018

No. of procedures	All	2016	2017	2018	p-value
	1197	296	417	484
Procedure type in breast
BCT	927 (77.4%)	218 (73.6%)	312 (74.8%)	397 (82.0%)	0.007
mastectomies	270 (22.6%)	78 (26.4%)	105 (25.2%)	87 (18.0%)
Procedure type in axilla:
none	202 (16.9%)	34 (11.5%)	72 (17.3%)	96 (19.8%)
SNB	858 (71.7%)	211 (71.3%)	304 (72.9%)	343 (70.9%)	0.002
ALND	87 (7.3%)	35 (11.8%)	25 (6.0%)	27 (5.6%)
SNB + ALND	50 (4.2)	16 (5.4%)	16 (3.8%)	18 (3.7%)
Histologic tumour type
Benign	64 (5.3%)	6 (2.0%)	19 (4.6%)	39 (8.1%)
In situ	214 (17.9%)	50 (16.9%)	84 (20.1%)	80 (16.5%)
Microinvasive carcinoma	19 (1.6%)	2 (0.7%)	12 (2.9%)	5 (1.0%)	0.004
Invasive carcinoma	899 (75.1%)	238 (80.4%)	302 (72.4%)	359 (74.2%)
Other	1 (0.1%)	0 (0.0%)	0 (0.0%)	1 (0.2%)
Mean tumour diameter ± S.D. (mm)	17.8 ± 13.3	18.9 ± 14.6	18.2 ± 13.6	16.8 ± 12.0	0.127

Results of the diagnostic surgical procedures split by the year of treatment

No. of procedures	All	2016	2017	2018	p-value
	224	78	66	80
Procedure type in axilla:
- none	208 (92.9%)	75 (96.2%)	59 (89.4%)	74 (92.5%)
- SNB	16 (7.1%)	3 (3.8%)	7 (10.6%)	6 (7.5%)	0.289
- ALND	0 (0.0%)	0 (0.0%)	0 (0.0%)	0 (0.0%)
- SNB + ALND	0 (0.0%)	0 (0.0%)	0 (0.0%)	0 (0.0%)
Histologic tumour type
- Benign	177 (79.0%)	63 (79.5%)	52 (78.8%)	62 (77.5%)
- In situ	28 (12.5%)	11 (14.1%)	6 (9.1%)	11 (13.8%)	0.610
- Microinvasive carcinoma	1 (0.4%)	1 (1.3%)	0 (0%)	0 (0.0%)
- Invasive carcinoma	14 (6.3%)	2 (2.6%)	6 (9.1%)	6 (7.5%)
- Other malignat	4 (1.8%)	1 (1.3%)	2 (3%)	1 (1.3%)
Mean tumour diameter ± S.D. (mm)	15.5 ± 14.1	15.0 ± 14.1	19.0 ± 18.7	12.2 ± 5.7	0.701

Quality indicators of therapeutic surgical procedures split by the year of treatment

	Recommendation:	All	2016	2017	2018	p-value
1. QI: waiting time
Median (days) Proportion of patients with waiting time less than 15 working days	Not more than 15 working days ≥ 90%	33 4.2%	38 1.7%	34 2.9%	28 6.9%	< 0.001
2. QI: proportion of patients (invasive and noninvasive cancers) who received a single (breast) operation for the primary tumour (excluding reconstruction)	Minimum standard: 80% Target: 90%	1088/1197 (90.9%)	266/296 (89.9%)	379/417 (90.9%)	443/484 (91.5%)	0.735
3. QI: proportion of patients with invasive breast cancer not greater than 3 cm (total size, including DCIS component) who underwent BCT	Minimum standard: 70% Target: 80%	669/801 (83.5%)	165/211 (78.2%)	220/265 (83.0%)	284/325 (87.4%)	0.019
4. QI: proportion of patients with invasive cancer and axillary clearance performed with at least 10 LN examined	Minimum standard: 95% Target: 98%	124/137 (90.5%)	45/51 (88.2%)	40/41 (97.6%)	39/45 (86.7%)	0.014
5. QI: weight of the excised specimen from the breast Mean ± S.D. (g) Proportion of specimens with weight ≤ 80g (%)	Proportion of specimen after BCT with weight less than 80g ≥ 90%	69.0 ± 42.5 70.0%	75.3 ± 50.3 61.8%	63.8 ± 35.9 75.6%	69.7 ± 42.3 70.0%	0.009