J Clin Med Res

Journal of Clinical Medicine Research, ISSN 1918-3003 print, 1918-3011 online, Open Access

Article copyright, the authors; Journal compilation copyright, J Clin Med Res and Elmer Press Inc

Journal website https://jocmr.elmerjournals.com

Original Article

Volume 16, Number 12, December 2024, pages 608-624

A Retrospective Chart Analysis Comparing Breast Cancer Detection Rates Between Annual Versus Biennial Mammograms

↓ Figure 2. Age by biennial or less-frequent-than-biennial screening. OR: odds ratio; CI: confidence interval.

↓ Figure 3. BI-RADS and screening frequency adjusted residuals (P < 0.050). BI-RADS: Breast Imaging Reporting and Data System.

↓ Figure 4. ER status, PR status and screening frequency adjusted residuals (P < 0.050). ER: estrogen receptor; PR: progesterone receptor.

↓ **Table 1.** Breast Imaging Reporting and Data System (BI-RADS) Categorization
BI-RADS category	Description
BI-RADS: Breast Imaging Reporting and Data System.
0	Additional views or sonography required
1	No abnormalities identified
2	Not entirely normal, but definitely benign
3	Probably benign
4A	Low suspicious for malignancy, but intervention required
4B	Intermediate suspicion for malignancy, intervention required
4C	Moderate suspicion, but not classic for carcinoma
5	Almost certainly malignant
6	Biopsy-proven carcinoma

↓ Table 1. Breast Imaging Reporting and Data System (BI-RADS) Categorization

BI-RADS category

Description

BI-RADS: Breast Imaging Reporting and Data System.

Additional views or sonography required

No abnormalities identified

Not entirely normal, but definitely benign

Probably benign

Low suspicious for malignancy, but intervention required

Intermediate suspicion for malignancy, intervention required

Moderate suspicion, but not classic for carcinoma

Almost certainly malignant

Biopsy-proven carcinoma

↓ **Table 2.** TNM Staging
Tumor	Lymph node	Metastasis	Grade	ER	PR	Stage
Grade: tumor grade (1 = low, 2 = intermediate, 3 = high). ER: estrogen receptor; PR: progesterone receptor; TNM stage: tumor, node, metastasis stage.
T1	N0	M0	1	Positive	Positive	IA
T1	N0	M0	1	Positive	Negative	IB
T1	N0	M0	1	Negative	Negative	IIA
T1	N0	M0	2	Positive	Positive	IIA
T1	N0	M0	2	Positive	Negative	IIB
T1	N0	M0	2	Negative	Negative	IIIA
T2	N0	M0	1	Positive	Positive	IIA
T2	N0	M0	1	Positive	Negative	IIB
T2	N0	M0	1	Negative	Negative	IIIA
T2	N0	M0	2	Positive	Positive	IIIA
T2	N0	M0	2	Positive	Negative	IIIB
T2	N0	M0	2	Negative	Negative	IIIC
T3	N0	M0	1	Positive	Positive	IIIA
T3	N0	M0	1	Positive	Negative	IIIB
T3	N0	M0	1	Negative	Negative	IIIC
T4	N0	M0	1	Any	Any	IIIC
T1	N1	M0	1	Any	Any	IIB
T1	N1	M0	2	Any	Any	IIIA
T2	N1	M0	1	Any	Any	IIIA
T2	N1	M0	2	Any	Any	IIIB
T3	N1	M0	1	Any	Any	IIIB
T3	N1	M0	2	Any	Any	IIIC
Any T	N2	M0	Any	Any	Any	IIIC
Any T	N3	M0	Any	Any	Any	IV
Any T	Any N	M1	Any	Any	Any	IV

↓ Table 2. TNM Staging

Tumor

Lymph node

Metastasis

Grade

Stage

Grade: tumor grade (1 = low, 2 = intermediate, 3 = high). ER: estrogen receptor; PR: progesterone receptor; TNM stage: tumor, node, metastasis stage.

Positive

Negative

IIA

Positive

IIA

Positive

Negative

IIB

Negative

IIIA

Positive

IIA

Positive

Negative

IIB

Negative

IIIA

Positive

IIIA

Positive

Negative

IIIB

Negative

IIIC

Positive

IIIA

Positive

Negative

IIIB

Negative

IIIC

Any

IIIC

Any

IIB

Any

IIIA

Any

IIIA

Any

IIIB

Any

IIIB

Any

IIIC

Any T

Any

IIIC

Any T

Any

Any T

Any N

Any

↓ **Table 3.** Elaboration of Tumor Spread Based on TNM Staging
T	Tumor size
TNM stage: tumor, node, metastasis stage; DCIS: ductal carcinoma in situ.
TX	The primary tumor cannot be assessed.
T0	No evidence of primary tumor.
Tis	Carcinoma in situ (DCIS, or Paget disease of the breast with no associated tumor mass)
T	Tumor is 2 cm (3/4 of an inch) or less across.
T1mi	Microinvasive carcinoma: tumor is 0.1 cm or less across.
T2	Tumor is more than 2 cm but not more than 5 cm (2 inches) across.
T3	Tumor is more than 5 cm across.
T4	Tumor of any size growing into the chest wall or skin.
N	Node involvement
NX	Nearby lymph nodes cannot be assessed.
N0	No spread to nearby lymph nodes.
N1	Cancer has spread to fewer than three lymph nodes located on the underarm or has spread to any number of lymph nodes located near the breastbone (internal mammary lymph nodes).
N2	Cancer has spread to four or more lymph nodes located on the underarm or has spread to lymph nodes located in the chest outside of the underarm.
N3	Cancer has spread to lymph nodes located in the neck.
M	Metastasis
MX	Distant spread cannot be assessed
M0	There is no evidence of distant metastases
M1	There is evidence of distant metastases.

↓ Table 3. Elaboration of Tumor Spread Based on TNM Staging

Tumor size

TNM stage: tumor, node, metastasis stage; DCIS: ductal carcinoma in situ.

The primary tumor cannot be assessed.

No evidence of primary tumor.

Tis

Carcinoma in situ (DCIS, or Paget disease of the breast with no associated tumor mass)

Tumor is 2 cm (3/4 of an inch) or less across.

T1mi

Microinvasive carcinoma: tumor is 0.1 cm or less across.

Tumor is more than 2 cm but not more than 5 cm (2 inches) across.

Tumor is more than 5 cm across.

Tumor of any size growing into the chest wall or skin.

Node involvement

Nearby lymph nodes cannot be assessed.

No spread to nearby lymph nodes.

Cancer has spread to fewer than three lymph nodes located on the underarm or has spread to any number of lymph nodes located near the breastbone (internal mammary lymph nodes).

Cancer has spread to four or more lymph nodes located on the underarm or has spread to lymph nodes located in the chest outside of the underarm.

Cancer has spread to lymph nodes located in the neck.

Metastasis

Distant spread cannot be assessed

There is no evidence of distant metastases

There is evidence of distant metastases.

↓ **Table 4.** Demographic Characteristics of 2,129 Women Diagnosed With Breast Carcinoma
Characteristic	Annual (n = 1,728)^a	Biennial (n = 384)^a	Less frequent than biennial (n = 107)^a
^aMean (SD); n (%). SD: standard deviation.
Age (years)	60 (8)	59 (8)	59 (7)
Race
White	1,497 (87%)	324 (84%)	98 (92%)
Black or African American	111 (6.4%)	24 (6.3%)	3 (2.8%)
Asian	17 (1.0%)	4 (1.0%)	1 (0.9%)
Other	103 (6.0%)	32 (8.3%)	5 (4.7%)
Ethnicity
Hispanic or Latina	98 (5.7%)	34 (8.9%)	5 (4.7%)
Not Hispanic or Latina	1,630 (94%)	350 (91%)	102 (95%)

↓ Table 4. Demographic Characteristics of 2,129 Women Diagnosed With Breast Carcinoma

Characteristic

Annual (n = 1,728)^a

Biennial (n = 384)^a

Less frequent than biennial (n = 107)^a

^aMean (SD); n (%). SD: standard deviation.

Age (years)

60 (8)

59 (8)

59 (7)

Race

White

1,497 (87%)

324 (84%)

98 (92%)

Black or African American

111 (6.4%)

24 (6.3%)

3 (2.8%)

Asian

17 (1.0%)

4 (1.0%)

1 (0.9%)

Other

103 (6.0%)

32 (8.3%)

5 (4.7%)

Ethnicity

Hispanic or Latina

98 (5.7%)

34 (8.9%)

5 (4.7%)

Not Hispanic or Latina

1,630 (94%)

350 (91%)

102 (95%)

↓ **Table 5.** Screening Frequency and Resultant BI-RADS Classification of Carcinoma Breast Diagnosis in Women Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Screenings
BI-RADS	Screening frequency	Total
χ² = 72.2, df = 8, P < 0.001, Cramer’s V = 0.13. BI-RADS: Breast Imaging Reporting and Data System.
No malignancy	741 (45.0%)	87 (23.3%)	29 (27.1%)	857 (40.3%)
Probably benign	196 (11.9%)	59 (15.8%)	19 (17.8%)	274 (12.9%)
Suspicion of malignancy	404 (24.5%)	138 (37.0%)	33 (30.8%)	575 (27.0%)
Almost certain malignant	259 (15.7%)	70 (18.8%)	23 (21.5%)	352 (16.5%)
Carcinoma	47 (2.9%)	19 (5.1%)	3 (2.8%)	69 (3.2%)
Total	1,647 (100.0%)	373 (100.0%)	107 (100.0%)	2,127 (100.0%)

↓ Table 5. Screening Frequency and Resultant BI-RADS Classification of Carcinoma Breast Diagnosis in Women Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Screenings

BI-RADS

Screening frequency

Total

Annual

Biennial

Less frequent than biennial

χ² = 72.2, df = 8, P < 0.001, Cramer’s V = 0.13. BI-RADS: Breast Imaging Reporting and Data System.

No malignancy

741 (45.0%)

87 (23.3%)

29 (27.1%)

857 (40.3%)

Probably benign

196 (11.9%)

59 (15.8%)

19 (17.8%)

274 (12.9%)

Suspicion of malignancy

404 (24.5%)

138 (37.0%)

33 (30.8%)

575 (27.0%)

Almost certain malignant

259 (15.7%)

70 (18.8%)

23 (21.5%)

352 (16.5%)

Carcinoma

47 (2.9%)

19 (5.1%)

3 (2.8%)

69 (3.2%)

Total

1,647 (100.0%)

373 (100.0%)

107 (100.0%)

2,127 (100.0%)

↓ **Table 6.** ER Status in Women Who Were Diagnosed With Breast Carcinoma Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Screening
ER status	Screening frequency	Total
χ² = 16.2, df = 4, P = 0.003. Cramer’s V = 0.08. ER: estrogen receptor.
Not determined	350 (34.3%)	60 (24.8%)	10 (15.6%)	420 (31.7%)
Negative	99 (9.7%)	29 (12.0%)	9 (14.1%)	137 (10.3%)
Positive	572 (56.0%)	153 (63.2%)	45 (70.3%)	770 (58.0%)
Total	1,021 (100.0%)	242 (100.0%)	64 (100.0%)	1,327 (100.0%)

↓ Table 6. ER Status in Women Who Were Diagnosed With Breast Carcinoma Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Screening

ER status

Screening frequency

Total

Annual

Biennial

Less frequent than biennial

χ² = 16.2, df = 4, P = 0.003. Cramer’s V = 0.08. ER: estrogen receptor.

Not determined

350 (34.3%)

60 (24.8%)

10 (15.6%)

420 (31.7%)

Negative

99 (9.7%)

29 (12.0%)

9 (14.1%)

137 (10.3%)

Positive

572 (56.0%)

153 (63.2%)

45 (70.3%)

770 (58.0%)

Total

1,021 (100.0%)

242 (100.0%)

64 (100.0%)

1,327 (100.0%)

↓ **Table 7.** PR Status in Women With Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Breast Cancer Screening
PR status	Screening frequency	Total
χ² = 18.9, df = 2, P = 0.001, Cramer’s V = 0.08. PR: progesterone receptor.
Not determined	358 (35.1%)	59 (24.4%)	10 (15.6%)	427 (32.2%)
Negative	174 (17.0%)	51 (21.1%)	15 (23.4%)	240 (18.1%)
Positive	489 (47.9%)	132 (54.5%)	39 (60.9%)	660 (49.7%)
Total	1,021 (100.0%)	242 (100.0%)	64 (100.0%)	1,327 (100.0%)

↓ Table 7. PR Status in Women With Undergoing Annual, Biennial, and Less-Frequent-Than-Biennial Breast Cancer Screening

PR status

Screening frequency

Total

Annual

Biennial

Less frequent than biennial

χ² = 18.9, df = 2, P = 0.001, Cramer’s V = 0.08. PR: progesterone receptor.

Not determined

358 (35.1%)

59 (24.4%)

10 (15.6%)

427 (32.2%)

Negative

174 (17.0%)

51 (21.1%)

15 (23.4%)

240 (18.1%)

Positive

489 (47.9%)

132 (54.5%)

39 (60.9%)

660 (49.7%)

Total

1,021 (100.0%)

242 (100.0%)

64 (100.0%)

1,327 (100.0%)

↓ **Table 8.** Nodal Involvement in Breast Cancer Screening Frequencies Occurring Annually, Biennially, and Less Frequent Than Biennially
Node involvement	Screening frequency	Total
χ² = 14.8, df = 8, Cramer’s V = 0.10.
N0	76 (7.4%)	25 (10.3%)	6 (9.4%)	107 (8.1%)
N1	715 (70.0%)	184 (76.0%)	44 (68.8%)	943 (71.1%)
N2	188 (18.4%)	25 (10.3%)	13 (20.3%)	226 (17.0%)
NX	11 (1.1%)	4 (1.7%)	0 (0.0%)	15 (1.1%)
Total	1,021 (100.0%)	242 (100.0%)	64 (100.0%)	1,327 (100.0%)

↓ Table 8. Nodal Involvement in Breast Cancer Screening Frequencies Occurring Annually, Biennially, and Less Frequent Than Biennially

Node involvement

Screening frequency

Total

Annual

Biennial

Less frequent than biennial

χ² = 14.8, df = 8, Cramer’s V = 0.10.

76 (7.4%)

25 (10.3%)

6 (9.4%)

107 (8.1%)

715 (70.0%)

184 (76.0%)

44 (68.8%)

943 (71.1%)

188 (18.4%)

25 (10.3%)

13 (20.3%)

226 (17.0%)

11 (1.1%)

4 (1.7%)

0 (0.0%)

15 (1.1%)

Total

1,021 (100.0%)

242 (100.0%)

64 (100.0%)

1,327 (100.0%)

↓ **Table 9.** A Comparison Between Screening Guidelines From Various Societies in the USA
Organization	Guidelines
American Cancer Society (ACS) [45]	Annual screening between 45 and 55 years
	Biennial screening > 55 years
US Preventive Services Task Force (USPSTF) [46]	Biennial screenings between 40 and 75 years
American Academy of Family Physicians [47]	Biennial screening between 40 and 75 years
American College of Radiology (ACR) [48]	Average risk: annual screening from 40 years beyond 75 years
National Comprehensive Cancer Network [49]	Higher risk: annual, earlier screening with additional imaging

↓ Table 9. A Comparison Between Screening Guidelines From Various Societies in the USA

Organization

Guidelines

American Cancer Society (ACS) [45]

Annual screening between 45 and 55 years

Biennial screening > 55 years

US Preventive Services Task Force (USPSTF) [46]

Biennial screenings between 40 and 75 years

American Academy of Family Physicians [47]

Biennial screening between 40 and 75 years

American College of Radiology (ACR) [48]

Average risk: annual screening from 40 years beyond 75 years

National Comprehensive Cancer Network [49]

Higher risk: annual, earlier screening with additional imaging