Cancer By County
Breast Cancer3-5,7,8

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Risk Factors

Many risk factors for breast cancer are known. The risk of breast cancer increases sharply after age 30. The risk of breast cancer is increased when close relatives have had breast cancer, particularly a first degree relative such as a mother or sister. The risk is even higher if the first degree relative with breast cancer was premenopausal and had bilateral breast cancer (breast cancer in both breasts). Some breast cancers in women with a family history may be the result of a specific inherited gene (or genetic trait). Within the past few years, two breast cancer genes have been discovered, BRCA-1 and BRCA-2; mutation of either of these genes is believed to increase susceptibility to breast cancer. Other breast cancers with a family history may be because of lifestyle similarities or the inheritance of certain other risk factors such as menstrual patterns and obesity.

Women who have had cancer in one breast have a higher risk of developing a second cancer. Women with ovarian or endometrial cancer also are at higher risk for breast cancer. Women with benign fibrocystic breast disease confirmed by biopsy are at higher risk of breast cancer. Several studies suggest that the increased risk associated with benign breast disease may be mostly among women with atypical hyperplasia (an abnormal increase in the number of cells in a specific area of the body such as the lining of the breast ducts).

Early age at the onset of menstruation and late age at menopause are risk factors for breast cancer. Menopause induced by the removal of the ovaries before age 40 reduces the risk of breast cancer. Never having children or having the first live birth at a late age are associated with an increased risk of breast cancer. The risk of breast cancer is higher among women of higher socio- economic status. This appears to be explained largely by the reproductive risk factors.

Large doses of radiation have been associated with breast cancer in women exposed to atomic bomb fallout at Hiroshima and Nagasaki. Women who were exposed to large doses of x-rays as part of the treatment for tuberculosis from 1935 to 1954 had a high incidence of breast cancer. The much lower doses of radiation used today for chest x-rays or mammograms are considered to be of little or no risk. (The benefits of mammography at intervals recommended by the American Cancer Society far outweigh any risk.)

Recent studies have found an increase in breast cancer risk among women who have three or more alcoholic drinks a day, compared to non-drinkers. Breast cancer risk increases with weight and body mass among postmenstrual women. A few studies found a small increase in breast cancer risk among women with high fat diets. However, more recent large studies have not found an association between fat intake and breast cancer.5

Long-term exposure to postmenopausal estrogen replacement therapy may increase the risk of breast cancer. Most studies have not found an association between oral contraceptive use and breast cancer. However, some recent studies suggest a possible increase in breast cancer before age 45 among women who used oral contraceptives for a long time or who started oral contraceptive use at an early age.5

The above risk factors partly explain the incidence of breast cancer among women.9 Pesticides and other chemicals that mimic or modify the action of estrogens are currently under study by various research organizations. Also under study are a diet high in fat, physical inactivity, hormone replacement therapy, genetic factors, and gene-environmental interactions.

The causes of male breast cancer are not well understood. Some factors thought to increase the risk of male breast cancer are excess weight in young adulthood, gynecomastia (abnormal swelling of the breasts), Klinefelter's syndrome (an extra X chromosome), and undescended testes; all possibly related to higher levels of estrogen. Men with a family history of breast cancer, especially a female relative who developed breast cancer before age 45, are at higher risk of breast cancer. High doses of ionizing radiation also can cause male breast cancer. It is thought that the lower estrogen levels in men compared to women may partially explain the much lower rate of breast cancer in men compared to women.

Prevention and Control

Given the known risk factors for breast cancer, opportunities for prevention are limited. The following should be studied further to see if they reduce the risk of breast cancer: moderate physical activity, a diet low in fat and high in fiber, weight control (particularly in women after menopause), and limited consumption of alcoholic beverages. A study of the use of tamoxifen, a drug that is prescribed to prevent recurrence of breast cancer, indicates that tamoxifen may prevent breast cancer in high risk women. However, there is concern that tamoxifen may have serious short- and long-term side effects. Other medications which may have similar benefits but are less hazardous are under study.

For now, early detection and treatment are the best means to increase survival and reduce mortality due to breast cancer. Mammography, breast examination by a nurse or physician, and breast self-examination are all methods to detect breast cancer early. Mammography is especially important because it can detect early breast cancers that even very skilled health practitioners may miss. Appendix I contains recommendations from the American Cancer Society for women about using these methods of early detection. Appendix II has information on the New Jersey Breast and Cervical Cancer Control Initiative which provides for free screening for eligible women in New Jersey.

Incidence and Mortality in the U.S.

Breast cancer is the most common type of cancer among women in the U.S., accounting for 30 percent of the newly diagnosed cases of cancer among women each year. About 178,700 new cases are estimated for 1998 in the U.S. Approximately one in eight women in the U.S. will have breast cancer at some time in her life, according to the American Cancer Society. The age-adjusted incidence rate of breast cancer among women in the U.S. steadily increased between 1940 and 1987, especially between 1982 and 1987, but has stabilized since 1987 at about 110 newly diagnosed cases per 100,000 women a year. Many researchers believe that some of the increase in breast cancer incidence since 1940 may be due to an increase in the proportion of women who have known risk factors for breast cancer, such as giving birth to the first child later in life and having fewer children. Another possible reason for the increase in the incidence of breast cancer, especially from 1982 to 1987, is that more women are using breast cancer screening methods such as mammography that identify breast cancer early. Thus, breast cancers that would have been diagnosed in later years (after 1982-1987) were diagnosed earlier. Breast cancer is rare among men; about 1,600 new cases of breast cancer in men are estimated to occur in 1998 in the United States, representing 0.25 percent of the total estimated cancers in men.

Breast cancer is the second most common cause of death due to cancer in women in the U.S. (lung cancer has recently become the most common) with 43,500 deaths estimated nationwide for 1998. The mortality rate of breast cancer among women is declining. The reasons for the decline are believed to include earlier detection which enables more successful treatment. The five-year relative survival rate for localized breast cancer is 97 percent, for regionally spread breast cancer it is 76 percent, and for women with distant metastases it is 21 percent.

Incidence in New Jersey - 1986-1996

Tables 10 through 12 present breast cancer incidence data by county for 1986 through 1996. Figure 6 shows statewide trends in breast cancer. Statewide, the breast cancer incidence rates were higher in white women than black women and were much higher in white and black women than in white or black men, who had similar rates (see Figure 6). This pattern held for most counties. In Hunterdon and Warren counties, black women had higher rates than white women (see Table 12), but these rates for black women may be unstable and should be interpreted cautiously because they were based on small numbers of women with breast cancer. Statewide, the breast cancer incidence rate steadily declined for white women from 1992 through 1996, but did not decline as consistently for black women (see Figure 6). The breast cancer rates for men changed little over the eleven-year time period.

Conclusion

The most important public health activity related to breast cancer at this time is screening to detect it early when the chances for survival are high. Research to uncover risk factors that are now unknown may provide additional opportunities for preventing breast cancer. In the meantime, moderate physical activity, a diet low in fat and high in fiber, weight control (particularly in women after menopause), and limited consumption of alcoholic beverages may reduce the risk of breast cancer.

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Table 10.
Breast Cancer Incidence
By County, White Females, New Jersey - 1986-19961

COUNTY 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
(Prelim.)

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

Atlantic

112

90.1

137

110.2

139

112.6

156

124.4

146

113.5

150

110.2

148

113.2

139

103.9

149

122.9

154

119.2

134

106.6

Bergen

643

110.5

699

120.7

710

124.5

736

129.8

703

123.4

692

124.0

746

132.2

761

135.1

674

119.4

643

111.3

649

115.8

Burlington

204

109.2

197

104.1

241

122.1

226

114.8

217

106.8

255

126.9

246

122.7

244

120.9

264

132.0

238

113.2

242

117.7

Camden

277

107.3

281

106.1

336

130.9

317

120.9

332

127.1

336

131.8

282

107.6

288

110.8

301

117.9

276

105.7

235

87.8

Cape May

80

99.0

87

108.3

76

110.8

80

115.3

102

143.6

84

109.7

83

110.6

85

109.3

92

118.8

94

115.8

78

93.3

Cumberland

71

90.5

67

91.1

76

98.4

57

70.5

100

128.9

86

108.5

98

126.1

82

109.2

75

99.2

76

99.3

95

130.1

Essex

368

101.1

424

119.5

440

126.8

430

128.7

430

131.8

423

135.5

420

130.4

372

118.5

379

123.0

336

114.1

344

114.8

Gloucester

138

132.9

136

127.7

127

112.3

146

126.8

136

116.9

143

118.9

154

126.4

132

109.1

149

121.6

136

113.2

106

82.6

Hudson

325

102.0

302

97.0

345

111.3

269

90.0

298

95.1

260

87.6

272

90.7

296

98.7

267

91.2

259

85.7

268

91.2

Hunterdon

67

122.5

68

124.7

66

119.2

68

112.6

85

138.6

75

128.1

100

167.0

74

113.9

78

124.6

79

129.4

92

138.4

Mercer

204

112.2

193

112.6

211

123.9

202

116.8

237

132.5

217

124.9

207

116.7

254

144.2

214

121.3

217

121.9

216

125.4

Middlesex

386

111.6

412

116.6

443

121.8

401

108.5

406

110.1

412

111.5

445

119.8

487

132.2

438

116.3

438

116.4

414

108.1

Monmouth

401

127.7

416

128.2

403

123.5

401

121.6

426

129.2

408

126.0

451

130.9

424

124.2

390

116.7

413

119.5

397

113.4

Morris

260

109.4

305

129.4

294

120.9

304

124.9

308

127.4

286

115.6

324

130.5

313

126.3

318

122.8

316

126.5

310

119.4

Ocean

385

112.7

419

119.3

433

124.8

398

105.7

464

118.7

465

121.5

459

120.0

413

104.8

464

116.6

471

117.8

438

114.2

Passaic

285

109.7

296

111.2

296

110.8

277

105.1

308

120.3

266

105.5

293

114.6

251

98.5

266

100.1

271

107.9

293

117.7

Salem

44

109.7

29

78.5

36

92.9

44

113.2

41

104.6

43

110.2

55

143.6

40

106.4

40

103.7

31

79.1

49

121.8

Somerset

139

111.4

158

123.8

176

134.3

144

109.6

140

103.2

176

129.2

130

92.9

161

112.9

148

104.2

165

112.9

158

103.3

Sussex

88

139.3

80

128.1

89

138.5

69

107.0

65

96.7

86

132.4

78

115.5

86

116.3

63

89.6

85

119.4

102

148.4

Union

317

102.3

391

127.3

359

115.1

366

121.2

383

129.7

341

110.7

335

112.0

316

104.9

335

110.3

336

111.0

326

112.0

Warren

63

112.5

88

145.0

106

189.7

69

121.3

57

94.4

84

144.1

67

110.9

73

127.6

69

116.6

76

122.2

68

109.1

STATE

4860

109.9

5188

116.9

5408

121.6

5164

116.1

5387

120.0

5291

119.0

5394

119.6

5293

117.8

5175

114.8

5112

112.8

5014

110.4


1Incidence rates - per 100,000 females, age-adjusted to the 1970 U.S. standard population. Cases of unknown county are included in the State numbers and rates. Source: New Jersey State Cancer Registry.

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Table 11.
Breast Cancer Incidence
By County1, Black Females, New Jersey - 1986-1996

COUNTY 1986 1987 1988 1989 1990 1991 1992 1993 1994 1995 1996
(Prelim.)

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

No.

Rate

Atlantic

14

67.2

24

111.2

22

105.7

26

114.2

17

70.1

17

79.5

35

148.7

17

73.7

26

99.8

25

90.6

26

91.0

Bergen

19

90.6

19

87.2

18

76.8

21

88.6

18

76.8

18

69.6

30

123.4

15

59.8

21

74.9

32

116.2

22

76.5

Burlington

17

89.9

26

129.0

31

146.6

23

95.6

30

127.4

28

107.4

31

130.0

24

89.3

15

52.9

21

77.7

26

100.2

Camden

34

93.8

34

93.6

47

128.9

32

79.6

37

92.2

42

106.2

43

105.2

42

100.9

45

103.0

44

96.1

38

85.3

Cumberland

7

75.9

6

61.0

5

54.8

9

94.1

6

53.2

---

---

15

125.3

9

79.8

10

78.5

10

95.3

13

114.1

Essex

130

81.8

150

92.7

146

89.6

173

107.1

153

91.8

155

94.2

172

100.6

169

99.7

137

80.2

158

89.2

154

87.7

Gloucester

10

102.3

5

45.7

10

97.9

6

55.5

17

136.4

9

66.6

19

155.4

9

67.5

12

88.6

19

126.5

17

127.3

Hudson

25

74.8

36

104.8

27

76.1

36

104.0

32

90.1

38

108.1

37

98.8

38

98.2

18

42.7

26

68.7

39

97.5

Mercer

38

134.9

23

84.5

28

93.4

32

104.8

24

77.6

49

150.3

27

82.7

41

126.1

40

116.8

51

148.6

31

85.5

Middlesex

17

83.5

23

115.6

19

95.5

14

61.1

17

76.6

24

106.7

15

61.6

25

108.5

33

114.6

30

111.1

29

106.4

Monmouth

19

77.7

20

78.9

24

94.1

24

94.0

24

90.5

22

75.9

18

60.8

21

71.4

33

108.0

29

91.2

22

65.4

Morris

---

---

5

62.6

---

---

7

106.5

8

136.9

---

---

7

95.4

---

---

12

152.9

6

61.1

---

---

Ocean

---

---

---

---

7

139.6

5

97.2

---

---

6

108.1

7

129.6

5

88.3

---

---

---

---

11

152.5

Passaic

21

72.2

19

63.3

20

67.0

28

100.3

19

61.3

27

76.6

19

58.5

23

66.7

31

81.8

30

81.2

37

91.7

Salem

---

---

5

97.9

---

---

---

---

5

99.7

---

---

12

202.1

7

96.7

---

---

6

106.4

7

96.4

Somerset

---

---

---

---

5

64.2

5

65.5

6

99.2

8

122.6

8

110.7

9

98.8

5

51.7

8

104.2

7

57.4

Union

43

95.2

53

112.1

52

110.7

52

111.4

63

133.3

53

106.2

50

104.3

47

90.9

61

114.7

51

95.1

41

75.3

STATE

413

85.7

457

93.0

472

93.3

497

97.9

490

94.1

504

94.9

554

101.6

508

91.6

513

88.7

556

94.3

526

88.0


1Incidence rates - per 100,000 females, age-adjusted to the 1970 U.S. standard population. Source: Cases of unknown county are included in the State numbers and rates. Counties with six or more years of fewer than five cases each year were removed from the table - Cape May, Hunterdon, Sussex, and Warren counties. The dashes indicate fewer than five cases. New Jersey State Cancer Registry.

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Table 12.
Breast Cancer Incidence
By County, Race And Gender, New Jersey - 1986-1996 Combined1

COUNTY

MALE

FEMALE

WHITE

BLACK

WHITE

BLACK

Number

Rate2

Number

Rate2

Number

Rate2

Number

Rate2

Atlantic

16

1.3

---

---

1564

112.0

249

95.2

Bergen

81

1.6

---

---

7656

122.3

233

85.7

Burlington

21

1.3

---

---

2574

117.0

272

102.8

Camden

25

1.1

---

---

3261

113.9

438

98.5

Cape May

10

1.2

---

---

941

112.2

30

79.3

Cumberland

11

1.7

---

---

883

104.7

93

79.2

Essex

39

1.4

16

1.4

4366

121.8

1697

92.2

Gloucester

10

1.0

---

---

1503

116.8

133

99.2

Hudson

31

1.2

---

---

3161

94.6

352

87.4

Hunterdon

---

--

---

---

852

128.8

15

210.2

Mercer

15

1.0

---

---

2372

123.3

384

109.9

Middlesex

38

1.2

---

---

4682

115.9

246

95.7

Monmouth

31

1.1

---

---

4530

123.8

256

82.6

Morris

28

1.3

---

---

3338

122.8

60

77.0

Ocean

45

1.3

---

---

4809

116.2

56

89.7

Passaic

24

1.0

---

---

3102

109.3

274

75.1

Salem

6

1.8

---

---

452

105.5

57

89.9

Somerset

14

1.1

---

---

1695

112.2

65

79.2

Sussex

9

1.6

---

---

891

120.7

---

---

Union

28

1.0

---

---

3805

114.4

566

104.0

Warren

---

---

---

---

820

125.8

10

129.5

STATE

488

1.2

46

1.1

57286

116.2

5490

93.0


1Incidence rates - per 100,000 population, age-adjusted to the 1970 U.S. standard population. Cases of unknown county are included in the State numbers and rates. The dashes indicate fewer than five cases. Source: New Jersey State Cancer Registry.
2Average annual rate.

Figure 6.

Figure 6


*1996 data are preliminary. Source: New Jersey State Cancer Registry.

Note: Although black males have slightly lower annual incidence rates for breast cancer than white males, their rates are so similar and so low that it is difficult to distinguish the two rates in the figure.