Table 1

Prognostic factors by season among 79 658 Danish women operated for early breast cancer between 1 June 1978 and 31 May 2010

CharacteristicWinterSpringSummerAutumnTotal
n%n%n%n%n%
Total18 76020 06720 03320 79879 658
Age at surgery*
 ≤39 years10515.610575.310015.010945.342035.3
 40–49 years324917.3360418.0352417.6363717.514 01417.6
 50–59 years490626.2525126.2523226.1546126.320 85026.2
 60–69 years520327.7550627.4552027.6570227.421 93127.5
 70–79 years323317.2343617.1354117.7364217.513 85217.4
 ≥80 years11186.012136.012156.112626.148086.0
Period of surgery
 1977–1989459224.5478323.8511525.5544826.219 93825.0
 1990–1999562630.0616030.7635931.7655931.524 70431.0
 2000–2010854245.5912445.5855942.7879142.335 01644.0
Tumour size
 0–10 mm283215.1313615.6297214.8321115.412 15115.3
 11–20 mm741939.5798339.8794539.7831040.031 65739.7
 21–50 mm746939.8796439.7805340.2820139.431 68739.8
 >50 mm10405.59844.910635.310765.241635.2
Nodal status§
 Negative976752.110 67253.210 72353.511 23354.042 39553.2
 1–3 positive577230.8598429.8591529.5601528.923 68629.7
 ≥4 positive322117.2341117.0339516.9355017.113 57717.0
Histological group
 Ductal grade I480825.6512925.6524226.2539025.920 56925.8
 Ductal grade II/?**726838.7767238.2754237.6789338.030 37538.1
 Ductal grade III335117.9350417.5351717.6362617.413 99817.6
 Lobular196310.5213510.6208610.4213710.3832110.4
 Other invasive13707.316278.116468.217528.463958.0
ER–PgR status
 Negative291915.6317615.8329916.5321715.512 61115.8
 Positive12 45366.413 05465.112 99464.913 84966.652 35065.7
 Unknown338818.1383719.1374018.7373217.914 69718.5
Per cent Er–PgR positive†† ‡‡81.080.479.881.180.6
Adjuvant systemic therapy
 None944950.410 25651.110 55152.710 94052.641 19651.7
 Chemotherapy§§474925.3506325.2484924.2504324.219 70424.7
 Endocrine therapy¶¶627033.4662933.0634731.7665432.025 90032.5
  • * χ2=12.2, df=15, p=0.66.

  • χ2=80.7, df=6, p=0.0001.

  • χ2=14.9, df=9, p=0.09.

  • § χ2=19.5, df=6, p=0.003.

  • χ2=25.1, df=12, p=0.014.

  • ** Unknown grade, n=1533.

  • †† Positive relative to sum of positive and negative.

  • ‡‡ χ2=12.7, df=3, p=0.005.

  • §§ χ2=11.7, df=3, p=0.009.

  • ¶¶ χ2=18.4, df=3, p=0.0004.

  • ER, oestrogen receptor; PgR, progesterone receptors.