Intrinsic and extrinsic flaws of the nomogram predicting bone-only metastasis in women with early breast cancer: An external validation study.
The recently developed MDACC nomogram purports to predict the risk of bone-only metastasis in women with early breast carcinoma based on five clinical and pathological characteristics. We set out to externally validate and assess its robustness using a tertiary breast cancer centre database.



All consecutive women treated for early breast cancer in our centre between January 1989 and December 2013 and who had all the nomogram variables documented were eligible for analysis.



We identified 1255 eligible women for external validation analysis. The median follow-up was 54 months (range: 1-312) and time to initial metastasis 20 months (range: 1-80). The correspondence between the actual bone-only metastasis and the nomogram predictions implied poor calibration of the nomogram in the validation cohort, be it in the whole cohort or when stratified by breast cancer subtype.



This external validation study of the MDACC nomogram showed limitations in its generalizability to a new and independent European patient population.
Department of Gynaecology, Centre Hospitalier Universitaire de Tours, Tours, France; INSERM U1069, Université François-Rabelais, Tours, France. Electronic address: l.ouldamer@chu-tours.fr.
Lobna
L
Ouldamer
Department of Obstetrics and Gynaecology, Hôpital Tenon, Paris, France; UMR S 707, Epidemiology, Information Systems, Modeling, Université Pierre et Marie Curie, Paris, France.
Sofiane
S
Bendifallah
Department of Gynaecology, Centre Hospitalier Universitaire de Tours, Tours, France.
Marie
M
Chas
Department of Gynaecology, Centre Hospitalier Universitaire de Tours, Tours, France.
Laura
L
Boivin
Department of Gynaecology, Centre Hospitalier Universitaire de Tours, Tours, France.
Lea
L
Bedouet
Department of Gynaecology, Centre Hospitalier Universitaire de Tours, Tours, France; INSERM U1069, Université François-Rabelais, Tours, France.
Gilles
G
Body
Department of Obstetrics and Gynaecology, Hôpital Tenon, Paris, France; INSERM UMR S 938, Université Pierre et Marie Curie, Paris, France.
Marcos
M
Ballester
Department of Obstetrics and Gynaecology, Hôpital Tenon, Paris, France; INSERM UMR S 938, Université Pierre et Marie Curie, Paris, France.
Emile
E
Daraï
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018931:Antineoplastic Agents, Hormonal / Q000627:therapeutic use; D001859:Bone Neoplasms / Q000453:epidemiology / Q000556:secondary*; D001932:Brain Neoplasms / Q000453:epidemiology / Q000556:secondary; D001943:Breast Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000453:epidemiology / Q000378:metabolism / Q000556:secondary* / Q000628:therapy; D018275:Carcinoma, Lobular / Q000453:epidemiology / Q000378:metabolism / Q000556:secondary* / Q000628:therapy; D017024:Chemotherapy, Adjuvant; D003661:Decision Support Techniques; D005260:Female; D006801:Humans; D008408:Mastectomy; D015412:Mastectomy, Segmental; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D049451:Nomograms; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D064726:Triple Negative Breast Neoplasms / Q000378:metabolism / Q000473:pathology / Q000628:therapy; D055815:Young Adult
D018931:Antineoplastic Agents, Hormonal; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
Bone metastases; Breast cancer; Molecular subtype; Nomogram