Felis ISSN 2398-2950

Mastectomy

Contributor(s): David Godfrey, Rob Lofstedt, Kathryn Pratschke

Introduction

  • Excision of mammary gland(s).

Uses

  • Surgical treatment of benign and malignant mammary neoplasia  Mammary gland: neoplasia. In cats, the majority of mammary tumors are malignant; benign conditions are rare other than fibroepithelial hyperplasia in young cats.
  • In cats, there are 4 paired mammary glands; T1 and 2 are the thoracic glands, A1 and 2 are the abdominal. Additional rudimentary glands can be seen in both males and females.

Local excision

  • 'Lumpectomy'.
  • Shelling out tumor from gland.
  • Not recommended for feline mammary tumors unless known to be benign.

Simple/local mastectomy

  • Tumor removal en bloc with the associated gland.
  • Not recommended for feline mammary tumors unless known to be benign.

Regional mastectomy

  • Removal of tumor with glands associated by vascular/lymphatic drainage and node.
  • Based on a concept of vascular and lymphatic drainage that is potentially too simplistic given the known variation in lymphatic and vascular anatomy.
  • Axillary lymph nodes drain T1, 2 and possible also A1. Inguinal nodes drain A2 and also possibly A1. Crossover lymphatics between right and left glands have not been convincingly demonstrated, but hematogenous spread between sides is possible.
  • Not recommended for feline mammary tumors unless benign or performed for short term palliation related to, for example, superficial ulceration.
  • Unilateral.

Radical mastectomy

  • Unilateral 'mammary strip'.
  • Removal of all glands in one chain together with draining lymph nodes.
  • Although some texts suggest this for feline mammary tumors, unilateral procedures risk leaving residual disease.

Bilateral radical mastectomy

  • Bilateral 'mammary strip'.
  • Removal of all mammary tissue from both right and left sides together with draining lymph nodes.
  • This is the currently recommended approach for all malignant feline mammary tumors.
  • May be performed as a single stage procedure or staged unilateral procedures.

Advantages 

  • The mainstay of treatment for malignant mammary tumors (adenocarcinoma) in cats is aggressive, early surgery to perform bilateral mammary strips. Whether there is any benefit to neoadjuvant or adjuvant therapies combined with surgery is currently unclear.

Disadvantages

  • Malignant disease is present histologically in up to 93% of cases, with circa 80% of those being mammary adenocarcinoma Mammary gland: neoplasia. Metastasis is reported in 50-90% of cases. Unfortunately, disease frequently progresses rapidly meaning that many cases are presented too late in the disease for surgery to be truly curative. 

Requirements

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Preparation

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Procedure

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Aftercare

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Outcomes

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Prognosis

Unfavorable prognostic markers

  • Tumor size - survival times are significantly better for tumors <2 cm (approximately 54 months) than those 2-3 cm (24 months) and >3 cm (4-12 months).
  • Degree of differentiation - poorly differentiated or undifferentiated tumors carry shorter survival times.
  • Histopathological type, invasive micropapillary carcinoma is worse, complex carcinoma is better.
  • Extent of surgery - aggressive surgery is required, with bilateral mammary strip being the most appropriate approach.
  • Clinical stage - metastatic disease and whether locoregional or distant influence survival time.
  • The situation currently regarding prognostic molecular markers remains unclear.

Further Reading

Publications

Refereed papers

  • Recent references from PubMed and VetMedResource.
  • Morris J (2013) Mammary tumors in the cat: size matters, so early intervention saves lives. J Fel Med Surg 15 (5), 391-400 PubMed.
  • Seixas F, Palmeria C, Pires M A et al (2011) Grade is an independent prognostic factor for feline mammary carcinomas: a clinicopathological and survival analysis. Vet J 187 (1), 65-71 PubMed.
  • Novosad C A, Bergman P J, O'Brien M G et al (2006) Retrospective evaluation of adjunctive doxorubicin for the treatment of feline mammary gland adenocarcinoma: 67 cases. JAAHA 42 (2), 110-120 PubMed.
  • Maudlin G N, Matus R E, Patnaik A K et al (1988) Efficacy and toxicity of doxorubicin and cyclophosphamide used in the treatment of selected malignant tumors in 23 cats. JVIM (2), 60-65 PubMed.

Other sources of information

  • Buracco P (2014) Mammary Glands. In: Feline Soft Tissue and General Surgery. Langley-Hobbs S L, Demetriou J L & Ladlow J F (eds). Saunders Elsevier Ltd. Chapter 21, pp 219-232.
  • Lana S E, Rutteman G R & Withrow S (2007) Feline Mammary Tumors. In: Small Animal Clinical Oncology. Withrow S J & Vail D M. 4th edn. Elsevier, pp 628-636.


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