Mammary Tumors

Question 1

Gemignani, JAVMA, 2018:
Mammary adenocarcinoma in cats

1. What % of cats had tumors in >1 mammary gland?
2. What % of cats had lymphatic invasion and what % had vascular invasion?
3. What % of lymph nodes removed had evidence of metastasis?
4. What % of cats had evidence of distant metastasis?
5. Incomplete and narrow margins were reported in what % of unilateral vs bilateral mastectomy cases?
6. Post-op complication rate?
7. Factors associated with disease progression?
8. Benefits of bilateral mastectomy over unilateral mastectomy?
9. Treatment with adjuvant chemotherapy was protective against death - true or false?

Answer 1

Gemignani, JAVMA, 2018:

1. 33% had tumors in >1 mammary gland
2. 40% had lymphatic invasion and 15% had vascular invasion
3. 44% of lymph nodes removed had evidence of metastasis
4. 0% had distant metastasis
5. Incomplete and narrow margins were reported in 24% of unilateral vs 10% of bilateral mastectomy cases
6. Post-op complication rate: 29% (more common with bilateral vs unilateral mastectomy, and more common with single-session bilateral vs staged bilateral mastectomy)
7. Factors associated with disease progression: unilateral mastectomy, tumor ulceration, lymph node metastasis at the time of surgery, tumors arising in a 4th (inguinal) mammary gland
8. Benefits of bilateral mastectomy over unilateral mastectomy: improved progression-free interval and MST
9. True

Question 2

Litterine-Kaufman, JAVMA, 2019:
Mammary masses in dogs

1. What % of the masses were benign or non-neoplastic?
2. What % of the masses were not of mammary origin?
3. Masses from which mammary glands had a lower prevalence of malignancy compared to the other glands?

Answer 2

Litterine-Kaufman, JAVMA, 2019:

1. 85% were benign or non-neoplastic
2. 5% were not of mammary origin
3. Masses from the 4th (caudal abdominal) mammary gland had a lower prevalence of malignancy than the other mammary glands combined

Question 3

Kristiansen, JVIM, 2013:
Effect of OHE at the time of mastectomy in dogs with benign tumors

Effect of OHE on new tumor development and survival?

Answer 3

Kristiansen, JVIM, 2013:

OHE at the time of mastectomy reduced the risk of new tumor development but did not affect survival

Question 4

Kristiansen, JVIM, 2016:
Effect of OHE at the time of mastectomy in dogs with mammary carcinomas

1. Effect of OHE on tumor recurrence, new tumor development, regional metastasis and distant metastasis?
2. Effect of OHE on hazard of death?
3. What subset of mammary carcinomas are likely to benefit from OHE at the time of mastectomy?

Answer 4

Kristiansen, JVIM, 2016:

1. OHE had no effect on tumor recurrence, new tumor development, regional metastasis and distant metastasis
2. OHE had no effect on the hazard of death
3. Subset of mammary carcinomas that are likely to benefit from OHE at the time of mastectomy: grade 2 tumors, estrogen receptor-positive tumors, tumors with increased pre-op serum 17b-estradiol concentrations