Table 2 Summary of each article included
Author and year | Country/study design/setting/aim of the study | Prior treatment/tumour characteristics/number of dogs and treatment/follow up time | Outcome/key findings |
|---|---|---|---|
MacEwen 1985 [7] | USA Randomized controlled trial University setting Aim: to evaluate the effect of levamisole and surgery on canine mammary cancer | No prior treatment Simple mastectomy: 72 dogs Radical mastectomy: 72 dogs All dogs had malignant tumours All dogs were followed up every 2 months until death, but not all dogs had died when the study was published | Outcomes: TTR and survival time MST not reached for dogs treated with simple mastectomy Surgical technique had no influence on outcome |
Simon 2006 [10] | Germany Randomized controlled trial University setting Aim: to investigate whether adjuvant doxorubicin or docetaxel will improve the treatment outcome in dogs with high-risk malignant mammary gland tumours and whether the use of docetaxel will be feasible in affected dogs | No prior treatment Number of tumours per dog: median 3 (range, 1–9) Diameter of largest tumour: median 6.6 cm (range, 1.4 – 11.5 cm) Stage I (T1N0M0): 6% of dogs (n = 31) Regional mastectomy: 17 dogs Radical mastectomy: 14 dogs All dogs had malignant tumours Follow-up time: 4 years (median 258 days, range 13–2585 days) | Outcomes: TTR (local or distant metastases) and MST Median not reached for recurrence-free interval Surgical technique had no influence on outcome |
Pena 2012 [30] | Spain Prospective cohort study University setting Aim: to describe and evaluate a canine-adapted histological grading method of canine mammary tumours as a prognostic indicator in a prospective study | Number of tumours per dog: median 1 (range, 1–3) Diameter of largest tumour: mean 2.2 cm (range, 0.5–14.0 cm) Stage I: 65% of dogs (n = 65) Lumpectomy, simple, regional or radical mastectomy: 65 dogs All dogs had malignant tumours Follow-up: 28–38 months | Outcomes: frequency of recurrences, TTR, mortality rate and survival time Surgical technique had no influence on outcome |
Betz 2012 [25] | Germany Prospective cohort study University setting Aim: to characterize outcome following surgery and identify independent prognostic factors in canine mammary tumours | No prior treatment with chemo or radiation Number of tumours per dog: median 2 (range, 1–9) Diameter of largest tumour: median 2.5 cm (range, 0.3–14.0 cm) Stage I: 57% of dogs (n = 134) Simple mastectomy: 30 dogs Regional mastectomy: 41 dogs Radical mastectomy: 63 dogs Malignant tumours: 24% of dogs (n = 134) Follow-up: 4 years | Outcomes: frequency of recurrences (local), TTR (local recurrence and distant metastases), survival time Surgical technique had no influence on outcome |
Stratmann 2008 [26] | Germany Prospective case series University setting Aim: to investigate the histologic diagnosis and incidence of new mammary tumour growth in the remaining mammary chain tissue after regional mastectomy | No prior treatment Number of tumours per dog: 1 Diameter of largest tumour: mean 2.2 cm (range, 1–3 cm) All dogs had stage T1NxM0 Regional mastectomy: 99 dogs Malignant tumours: 74% of dogs (n = 99) All tumours had clean margins Follow-up: median 3.8 years (range, 1–5 years) | Outcomes: new mammary lesion development frequency and TTR New mammary lesion development frequency: 58% of dogs (n = 99) (these dogs developed a new tumour in the ipsilateral chain) TTR, range 1–60 months The authors recommended radical mastectomy rather than regional mastectomy because of the high frequency of tumour recurrence in ipsilateral chain |
Misdorp 1976 [31] | Netherlands Retrospective case series Private practice setting Aim: to analyse 10 mammary tumour characteristics in dogs with mammary cancer with special reference to their association with prognosis | Simple mastectomy: 59 dogs Radical mastectomy: 42 dogs All dogs had malignant tumours Follow-up: 2 years | Outcome: mortality rate Surgical technique had no influence on outcome. Surgical technique had no influence on overall outcome, but simple mastectomy gave better outcome in dogs with noninvasive tumours less than 5 cm and not involving surrounding tissue and radical mastectomy gave better outcome in dogs with severely infiltrating tumours |
Netherlands Retrospective case series Private practice setting Aim: to analyse 14 tumour and host characteristics for association with prognosis in dogs surgically treated for mammary cancer | Simple mastectomy: 211 dogs Radical mastectomy: 42 dogs All dogs had malignant tumours Clean margins: 49% of cases (n = 178) Follow-up: 2 years | Outcomes: frequency of recurrences (local or distant metastases), survival time Surgical technique had no influence on overall outcome, but in dogs with smaller low-grade tumours simple mastectomy gave better outcome. In dogs with high-grade tumours radical mastectomy gave better outcome | |
Allen 1989 [27] | USA Retrospective case series University setting Aim: to evaluate prognostic value of specific physical findings, histological type and relative effects of different types of surgical excision in dogs with mammary cancer | 63% of dogs (n = 128) had more than one tumour Invasion into skin, muscle or body wall: 18% of dogs (n = 97) (not possible to separate ulcerated tumours from tumours fixated to underlying tissue) Lumpectomy: 18 dogs Simple mastectomy: 6 dogs Regional mastectomy: 13 dogs Radical mastectomy (unilateral): 14 dogs Radical mastectomy (bilateral): 18 dogs Malignant tumours: 65% of dogs (n = 97) Follow-up: > 1 year | Outcome: Frequency of recurrences (local) Surgical technique had no influence on outcome A surgical margin of 2 cm or more from the lesion is suggested as enough to minimize patient morbidity |
Wey 1999 [24] | Germany Retrospective case series University setting Aim: to evaluate incidence, age and breed of dogs with mammary tumours as well as prognosis following surgical treatment | Prior surgery: 19% of dogs (n = 75) Number of tumours per dog: mean 6.9 Ulceration: 8% dogs Fixation to underlying tissue: 8% dogs Diameter of largest tumour: < 3 cm in 64% of dogs (stage I) (n = 75) Lumpectomy: 1 dog Regional mastectomy: 15 dogs Radical mastectomy: 59 dogs Malignant tumours: 83% of dogs (n = 75) Follow-up: 1.5–2.5 years | Outcome: frequency of recurrences (local recurrences, regional and distant metastases) Surgical technique had no influence on outcome |
Itoh 2004 [33] | Japan Retrospective case series Private practice setting Aim: to evaluate clinical outcomes of both benign and malignant mammary gland tumours with concern to the differences between small-breed dogs and others | Diameter of largest tumour: < 3 cm in 67% of dogs (n = 81) Regional or radical mastectomy (unilateral or bilateral): 101 dogs Malignant tumours: 39% of dogs (n = 101) Follow-up: > 1 year | Outcome: mortality rate Surgical technique had no influence on outcome for carcinoma cases |
Chang 2005 [22] | Taiwan Retrospective case series University setting Aim: to identify prognostic factors for female dogs that have undergone surgical removal of malignant mammary tumours | Diameter of largest tumour: mean ± SD 7.2 ± 4.9 cm (range, 0.5–21 cm) Lumpectomy: 7 dogs Simple mastectomy: 24 dogs Regional mastectomy: 33 dogs Radical mastectomy: 10 dogs All dogs had malignant tumours Follow-up: 2 years | Outcome: survival time Surgical technique had no influence on outcome |
Dias et al. [32] | Brasil Retrospective case series University setting Aim: to investigate the relationship between survival time after mastectomy and a number of clinical and morphological variables | Diameter of largest tumour: < 3 cm in 49% of dogs (n = 143) Regional mastectomy, unilateral radical mastectomy (38% of dogs, most frequent) or bilateral mastectomy: 139 dogs Malignant tumours: 77% of dogs (n = 143) Follow-up: up to 64 months | Outcome: survival time Surgical technique had no influence on outcome |