Retrospective clinical study on outcome in cats with nasal planum squamous cell carcinoma treated with an accelerated radiation protocol

Abstract

BackgroundCutaneous squamous cell carcinoma of the nasal planum in cats is a common indication for antitumor treatment such as external beam radiation therapy. Curative-intent radiation therapy has been described as a valuable treatment option, resulting in long and stable tumor control in these patients. The aim of the current study was to evaluate outcome and toxicity, as well as possible prognostic factors using an accelerated hypofractionated radiation therapy protocol.Cats with squamous cell carcinoma of the nasal planum treated with an accelerated radiation protocol (10 × 4.8 Gy, over one week) were retrospectively evaluated. Tumor- and treatment-associated variables were evaluated in respect to local control and survival.ResultsForty-four cats met the inclusion criteria for this study. All cats showed complete response to therapy. Median disease-free interval (DFI) for all cases was 916 days (95% CI: 456-1377). One- and two-year DFIs were 71% (95% CI: 56-86%) and 60% (95% CI: 43-77%). Of the tested variables, only tumor volume showed a tendency to influence DFI, with larger tumors having a 5.4 times greater risk of recurrence than the smaller ones (HR 1.33 (95% CI: 0.99-1.79), p = 0.054). Median overall survival (OS) was 902 days (95% CI: 862-942). One- and 2-year OSs were 79.3% (95% CI: 67.3-91.3) and 58.4% (95% CI: 42.8-74). Of the tested variables, again, only tumor volume influenced OS with larger tumors having a 6.3 times greater risk of dying than the smaller ones (HR 1.36 (95% CI: 1.07-1.73), p = 0.010). The acute and late toxicity profile was low and hence clinically acceptable.ConclusionsCurative-intent radiation therapy with an accelerated fractionation schedule can be considered a safe, cosmetically superior treatment option for cutaneous squamous cell carcinomas of the nasal planum in cats, resulting in long and stable tumor control.

The Advantage of FLASH Radiotherapy Confirmed in Mini-pig and Cat-cancer Patients

“…The cohort was too small to allow definitive conclusion for tumor control and, the antitumor effect of FLASH-RT was evaluated as a secondary endpoint. SCC of the nasal planum is an appropriate model for which surgery can be functionally devastating and for which Conv-RT is commonly used in clinical practice, albeit with relatively poor outcome and severe toxicity (16,17,24). An obvious interest of FLASH-RT is the possibility to use a single curative fraction, whereas Conv-RT requires relatively complex logistics with several fractions and multiple anesthesias that impair the cats' quality of life.…”

“…This observation needs to be extended in a larger cohort of cats but it is in contrast with all previously mentioned studies where frequent grade 2 of 3 (21) toxicity (>30% of patients in ref. 24) was reported, along with PFS at one year of between 50% and 80% (16,24). A second superiority of FLASH-RT for the treatment of domestic animals is its very convenient single-dose administration.…”

A Retrospective Multicentric Study of Electrochemotherapy in the Treatment of Feline Nasal Planum Squamous Cell Carcinoma

“…For these reasons, numerous local antitumor techniques have been applied in the treatment of npSCC, which include cryosurgery, radiation therapy, photodynamic therapy, intralesional chemotherapy and electrochemotherapy. Systemic chemotherapy has also been used; however, it is usually limited to advanced-stage cases and results have been underwhelming [ 2 , 4 , 10 , 11 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ].…”

“…ECT is minimally invasive, with minor or no side effects. It can be repeated several times, requires general anesthesia and the costs are lower than other treatment approaches, such as radiation therapy [ 21 ]. ECT can also be used in combination with several other therapeutic approaches, such as surgery, radiation therapy and gene therapy [ 30 , 36 , 37 ].…”

Evaluation of long-term outcome and prognostic factors of feline squamous cell carcinomas treated with photodynamic therapy using liposomal phosphorylated meta-tetra(hydroxylphenyl)chlorine

“…Radiation therapy has been reported to achieve appealing response rates and control durations but is associated with multiple treatment sessions for the Evaluation of long-term outcome and prognostic factors of feline squamous cell carcinomas treated with photodynamic therapy using liposomal phosphorylated metatetra(hydroxylphenyl)chlorine patient and should be reserved for larger, more invasive stages of the tumour. [3][4][5][6] Electrochemotherapy, cryotherapy and strontium-90 plesiotherapy also achieve satisfying lesion control but are not widely available. [7][8][9] Photodynamic therapy (PDT) is a non-invasive treatment modality, which involves the use of a photosensitiser, light and endogenous molecular oxygen to kill cancer cells.…”