Outcome of intensity‐modulated radiation therapy‐based stereotactic radiation therapy for treatment of canine nasal carcinomas

Abstract

Stereotactic radiation therapy (SRT) has emerged as a convenient definitive treatment modality in veterinary medicine, but few studies exist evaluating outcome with treatment for canine nasal tumors, and no studies report the treatment of one single tumor histotype. This retrospective, observational study evaluates toxicity, response, and survival in 17 dogs with nasal carcinomas treated with SRT. Dogs received a median of 3000 centigray in three fractions via 6-MV linear accelerator. Eighty-eight percent of patients (n = 15) demonstrated clinical benefit. Of dogs with repeated CT imaging (n = 10), 60% (n = 6) achieved a partial response and 10% (n = 1) achieved a complete response. Median progression-free survival (PFS) was 359 days. Median survival time (MST) was 563 days. Among dogs evaluable for acute toxicity, 50% (n = 10) developed low grade toxicity (grade 1, n = 4; grade 2, n = 1). No patients developed grade 3 toxicity. 16 dogs (87%) evaluable over the long term developed signs consistent with possible late toxicity. The majority of late toxicities were mild (alopecia, hyperpigmentation, and leukotrichia n = 10; ocular discharge and keratoconjunctivitis sicca n = 5). Thirty-seven percent of patients (n = 6) developed seven possible grade 3 late toxicities (blindness, n = 3; fistula, n = 1; seizures, n = 3), which were difficult to distinguish from progressive disease in most patients. Of the prognostic factors evaluated (demographics, tumor stage, dosimetric data, epistaxis, facial deformity, clinical response, image-based response, nonsteroidal anti-inflammatory drugs, and chemotherapy), only clinical response was a positive prognostic factor on MST (P < .00). No factors were found to be significantly associated with PFS.

The Treatment Combining Antiangiogenesis with Chemoradiotherapy Impinges on the Peripheral Circulation Vascular Endothelial Cells and Therapeutic Effect in the Patients with Locally Advanced Nasopharyngeal Carcinoma

“…The mainstream treatment for advanced local nasopharyngeal carcinoma patients is a comprehensive treatment combining with radiotherapy, chemotherapy, and targeted therapy, which greatly improves patients' five-year survival rate and especially has that of the advanced local nasopharyngeal carcinoma (stages III and IVa) which reach nearly 80%. Failure of nasopharyngeal carcinoma IMRT mainly attributes to the distant metastasis of this cancer (11)(12)(13)(14). Therefore, controlling local recurrence and distant metastasis might ensure the long-term survival of patients.…”

Outcomes of megavoltage radiotherapy for canine intranasal tumors and its relationship to clinical stages

“…performed intensity-modulated radiotherapy for stage 4 cases and reported an MST of 319 days ( Stevens et al ., 2020 ), which is superior to our result. Recently, clinical applications of new therapies, such as stereotactic radiotherapy and stereotactic body radiotherapy, have been reported ( Gieger and Nolan, 2018 ; Mayer et al ., 2019 ; Fox-Alvarez et al ., 2020 ), and their use may extend to stage 4 tumors in the future.…”

“…Better treatment results with an MST of ≥500 days have been reported for the combination of radiotherapy and intralesional chemotherapy ( Lana et al ., 1997 , 2004 ). Furthermore, clinical applications of stereotactic radiotherapy and stereotactic body radiotherapy have recently been reported, and the MST for affected dogs has been further extended to 388–586 days ( Gieger and Nolan, 2018 ; Mayer et al ., 2019 ; Fox-Alvarez et al ., 2020 ). Recurrence of intranasal tumors is considered to have a significant effect on survival, and the efficacy and safety of re-irradiation are being investigated for recurrent tumors in order to prolong the survival time of affected dogs ( Bommarito et al ., 2011 ; Gieger et al ., 2013.…”

Comparative study of the collapsed cone convolution and Monte Carlo algorithms for radiation therapy planning of canine sinonasal tumors reveals significant dosimetric differences

“…Currently, a consensus of standard normal tissue constraints for SBRT has not been established in veterinary medicine. Limited normal tissue tolerance data in veterinary medicine were reported in several SBRT publications using various treatment protocols and dose calculation methods 6–10 . Therefore, it is important to consider how normal tissue tolerances are determined.…”

“…Stereotactic body radiation therapy is an alternative to fractionated radiation therapy and may provide similar clinical outcomes with fewer acute toxicities compared to historical conventional fractionated radiation therapy protocols. [6][7][8][9][10] Dose calculating algorithms play an increasingly crucial role in modern computer-based radiation therapy due to the requirement of high dosimetric precision to assure tumor control and prevent detrimental adverse events.…”