Anal Adenocarcinoma Research Articles

Efficacy and tolerance of short cycles of palliative radiotherapy in advanced anal sac adenocarcinomas in dogs

Successful management of advanced anal sac gland adenocarcinomas (AGASACA) often requires a multimodal approach. In recent years the role of palliative radiotherapy (pRT) has become increasingly more important, mainly in dogs with severe local clinical signs. This study describes efficacy and tolerance of short cycles of pRT. Retrospective single-institution study including dogs with AGASACA treated with at least one short cycle of pRT (IMRT, 4Gy BID for two consecutive days). All dogs were staged with CT and followed to death. Outcome measures were PFS and OST from the first pRT. Potential prognostic factors were evaluated. Twelve dogs were included (one stage II, four stage III, seven stage IV). Three dogs had one cycle, seven had two cycles, and two had three cycles of pRT. All dogs experienced a clinical benefit after pRT. One dog also had surgery, four systemic treatment, and five both. Eleven dogs died during the follow-up (four for local progression, six for systemic progression, one unknown). The median PFS was 198 days (95% CI 98—298) and the OST was 250 days (95% CI 124—376). Mild, acute, short-term GI toxicity occurred in seven dogs (five G1; two G2). None of the dogs experienced clinically relevant late toxicity. Short cycles of radiotherapy can be effectively used as a palliative treatment for advanced AGASACA with minimal toxicity. The small number of patients did not allow to assess the benefits of combining RT with other treatment modalities or the identification of meaningful prognostic factors.

Comparison of computed tomography findings between perianal tumors originating from the anal sacs and perianal glands in dogs.

Tumors originating from the anal sacs and perianal glands are common tumors of the perianal region. However, differentiation of perianal tumors based on CT findings remains challenging because perianal tumors can show overlapping CT characteristics. Therefore, this retrospective, multi-institutional study aimed to identify the CT findings that can differentiate between tumors originating from the anal sacs and perianal glands in canines. Twenty dogs were included, with nine apocrine gland anal sac adenocarcinomas (AGASACAs), six perianal gland adenomas, three perianal gland carcinomas, and two perianal gland epitheliomas. The tumor CT features included the tumor growth pattern, tumor shape, cystic changes within the tumor, contrast enhancement pattern, displacement of the anus, and identification of the anal sacs. The prevalences of suspected metastatic lymphadenopathy of the iliosacral lymph centers and lung metastases were evaluated. The tumor volumes and values normalized to body weight were also assessed. The tumor growth patterns differed significantly between AGASACAs and perianal gland tumors. AGASACAs mostly showed unilateral growth, whereas perianal gland tumors mostly exhibited bilateral growth. CT features, except for the tumor growth pattern, failed to show significant differences between tumors arising from the anal sacs and those arising from the perianal glands. Although histopathological diagnosis remains the gold standard, this study's findings suggest that CT analysis of tumor growth patterns may help differentiate AGASACAs from perianal gland tumors.

Incorporation of pre- and intra-operative sentinel lymph node mapping techniques in dogs with apocrine gland anal sac adenocarcinoma

The high incidence of nodal metastasis, variable lymphatic drainage patterns, and prognostic significance of nodal metastasis in dogs with apocrine gland anal sac adenocarcinoma (AGASACA) highlight the need for development of standardized techniques for lymph node staging in canine AGASACA. The aim of this study was to develop and describe the utility of pre- and intra-operative sentinel lymph node (SLN) mapping techniques for subsequent nodal extirpation and histologic assessment in dogs with AGASACA. A prospective clinical trial was performed as a pilot study. Eight client-owned dogs with unilateral AGASACA were enrolled. Preoperative contrast-enhanced ultrasound (CEUS) via transrectal ultrasound (TRUS) and CT-lymphography (CTL) was followed by intraoperative SLN mapping within 7 days utilizing a visible dye (methylene blue [MB]) and a near-infrared (NIR) fluorescent dye (indocyanine green [ICG]) with subsequent nodal extirpation and routine anal sacculectomy. In all dogs, preoperative CTL and intraoperative SLN mapping identified at least one SLN. Pre- and intra-operative findings differed in 4/8 dogs. Preoperative CEUS identified a SLN in 7/8 dogs, but the exact location of the SLN was indeterminate. Extirpated lymph nodes were metastatic in 2/8 dogs. Preoperative CTL and intraoperative MB and ICG were an effective combination of SLN mapping techniques in dogs with AGASACA. These techniques each provided unique advantages. Combined, they identified and guided extirpation of early metastatic lymph nodes. Large-scale, prospective studies utilizing the techniques described are needed to accurately determine the incidence and significance of early/occult nodal metastasis in canine AGASACA.

Total neoadjuvant treatment for anal adenocarcinoma with inguinal lymph node metastasis: A case report

BackgroundMetastasis of anal adenocarcinoma to inguinal lymph nodes is a rare occurrence and published literature on the optimal management strategy for these patients is limited. Case presentationWe present a case where the use of total neoadjuvant therapy (long course concurrent chemoradiotherapy followed by chemotherapy alone), surgical resection of primary anal disease and selective inguinal lymph nodes is dissection was used to treat a male in his sixties with anal adenocarcinoma with inguinal lymph node metastasis. This was a novel approach in our centre where the management of rectal adenocarcinoma was extrapolated to treat anal adenocarcinoma. ConclusionThere is no clear guideline for management of anal adenocarcinoma with metastasis to inguinal lymph nodes. This case offers an approach for future patients with similar pathology that appears feasible in the short term 1 year follow up.

Fistula associated anal adenocarcinoma: report of a case

Fistula associated anal adenocarcinoma: report of a case

The inguinal lymph nodes as regional lymph nodes in anal canal adenocarcinomas: a nationwide database analysis in Japan.

To establish if it is appropriate to treat the inguinal lymph node (LN) of anal canal adenocarcinoma (ACA) as the intermediate LN according to the Japanese classification. The characteristics of 346 ACA patients were examined from the nationwide registry. The effect of LN dissection was evaluated using the therapeutic value index (TVI). Furthermore, the prognostic classification ability of N factors and stage was evaluated using Akaike's information criterion (AIC), the concordance index (C-index), and the 5-year overall survival (OS) rate. The rate of metastasis of the inguinal LN was 7.5% and the TVI was 3.05. Evaluation using AIC and the C-index showed better results when the inguinal LN was treated as the intermediate LN. The 5-year OS rate for 66 patients with perirectal or intermediate LN metastasis, 7 with inguinal LN metastasis, and 13 with inguinal and perirectal or intermediate LN metastasis were 49.2%, 68.6%, and 47.6%, respectively. When inguinal LN metastases were treated as N3, the 5-year OS rates were 66.7% for those with T1N3 and T2N3 disease, and 49.2% for those with T3N3 disease. The inguinal LN of ACA was evaluated and staged as the intermediate LN to devise an appropriate treatment strategy.

Short- and long-term outcomes of surgical treatment for inguinal lymph node metastasis in rectal and anal canal adenocarcinoma.

The significance of lymphadenectomy and its indications in patients with inguinal lymph node metastasis (ILNM) of anorectal adenocarcinoma is unclear. This study aimed to clarify the surgical outcomes and prognostic factors of inguinal lymphadenectomy for ILNM. This study included patients who underwent surgical resection for ILNM of rectal or anal canal adenocarcinoma with pathologically positive metastases between 1997 and 2011 at 20 participating centres in the Study Group for Inguinal Lymph Node Metastasis from Colorectal Cancer organized by the Japanese Society for Cancer of the Colon and Rectum. Clinicopathological characteristics and short- and long-term postoperative outcomes were retrospectively analysed. In total, 107 patients were included. The primary tumour was in the rectum in 57 patients (53.3%) and in the anal canal in 50 (46.7%). The median number of ILNMs was 2.34. Postoperative complications of Clavien-Dindo Grade III or higher were observed in five patients. The 5-year overall survival rate was 38.8%. Multivariate analysis identified undifferentiated histological type (P < 0.001), pathological venous invasion (P = 0.01) and pathological primary tumour depth T0-2 (P = 0.01) as independent prognostic factors for poor overall survival. The 5-year overall survival after inguinal lymph node dissection was acceptable, and it warrants consideration in more patients. Further larger-scale studies are needed in order to clarify the surgical indications.

A Population-Based and Propensity Score-Matched Investigation of the Occurrence, Management, and Prognosis of Anal Mucinous Adenocarcinoma Patients

Introduction: Anal mucinous adenocarcinoma (AMAC) is an extremely rare form of anal cancer. Our objective was to examine the incidence, management, and prognostic factors of AMAC. Methods: We analyzed age-adjusted incidence (AAI) rates over time and compared the prognosis of AMAC with anal squamous cell carcinoma (ASCC) and adenocarcinoma (AAC) using propensity score matching and Kaplan-Meier analysis. Patients were classified based on summary stage and treatments to determine cancer-specific survival. Results: AAI of AMAC fluctuated within a narrow range (0.082–0.237 per million person-years) from 2000 to 2018. AMAC had a slight non-significant trend of worse prognosis than ASCC (p = 0.348) and a better prognosis than AAC (p < 0.01). Females made up a larger proportion of patients diagnosed with the distant disease (p < 0.05) and unmarried (p < 0.05) and somewhat less probably to need surgical removal (p < 0.01) and radiotherapy (p < 0.01). Elderly patients have lower rates of survival (p < 0.05). Localized stage was associated with better prognosis (p < 0.05). Surgery was associated with a tendency toward better survival (p = 0.095). Conclusions: AMAC exhibits a low incidence yet favorable prognosis compared to typical AAC and slightly worse compared to ASCC. Elderly age is associated with poorer prognosis, while localized stage indicates better prognosis. Surgery demonstrates a trend toward improved survival.

Immunohistochemical Expression of Human Epidermal Growth Factor Receptor 2 and Ki67 in Apocrine Gland Anal Sac Adenocarcinoma.

Apocrine gland anal sac adenocarcinoma is an aggressive neoplasm, and surgery remains the treatment of choice, although it is controversial in advanced cases. The prognostic factors are not well established. Human Epidermal Growth Factor Receptor 2 (HER2) is a membrane protein related to tumorigenesis, whereas Ki67 is a nuclear protein related to cell proliferation. Both are potential prognostic markers and therapeutic targets. This study aimed to evaluate the expression of HER2 and Ki67 markers in canine apocrine gland anal sac adenocarcinoma. The tumor samples were divided into four groups: largest tumor diameter less than 2.5 cm, largest tumor diameter greater than 2.5 cm, metastatic lymph nodes, and control group of non-neoplastic anal sacs. Each contained 10 samples. Immunohistochemistry was performed to verify the expression of HER2 and Ki67 markers. Positive HER2 staining was observed in 45% of the neoplastic cases and negative HER2 staining in 100% of the control group. The Ki67 expression had a median of 25% in all groups, except for the control group, which had a median of 8%. The HER2 and Ki67 expression was present in apocrine gland anal sac adenocarcinoma, making them potential therapeutic targets. However, it was not possible to determine the clinical value of either marker.

Perianal Paget's Disease Metachronically Associated with Adenocarcinoma

Abstract Introduction This article describes an unusual case of perianal Paget's Disease in a 42-year-old man, highlighting distinct characteristics about more typical cases. Case report 42-year-old male patient with persistent perianal lesion, recurrent abscesses, and discomfort. Magnetic resonance imaging indicated a possible fistulous path. Biopsy revealed secondary anal Paget's disease and adenocarcinoma. Chemotherapy and radiotherapy treatment demonstrated a positive response. Discussion Perianal Paget's Disease is a rare condition of the anal canal that is part of the Extramammary Paget's Disease (EMPD) group. Symptoms include itching, pain, perianal bleeding, and skin lesions. Diagnosis can be challenging and usually involves performing a histopathological biopsy associated with an immunohistochemical study. Treatment varies and may involve surgery, radiotherapy, and chemotherapy. Due to the rarity of the disease, the best therapeutic approach is not yet well defined, and follow-up is essential due to the risk of recurrence. Conclusion Perianal Paget's Disease is rare and requires differentiation from other conditions. Early detection is essential to prevent malignancy.

Radiotherapy for Canine Apocrine Gland Anal Sac Adenocarcinoma: Survival Outcomes and Side Effects of a Palliative Treatment Protocol of 20 Gy in Five Consecutive Fractions.

This research aims to evaluate the outcomes of a radiotherapy protocol, consisting of five fractions of 4 Gy each, resulting in a total dose of 20 Gy for apocrine gland anal sac tumors and local lymph nodes in canines. This protocol was assessed as a palliative treatment for macroscopic tumors alone, or in combination with additional therapies under different scenarios. Medical records from fifty canine patients met the inclusion criteria and were divided into different treatment groups: radiotherapy alone (n = 22, 44%), radiotherapy with chemotherapy or targeted therapy with toceranib (n = 18, 36%), surgery with radiotherapy (n = 5, 10%), and surgery with radiotherapy and chemotherapy or targeted therapy with toceranib (n = 5, 10%). Patients who received radiotherapy alone had a median survival time of 384 days (95% CI 198-569) and 628 days (95% CI 579-676) for RT + additional therapies. The median time to progression for patients with radiotherapy alone was 337 days (95% CI 282-391 days), and 402 days (95% CI 286-517 days) for radiotherapy plus additional treatments. Acute side effects were mild, with the majority having diarrhea (61%), and only one patient developed grade III late effects VRTOG v2 classification; however, this happened 22 months after the first radiotherapy protocol after re-irradiation. The results demonstrate that radiotherapy alone under this protocol provided a comparable median time to progression vs. radiotherapy plus additional treatments while maintaining acceptable side effects. The combination of this protocol with other treatment modalities offers attractive results for local disease control and survival while maintaining acceptable toxicities. Overall, these findings contribute to the growing evidence supporting the role of radiotherapy in managing apocrine gland anal sac adenocarcinoma in dogs.

Significance of lateral lymph node dissection in squamous cell carcinoma of the anal canal: a retrospective cohort study.

The JCOG (Japan Clinical Oncology Group) 0212 study did not confirm the noninferiority of mesorectal excision (ME) alone to ME with LLND for rectal or anal adenocarcinomas. Furthermore, the significance of LLND for SCCs remains unknown. We evaluated the significance of lateral lymph node dissection (LLND) of squamous cell carcinoma (SCC) of the anal canal. This retrospective cohort study was conducted in 435 patients with SCCs among 1,781 patients with anal canal tumors. In 40 patients who underwent LLND, the 5-year relapse-free survival (5y-RFS) and 5-year overall survival (5y-OS) were compared between groups with positive and negative histopathological findings. In 71 patients with negative lateral lymph node metastasis in the preoperative diagnosis, the 5y-RFS, 5y-OS, and 5-year local recurrence-free survival were compared between patients who did and did not undergo LLND. The clinical and pathological T stages predicted pathological lateral pelvic lymph node metastasis. There was no statistically significant difference in 5y-RFS and 5y-OS between patients who did and did not undergo LLND. Among patients who underwent LLND, 5y-RFS in those with positive histopathological findings (15.0%) was worse than that in those without (59.2%) (p = 0.002). In patients who underwent LLND, 5y-RFS in those with positive histopathological findings than in those without LLND did not contribute to prognosis.

Histopathological diagnosis and surgical complications following bilateral anal sacculectomy for the treatment of unilateral canine apocrine gland anal sac adenocarcinoma: 35 cases (2019-2023).

To report the histopathological diagnosis of both anal sacs in dogs undergoing bilateral anal sacculectomy for the treatment of unilateral apocrine gland anal sac adenocarcinoma and to compare the surgical complication rate associated with this procedure in this population with previously published literature. Records were retrospectively reviewed for dogs that underwent bilateral anal sacculectomy for the treatment of apparently unilateral apocrine gland anal sac adenocarcinoma, at a single institute between 2019 and 2023. Clinical staging, surgical treatment, histological findings, intra- and postoperative complications were evaluated. Thirty-five dogs were included. Only five of 35 (14%) dogs were found to have histologically normal contralateral anal sacs. Non-neoplastic anal sac disease was found in 23 of 35 (66%) dogs and bilateral apocrine gland anal sac adenocarcinoma was seen in seven of 35 (20%) dogs. None of the dogs diagnosed with bilateral neoplasia had evidence of bilateral neoplasia before surgery despite a thorough work-up. Complications attributable to the primary tumour removal were seen in 9% of dogs intraoperatively and 14% of dogs postoperatively, commonly tumour capsule disruption and surgical site infection, respectively. Bilateral anal sac disease was diagnosed histologically in the majority of presumed normal anal sacs, with 20% of cases being found to have bilateral apocrine gland anal sac adenocarcinoma. The surgical complication rates of this cohort were comparable to those reported for unilateral anal sacculectomy alone. These findings promote and encourage the use of bilateral anal sacculectomy in cases of suspected unilateral anal sac neoplasia.

The Use of Sentinel Lymph Node Mapping for Canine Mast Cell Tumors.

Cancer is the leading cause of death in companion animals. The evaluation of locoregional lymph nodes, known as lymph node mapping, is a critical process in assessing the stage of various solid tumors, such as mast cell tumors (MCTs), anal gland anal sac adenocarcinoma, melanoma, and mammary gland adenocarcinoma. MCTs are among the most prevalent skin malignancies in dogs. Staging is used to describe the extent of neoplastic disease, provide a framework for rational treatment planning, and evaluate treatment results. The aim of this review is to present the current knowledge on sentinel lymph node (SLN) mapping in canine MCTs, its influence on treatment decisions and prognosis, as well as the advantages and limitations of different SLN techniques currently available in veterinary oncology. A search methodology was adopted using the PubMed, Scopus, and Google Scholar databases. Critical analyses of up-to-date research have shown that lymphoscintigraphy can achieve a lymph node detection rate of between 91 and 100%. This method is becoming increasingly recognized as the gold standard in both human and veterinary medicine. In addition, initial studies on a limited number of animals have shown that computed tomographic lymphography (CTL) is highly effective in the SLN mapping of MCTs, with detection rates between 90 and 100%. The first study on contrast-enhanced ultrasound (CEUS) also revealed that this advanced technique has up to a 95% detection rate in canine MCTs. These methods provide non-ionizing alternatives with high detection capabilities. Furthermore, combining computed tomography and near-infrared fluorescence (NIR/NIR-LND) lymphography is promising as each technique identifies different SLNs. Indirect lymphography with Lipiodol or Iohexol is technically feasible and may be also used to effectively detect SLNs. The integration of these mapping techniques into routine MCT staging is essential for enhancing the precision of MCT staging and potentially improving therapeutic outcomes. However, further clinical trials involving a larger number of animals are necessary to refine these procedures and fully evaluate the clinical benefits of each technique.

Outcomes of dogs with apocrine gland anal sac adenocarcinoma treated via modified closed anal sacculectomy (2015-2022).

To evaluate the postoperative complication rate and local recurrence rate of apocrine gland anal sac adenocarcinoma (AGASACA) in dogs surgically treated with a modified closed anal sacculectomy technique between 2015 and 2022. Observational clinical retrospective study. Forty-seven client-owned dogs histologically diagnosed with AGASACA. Medical records were evaluated for patient demographics and history, physical examination findings, diagnostic imaging, incidence of concurrent neoplasia, postoperative complications, and incidence and time to local recurrence. Dogs with at least 150 days of follow-up were included in evaluation of local recurrence. Two dogs were euthanized at 4 and 11 days after surgery. Forty-five dogs were included for long-term local recurrence evaluation, with a median of 364 days of follow-up (range 156-2156 days). Only one dog (2.2%) developed local recurrence with a time to recurrence of 90 days. Postoperative complications were reported in 15 dogs (31.9%) and were considered minor in 14 dogs (93.3%) and major in one dog (6.7%). Mean survival time for the 20 dogs that were deceased as of November 1, 2022 was 521 days (range 156-1409 days) and the median survival time was 388 days. The modified closed anal sacculectomy technique resulted in a lower AGASACA local recurrence rate than previously reported in the veterinary literature with a comparable postoperative complication rate. Given the low recurrence rate found in this study, the modified closed anal sacculectomy technique may reduce the need for adjuvant radiation therapy and potentially chemotherapy in AGASACA patients.

Comprehensive genomic profiling of advanced anal adenocarcinoma.

4 Background: Anal adenocarcinoma (anal AD) is a rare and aggressive gastrointestinal malignancy. Because of its rarity, no standard therapy is established and treatment strategy for advanced rectal adenocarcinoma (rectal AD) is extrapolated. Little is known for genetic alterations (GAs) and their therapeutic implications in advanced anal AD. We aim to investigate to clarify genomic profiles of advanced anal AD in comparison of advanced rectal AD. Methods: We retrospectively extracted data on patients with advanced anal AD and advanced rectal AD who underwent comprehensive genomic profiling (CGP) tests and were registered for the Center for Cancer Genomics and Advanced Therapeutics (C-CAT) in Japan. CGP tests were performed by NCC Oncopanel or FoundationOne CDx. We examined somatic GAs, microsatellite instability (MSI) status, and tumor mutation burden (TMB). TMB-high was defined as ≥10 mutations/Mb. Actionable GAs were counted if they were classified as “pathogenic/oncogenic” or “likely pathogenic/likely oncogenic” variants. Druggable GAs are actionable GAs with approved drugs for anal AD or other types of cancer or clinical trials showing efficacy for either anal AD or different types of cancer. Results: From June 2019 to April 2023, 45 patients with anal AD and 1915 patients with rectal AD were enrolled into the C-CAT database. In the anal AD group, most common actionable GAs were TP53 (89%), KRAS (51%), ERBB3 (22%), MYC (20%), SMAD4 (20%), and ERBB2 (11%). Compared with the rectal AD group, the anal AD group had a significantly higher frequency of actionable GAs in ERBB3 (22% vs. 2%, p &lt; 0.01), MYC (20% vs. 8%, p &lt; 0.01), and BRCA2 (7% vs. 1%, p &lt; 0.01), and a significantly lower frequency of actionable GAs in APC (7% vs. 85%, p &lt; 0.01). The proportion of MSI-high and TMB-high in the anal AD group and the rectal AD group were 0% vs. 0.2% (p = 0.79), and 7% vs. 5% (p = 0.54). Common druggable GAs in anal ADs included KRAS G12D mutation (22%), ERBB2 amplification (7%), BRCA2 mutation (7%), BRAF V600E mutation (2%). Compared with the rectal AD group, the anal AD group had a significantly higher frequency of druggable GAs in BRCA2 mutation (7% vs. 1%, p &lt; 0.01). Conclusions: The present study showed that anal AD had a different profile of GAs compared with advanced rectal AD. CGP tests are useful tool for identifying druggable GAs in advanced anal AD for expanding therapeutic opportunities.

Anal sac adenocarcinoma in a dog – case report

Anal sac adenocarcinoma in a dog – case report

Management and staging of anal adenocarcinoma in the United States: a population-based analysis

BackgroundAnal adenocarcinoma is rare with no standardized treatment regimen or staging system. Therefore, different combinations of chemotherapy, radiation, and surgery are used in management. Within the staging system, tumor stage can be based on the depth of invasion, as for rectal adenocarcinoma, or size, as in anal squamous cell carcinoma. This study aimed to analyze patterns of care and clinically available staging systems for anal adenocarcinoma using a national database. MethodsAdults diagnosed with anal adenocarcinoma were identified in the Surveillance, Epidemiology, and End Results database (2004–2019). In addition, 6 different treatment regimens were identified. Stages were categorized according to the American Joint Committee on Cancer classifications of rectal adenocarcinoma and anal squamous cell carcinoma. ResultsOf 1040 patients, 48% were female, the median age was 67 years, and 18% had distant metastases. Chemoradiotherapy + abdominoperineal resection was the most common treatment regimen (22%). Moreover, 5-year overall survival (OS) and disease-specific survival (DSS) were the highest for local excision only (67% and 85%) and the lowest in the alternative group (34% and 48%). After adjustment, the treatment groups that did not include surgery were associated with worse 5-year OS. In multivariable analysis, the T stage based on depth of invasion showed incrementally lower OS for T2 and T3 anal adenocarcinomas. ConclusionOmission of surgical resection in combination with chemoradiotherapy was associated with worse OS and DSS, suggesting the relevance of surgery in anal adenocarcinoma management. Prognostically, rectal staging based on depth of invasion better discriminated between T stages, indicating that providers should consider using this system in practice.

Stereotactic radiotherapy for advanced canine anal sac adenocarcinoma: an exploratory study.

For dogs with anal sac adenocarcinoma (ASAC), metastasis to intra-abdominal and pelvic lymph nodes occurs early in the disease course. Death is usually related to locoregional progression. Surgical excision is the treatment of choice, but may not be possible in advanced cases. Dogs treated with RT in the gross disease setting showed a 38%-75% overall response rate, but side effects to organs at risk in this area (especially the colon, bladder, and spinal cord) were reported. Stereotactic radiation therapy (SRT) utilizes highly conformal treatment planning with rapid dose fall-off and hypofractionation. SRT may help to reduce the risk of late side effects of radiation while also creating a larger biological effect on ASACs. A primary aim of this prospective, descriptive, exploratory study was to describe the safety and feasibility of an SRT protocol in a small sample of dogs with ASAC, using objective and subjective measures to monitor acute and late side effects. A secondary aim was to describe the anti-tumor response of the SRT protocol using CT at 3- and 6 months posttreatment. Five dogs completed the radiation protocol. Four had follow-up CT characteristics of complete response (1), partial response (2), and stable disease (1). Minimal acute side effects were observed. Despite some large tumor volumes, constraints for OAR were achieved in all but the spinal cord for one patient. Findings indicated that SRT is a safe and feasible treatment for dogs with ACAC. Future studies are warranted to compare patient outcomes for SRT versus other treatments.

Spotlight on capecitabine for the treatment of unresectable or metastatic carcinoma of various origin: A retrospective study of 25 dogs.

Capecitabine, the oral prodrug of 5-fluorouracil, is indicated in people to treat various malignant epithelial cancers. In dogs, capecitabine has not been extensively evaluated. The aim of this retrospective study was to investigate toxicity and preliminary efficacy of single agent capecitabine in dogs with advanced malignant epithelial cancers of any site, for which no effective therapy existed, conventional treatment failed or was declined. Capecitabine was administered orally at 750 mg/m2 from day 1 to 14, followed by 1-week rest period, given as 3-week cycles. Safety evaluation was performed after 2 cycles, and every 2-3 cycles thereafter. Tumour response was determined every 2-3 cycles. Twenty-five dogs with hepatocellular carcinoma (n = 6), lung papillary carcinoma (n = 4), anal sac adenocarcinoma (n = 3), colic adenocarcinoma (n = 2), and other individually represented epithelial cancers (n = 10) were included. Dogs received a median of 4 cycles (range, 2-43) for a median of 84 days (range, 42-913). Toxicity occurred in 17 (68.0%) dogs; the most frequent adverse events were gastrointestinal, with the majority being self-resolving and of mild grade. Of the 22 dogs with macroscopic disease, 3 (13.6%) achieved partial remission, 16 (72.7%) were stable and 3 (13.6%) progressed; overall clinical benefit rate was 86.4%. Median progression-free interval was 93 days (95% CI 42-154; range, 1-521) and median tumour-specific survival was 273 days (95% CI 116-482; range 45-913). These findings suggest that capecitabine is an attractive option for the treatment of several types of carcinomas in dogs. Prospective studies are warranted to optimize the scheduling of capecitabine and confirm its efficacy.