Lubricant use during intercourse and time to pregnancy: a prospective cohort study.

OBJECTIVE: To assess the extent to which lubricant use during intercourse is associated with time to pregnancy (TTP). DESIGN: Prospective cohort study. SETTING: Denmark and North America. POPULATION: A total of 6467 women aged 18-49 years who were not using contraception or fertility treatment. METHODS: We pooled data from two continuing prospective cohort studies of pregnancy planners in Denmark (2011-2017) and North America (2013-2017). Female participants completed bimonthly questionnaires for 12 months or until they reported pregnancy. After restricting the study to women without a history of infertility who had been trying to conceive for six or fewer cycles at enrollment, 6467 women were retained for analysis. Self-reported lubricant use was categorised as water-based/not pH balanced, water-based/pH balanced 'fertility friendly', silicone-based, oil-based, or a combination of these. We used proportional probability models to calculate fecundability ratios (FRs) and 95% confidence intervals (95% CIs) for the association between lubricant use and fecundability, after adjusting for cohort and sociodemographic and lifestyle factors. MAIN OUTCOME MEASURE: Fecundability. RESULTS: At baseline, 17.5% of participants reported the use of lubricants, most commonly water-based/not pH balanced (11.4%). Compared with non-use of lubricants, FRs were 1.02 (95% CI 0.93-1.11) for water-based/not pH-balanced lubricant use, 1.01 (95% CI 0.86-1.18) for water-based/pH balanced 'fertility friendly' lubricant use, 1.23 (95% CI 0.94-1.61) for oil-based lubricant use, and 1.27 (95% CI 0.93-1.73) for silicone-based lubricant use. Associations between oil-based lubricant use and fecundability were inconsistent across subgroups of study cohort, age, parity, and intercourse frequency. CONCLUSIONS: Lubricant use was not associated with reduced fecundability in the preconception cohorts of pregnancy planners studied. TWEETABLE ABSTRACT: Lubricant use during intercourse was not associated with time to pregnancy in a study of pregnancy planners.

Caffeine and caffeinated beverage consumption and risk of spontaneous abortion.

STUDY QUESTION: Is caffeine and caffeinated beverage consumption associated with the risk of spontaneous abortion (SAB)? SUMMARY ANSWER: While preconceptional caffeine consumption was not materially associated with an increased risk of SAB, consumption during early pregnancy was associated with a small increased risk of SAB, although the relation was not linear. WHAT IS KNOWN ALREADY: Caffeine has been hypothesized as a risk factor for SAB since the 1980s; however, results from previous studies have been conflicting. STUDY DESIGN, SIZE, DURATION: This prospective cohort study included 5132 Danish women planning pregnancy and enrolled from 2007 to 2010. PARTICIPANTS/MATERIALS, SETTING, METHODS: Participants were women who conceived after entry into the Snart-Gravid cohort and who were aged 18-40, in a stable relationship with a male partner, and did not use fertility treatments to conceive. Women reported their daily caffeine and caffeinated beverage consumption on questionnaires before conception and during early pregnancy. All exposure measurements were prospective with respect to outcome ascertainment. We estimated hazard ratios (HRs) of SAB for categories of caffeine consumption in milligrams (mg) per day and the corresponding 95% confidence intervals (CIs) using Cox proportional hazards regression models with gestational weeks as the time scale. MAIN RESULTS AND THE ROLE OF CHANCE: There were 732 women (14.3%) who were identified as having a SAB. In the preconceptional period, caffeine consumption was not materially associated with SAB risk (HR comparing ≥300 with <100 mg/day: 1.09; 95% CI: 0.89, 1.33). In early pregnancy, the HRs for 100-199, 200-299 and ≥300 mg/day of caffeine consumption were 1.62 (95% CI: 1.19, 2.22), 1.48 (95% CI: 1.03, 2.13) and 1.23 (95% CI: 0.61, 2.46), respectively, compared with that for <100 mg/day. LIMITATIONS, REASONS FOR CAUTION: The observed results may be affected by non-differential exposure misclassification, reverse causation and residual confounding. WIDER IMPLICATIONS OF THE FINDINGS: This is the largest study to date of prospectively measured, preconception caffeine consumption and risk of SAB. We were able to reduce the likelihood of differential left truncation bias and recall bias present in other analyses. STUDY FUNDING/COMPETING INTERESTS: Snart-Gravid was funded by the NICHD (R21-050264). Dr. Hahn's work was funded in part by the BU Reproductive, Perinatal, and Pediatric Epidemiology Training Grant NIH #T32HD052458. There are no competing interests.

A tumor-related lymphoid progenitor population supports hierarchical tumor organization in canine B-cell lymphoma.

BACKGROUND: Tumors have heterogeneous properties, which could be explained by the existence of hierarchically and biologically distinct tumor cells such as tumor-initiating cells (TICs). This model is clinically important, as TICs are promising targets for cancer therapies. However, TICs in spontaneous B-cell lymphoma have not been conclusively identified. HYPOTHESIS/OBJECTIVES: Tumor cells with a progenitor phenotype exist in B-cell lymphoma, reflecting a hierarchical organization. ANIMALS: Twenty-eight client-owned dogs with previously untreated B-cell lymphoma and 6 healthy dogs. METHODS: This was a prospective study. Flow cytometry was used to identify lymphoid progenitor cells (LPCs) that coexpressed hematopoietic progenitor antigens CD34, CD117, and CD133, with lymphoid differentiation markers CD21 and/or CD22 in B-cell lymphoma. The polymerase chain reaction for antigen receptor rearrangements was used to analyze clonality and relatedness of tumor populations. A xenograft model with NOD/SCID/IL-2Rγ(-/-) mice was adapted to expand and serially transplant primary canine B-cell lymphoma. RESULTS: LPCs were expanded in lymph nodes from 28 dogs with B-cell lymphoma compared with 6 healthy dogs (P= .0022). LPCs contained a clonal antigen receptor gene rearrangement identical to that of the bulk of tumor cells. Canine B-cell lymphoma xenografts in recipient mice that maintained LPCs in the tumors were recurrently observed. CONCLUSIONS AND CLINICAL IMPORTANCE: These results suggest the presence of a hierarchy of tumor cells in B-cell lymphoma as has been demonstrated in other cancers. These findings have the potential to impact not only the understanding of lymphoma pathogenesis but also the development of lymphoma therapies by providing novel targets for therapy.

Recommended guidelines for the conduct and evaluation of prognostic studies in veterinary oncology.

There is an increasing need for more accurate prognostic and predictive markers in veterinary oncology because of an increasing number of treatment options, the increased financial costs associated with treatment, and the emotional stress experienced by owners in association with the disease and its treatment. Numerous studies have evaluated potential prognostic and predictive markers for veterinary neoplastic diseases, but there are no established guidelines or standards for the conduct and reporting of prognostic studies in veterinary medicine. This lack of standardization has made the evaluation and comparison of studies difficult. Most important, translating these results to clinical applications is problematic. To address this issue, the American College of Veterinary Pathologists' Oncology Committee organized an initiative to establish guidelines for the conduct and reporting of prognostic studies in veterinary oncology. The goal of this initiative is to increase the quality and standardization of veterinary prognostic studies to facilitate independent evaluation, validation, comparison, and implementation of study results. This article represents a consensus statement on the conduct and reporting of prognostic studies in veterinary oncology from veterinary pathologists and oncologists from around the world. These guidelines should be considered a recommendation based on the current state of knowledge in the field, and they will need to be continually reevaluated and revised as the field of veterinary oncology continues to progress. As mentioned, these guidelines were developed through an initiative of the American College of Veterinary Pathologists' Oncology Committee, and they have been reviewed and endorsed by the World Small Animal Veterinary Association.

Dose-titration effects of fish oil in osteoarthritic dogs.

BACKGROUND: Food supplemented with fish oil improves clinical signs and weight bearing in dogs with osteoarthritis (OA). OBJECTIVE: Determine whether increasing the amount of fish oil in food provides additional symptomatic improvements in OA. ANIMALS: One hundred and seventy-seven client-owned dogs with stable chronic OA of the hip or stifle. METHODS: Prospective, randomized clinical trial using pet dogs. Dogs were randomly assigned to receive the baseline therapeutic food (0.8% eicosopentanoic acid [EPA] + docosahexaenoic acid [DHA]) or experimental foods containing approximately 2- and 3-fold higher EPA+DHA concentrations. Both veterinarians and owners were blinded as to which food the dog received. On days 0, 21, 45, and 90, serum fatty acid concentrations were measured and veterinarians assessed the severity of 5 clinical signs of OA. At the end of the study (day 90), veterinarians scored overall arthritic condition and progression of arthritis based on their clinical signs and an owner interview. RESULTS: Serum concentrations of EPA and DHA rose in parallel with food concentrations. For 2 of 5 clinical signs (lameness and weight bearing) and for overall arthritic condition and progression of arthritis, there was a significant improvement between the baseline and 3X EPA+DHA foods (P=.04, .03, .001, .0008, respectively) but not between the baseline and the 2X EPA+DHA foods. CONCLUSIONS AND CLINICAL IMPORTANCE: Increasing the amount of fish oil beyond that in the baseline food results in dose-dependent increases in serum EPA and DHA concentrations and modest improvements in the clinical signs of OA in pet dogs.

Masitinib is safe and effective for the treatment of canine mast cell tumors.

BACKGROUND: Activation of the KIT receptor tyrosine kinase is associated with the development of canine mast cell tumors (MCT). HYPOTHESIS/OBJECTIVE: To evaluate the efficacy of masitinib, a potent and selective inhibitor of KIT, in the treatment of canine MCT. ANIMALS: Two hundred and two client-owned dogs with nonmetastatic recurrent or nonresectable grade II or III MCT. METHODS: Double-blind, randomized, placebo-controlled phase III clinical trial. Dogs were administered masitinib (12.5 mg/kg/d PO) or a placebo. Time-to-tumor progression (TTP), overall survival, objective response at 6 months, and toxicity were assessed. RESULTS: Masitinib increased overall TTP compared with placebo from 75 to 118 days (P = .038). This effect was more pronounced when masitinib was used as first-line therapy, with an increase in the median TTP from 75 to 253 days (P = .001) and regardless of whether the tumors expressed mutant (83 versus not reached [P = .009]) or wild-type KIT (66 versus 253 [P = .008]). Masitinib was generally well tolerated, with mild (grade I) or moderate (grade II) diarrhea or vomiting as the most common adverse events. CONCLUSIONS AND CLINICAL IMPORTANCE: Masitinib is safe and effective at delaying tumor progression in dogs presenting with recurrent or nonresectable grade II or III nonmetastatic MCT.

Prophylactic trimethoprim-sulfadiazine during chemotherapy in dogs with lymphoma and osteosarcoma: a double-blind, placebo-controlled study.

BACKGROUND: The administration of chemotherapy is associated with risk for morbidity. Management of chemotherapy-related morbidity in veterinary oncology has been primarily supportive. HYPOTHESIS: The purpose of this study was to evaluate the effect of prophylactic antimicrobial use on chemotherapy-associated morbidity in dogs with lymphoma or osteosarcoma. ANIMALS: Dogs presenting with histologically confirmed osteosarcoma or lymphoma were eligible. METHODS: Patients were randomized to receive placebo or trimethoprim-sulfadiazine for 14 days after their first doxorubicin chemotherapy. Both owner and clinician were blinded with respect to treatment. Patient assessment included CBC, physical examination and performance, and toxicosis grading on days 7 and 14. Investigated outcomes were hospitalization, suspicion of infection, gastrointestinal toxicity, neutropenia, nonhematologic toxicity, and quality of life. RESULTS: Seventy-three dogs were enrolled; 34 had osteosarcoma, and 39 had lymphoma. Dogs receiving trimethoprim-sulfadiazine (n = 36) had a significantly reduced hospitalization rate (P = .03), nonhematologic toxicity (P = 0.039), grade 2-4 nonhematologic toxicity (P < .0001), grade 2-4 gastrointestinal toxicity (P = .007). and altered performance (P = .015). By group, dogs with osteosarcoma (n = 34) that received the antimicrobial experienced fewer occurrences of nonhematologic toxicity (P = .02) and less severe nonhematologic toxicity (P = .038). Dogs with lymphoma (n = 39) had significant reductions in the occurrence of hospitalization (P = .035), severity of nonhematologic toxicity (P = .036), and alterations of performance (P = .015). CONCLUSIONS: The use of prophylactic trimethoprim-sulfadiazine has benefit in reducing morbidity in dogs with osteosarcoma or lymphoma during the first 14 days after treatment with doxorubicin.

Ultrasonographic and cytopathological diagnosis of exocrine pancreatic carcinoma in the dog and cat.

This study describes the ultrasonographic and cytopathological characteristics of malignant neoplasms of the exocrine pancreas and their value in making an antemortem diagnosis. The medical records of eight dogs and five cats were reviewed. The clinical presentations were variable and at times mimicked pancreatitis. Overall, cytopathology of ultrasound or fluoroscopic-guided biopsies or fine-needle aspirates, or impressions from surgical biopsies were helpful in establishing the diagnosis in 10 of 12 animals where it was performed. Histopathology of ultrasound or fluoroscopic-guided biopsies provided a diagnosis in five of six cases where it was performed.

Risk factor analysis for breast cellulitis complicating breast conservation therapy.

Women who undergo breast conservation therapy for early-stage breast cancer can develop breast cellulitis, a complication for which risk factors are undefined. A matched case-control investigation was conducted to identify risk factors for the development of breast cellulitis among patients who have undergone breast conservation therapy. Patients comprised 17 patients with cases of breast cellulitis diagnosed after partial mastectomies that had been performed from 1992 through 1997 and 34 control patients who were matched to case-patients by date of breast lumpectomy and by primary surgeon. Statistical analyses indicated the following factors were associated with breast cellulitis: drainage of a hematoma (P=.010); postoperative ecchymosis (P=.021); lymphedema (odds ratio [OR], 10. 154; 95% confidence interval [CI], 1.348-208.860); resected breast tissue volume (OR, 1.456; 95% CI, 1.035-2.168); and previous number of breast seroma aspirations (OR, 3.445; 95% CI, 1.036-19.771). This is the first matched case-control study to identify risk factors for the development of breast cellulitis after breast conservation therapy.

Direct action by doxycycline against canine osteosarcoma cell proliferation and collagenase (MMP-1) activity in vitro.

BACKGROUND: Matrix metalloproteinases (MMPs) produced by tumor cells disrupt the integrity of the extracellular matrix (ECM). Inhibiting MMPs activity could significantly reduce tumor invasion and metastasis. MATERIALS AND METHODS: Canine osteosarcoma (OSA) cells were exposed to doxycycline in vitro to determine whether this chemically modified tetracycline had antiproliferative and anticollagenolytic activity. RESULTS: Doxycycline significantly reduced cell proliferation in a dose dependent manner. Doxycycline at the doses of 5 and 10 micrograms/ml suppressed cell number 50% and 72%, respectively. Furthermore, doxycycline significantly reduced collagenase activity at the doses of 10 and 20 micrograms/ml by 35% and 50%, respectively. OSA cells did not produce any endogenous collagenase in the culture medium. CONCLUSIONS: This study has shown that doxycycline at doses greater than 5 micrograms/ml in vitro significantly decreases cell proliferation and collagenase (MMP-1) activity. Prospective studies should be conducted to determine if doxycycline, a chemically modified tetracycline with low systemic toxicity, has specific anti-collagenase activity in vivo. Our studies indicate that canine osteosarcoma represents a suitable model for additional in vitro and in vivo studies.

The use of colonic irrigation to control fecal incontinence in dogs with colostomies.

OBJECTIVE: To determine if once-daily colonic irrigation results in fecal continence for a 24-hour period in dogs with colostomies and if colonic volume increased in response to the irrigation. STUDY DESIGN: A prospective controlled experimental study. ANIMALS: Four intact male and one intact female mixed breed dogs. MATERIALS: All dogs received left end-on paralumbar colostomies. Four dogs received once-daily colonic irrigation for 8 weeks, whereas the control dog did not. Daily fecal weights were recorded for the length of the study in all dogs. Barium enema studies and volumetric studies were used to determine colonic volumes. RESULTS: Daily fecal weights were significantly decreased in treatment dogs compared with the control dog. Colonic volume increased in irrigated dogs in response to daily irrigation over the 8 week period of the study. CONCLUSIONS: Colonic irrigation resulted in significantly decreased fecal production over a 24-hour period. Therefore management of dogs with colostomies would be more practical and cost effective. It did not result in complete fecal continence in this study. Further clinical studies are indicated to determine if longer periods of irrigation would result in complete continence.

Detection and clinical significance of plasma glutathione-S-transferases in dogs with lymphoma.

BACKGROUND: The objective of this study was to determine if glutathione-S-transferases were detectable in the plasma of dogs and to determine if concentrations of the a- and pi-subtypes were related with tumor response to single agent anthracycline (e.g., doxorubicin) chemotherapy in dogs with lymphoma. MATERIALS AND METHODS: Plasma was obtained from 10 healthy, normal dogs and from 11 dogs with lymphoma before treatment, 3 weeks after 1 dose of doxorubicin and every 3 weeks thereafter until relapse (the physical detection of recurrent and enlarged peripheral lymph nodes). Plasma concentration of alpha and pi-GST was determined by use of an ELISA technique with well plates pre-coated with IgG[anti-Canine alpha-GST or anti-Human pi-GST]. RESULTS: Mean plasma alpha-GST concentrations did not significantly decline after 1 dose of doxorubicin chemotherapy; however, mean plasma alpha-GST concentrations were markedly increased (p < 0.05) at the time of relapse (the physical detection of recurrent and enlarged peripheral lymph nodes). CONCLUSIONS: In this study we show that a relationship exists between the plasma alpha-GST concentration and the clinical response of dogs with lymphoma to doxorubicin chemotherapy.

Right leg muscle atrophy and osteopenia caused by renal adenocarcinoma in a cockatiel (Melopsittacus, undulatus).

A 7-year-old cockatiel presented with a 1 week history of right leg lameness. A renal adenocarcinoma invading and constricting the right ischiatic nerve resulted in disuse atrophy of the affected leg and radiographic evidence of osteopenia. This report illustrates the natural behavior, radiographic, and pathologic appearance of malignant renal tumors in birds.

Serum alpha 1-acid glycoprotein concentrations before and after relapse in dogs with lymphoma treated with doxorubicin.

OBJECTIVE: To determine whether serum alpha 1-acid glycoprotein (AGP) concentration was a useful marker of relapse in dogs with lymphoma that were in clinical remission following treatment with doxorubicin. DESIGN: Cohort study. ANIMALS: 12 dogs with lymphoma and 10 healthy dogs. PROCEDURE: Serum AGP concentration was measured in the healthy dogs and in the dogs with lymphoma before treatment, 3 weeks after the first dose of doxorubicin was administered, and every 3 weeks thereafter until relapse (i.e., recurrence of clinically detectable disease such as palpable enlargement of peripheral lymph nodes). Serum AGP concentrations were determined by use of a radial immunodiffusion kit. RESULTS: Mean serum AGP concentration in healthy dogs was significantly less than concentration in dogs with lymphoma prior to treatment. Mean serum AGP concentrations after the first and each subsequent dose of doxorubicin were not significantly different from concentration in healthy dogs. However, mean serum AGP concentrations 3 weeks prior to and at the time of relapse were significantly higher than concentration measured after the first dose of doxorubicin, and were not significantly different from concentration measured before treatment. CLINICAL IMPLICATIONS: Results suggest that measuring serum AGP concentration may be a useful method of predicting relapse before recurrence of clinically detectable disease in dogs with lymphoma undergoing treatment with doxorubicin.

Unusual metastatic behavior and clinicopathologic findings in eight cats with cutaneous or visceral hemangiosarcoma.

Eight cats with visceral or cutaneous hemangiosarcoma were evaluated, and unusual metastatic and clinicopathologic behavior was evident in each. Cutaneous hemangiosarcoma is generally believed to be locally aggressive and slow to metastasize. These 8 cats with cutaneous hemangiosarcoma, however, developed metastatic disease after initial surgical resection; only 1 had local regrowth of the tumor. All cats with visceral hemangiosarcoma had metastasis at the time of diagnosis, which is consistent with cats of other reports. Three of 8 cats had evidence of disseminated intravascular coagulation, including increased prothrombin time and partial thromboplastin time, decreased number of platelets, and anemia. These potential complications need to be considered when planning diagnostic and treatment protocols.

Inhibitors of intracellular chloride regulation induce cisplatin resistance in canine osteosarcoma cells.

The objective of this study was to examine the role of ion transport mechanisms in clinical anticancer drug resistance. Reduction in intracellular accumulation of cisplatin is believed to be an early change in cisplatin-resistant cells, and may be dependent on the concentration of intracellular chloride (Cl-) ions and intracellular pH. The primary aim of this study was to describe the modifying effects of NHMA (5-N,N hexamethylene; amiloride), a Na+/H+ antiport inhibitor, and/or SITS (4-acetamido-4';isothiocyanostilbene-2,2'-disulfonic acid), a HCO3-/Cl- transport inhibitor, in bicarbonate-containing or bicarbonate-free media on cisplatin (cis-diamminedichloroplatinum(II); CDDP) toxicity between known cisplatin-sensitive (COS31) and cisplatin-resistant (COS31/rCDDP) canine osteosarcoma cells. This study has shown that cell survival can be influenced by the inhibition of the Na(+)-dependent HCO3-/Cl- exchanger using SITS. The addition of SITS increases the intracellular Cl- concentration in canine osteosarcoma cells cultured in a bicarbonate-containing media. In a bicarbonate-free media, the addition of SITS results in a decrease in the cytotoxic action of cisplatin.

Unusual presentation of an Amazon parrot (Amazona species) with hepatocellular carcinoma.

Non-haematopoietic hepatic malignancies are uncommon in birds. The clinical presentation (i.e. chronic buphthalmos)and non-specific radiographic findings observed in this adult Amazon parrot (Amazona spp.) were not consistent with previous reports describing the natural behaviour of metastatic hepatocellular carcinoma in birds.

An in vivo/in vitro experimental model system for the study of human osteosarcoma: canine osteosarcoma cells (COS31) which retain osteoblastic and metastatic properties in nude mice.

BACKGROUND: In this report we describe the establishment, characterization, and research utility of a cell line derived from a dog having a spontaneously occurring osteosarcoma. MATERIALS AND METHODS: Tumor samples were collected from a dog with a naturally occurring osteosarcoma and processed for light microscopy, electron microscopy, immunocytochemistry, immunohistochemistry, karyology, and cell culture. Established cells from passage 31 (COS31; canine Qsteosarcoma cells from passage 31) were inoculated subcutaneously between the scapula and in the right abdominal side of athymic nude mice and evaluated similarly. RESULTS: COS31 cells derived in cell culture and in nude mice had morphological and biochemical properties comparable in all respects to the original canine tumor specimen. CONCLUSIONS: The ability of COS31 cells to produce tumors in nude mice (i.e. a small animal model) typical of canine osteosarcoma (i.e. a large animal model) with a similar pathological and biological behavior (e.g. alkaline phosphatase and osteocalcin positive immunostaining, osteoid production, rapid growth, and wide spread metastases) demonstrates the potential utility of COS31 cells as a in vitro and in vivo model system in the development of new strategies in the treatment of human osteosarcoma.

In vitro reversal of glutathione-S-transferase-mediated resistance in canine osteosarcoma (COS31) cells.

BACKGROUND: In this report we describe the establishment, characterization, and research utility of a cell line derived from a dog having a spontaneously occurring osteosarcoma (COS) made resistant to the cytotoxic effects of cisplatin chemotherapy. MATERIALS AND METHODS: Established cells from passage 31 (COS31) were exposed to increasing sublethal concentrations of cisplatin in vitro. RESULTS: A 2.2-fold increase in glutathione-S-transferase (GST) activity was found to be induced in this cell line (COS31/rCDDP) compared to parent cells. Furthermore, these cells were 7.8-fold more resistant to the cytotoxic effects of higher concentrations of cisplatin compared to parent cells. Ethacrynic acid was found to inhibit GST enzymatic activity and increase cisplatin cytotoxicity in resistant COS31 (COS31/rCDDP) cells. CONCLUSIONS: Inhibiting the function of GST with ethacrynic acid pretreatment in humans and dogs with osteosarcoma may result in more tumor cells than normal cells killed in vivo by cisplatin, thus significantly prolonging lifespan without increasing host toxicity.

Prognosis factors for survival in cats after removal of a primary lung tumor: 21 cases (1979-1994).

OBJECTIVE: To identify possible prognostic factors for survival time in cats with a primary lung tumor after surgical excision. STUDY DESIGN: Retrospective clinical study. ANIMAL POPULATION: 21 cats with histologically confirmed primary lung tumors removed surgically. METHODS: Medical records for cats treated between 1979 and 1994 at 14 participating veterinary referral hospitals were reviewed. RESULTS: After surgical resection and recovery, 18 cats died from metastatic disease with a median survival time of 115 days (range, 13 to 1,526 days). Three cats were lost to follow-up at 119 days, 251 days, and 410 days after the surgical procedure. Contingency table analysis to determine if an association existed between clinical findings (breed, age, gender, body weight, clinical signs, duration of clinical signs, and radiographic findings) or histological features and survival time was performed. Only histological morphology of the primary lung tumor showed a significant association with survival time. Twelve cats with moderately differentiated tumors had a significantly longer survival time (median, 698 days; range, 19 to 1,526 days) than the nine cats with poorly differentiated tumors (median, 75 days; range, 13 to 634 days). CONCLUSIONS: Surgical resection of a solitary primary lung tumor in cats is indicated. CLINICAL RELEVANCE: A poor prognosis for long-term survival is warranted for those cats having a poorly differentiated primary lung tumor.