Watch and Wait Strategy for Rectal Cancer: How Long Should We Wait for a Clinical Complete Response?

BACKGROUND: The objective of this study was to determine how long to wait in locally advanced rectal tumor (LARC) patients who receive total neoadjuvant therapy (TNT) and achieve a clinical complete response (cCR), and to identify the clinical parameters that affect the waiting period for the watch-and-wait strategy (W &W). MATERIALS AND METHODS: The data of patients who achieved cCR between February 2015 and June 2020 were examined retrospectively. The week in which patients with cCR at the end of TNT achieved clearance was determined by reanalyzing recorded endoscopy video images. In the assessment at the time of the initial diagnosis, tumor characteristics, such as digital rectal examination findings, MRI stage, location with respect to the puborectalis muscle, annularity, and tumor size, were recorded prospectively. RESULTS: A total of 54 patients were included in this study. According to the MRI-T stage, 14 cases were cT3a, 22 were cT3b, and 18 were cT3c-T4. Forty-four percent of the cases achieved cCR at 8-10 weeks, 19% at 12-16 weeks, 20% at 16-22 weeks, and 17% at 20-26 weeks. Patients with tumors that were early MRI-T stage (cT3a), negative clinical circumferential resection margin, mobile, small (≤4 cm), located above the puborectalis muscle and showed <180 degrees annularity achieved cCR significantly earlier than those with other tumors (p<0.05). CONCLUSION: In this study, cCR was achieved in less than half (44%) of the cases during the 8-10 week waiting period. In the W&W strategy, the initial assessment for cCR seems insufficient, and we may need to wait up to 26-30 weeks, especially in patients with advanced-stage tumors.

Optical coherence tomography parameters as predictors of treatment response to a 577-nm subthreshold micropulse laser in chronic central serous chorioretinopathy.

To determine the relation between retinal microstructural changes and the response to 577-nm subthreshold micropulse laser (SML) treatment in chronic central serous chorioretinopathy (cCSC). This retrospective study included 39 eyes of 39 patients with cCSC, treated with the 577-nm SML. The eyes were evaluated in three groups: complete remission, partial remission, and failure groups. The presence of some baseline retinal microstructural changes, thickness of the outer nuclear layer (ONL), status of the ellipsoid zone (EZ), and retinal pigment epithelium (RPE) were evaluated. The changes in central macular thickness (CMT), subretinal fluid (SRF) height, and best-corrected visual acuity (BCVA) were calculated. There were 14, 13, and 12 eyes in the complete remission, partial remission, and failure group, respectively. The baseline EZ and RPE were found intact in 71.4% and 64.3% of the eyes in the complete remission group, respectively; however, these rates were respectively 25% and 16.7% in the failure group (p < 0.05). Extrafoveal foci were present in 35.7% of the eyes in the complete remission group, but none was found in the failure group (p < 0.05). Although there was no statistically significant difference, the baseline ONL thickness was higher, and the hyperreflective dots, retinal bumps, subretinal fibrinous exudates, and PEDs were seen less in the complete remission group. The changes of the BCVA were not significant in any of the groups at the last visit (p > 0.05). The presence of baseline intact EZ and RPE, and extrafoveal foci can potentially be used as predictors of the SML treatment success in cCSC.

Comparison of the efficacy and safety of anti-VEGF monotherapy versus anti-VEGF therapy combined with subthreshold micropulse laser therapy for diabetic macular edema.

The purpose of this study is to compare the efficacy and safety of 577-nm subthreshold micropulse laser (SML) and intravitreal bevacizumab injection (IVB) combined therapy with IVB monotherapy in the treatment of diabetic macular edema (DME). This retrospective study included 80 eyes of 80 patients; 40 eyes were treated with IVB monotherapy, and 40 eyes were treated with SML-IVB combined therapy. The mean number of required IVB injections and changes of best corrected visual acuity (BCVA) and central macular thickness (CMT) values were compared between the groups. The mean age of the patients was 60.19±7.43 years. The baseline characteristics of the patients were similar between the groups. In the SML-IVB combined group, the mean number of required SML sessions was 2.1±0.81. The mean number of required IVB injections was 4.38±0.81 in the SML-IVB combined group and 5.65±1.51 in the IVB monotherapy group (p<0.05). The increase of the BCVA was significant in the SML-IVB combined group at the 3rd, 6th, 9th, and 12th months; however, in the IVB monotherapy group, it was only significant at the 3rd month (p<0.05). The mean CMT values of the 3rd, 9th, and 12th months were similar between the groups (p>0.05); only at the 6th month was it significantly lower in the SML-IVB combined group (p<0.05). When compared with baseline, the decrease of the CMT was statistically significant in both groups at the 3rd, 6th, 9th, and 12th months (p<0.05). In this study, a significant benefit of adding SML to IVB therapy was found with less IVB need, although a very significant increase in BCVA could not be achieved. The use of SML-IVB combined treatment may be an effective and safe alternative for DME.

Efficacy and safety of iris-supported phakic lenses (Verisyse) for the treatment of high myopia: 5-year results.

PURPOSE: Evaluating efficacy and safety of iris-supported phakic lenses (Verisyse) for high myopia treatment. METHODS: Patients treated with Verisyse (Abbott Medical Optics, Santa Ana, CA, USA) intraocular lens (IOL) implants were evaluated retrospectively. Patients with follow-up periods of more than 5 years were included in the study. Pre- and postoperative fifth-year spheric equivalent (SE) of manifest refraction values, uncorrected and corrected distance visual acuities (UDVA and CDVA, respectively), and endothelial cell density (ECD) values were recorded. Complications were evaluated. RESULTS: Forty-seven eyes of 31 patients were included in the study. Pre- and postoperative fifth year mean SE was - 12.50 ± 3.51D and - 0.72 ± 0.40D, respectively. Pre- and postoperative fifth-year UDVA was 1.56 ± 0.22 and 0.33 ± 0.18 logMAR (p < 0.001), respectively. The safety index (pre- and postoperative CDVA) was 1.39 ± 0.63 at the 5-year follow-up (p > 0,05). The efficacy index (ratio of mean postoperative UDVA to mean preoperative CDVA) of the patients was 1.14 ± 0.60. The mean postoperative endothelial cell loss at 5 years was -7.42%. None of the patients had lost 25% of their preoperative endothelial cells at 5-year follow-up. The mean postoperative endothelial cell loss was -3.05% at 1 year, -1.23% between years one and three, -1.02% between the third and fifth years. CONCLUSION: Verisyse IOL implantation is an effective and safe for high myopia surgical treatment. However, the 5-year follow-up period is not sufficient to evaluate the safety profiles in terms of endothelial cells.

Treatment of intravitreal bevacizumab combined with focal laser photocoagulation in the case of macular telangiectasia type 2 with retinal arterial macroaneurysm.

Macular telangiectasia type 2 (Mac Tel 2) is a bilateral disease of unknown cause with characteristic changes of the retinal vasculature. To the best of our knowledge, we could not find any reported cases of Mac Tel 2 with retinal arterial macroaneurysm (RAM). Our aim is to report a case of Mac Tel 2 with RAM.

Treatment of intravitreal bevacizumab combined with focal laser photocoagulation in the case of macular telangiectasia type 2 with retinal arterial macroaneurysm.

Macular telangiectasia type 2 (Mac Tel 2) is a bilateral disease of unknown cause with characteristic changes of the retinal vasculature. To the best of our knowledge, we could not find any reported cases of Mac Tel 2 with retinal arterial macroaneurysm (RAM). Our aim is to report a case of Mac Tel 2 with RAM.

Prognostic value of ocular trauma score for open globe injuries associated with metallic intraocular foreign bodies.

BACKGROUND: The prognostic value of the ocular trauma score (OTS) in patients who underwent 23-gauge pars plana vitrectomy (23-G PPV) for surgical removal of posterior segment metallic intaocular foreign bodies (IOFB) was evaluated. METHODS: Patients who underwent 23-G PPV for surgical removal of retained metallic IOFBs were retrospectively analyzed. OTS score for each patient was calculated and raw scores were converted to their corresponding OTS categories. The final VAs in study patients were compared with their respective OTS categories. RESULTS: Twenty-five eyes from 25 patients were examined. Twenty-four (96%) of the patients were male, and the mean age was 34 ± 12 years. The time from injury to 23-G PPV was 9 ± 4 days. Fourteen (56%) patients had zone 1 trauma, eight (32%) patients had zone 2 trauma, and three (12%) patients had zone 3 trauma. Postoperative visual acuity was ≥ 20/200 in 14 (56%) of the patients and ≥ 20/40 in seven (28%) eyes. At the final visit, anatomical success was achieved in 86% of patients with retinal detachment at presentation. No statistically significant differences were found between our final VAs and OTS scores. CONCLUSION: OTS, which provides prognostic information after general ocular trauma, may also provide valuable prognostic information for patients who undergo 23-G PPV for the surgical removal of metallic posterior segment IOFBs.

Trichomegaly Induced by Cetuximab: Case Series and Review the Literature.

Trichomegaly is a rare side effect of epidermal growth factor receptor inhibitors. We present here 4 patients who treated with cetuximab (an epidermal growth factor receptor inhibitor) for metastatic colorectal cancer. All of the cases were treated with cetuximab 500 mg/m biweekly in combination protocol. The mean period from the start of the treatment until the development the trichomegaly was 4.75 (3-6) months. In all of the patients after the end of the cetuximab therapy, trichomegaly was regressed. Only 1 case resolved with topical treatment that conjunctivitis with trichomegaly. Trichomegaly is an important ocular toxicity of cetuximab that can cause visual discomfort and corneal damages. However, these side effects usually do not require discontinuation of treatment.

Dramatic Response to Catumaxomab Treatment for Malign Ascites Related to Renal Cell Carcinoma With Sarcomotoid Differentiation.

Refractory malignant ascites (MA) is a common complication in cancer patients. Renal cell carcinoma (RCC) is rarely present with peritoneal ascites, which is commonly associated with carcinomas of the gastrointestinal and female reproductive tracts; including especially ovarian high-grade serous carcinoma. Currently, chemotherapy and paracentesis represent the most widely used methods to relieve the symptoms. Recently, intraperitoneal therapy with catumaxomab-a trifunctional hybrid antibody-has been introduced for the treatment of MA. The benefit of this treatment has been demonstrated in patients with distinct abdominal malignancies. In this case report, we present the first case of successful catumaxomab treatment against MA in a patient with advanced RCC with sarcomatoid differentiation. After the second administration of catumaxomab, paracentesis became no longer necessary. Catumaxomab might represent a safe treatment option for MA in the course of metastatic RCC with sarcomatoid differentiation.

Clinical and pathological characteristics and their effect on survival in elderly patients with gastrointestinal stromal tumors.

PURPOSE: Gastrointestinal stromal tumors (GISTs) are common tumors of the gastrointestinal tract. Their most frequent location is the stomach. Although the clinical and pathological characteristics of the disease are well-known, the clinical and pathological characteristics and the response to treatment are not clear in elderly patients. The purpose of this study was to evaluate the characteristics of GISTs in elderly patients with an aim at improving the therapeutic methodology and survival. METHODS: In this study, clinicopathological characteristics, evaluation of treatments administered and survival analyses were performed in patients aged 65 years or above, whose data were registered via a web-based patient records system following admission to three centers. RESULTS: A total of 85 patients aged 65 years or above were included in the study. According to the risk classification, 24 (28.2%) were in the low risk group, 20 (23.5%) in the moderate risk group, and 41 (48.3%) in high risk group, while no patient was in the very low risk group. At baseline, 70% of the patients had localized disease and 30% metastatic disease. The tumor was located in the stomach in the majority of the patients (45.6%). The tumor size most commonly seen was 5-10 cm (N=31; 36.4%). Of the 85 patients 23 (27%) were treated with imatinib 400 mg/d. Eight patients (9.4%) with metastatic disease switched from imatinib to sunitinib. At a median follow-up of 76 months (range 1-323), median overall survival (OS) was 72 months, without significant difference between elderly and younger patients. CONCLUSION: Clinicopathological characteristics and their prognostic impact on the disease course of elderly GIST patients should be elucidated in depth. Since age didn't show prognostic importance, other parameters should be used as prognostic/predictive factors in the tyrosine kinase inhibitors era in order to obtain improved therapeutic results.

Prognostic relevance of sunitinib toxicities and comparison of continuous vs. intermittent sunitinib dosing schedule in metastatic renal cell cancer patients.

AIM OF THE STUDY: Sunitinib-related side effects may develop as a result of the pharmacokinetic pathway affects the of the drug. MATERIAL AND METHODS: Data on mRCC patients were obtained from the hospital archives. Outcomes of patients were evaluated in terms of related prognostic factors, sunitinib adverse events during the treatment, and two different sunitinib dosing schedules. RESULTS: Seventy patients diagnosed with mRCC and treated with sunitinib were analyzed for prognostic factors and survival rates. During the mean follow-up of 33.5 months, 38 (54%) patients were alive and 32 (46%) patients died. The median time of overall survival (OS) and progression-free survival (PFS) was 27 months (12-61) and 19 months (5-45), respectively. In univariate analysis, good prognostic risk group according to the Memorial Sloan-Kettering Cancer Center (MSKCC), hypothyroidism as sunitinib toxicity and patients on sunitinib treatment more than 1 year were favorable prognostic factors for OS. Leukopenia and fatigue as sunitinib toxicity were poor prognostic factors for OS. PFS and OS of the patients were not significantly different when we compared intermittent (4/2) vs. continuous treatment dosing schedules. CONCLUSIONS: As a result of this trial, having hypothyroidism as an adverse effect of sunitinib was a favorable prognostic factor for OS and PFS in mRCC patients. It was also found that 4/2 and continuous dosing schedules of sunitinib did not give rise to different outcomes in mRCC patients.

Epidermal growth factor receptor in CRC patients in the era of the RAS.

The aim of this study was to investigate EGFR expression patterns and the effect of EGFR expression on stage, prognosis and response to conventional chemotherapy agents other than monoclonal antibodies in CRC patients. This study included 59 metastatic CRC patients. The expression of EGFR was quantified by immunochemistry in biopsy specimens that were obtained before treatment was initiated. The cases were considered to be positive for EGFR if >1% of the tumor cells had complete circumferential membranous staining. The median age of the patients was 54.6 years, and 59% of the patients were male. Twenty-six patients presented with stage IV disease, and the remaining patients developed distant metastasis during follow-up. Fifty-one patients were treated with regimens containing irinotecan. The numbers of patients with EGFR expression in the primary tumors, the metastatic lymph nodes and the normal colonic tissue were 34 (65.4%), 10 (76.9%) and 34 (65.4%) respectively. The initial disease stage and lymph node stage were correlated with EGFR expression (p<0.05). Additionally, EGFR positivity was correlated with a statistically significant reduction in the response rate to chemotherapy, the overall survival (21 vs. 28 months) and the progression-free survival (15 vs. 22 months) in metastatic patiens treated with chemotherapy other than targeted therapies. In conclusion, EGFR expression in correlated with stage in all CRC patients and response to chemotherapy and survival in metastatic CRC patients.

The Evaluation of Relationship Between Body Mass Index and Nasal Geometry Using Objective and Subjective Methods.

INTRODUCTION: It is known that obesity causes obstructive sleep apnea syndrome by increasing upper airway resistance. Also, obese patients are admitted to the ear, nose, and throat clinic very often because of nasal obstruction complaint. The aim of this study is to identify the change and relation among body mass index (BMI), nasal resistance, reduction in nasal ariflow, nasal anatomy, and patients' subjective complaints. MATERIAL AND METHOD: A total of 67 patients admitted to our clinic between August 2013 and January 2014 were included in the study.The study group comprised 33 patients who had a chief complaint-nasal obstruction and the other group consisted of 34 patients who had no complaint and nasal pathology. Both the groups were checked with acoustic rhinometry (AR), active anterior rhinomanometer, nasal obstruction symptom evaluation (NOSE), and visual analog study (VAS) questionnaire. RESULTS: There is a significant statistical correlation between the body mass increase and VAS and NOSE score increase (P < 0.05). But the authors did not find any statistically significant relation between BMI and total inspiratory and expiratory MR and MF measured by anterior active rhinomanometer and left and right nasal cavity MCA, and volume measured by acoustic rhinometery (P > 0.05). CONCLUSIONS: Contrary to belief, obesity does not change the nasal resistance, airflow, and anatomy but it can cause subjective nasal complaints.

Cutaneous melanoma in Turkey: analysis of 1157 patients in the Melanoma Turkish Study.

PURPOSE: To develop a large Turkish National Melanoma registry in order to define demographic and clinicopathologic characteristics of patients with melanoma. METHODS: The data was collected from 1635 patients with melanoma through a web-based registry system in 22 centers. Herein we present the results of 1157 patients with cutaneous melanoma. RESULTS: The patient median age was 56.4 years and 646 (55.8%) were males. The commonest subtype was superficial spreading type (357, 30.9%). The commonest primary site was the lower extremities (N=353, 30.5%). The most common Breslow thickness was 1-2 mm (361 patients, 43.5%). Only 104 (12.5%) patients had a thickness <1mm. Among 694 patients with available data, 136 (19.6%) presented with stage 4 disease while the most frequent stage was stage 3, encountered in 393 (56.6% patients). CONCLUSION: Our melanoma registry is the largest in our country providing a snapshot view of cutaneous melanoma and its care. Our patients presented with more advanced stages and they had worse prognosis compared to SEER database.

Analysis of resected gastric cancer in Turkish population.

BACKGROUND/AIMS: Gastric cancer is still an important health issue in Eastern Europe and Middle East, including Turkey, although its prevalence is decreasing in the western world. METHODOLOGY: In order to define the profiles of the patients operated with a diagnosis of gastric cancer in Turkey, a multicenter retrospective study was conducted. RESULTS: Six hundred and forty-eight of the 840 patients with complete data in all parameters were included in the analysis. The median follow-up time was 17.16 months (range, 6-143.63 months). Mean age was 57 +/- 11.7 (19-85). There was a recurrent disease in 42% of the tumors located at cardia, corpus or antrum, and 86% of diffuse tumors (p < 0.0001). The ratio of patients with recurrent disease was greater in stage III and IV tumors There were also greater recurrence ratios in patients with node positive (pN1-3) patients than pN0 tumors, and pT3-4 tumors than pT1 or pT2 tumors. Any recurrence was found in 48% of the tumors with lymphovascular invasion, while in 39% without lymphovascular invasion (p = 0.026). A statistically significant difference was found in the recurrence status of patients with positive/dissected node ratio of < 10% and > or = 10% (p < 0.0001). CONCLUSIONS: Gastric cancer cases in Turkey are seen at a younger age, and at a higher stage. Proximal gastric cancer is seen much less than the western series. Prognostic significance of lymphovascular invasion in both univariate, and multivariate analyses is noteworthy.

End-of-study results of Turkish gastric cancer patients from the global REGATE study.

PURPOSE: Registry of Gastric Cancer Treatment Evaluation (REGATE) study was an international, prospective study including over 10000 patients from 22 countries, designed to describe the pattern of care in gastric cancer globally. The aim of this study was to summarize the data of the Turkish arm and compare them with the global results. METHODS: Ten centers from Turkey took part in the REGATE registry. Between 2004 and 2008, 395 patients (median age, 60 years; range, 18-91, 67.6% men) with newly diagnosed primary adenocarcinoma of the stomach were followed at initial visit and 8-10 months later, at the time of treatment completion. Data on patient demographics, medical history, histopathology, cancer stage, planned and realized treatments was prospectively collected. Data processing and analysis were conducted centrally. RESULTS: In Turkey, the majority of patients were diagnosed at an advanced stage, while the rate of surgery was lesser compared with the rest of the world. Realized treatment included more palliative-only therapy than initially planned (63.3%), while no therapy was recommended in 21.8%. Surgery involved total gastrectomy (46.3%) or distal subtotal gastrectomy (51.9%), with 87% R0 resection, 51.0% D1 and 44.9% D2 lymph node dissection. Combination chemotherapy was administered in more than half of the patients receiving palliative therapy (57.9%). Chemoradiotherapy was used in 66.7% of the cases receiving adjuvant therapy. Radiotherapy was applied to 32% of the cases receiving palliative therapy. CONCLUSION: Advanced stage gastric cancer is highly prevalent in Turkey. Increasing public awareness and implementing screening programs in high risk groups may help identify gastric cancer at earlier stages.

Brucella infection presenting as infective endocarditis complicated by embolic stroke.

Brucellosis (undulant fever) is a zoonotic infection caused by Brucella species. It typically presents with fever, malaise, night sweats, and arthralgia. One of its rare complications is infective endocarditis, which occurs in approximately 1.3% of patients and can be further complicated by embolic stroke. This report describes a rare occurrence of Brucella endocarditis presenting as an embolic stroke. A 34-year-old male presented with sudden left-sided weakness and fever. He reported headaches, fever, and generalized weakness in the preceding week. The patient worked on a farm and hence had animal contact. A neurological exam showed left-sided facial weakness, and power of 0/5 and 1/5 in the left upper and lower extremities, respectively. CT scan of the head revealed a right middle cerebral artery (MCA) territory infarct with penumbra and a right MCA occlusion. He underwent a cerebral artery thrombectomy with successful recanalization. However, he continued to have fever and high inflammatory markers. Echocardiography showed aortic valve vegetation and blood cultures grew Brucella melitensis. A multidisciplinary meeting was held to determine the optimal management, which included a course of rifampicin and doxycycline.

Real-World Efficacy and Safety of First-Line Nivolumab Plus Chemotherapy in Patients with Advanced Gastric, Gastroesophageal Junction, and Esophageal Adenocarcinoma: A Nationwide Observational Turkish Oncology Group (TOG) Study.

Based on the CheckMate 649 trial, nivolumab plus chemotherapy is the recommended first-line treatment for HER2-negative unresectable advanced or metastatic gastric, gastroesophageal junction (GEJ), or esophageal adenocarcinoma. This nationwide, multicenter, retrospective study evaluated the real-world effectiveness of this regimen in Turkish patients and identified subgroups that may experience superior outcomes. Conducted across 16 oncology centers in Turkey, this study retrospectively reviewed the clinical charts of adult patients diagnosed with HER2-negative unresectable advanced or metastatic gastric, GEJ, or esophageal adenocarcinoma from 2016 to 2023. This study included 111 patients (54 women, 57 men) with a median age of 58 years. The median progression-free survival (PFS) and overall survival (OS) were 11.7 months and 18.2 months, respectively, whereas the objective response rate (ORR) was 70.3%. Multivariable analyses revealed that previous curative surgery was a favorable independent prognostic factor for both PFS and OS. Conversely, an Eastern Cooperative Oncology Group performance status of 2 emerged as an adverse independent prognostic factor for OS. The safety profile of nivolumab plus chemotherapy was found to be manageable. Our findings support the use of nivolumab plus chemotherapy for the first-line treatment of Turkish patients with HER2-negative unresectable advanced or metastatic gastric, GEJ, or esophageal adenocarcinoma. Patient selection based on clinical characteristics is crucial for optimizing treatment outcomes.

A randomized, double-blind, placebo-controlled study to assess QTc interval prolongation of standard dose aflibercept in cancer patients treated with docetaxel.

: The effect of repeated doses of aflibercept on ventricular repolarization in cancer patients was evaluated in an intensive electrocardiogram trial. This randomized, placebo-controlled, double-blind trial was conducted in 87 treated solid tumor patients. Treatment was with 6 mg/kg aflibercept, 1-hour intravenous (n = 43), or placebo (n = 44), combined with ≤75 mg/m docetaxel, every 3 weeks. Electrocardiograms were collected for 6 hours posttreatment using digital 12-lead Holter recorders, at day 1, in cycles 1 and 3. Free and vascular endothelial growth factor-bound aflibercept concentrations were assessed at similar time points. Eighty-four patients (43 placebo and 41 aflibercept) were evaluable for QT interval, Fridericia correction (QTcF) at cycle 1 and 59 (31 placebo and 28 aflibercept) at cycle 3. During cycle 3, from 30 minutes to 6 hours after the start of aflibercept, the maximum observed upper limit of the QTcF 90% confidence interval was 16 ms, for a mean of 8.4 ms. QTcF prolongation above 480 ms and 60 ms above baseline was observed in 1 aflibercept patient (2%). The slope of the relationship between free aflibercept concentration and QTcF was 0.048 (95% confidence interval, 0.013-0.082), corresponding to a 5-ms increase per 100 µg/mL increase in concentration. These results exclude a clinically important effect of aflibercept on ventricular repolarization.

Serum thymidine kinase 1 levels correlates with FDG uptake and prognosis in patients with non small cell lung cancer.

CONTEXT: TK1 found to be elevated biomarker in many solid cancers. OBJECTIVES: The study aimed to assess the prognostic significance of a serum TK1 in patients with metastatic NSCLC. METHODS: The study included 48 consecutive patients, newly diagnosed with metastatic NSCLC, and 10 healthy volunteers. Serum TK1 activity determined by ELISA method. RESULTS: Patients with a bTK1 level >156 Du L(-1) had significantly shorter survival. TK1 level showed a strong correlation with primary tumor SUV(max). DISCUSSION AND CONCLUSION: The magnitude of maximum fluorodeoxyglucose uptake in primary tumors and the serum TK1 level in patients with metastatic NSCLC were found to be independent prognostic predictors of overall survival.