Comparison between de novo and metachronous metastatic breast cancer: the presence of a primary tumour is not the only difference-a Dutch population-based study from 2008 to 2018.

PURPOSE: The aim of this study was to compare characteristics and survival of patients with de novo and metachronous metastatic breast cancer. METHODS: Data of patients with metastatic breast cancer were obtained from the Netherlands Cancer Registry. Patients were categorized as having de novo metastatic breast cancer (n = 8656) if they had distant metastases at initial presentation, or metachronous metastatic disease (n = 2374) in case they developed metastases within 5 or 10 years after initial breast cancer diagnosis. Clinicopathological characteristics and treatments of these two groups were compared, after which multiple imputation was performed to account for missing data. Overall survival was compared for patients treated with systemic therapy in the metastatic setting, using Kaplan Meier curves and multivariable Cox proportional hazards models. The hazard ratio for overall survival of de novo versus metachronous metastases was assessed accounting for time-varying effects. RESULTS: Compared to metachronous patients, patients with de novo metastatic breast cancer were more likely to be ≥ 70 years, to have invasive lobular carcinoma, clinical T3 or T4 tumours, loco-regional lymph node metastases, HER2 positivity, bone only disease and to have received systemic therapy in the metastatic setting. They were less likely to have triple negative tumours and liver or brain metastases. Patients with de novo metastases survived longer (median 34.7 months) than patients with metachronous metastases (median 24.3 months) and the hazard ratio (0.75) varied over time. CONCLUSIONS: Differences in clinicopathological characteristics and survival between de novo and metachronous metastatic breast cancer highlight that these are distinct patients groups.

Time-varying prognostic value of primary tumor sidedness in metastatic colorectal cancer: A population-based study and meta-analysis.

We studied the prognostic value of primary tumor sidedness in metastatic colorectal cancer over time and across treatment lines. Population data on synchronous metastatic colorectal cancer patients were extracted from the Netherlands Cancer Registry and SEER database. Pubmed, EMBASE and Cochrane library were searched for prospective studies on metastatic colorectal cancer to conduct a meta-analysis. Inclusion criteria consisted of metastatic disease, systemic treatment with palliative intent and specification of primary tumor location. Data were pooled using a random-effects model. For the population-based data, multivariable Cox models were constructed. The Grambsch-Therneau test was conducted to evaluate the potential time-varying nature of sidedness. Meta-regression incorporating treatment-line as variable was conducted to test the pre-specified hypothesis that the prognostic value of sidedness varies over time. Analysis of 12 885 and 16 160 synchronous metastatic colorectal cancer patients registered in the Netherlands Cancer Registry and SEER database, respectively, indicated a time-varying prognostic value of sidedness (P < .01). Thirty-one studies were selected for the meta-analysis (9558 patients for overall survival analysis). Pooled univariable hazard ratioleft-sided/right-sided for overall survival was 0.71 (95% CI: 0.65-0.76) in 1st-line, 0.76 (0.54-1.06) in 2nd-line and 1.01 (0.86-1.19) in 3rd-line studies. Hazard ratios were significantly influenced by treatment line (P = .035). The prognostic value of sidedness of the primary tumor in metastatic colorectal cancer patients treated with palliative systemic therapy decreases over time since diagnosis, suggesting that sidedness may not be a useful stratification factor in late-line trials. This decrease in prognostic value should be taken into account when providing prognostic information to patients.

Sixty-Day Mortality of Patients With Metastatic Colorectal Cancer Randomized to Systemic Treatment vs Primary Tumor Resection Followed by Systemic Treatment: The CAIRO4 Phase 3 Randomized Clinical Trial.

Importance: The role of primary tumor resection (PTR) in synchronous patients with metastatic colorectal cancer (mCRC) who had unresectable metastases and few or absent symptoms of their primary tumor is unclear. Studying subgroups with low postoperative mortality may identify patients who potentially benefit from PTR. Objective: To determine the difference in 60-day mortality between patients randomized to systemic treatment only vs PTR followed by systemic treatment, and to explore risk factors associated with 60-day mortality. Design, Setting, and Participants: CAIRO4 is a randomized phase 3 trial initiated in 2012 in which patients with mCRC were randomized to systemic treatment only or PTR followed by systemic treatment with palliative intent. This multicenter study was conducted by the Danish and Dutch Colorectal Cancer Group in general and academic hospitals in Denmark and the Netherlands. Patients included between August 2012 and December 2019 with histologically proven colorectal cancer, unresectable metastases, and a primary tumor with few or absent symptoms were eligible. Interventions: Systemic treatment, consisting of fluoropyrimidine-based chemotherapy with bevacizumab vs PTR followed by fluoropyrimidine-based chemotherapy with bevacizumab. Main Outcomes and Measures: The aim of the current analysis was to compare 60-day mortality rates in both treatment arms. A secondary aim was the identification of risk factors for 60-day mortality in the treatment arms. These aims were not predefined in the study protocol. Results: A total of 196 patients were included in the intention-to-treat analysis (112 [57%] men; median [IQR] age, 65 [59-70] years). Sixty-day mortality was 3% (95% CI, 1%-9%) in the systemic treatment arm and 11% (95% CI, 6%-19%) in the PTR arm (P = .03). In a per-protocol analysis, 60-day mortality was 2% (95% CI, 1%-7%) vs 10% (95% CI, 5%-18%; P = .048). Patients with elevated serum levels of lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, and/or neutrophils who were randomized to PTR had a significantly higher 60-day mortality than patients without these characteristics. Conclusions and Relevance: Patients with mCRC who were randomized to PTR followed by systemic treatment had a higher 60-day mortality than patients randomized to systemic treatment. Especially patients randomized to the PTR arm with elevated serum levels of lactate dehydrogenase, neutrophils, aspartate aminotransferase, and/or alanine aminotransferase were at high risk of postoperative mortality. Final study results on overall survival have to be awaited. Trial Registration: ClinicalTrials.gov Identifier: NCT01606098.

Role of Up-Front Primary Tumor Resection and Tumor Sidedness in the Survival of Synchronous Metastatic Colon Cancer Patients.

INTRODUCTION: Uncertainty exists about a possible survival benefit of primary tumor resection (PTR) in synchronous metastatic colon cancer (mCC). Since sidedness of the primary tumor is regarded as an important prognostic factor, our objective was to study the interaction between PTR and sidedness in synchronous mCC. METHODS: In this retrospective study, we used data from 2 first-line phase 3 randomized controlled trials (RCTs). A mixed Cox regression model was used to study the multiplicative interaction between PTR and sidedness. We adjusted for age, treatment arm, WHO performance status, number of affected organs by metastases, serum lactate dehydrogenase, and year of enrollment. RESULTS: We found that PTR is associated with better survival in both right-sided (hazard ratio [HR] 0.59 [95% confidence interval 0.42-0.8 2]) and left-sided mCC (HR 0.70 [95% confidence interval 0.52-0.93]). The interaction between PTR and sidedness was not significant (p = 0.45). CONCLUSION: Our data suggest that the prognostic value of PTR is independent of sidedness. Validation of these results will be performed in ongoing RCTs.

Interaction Between Primary Tumor Resection, Primary Tumor Location, and Survival in Synchronous Metastatic Colorectal Cancer: A Population-Based Study.

OBJECTIVES: Location of the primary tumor has prognostic value and predicts the effect of certain therapeutics in synchronous metastatic colorectal cancer. We investigated whether the association between primary tumor resection (PTR) and overall survival (OS) also depends on tumor location. METHODS: Data on synchronous metastatic colorectal cancer patients from the Netherlands Cancer Registry (n=16,106) and Surveillance, Epidemiology, and End Results (SEER) registry (n=19,584) were extracted. Cox models using time-varying covariates were implemented. Median OS for right-sided colon cancer (RCC), left-sided colon cancer, and rectal cancer was calculated using inverse probability weighting and a landmark point of 6 months after diagnosis as reference. RESULTS: The association between PTR and OS was dependent on tumor location (P<0.05), with a higher median OS of upfront PTR versus upfront systemic therapy in Netherlands Cancer Registry (NCR) of 1.9 (95% confidence interval: 0.9-2.8), 4.3 (3.3-5.6), and 3.4 (0.6-7.6) months in RCC, left-sided colon cancer and rectal cancer, respectively. In SEER data, the difference was 6.0 (4.0-8.0), 8.0 (5.0-10.0), and 10.0 (7.0-13.0) months, respectively. Hazard plots indicate a higher hazard of death 2 to 3 months after PTR in RCC. CONCLUSION: Upfront PTR is associated with improved survival regardless of primary tumor location. Patients with RCC appear to have less benefit because of higher mortality during 2 to 3 months after PTR.

The Impact of Primary Tumor Location in Synchronous Metastatic Colorectal Cancer: Differences in Metastatic Sites and Survival.

PURPOSE: We explored differences in survival between primary tumor locations, hereby focusing on the role of metastatic sites in synchronous metastatic colorectal cancer (mCRC). METHODS: Data for patients diagnosed with synchronous mCRC between 1989 and 2014 were retrieved from the Netherlands Cancer registry. Relative survival and relative excess risks (RER) were analyzed by primary tumor location (right colon (RCC), left colon (LCC), and rectum). Metastatic sites were reported per primary tumor location. Survival was analyzed for metastatic sites combined and for single metastatic sites. RESULTS: In total, 36,297 patients were included in this study. Metastatic sites differed significantly between primary tumor locations, with liver-only metastases in 43%, 54%, and 52% of RCC, LCC, and rectal cancer patients respectively (p < 0.001). Peritoneal metastases were most prevalent in RCC patients (33%), and lung metastases were most prevalent in rectal cancer patients (28%). Regardless of the location of metastases, patients with RCC had a worse survival compared with LCC (RER 0.81, 95% CI 0.78-0.83) and rectal cancer (RER 0.73, 95% CI 0.71-0.76). The survival disadvantage for RCC remained present, even in cases with metastasectomy for liver-only disease (LCC: RER 0.66, 95% CI 0.57-0.76; rectal cancer: RER 0.84, 95% CI 0.66-1.06). CONCLUSIONS: This study showed significant differences in relative survival between primary tumor locations in synchronous mCRC, which can only be partially explained by distinct metastatic sites. Our findings support the concept that RCC, LCC and rectal cancer should be considered distinct entities in synchronous mCRC.