# I. Introduction olorectal cancer is the second leading cause of death in Spain and up to 20% is diagnosed in an advanced stage, normally with hepatic or lung metastasis. Brain metastases are an uncommon complication of colorectal cancer (1.8-5% of all BM), even more unusual in the beginning (<1%). Overall survival(OS) after diagnosis of BM is 2.6 to 7.4 months. However, we try to perform metastesectomies whenever possible. We submit a rare case whith unique frontal brain metastases of rectal adenocarcinoma without affecting other organs. Emphasize on a multidisciplinary approach to achieve a prolonged survival. # II. Case Presentation A 61 year-old woman, with no personal previous history who debut with dizziness, gait disturbance and memory loss. Performance Status 1. Occasional bleeding tools. No fever. First of all, brain CT showed a single lesion in left frontal lobe, so she was admitted to complete the study. To better qualify the lesion, brain MRI showed the same nodule, suggesting a metastasic disease (figure 1). As digestive disorders were recent too, colonoscopy was the third test: mass occupying lesión 100% of the circumference and medium rectum location. PA: lowgrade colorectal adenocarcinoma. (figure 2) CT chest-abdom-pelvis: no further disease. Pelvis MRI: 7cm tumor from anal margin. # Clinical statage: cT3N1M1 (single brain metastasis). According to give a treatment with a curative intention, Tumor Committee decided brain surgery followed by short course rectal RT and low anterior resection (LAR). # III. Differential Diagnosis Approaching to a brain lesion discovered with no previous recent trauma, bleeding or halo images suggesting infection or abscess; first possibilities are malignancies and the most frequent ones are lymphoma, metastasis and astrocytoma / glioblastoma multiforme. Less common are ependymoma, tumors of the pineal gland or choroid plexus. In primary malignancies with brain metastases such as melanoma, lung, kidney or thyroid, brain lesions bleeding would be usual and MRI should be hyperintense on T2 lesion if bleeding was within 6 hours or hypointense on T2 if bleeding was after 24 hours. Central view for MRI is hyperintense with abscess, while in the tumor is hypointense. Definitive diagnosis is based on histology, and when the lesion is technically resectable, surgery resection must be performed with intraoperative confirmation. # IV. Treatment # Digestive Tumor Committee decided neurosurgery because it was an unique and resectable lesion (10.09.2013). Performance Status 1. Definitive Histological diagnosis was a 3.1 x 2.2 x 2 cm metastasis of colorectal adenocarcinoma (CK20 +, CK7 -and CEA +) with extensive tumor necrosis. Microscopical surgical margin affected. Adjuvant treatment was mFOLFOX6 + Bevacizumab x 3 cycles and final toxicity was diarrhea and neuropathy. CT showed no signs of tumor recurrence at the end of treatment on 24/09/14. Actually Performance Status 0 and no neurologic symptoms. # Volume XVII Issue 1 Version I # Outcome and Follow-Up More than 26 months of DFS and more than 36 months of OS. # V. Discussion Initial presentation as cerebral involvement is unusual, being 1-4% the incidence of brain metastases associated to colorectal cancer. According to Ko Chu Fang, 3773 patients with colorectal cancer were reviewed, which 37 (1.03%) developed metastases between 1970 and 1996. 55% had a solitary lesion while 45% were multiple. Regarding location, 62% were in temporoparietal lobes, 13% in cerebellum, 13% cerebellum and cerebrum, 8% frontal lobe and 4% in posterior fossa brain. Rectal origin occurs in 56.4%. [1] This case is unusual in rectal cancer disease because of the synchronous diagnosis and absence of metastatic disease in other organs (liver and lung as usual). In Kye series, 39 patients presented with colorectal brain metastases, 79.5% presented with pulmonary metastases and only 1% as an exclusive involvement in brain. [2] In E Magni serie of 41 patients, 4.9% did not involve other extracranial metastatic locations [3] Diagnosis of brain metastases appear after a mean of 36 +/-19 months and diagnosis of colorectal cancer in 77% of reported cases, with just a remaining 23% present in the beginning. In E Magni serie, 17.1% was synchronous too. According to the treatment, a literature review only describes very few cases treated with radiosurgery, being this indication increasing in those patients with multiple lesions <35 mm, minimum mass effect and affected margins. Results in NCCTG N0574 (Alliance) demonstrated better OS and quality of life with radiosurgery + RT [4]. Recently, a literature review of 80 patients with brain metastasis reported OS of 6 months in patients who recevied gamma knife radiosurgery (22 patients), 3 months in whole radiotherapy and 13 months in 10 patients on gamma knife + whole radiotherapy. [5] Among a serie of 41 patients (E Magni) OS after diagnosis of brain metastases was 5 months: 4.2 months in patients treated with radiotherapy (29.3%), 11. 9 months in those with radio and chemotherapy (21.9 %),and 21.4 months in those with surgery +/-radio or chemotherapy ( 29.3%). We emphassyze our case with OS 24 months, never published. Also, prognostic factors in colorectal cancer has been studied to determine the best therapeutic approach. KRAS mutated patients use to present more common pulmonary and CNS involvement (62 and 56.5%), and liver metastasis are less common. [6]. Regarding primary tumor treatment, Shin et al published the results of RT short course schedule (5 days x 5 Gy) and it seems to be effective in local control and "down-staging" with 85% R0 resections. [7,8] However, when hepatic progression is demonstrated, chemo is the preferred treatment. Adam showed a survival benefit after surgery in liver tumors in response, however this benefit was lower in progression disease. In the case, we decided initially neoadjuvant CT (ESMO Guidelines) with Bevacizumab (KRAS mutated) (Cairo-2, ARTIST): 45-55% RR, PFS 9-12 months. [9,10,11]. As a partial response was achieved after chemo and liver resection was feasible too, liver surgery was performed because of the impact on survival. [12] And our last point: chemo maintenance? OPTIMOX trial showed no difference in survival compared to maintenance treatment until progression, so both options are a good idea and depends on the tolerabilty and performance status of each patient [13] Learning Points/Take Home Messages ? Debut of rectal cancer with synchronous single and unique frontal brain metastasis is unusual. ? Overall survival in brain metastases from colorectal cancer is less than 6 months; achieving with Figure Captions![up to 11 months in literature and in our case >24 months. ? Differential diagnosis of single brain lesion by image is inconclusive. Definitive diagnosis can be achieved with surgery. ? Radical surgery treatment of metastatic brain lesion improves prognosis and quality of life. Thinking in isolated brain metastasis as oligometastasic disease. ? In this case we demostrate liver progression with PET-CT. This technique is useful for surgical decisions. ? Overall survival > 2 years from the debut despite poor prognostic factors (KRAS mutated, brain and liver metastases). ? Benefit of multidisciplinary approach.](image-2.png "") 123![Figure 1: Unique frontal brain metastases](image-3.png "Figure 1 :Figure 2 :Figure 3 :") RT of primary tumor including pelvis and rectumin short course 5 sessions of 5Gy and subsequent LARwas accomplished on 25/11/13.Definitive Histological diagnosis: rectumadenocarcinoma ypT4b N2a (4/39) L0V1 R1 (radialmargin) Wild KRAS type and mutated NRAS.Because of surgery infection, no possible"adjuvant" chemo. As brain margin affected and nochance of chemo, radiosurgery treatment in CentralNervous System (total dose of 35 Gy) was completedfrom 02/05/14 to 02/17/14.PET-CT reassessment at 2 months (figure 3):liver metastatic spread in both lobes (Sg II 6 mm, 19 mm Sg III, VIII 7 mm Sg, Sg V 20 mm) without other evidence of disease.Year 2017Not seen in previous CT, probably present.Performance Status 1. Chemotherapy treatmentmFOLFOX6 +D D D D ) F( © 2017 Global Journals Inc. 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