脑癌或许并非起源于大脑

  仅有一般的脑癌开始于脑部，而其余的脑癌都是由来自机体其它部位的转移性肿瘤转移到脑部所致。近日来自宾夕法尼亚州赫尔希医疗中心的科学家通过研究发现，15%至30%的癌症患者都会在疾病发生的过程中在某个时间点发生癌症的脑部转移；肺癌和乳腺癌作为两大常见的癌症都有可能转移到脑部形成脑癌。
  一旦脑癌被发现，治疗就会因多种因素而改变，其中包括肿瘤位点、数量及尺寸、以及病人的疾病是否已经被控制等等。γ线刀放射外科手术是一种非侵入性门诊手术，其可以帮助医生通过以高剂量放射靶向作用肿瘤来治疗多种机体损伤，有时候外科手术也被用于移除大量的损伤，并且跟随γ线刀后进行治疗。
  Zacharia表示，这将是肿瘤管理的一次革命性进展，我们可以直接高效及高准确性地靶向作用许多小型难以触及的损伤；我们开发的新型疗法是一种激光消融术，其作为一种微创伤手术可以引导医生们对肿瘤进行小型激光治疗，并且利用激光产生的热量来直接靶向作用肿瘤，而且病人次日就可以回家休息。
  疾病严重且对疗法耐受的患者或许会因对大脑的连续辐射治疗而获益，因为连续辐射可以产生对认知损伤的副作用，而研究者告诉医生们你应当尽量避免对年轻患者进行这样的疗法。和治疗其它癌症不同，化疗通常对于脑癌并没有用，尤其是转移性的脑癌，因为存在保护大脑的血液屏障。
  神经胶质瘤和脑膜瘤是源于大脑的两种类型的肿瘤，神经胶质瘤主要位于大脑中，往往会从良性紧抓成为恶性，而脑膜瘤则是位于实际大脑物质外部的良性且发展缓慢的肿瘤。脑瘤并不总是许多人认为的死刑，目前研究者有最优良的技术，而且研究者们还在不断去研究探索来开发治疗多种脑癌的新型靶向性疗法。（转化医学网360zhyx.com）
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Only half of brain cancers actually start in the brain. The rest—as in the case of former President Jimmy Carter—are metastatic tumors from cancer that originated elsewhere in the body. 

Dr. Brad Zacharia, director of neuro-oncology and skull-base surgery at Penn State Hershey Medical Center, said between 15 and 30 percent of patients who have cancer will develop metastases to the brain at some point during the course of their disease.

Lung cancer and breast cancer—two of the most common cancers—are most likely to metastasize to the brain.

Once brain cancer is discovered, treatment varies based on a number of factors. Those include the location of tumors, the size and number of tumors, and how the patient's disease elsewhere in the body is being controlled.

"There is a lot to consider," Zacharia said.

When the cancer appears as a single lesion causing symptoms such as weakness or language confusion—and it is located in a place considered safe or accessible for surgery—surgical removal is often the best course of action.

Gamma knife radiosurgery is a noninvasive, outpatient procedure that allows doctors to treat a number of lesions in a single day by targeting the tumors with high doses of radiation. Sometimes, surgery is used to remove larger lesions and followed up with gamma knife radio surgery.

"This is really a revolution in the way these tumors are managed," Zacharia said. "We can directly target a multitude of small and difficult-to-access lesions with incredible accuracy and efficacy in a noninvasive way. In select cases, it has been shown to be equally as effective as surgery."

A new therapy just starting at Penn State Hershey is laser ablation, a minimally invasive surgery in which doctors guide a small laser into the tumor and use heat from the laser to target it directly. Patients go home the following day.

"It has been tolerated very well and can be used in difficult-to-access tumors or those that have undergone radiation and recurred," Zacharia said.

Patients who are very ill and cannot tolerate directed therapy—or who have many lesions in inaccessible locations—may benefit from general radiation to the brain. Because general radiation can produce cognitive side effects with time, Zacharia said doctors may try to avoid that course of treatment for younger patients.

"The targeted therapies have gotten so good that we are getting away from using that," he said.

Unlike other types of cancer, chemotherapy is not usually effective for brain tumors—especially metastatic ones—because of a blood barrier that protects the brain, Zacharia said.

The two types of tumors that originate in the brain are gliomas, which are inside the brain and can range from benign to malignant, and meningiomas, which are benign and slow-growing tumors outside the actual brain substance.

Zacharia said a brain tumor is not always the death sentence many people think it is. "We have good techniques and it's not as dire as people think," he said. "From a neurosurgery standpoint, we have gotten pretty good at managing these patients with our arsenal of therapies and advances."