有异常临床症状者应考虑患有癌症的可能，尤其是发现局部肿块者，结合实验室及影像学检查可辅助诊断癌症，但最终明确癌症的类型、分期等信息，需要依靠病理学检查。
癌症的症状多样，除可引起局部压迫和阻塞等症状外，还可因浸润和转移而导致相应的临床表现，有时会出现贫血、发热、体重下降、夜汗、感染、恶病质等全身表现。
A mutation from the mistake-correcting machinery of a cell could result in that cell and its young children to accumulate problems a lot more rapidly.
筛查规划仅对某些类型而非所有类型的癌症有效，而且一般来说，筛查规划比早期诊断复杂得多并需要更大量的资源，包括需要特殊设备和专门人员。即使建立了筛查规划，早期诊断规划也依然必要，以便查明那些发生在不符合筛查的年龄或风险因素标准的人群中的癌症病例。
[188] The performance of chemotherapy is usually limited by its toxicity to other tissues in the body. Even if chemotherapy doesn't provide a permanent get rid of, it may be practical to scale back signs and symptoms such as suffering or to reduce the dimensions of the inoperable tumor inside the hope that surgical procedure will become attainable Down the road.[citation necessary]
有多种类型，常见药物有利妥昔单抗、曲妥珠单抗、贝伐珠单抗、替吡法尼、伊马替尼、索拉非尼、舒尼替尼、血管抑素、硼替佐米等。
健康饮食。选择富含水果和蔬菜的饮食。选择全谷物和瘦肉蛋白质。限制摄入加工肉类。
多數癌症是自發性的（英语：sporadic），但是有些癌症還是與遺傳有關，通常遺傳到缺陷的腫瘤抑制基因時會有較顯著的影響和症狀。舉例而言：
如伴有局部感染可使用消炎药，与病毒感染相关者可使用抗病毒药物，癌性疼痛者可用阿片类镇痛药物等。
症状性癌症的早期诊断在所有环境中并且对大多数癌症都意义重大。癌症规划应旨在减少诊断、治疗和支持性护理方面的延误和障碍。
Environmental or Way of living variables that triggered most cancers to produce in an individual is usually recognized by examining mutational signatures from genomic sequencing of tumor DNA.
In The us and some other 癌症 cultures, cancer is thought to be a disease that needs to be "fought" to end the "civil insurrection"; a War on Most cancers was declared while in the US. Armed service metaphors are significantly prevalent in descriptions of cancer's human effects, and they emphasize the two the point out on the affected person's health and the necessity to take rapid, decisive steps himself rather then to delay, to disregard or to count entirely on Some others. The armed forces metaphors also assistance rationalize radical, destructive therapies.[242][243]
癌症复发。癌症幸存者有癌症复发的风险。有些癌症比其他癌症更容易复发。请咨询医生如何降低癌症复发的风险。治疗后，医生可能会为您设计一份随访护理计划。该计划可能包括在治疗后的几个月和几年里定期进行扫描和检查，以寻找癌症复发的迹象。
相反的，子宮頸抹片檢查在所有種類的癌症篩檢中則具有最好的成本效益。以公共衛生考量來看，子宮頸癌的病程發展通常十分緩慢，長達數年，又具有明顯的危險因子（性接觸），因此有相當高的機會可在癌症仍是早期時篩檢出來，最重要的是，抹片的成本很低，能夠大量推行。基於這些原因，一項癌症篩檢是否應該進行，民眾的健康改善程度和篩檢的成本與治療的風險都必須列入考慮。