RECIST（The Response Evaluation Criteria In Solid Tumors）標準是壹系列腫瘤治療效果的定義，即有效、穩定、無效。該標準最早於 2000 年由美國國家腫瘤研究所和加拿大國立腫瘤研究院制定（v1.0），2009 年經修訂再版（v1.1），目前已成為腫瘤治療評價標準的基石。
具體評價步驟為：1、基線期記錄目標病竈和非目標病竈；2、按照標準對目標病竈和非目標病竈進行評價；3、綜合進行總體評價
At baseline, tumour lesions/lymph nodes will be categorised measurable or non-measurable as follows:
Tumour lesions: Must be accurately measured in at least one dimension (longest diameter in the plane of measurement is to be recorded) with a minimum size of:
Malignant lymph nodes: To be considered pathologically enlarged and measurable, a lymph node must be ≥15 mm in short axis when assessed by CT scan (CT scan slice thickness recommended to be no greater than 5 mm). At baseline and in follow-up, only the short axis will be measured and followed.
可測量病竈舉例。A 64歲男性結腸癌患者胸部CT掃描。左下葉分葉狀結節，最長直徑2.5 cm，為轉移竈。B 75歲肺癌女性腹部CT掃描顯示肝臟轉移病竈，最長直徑2.1厘米。C 女性胸部正位片顯示最長直徑4.2厘米的腫塊(箭頭所指)，代表肺癌。
All other lesions, including small lesions (longest diameter <10 mm or pathological lymph nodes with ≥10 to <15 mm short axis) as well as truly non-measurable lesions.
Lesions considered truly non-measurable include: leptomeningeal disease, ascites, pleural or pericardial effusion, inflammatory breast disease, lymphangitic involvement of skin or lung, abdominal masses/abdominal organomegaly identified by physical exam that is not measurable by reproducible imaging techniques.
不可測量病竈舉例。A 52歲女性肺癌患者胸部CT掃描顯示肺內多處小於10毫米的小結節，這些結節為粟粒轉移。B 59歲女性乳腺癌患者肺基底部CT掃描顯示硬化性骨轉移。C 45歲男性胃癌患者腹部CT顯示大量腹水。D 70歲女性肺癌患者胸部CT顯示下葉小葉間隔及支氣管血管束不規則增厚;這些發現與肺癌的淋巴管播散相壹致。
非小細胞肺癌患者，使用 EGFR 抑制劑治療。A 患者治療前肺部 CT 顯示右肺占位，長徑 2.8 cm；B 圖為治療 1 周期後復查，病竈長徑縮小為 1.3 cm，減小 54%，因此是部分緩解（PR）（≥ 30%）；C 圖為再次復查，病竈長徑 1.7 cm，雖然較 B 圖 1.3 cm 增加 30%（≥ 20%），但變化長度絕對值小於 0.5 cm，因此仍為穩定（SD）；D 圖為再次復查，與治療後第壹次 B 圖比較，增加＞30%，長度超過 0.5 cm，為疾病進展（PD）
It is assumed that at each protocol specified time point, a response assessment occurs. Table 1 provides a summary of the overall response status calculation at each time point for patients who have measurable disease at baseline.
When patients have non-measurable (therefore non-target) disease only, Table 2 is to be used.
The best overall response is determined once all the data for the patient is known.
Best response determination in trials where confirmation of complete or partial response IS NOT required: Best response in these trials is defined as the best response across all time points (for example, a patient who has SD at first assessment, PR at second assessment, and PD on last assessment has a best overall response of PR).