September 26, 2023

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Evaluation index for clinical efficacy of solid tumors (RECIST1.1)

Evaluation index for clinical efficacy of solid tumors (RECIST1.1)

Evaluation index for clinical efficacy of solid tumors (RECIST1.1).  The therapeutic effect of tumors is an important content that doctors and patients pay attention to. This article makes a relevant inventory of the RECIST 1.1 version of the evaluation standard for the efficacy of solid tumors.

Evaluation index for clinical efficacy of solid tumors (RECIST1.1)

Baseline lesion classification

Measurable lesions

➤ Neoplastic lesions

At least one size that is not smaller than the lower limit (detected by the instrument) must be accurately measured; 10 mm in clinical testing is measured with a caliper (not measurable with a caliper); a lesion with a diameter greater than 10 mm is scanned with a CT scan ≤ 5 mm); 20 mm with chest X-ray

➤ Malignant lymph nodes

When using CT scan (CT scan thickness ≤ 5 mm): The short axis of the lymph node must be 15 mm before it can be considered pathologically enlarged and measurable. During preoperative and follow-up work, only the short axis length is measured and tracked. Note: (different from other measurable lesions using the longest axis as the diameter, the shortest axis is used as the diameter when measuring malignant tumor lymph nodes)

Unmeasurable lesions

✪ Small lesions with the longest diameter less than 10 mm or pathological lymph nodes with a short axis of 10 mm to less than 15 mm

✪ Really unmeasurable lesions: meningeal disease, ascites, pleural or pericardial effusion, inflammatory breast disease, etc. as determined by pathological examination (all cannot be measured by existing imaging techniques).

✪ Bone disease is an unmeasurable disease. The soft tissue components can be evaluated by CT or MRI, except those that meet the definition that can be evaluated at baseline.

✪ Tumor lesions located in the previously irradiated area or other localized treatment areas are usually not considered measurable unless it is proven that the lesion is still continuing.

When evaluating tumors, select lesions for measurement evaluation, and follow-up measurement in the follow-up process. These lesions are called target lesions. The lesions other than the target lesions are called non-target lesions. Non-target lesions have their own unique value in tumor evaluation.


Target lesion

In general, all measurable lesions should be regarded as baseline target lesions, and the longest diameter of each lesion should be recorded (the short axis of pathological lymph nodes should be recorded). The sum of the diameters of all target lesions at baseline (the longest diameter of non-lymph nodular lesions and the shortest axis of lymph node lesions) is the basis for the evaluation and comparison performed in the trial.

✪ If two lesions are fused, measure the fused mass; if the target lesion is split, use the sum of each part.

✪ The measurement of the smaller target lesion should continue to be recorded. The target lesion becomes too small to be measured. If the lesion is considered to have disappeared, it is recorded as 0 mm; otherwise, it should be recorded as the default value of 5 mm.

✪ If the lymph node shrinks to <10 mm (normal), the actual measurement results should still be recorded.

Non-target lesions

✪ All unmeasurable diseases are non-target lesions.
✪ All measurable lesions that are not identified as target lesions are also included in non-focal diseases.
✪ Non-target lesions do not need to be measured, but the evaluation is expressed as none, uncertain, with/not enlarged, and enlarged. Multiple non-target lesions of an organ are recorded as one item on the case report form (eg: multiple enlarged pelvic lymph nodes or multiple liver metastases)

Measurement of the lesion

Timing of measurement

There is a baseline for tumor efficacy evaluation, and the examination results after treatment should be compared with this time.

This is why doctors generally require a comprehensive examination before all patients are hospitalized for treatment. All baseline assessments must be performed as close to the start of treatment as possible, not earlier than four weeks.

Choice of method

When evaluating the same lesion, the same techniques and methods should be used at baseline and follow-up. Generally speaking, lesions must be evaluated by imaging methods, and clinical examinations cannot be used alone.

Only superficial lesions below 10 mm (such as subcutaneous nodules) are considered for clinical testing using calipers. For superficial skin lesions, it is recommended to use color photos for recording, and the photos are attached with a scale for measuring the size of the lesion.

When the lesion can be used for both clinical examination and imaging examination, imaging examination is the first choice.

✪ Chest X-ray: CT is more sensitive than X-rays in discovering new lesions, so CT is preferred, especially at important treatment endpoints

✪ CT | MRI: CT (slice thickness ≤ 5 mm) is currently the most effective and reproducible detection method used to assess the effect of lesions; MRI is available for whole body scanning.

✪ Ultrasound examination: Ultrasound results largely depend on the examiner’s operation, and are not suitable for assessing the size of the lesion, and should not be used for measurement methods.

✪ Endoscopy, laparoscopy: Routine assessment of solid tumors is not used, but it is useful when biopsy confirms complete pathological remission or confirms complete remission or recurrence after surgical resection.

✪ Tumor markers: Tumor markers cannot be used alone to evaluate the efficacy of solid tumors. If it is used to judge a patient’s complete remission, the markers must be normalized, such as changes in CA-125 (in the recurrence of ovarian cancer) and changes in PSA (in the recurrence of prostate cancer).

✪ Cytology, histology: when necessary, it can be used to distinguish partial remission from complete remission

For example, when identifying the tumor types of residual lesions, for example, germ cell tumors, it is known that residual benign tumor lesions can be preserved.

It is necessary to distinguish between benign and malignant lesions. When it is known that the exudate during treatment may have serious adverse consequences (such as certain paclitaxel chemotherapeutics or angiogenesis inhibitors), even if the measurable tumor meets the effective or stable standard, any exudation that occurs during the treatment and worsens It is necessary to consider the use of cytology to confirm the nature of the tumor to distinguish whether the efficacy of the evaluable tumor is effective, stable (ineffective) or progressing.


Tumor efficacy evaluation

It can be roughly divided into five conditions: complete remission, partial resolution, disease progression, stable disease, and unclear disease.

Target lesion

✪ Complete remission (CR): Except for nodular diseases, all target lesions disappeared completely. All target nodules must be reduced to normal size (short axis <10 mm). All target lesions must be evaluated.

✪ Partial remission (PR): The sum of the diameters of all measurable target lesions is lower than the baseline by ≥ 30%. The short diameter is used for the sum of target nodules, and the longest diameter is used for the sum of all other target lesions. All target lesions must be evaluated.

✪ Disease progression (PD): take the minimum value of the sum of the diameters of all target lesions measured during the entire experimental research process as a reference, and the relative increase in diameter sum by at least 20% (if the baseline measurement value is the smallest, refer to the baseline value); In addition, the absolute value of the diameter sum must be increased by at least 5 mm (the appearance of one or more new lesions is also regarded as disease progression).

✪ Stable disease (SD): The reduction of the target lesion does not reach the PR, and the increase does not reach the PD level, which is between the two. The minimum sum of the diameters can be used as a reference during the study.

Non-target lesions

✪ CR: All non-target lesions disappeared or the level of tumor markers is normal. The size of all lymph nodes must be “normal” (short axis <10 mm).

✪ Non-CR/non-PD: Any non-target lesions persist and/or tumor marker levels are higher than the upper limit of normal.

✪ PD: The disease has clearly progressed. Usually, the overall tumor burden must be increased enough to stop treatment. In the case of SD or PR of the target lesion, progress due to a clear enlargement of the non-target lesion is rare.

✪ Unclear: Progress was not measured, 1 or more non-target lesions were not evaluated, or the evaluation method was inconsistent with the baseline method.

New lesion

The appearance of any new and clear malignant tumor lesions indicates disease progression. If the new lesion is not clear, for example due to its small size, further evaluation will clarify the cause. If repeated evaluations identify lesions, then progress should be recorded on the date of the first evaluation. The lesions found in the previously unscanned area are considered as new lesions.

Confirmation of efficacy

✪ Patients evaluated as CR or PR must repeat the evaluation at least 4 weeks later

✪ Patients who are evaluated as SD should be evaluated repeatedly after the interval specified in the protocol (generally no less than 6-8 weeks)

✪ If it is clear that CR depends on residual lesions that have decreased in size but have not completely disappeared, biopsy or fine-needle aspiration of residual lesions is recommended for research. If no disease is found, the subjective condition is recorded as CR.

✪ If it is clear that the progress depends on the lesion that may have increased due to necrosis, then the lesion should be biopsy or fine needle aspiration to determine the status.




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