The World Health Organization (WHO) organized two meetings to standardize the reporting of cancer treatment results. These meetings involved representatives from various organizations and led to the development of recommendations for standardized data collection and reporting. These recommendations aim to enable valid comparisons of treatment outcomes among different studies and are proposed for international acceptance. The guidelines emphasize the importance of standardization in assessing and reporting cancer treatment results to increase the availability of usable therapeutic information for physicians. The report outlines the minimum data required for patient and tumor characteristics, including patient identification, medical history, performance status, tumor site, measurability, and staging. It also provides detailed descriptions for the reporting of treatment modalities such as surgery, radiotherapy, chemotherapy, immunotherapy, and combined modality therapy. Toxicity is classified into acute, subacute, and chronic categories, with specific grading systems for acute and subacute toxicity. The report defines objective response criteria for cancer treatment, including complete response, partial response, no change, and progressive disease. Special criteria are provided for bone metastases. It also outlines the reporting of recurrence, relapse, disease-free interval, and disease-free survival, emphasizing the importance of accurate dates and independent verification. The report discusses the importance of frequency and duration in evaluating treatment outcomes, along with the proper use of numerators and denominators in reporting results. It highlights the need for accurate date recording and the definition of "cure" in cancer treatment. The patient population is classified based on eligibility, treatment, and evaluation for therapy efficacy. The life table method is recommended for summarizing frequency and duration data. The guidelines aim to ensure consistency and comparability of cancer treatment results across different studies and institutions.The World Health Organization (WHO) organized two meetings to standardize the reporting of cancer treatment results. These meetings involved representatives from various organizations and led to the development of recommendations for standardized data collection and reporting. These recommendations aim to enable valid comparisons of treatment outcomes among different studies and are proposed for international acceptance. The guidelines emphasize the importance of standardization in assessing and reporting cancer treatment results to increase the availability of usable therapeutic information for physicians. The report outlines the minimum data required for patient and tumor characteristics, including patient identification, medical history, performance status, tumor site, measurability, and staging. It also provides detailed descriptions for the reporting of treatment modalities such as surgery, radiotherapy, chemotherapy, immunotherapy, and combined modality therapy. Toxicity is classified into acute, subacute, and chronic categories, with specific grading systems for acute and subacute toxicity. The report defines objective response criteria for cancer treatment, including complete response, partial response, no change, and progressive disease. Special criteria are provided for bone metastases. It also outlines the reporting of recurrence, relapse, disease-free interval, and disease-free survival, emphasizing the importance of accurate dates and independent verification. The report discusses the importance of frequency and duration in evaluating treatment outcomes, along with the proper use of numerators and denominators in reporting results. It highlights the need for accurate date recording and the definition of "cure" in cancer treatment. The patient population is classified based on eligibility, treatment, and evaluation for therapy efficacy. The life table method is recommended for summarizing frequency and duration data. The guidelines aim to ensure consistency and comparability of cancer treatment results across different studies and institutions.