input: The following are multiple choice questions (with answers) about medical knowledge.   This study aims to evaluate local failure patterns in node negative breast cancer patients treated with post-mastectomy radiotherapy including internal mammary chain only. Retrospective analysis of 92 internal or central-breast node-negative tumours with mastectomy and external irradiation of the internal mammary chain at the dose of 50 Gy, from 1994 to 1998. Local recurrence rate was 5 % (five cases). Recurrence sites were the operative scare and chest wall. Factors associated with increased risk of local failure were age<or = 40 years and tumour size greater than 20mm, without statistical significance.   **Question:** Should chest wall irradiation be included after mastectomy and negative node breast cancer?   (A) Yes   (B) No   (C) Maybe
output: ['(C) Maybe <> answer', 'The following are multiple choice questions (with answers) about medical knowledge. <> instruction', '(A) Yes  (B) No  (C) Maybe <> possible answers', 'This study aims to evaluate local failure patterns in node negative breast cancer patients treated with post-mastectomy radiotherapy including internal mammary chain only. Retrospective analysis of 92 internal or central-breast node-negative tumours with mastectomy and external irradiation of the internal mammary chain at the dose of 50 Gy, from 1994 to 1998. Local recurrence rate was 5 % (five cases). Recurrence sites were the operative scare and chest wall. Factors associated with increased risk of local failure were age<or = 40 years and tumour size greater than 20mm, without statistical significance. \n   Should chest wall irradiation be included after mastectomy and negative node breast cancer? <> context']