The aim of this study was to investigate the clinical effectiveness of a psychiatric intervention program consisting of 5 weekly structured interventions and 3 additional group meetings every two months. Previous studies revealed that a 5 weekly structured intervention program was effective for alleviating psychological discomforts in Japanese breast cancer patients, and that the effectiveness persisted for 6 months for patients without lymph node metastasis or adjustment disorders. Since this 5-session intervention did not have persistent effects in patients with lymph node metastasis and/or adjustment disorders, 3 additional group meetings every two months were added after completion of the 5 weekly structured interventions. A total of 43 breast cancer patients completed the full program. The Profile of Mood States (POMS) scores were compared before, immediately after 5 sessions, immediately after the 3 additional interventions, and 6 months after all programs. As analyzed by POMS scores, the clinical effectiveness of a structured group intervention program persisted for 6 months for patients even with nodal metastases and/or adjustment disorders. These findings of the present study suggested that the 5 weekly intervention program was sufficient for patients without lymph node metastasis or adjustment disorders. In contrast, this intervention program alone was insufficient for patients with nodal metastases and/or adjustment disorders. For them, a new psychiatric intervention program consisting of 5 weekly structured interventions and 3 additional group meetings every two months were effective and sufficient.