Training material III
Surgical treatment of thyroid cancer
甲状腺癌在病理方面可简单地分为三类:
1、乳头状腺癌: 在临床上最常见，恶性程度较轻，主要是转移至颈部淋巴结。
2、腺泡状腺癌: 恶性程度中等度，主要经血运转移，至骨和肺部。
3、未分化的单纯癌: 恶性程度甚高，极早转移至颈部淋巴结，也可经血运转移至骨和肺部，预后较差。
甲状腺癌在临床方面，手术处理的疗效是符合于病理分类的:
1、在乳头状腺癌，如果切除原发患的同时，将颈部淋巴结仔细、彻底地加以清除，五年治愈率可达90%以上。
2、在腺泡状腺癌，如果颈部淋巴结已有转移，大多已有远处转移，因此即使彻底清除了颈部淋巴结，也不能增高手术疗效。
3、未分化的单纯癌，发展甚快，一般在发病后2-3个月即出现压迫症状 (疼痛、声嘶，呼吸困难) 或远处转移，强行手术切除，不但无益，而且可加速癌细胞经血运的扩散，因此如果怀疑为恶性甚高的单纯癌，可先行穿刺作活组织检查证实之，治疗则以放射为主。
手术切除乳头状腺癌或腺泡状腺癌，一般在气管内麻醉下进行，操作步骤与甲状腺部分切除相同，但要注意以下几个问题:
1、切口要宽大，胸锁乳突肌前缘要剪开，显露就好。
2、不可损破内层被膜，当然也不宜应用丝线穿扎腺体作牵拉用，以防止癌细胞种植在切口中。
3、不保留腺体背面部分，而切除全部腺体，但应尽量保留甲状旁腺，也应尽量不损伤喉返神经，如果癌肿局限在一叶的腺体内，可将患叶的腺体连同甲状腺峡部全部切除之，如果癌肿已侵及左右两叶，就需将两叶腺体连同甲状腺峡全部切除之，但至少应保留一侧的甲状旁腺，不使术后发生严重的手足抽搐，甲状腺内层被膜的完整与否 (被癌组织穿破与否)，对原发癌的能否完全切除，具有决定性的意义。
在切除原发癌肿后，接着就应仔细、彻底地清除患侧的颈部淋巴结。
1、清除颈外侧部的淋巴结组织。
2、颈总动脉和颈内静脉深面的淋巴结，
3、再清除气管前，甲状腺峡部以上的淋巴结。
4、然后再清除甲状腺后气管旁，喉返神经周围的以及上纵隔内的淋巴结，同时切除胸锁乳突肌和其他重要组织 (一侧的颈内静脉和颈总动脉等) 是无需的，并不能增高手术疗效。
如果已有远处转移，对局部可以全部切除的腺癌不但应将患叶的腺体全部切除，患侧的颈部部淋巴结加以清除，同时还应切除健叶的全部腺体，这样一方面可防止由于原发癌的发展、增大而发生压迫性症状，另方面可试用放射碘 131 来治疗远处转移。腺癌的远处转移只能在切除整个甲状腺后，才能撮取放射性碘，如果远处转移，撮取放射性碘量极低微，则在切除整个甲状腺后，由于垂体前叶促状腺激素的分泌增多，反而促使远处转移迅速发展，对这种试用放射性碘无效的病例，应早期给予足够量的甲状腺制剂，以抑制促甲状腺素的产生，远处转移可因此而缩小，至少不再继续发展，手术中可能要施行气管切开以保持呼吸道通畅。
Thyroid cancer in pathology can be simply divided into three categories:
- Papillary adenocarcinoma: It is the most common adenocarcinoma in clinic, with mild malignancy, mainly involving metastasis to the cervical lymph nodes.
- Alveolar adenocarcinoma: The malignancy is moderate, and it is mainly transferred through blood supply to bone and lung.
- undifferentiated simple carcinoma: the malignancy is very high, and it metastasizes to the cervical lymph nodes very early, or it can metastasize to the bone and lung through blood supply, with poor prognosis.
Clinically, the efficacy of surgical treatment of thyroid cancer is in line with the pathological classification:
- in the papillary adenocarcinoma, if the resection of the primary disease at the same time, the neck lymph nodes carefully and thoroughly removed, five years the cure rate can reach more than 90%.
- n acinar adenocarcinoma, if the cervical lymph nodes have metastasized, most of them have distant metastasis. Therefore, even if the cervical lymph nodes are completely removed, the surgical efficacy cannot be improved.
- undifferentiated pure cancer, development is very fast, generally in 2 to 3 months after the onset of the compression symptoms (pain, hoarseness, dyspnea) or distant metastasis, forced surgical resection, not only useless, and can accelerate the spread of cancer cells through the blood supply, so if it is suspected to be very high malignant pure cancer, can first puncture for biopsy confirmed, treatment is given priority to with radiation.
Surgical resection of papillary adenocarcinoma or acinar adenocarcinoma, generally under endotracheal anesthesia, the operation steps are the same as partial thyroidectomy, but should pay attention to the following questions:
- incision to wide, sternocleidomastoid muscle leading edge to cut open, show.
- do not damage to break the inner capsule, of course, also should not use silk thread wear tie gland for pulling, in order to prevent cancer cells planted in the incision.
- The back part of the gland is not preserved, and all the glands are excised. The parathyroid should be preserved as much as possible, and the recurrent laryngeal nerve should not be damaged as much as possible. If the cancer is confined to one lobe of the gland, all the glands in the lobe together with the thyroid isthmus can be excised. If the cancer has invaded the left and right lobes, the two lobe glands together with the thyroid isthmus should be excised completely. However, at least one side of the parathyroid should be preserved, so that no severe convulsion of hands and feet occurs after the operation. Whether the inner capsule of the thyroid is intact or not (worn out by the cancer tissue) is of decisive significance for the complete resection of primary cancer.
After resection of the primary cancer, careful and thorough removal of the cervical lymph nodes on the affected side should follow.
- remove the lateral cervical lymph node tissue.
- the common carotid artery and internal jugular vein deep lymph nodes,
- before the removal of trachea, thyroid isthmus above the lymph nodes.
- After that, the paratracheal lymph nodes around the recurrent laryngeal nerve and the lymph nodes in the upper mediastinum should be removed. Meanwhile, the sternocleidomastoid muscle and other important tissues (internal jugular vein and common carotid artery on one side) should be removed. This is unnecessary and cannot increase the curative effect of the operation.
If there is distant metastasis, the local adenocarcinoma can be completely removed not only should be the gland of the diseased leaves all resection, the affected side of the neck lymph nodes to be removed, at the same time should also remove all the glands of the healthy leaves, so on the one hand can prevent due to the development of primary cancer, increase and oppressive symptoms, on the other hand can try radiation iodine 131 to treat distant metastasis. Distant metastasis of adenocarcinoma can only take radioactive iodine after the whole thyroid gland is resected. If the distant metastasis takes radioactive iodine with extremely low amount, then after the whole thyroid gland is resected, the distant metastasis will develop rapidly because of the secretion increase of thyroid-stimulating hormone in anterior pituitary gland. In the case that radioactive iodine is ineffective for trial use, thyroid preparations with sufficient amount should be given early to inhibit the production of thyrotropin. The distant metastasis can shrink because of this, and at least it will not continue to develop. Tracheotomy may be performed during the operation to keep respiratory tract unobstructed.
This article was originally published in Proceedings of Wuhu Annual Surgical Conference,1996；28-30 Changhang Hospital, Li Mingjie
from 外科截瘫14例手术分析
