Page 11 - ARNM-1-1

Advances in Radiotherapy
& Nuclear Medicine Seed implantation head-and-neck carcinoma

corresponding time points were 96.6%, 92%, and 92%. The 5 cm; (iii) with Karnofsky Performance Status (KPS) scores
disease-free survival (DFS) rates at 3, 5, and 10 years were ≥70; (iv) who refused further surgery or EBRT; (v) with no
93.1%, 88.4%, and 88.4%, respectively. In addition, the rates ulcer or invasion of the skin; and (vi) with life expectancy
[13]
of freedom from distant metastasis at 3, 5, and 10 years were more than 3 months. Jiang et al. published a pilot trial
96.6%, 91.2%, and 91.2 %, respectively. Notably, the patients on 64 consecutive patients with 81 lesions that received
experienced face recovery of the facial nerve function, I-125 RSI-BT under ultrasound guidance. The study
and no severe RT-related complications were observed. reported a total response rate (RR) was 80.2%, with 22
According to these results, it is suggested that I-125 RSI-BT lesions (27%) achieving complete remission and 43 lesions
could be used to treat tumors that cannot be completely (53%) showing partial remission. The LC rates at 1, 3,
resected in the head-and-neck region. The advantages of and 5 years were 75.2%, 73.0%, and 69.1%, respectively.
intra-operative I-125 RSI-BT, as demonstrated in the above- Notably, the results for cervical lymph node recurrence
mentioned studies, include (i) easier identification of the outperformed those for recurrence or residual disease of
objective region for I-125 seed implantation BT through primary head-and-neck neoplasms, with a 5-year LC rate
visual assessment during the operation; (ii) improved of 72.7% for cervical lymph node recurrence and 39.9%
radiation protection by sparing of adjacent normal tissues; for recurrence or residual disease of primary head-and-
and (iii) achievement of accurate real-time optimization neck neoplasms. The analysis revealed that the D90 (the
for dose calculation during the operation, as the target percentage of the minimum dose that covered 90% of
definition can be performed more easily and effectively. the target volume) served as an independent prognostic
I-125 RSI-BT has been demonstrated as an effective and factor of LC. In addition, the location of lesion recurrence
safe salvage modality without RSI-relative toxicity that is and the time to tumor progression was identified as
more than Grade 2. Further investigation with multiple, prognostic factors for OS. The OS rates at 1, 3, and 5 years
prospective, and randomized clinical trials to compare were 57.4%, 31%, and 26.6%, respectively, with MST of
intra-operative I-125 RSI-BT with post-surgical EBRT for 20 months. Among patients who had received EBRT, two
residual or unresectable HNC disease is warranted. patients (3%) experienced Grade 4 skin ulceration, while
11 patients (17%) experienced Grade 1 or 2 skin reactions.
3. Percutaneous ultrasound-guided I-125 The post-plan evaluation indicated that the D90 ranged
RSI-BT for rHNC from 90 to 160 Gy (median 130 Gy). The LC would be
3.1. History of percutaneous ultrasound-guided improved if D90≥130 Gy. The preliminary clinical results
RSI-BT showed that the RSI-BT, as a salvage modality for rHNC
following EBRT, is safe, feasible, and effective. However,
Transrectal ultrasonography (TRUS)-guided LDR-BT was the post-plan evaluation of D90 has shown a wide range
first developed in Denmark in the 1970s . TRUS-guided of values, varying from 90 to 160 Gy. In addition, when the
[23]
LDRBT has become a standard technique since the 1990s. indication selection was not limited by the diameter of the
The technique has demonstrated improved treatment tumors, the prognosis was suboptimal.
outcomes and is considered a minimally invasive procedure,
offering favorable comparisons to surgery or EBRT [24,25] . The disadvantages of ultrasound guidance are that:
In the USA, LDR-BT was subsequently endorsed for the (i) ultrasound images are two-dimension (2D); (ii) the
treatment of low-risk prostate carcinoma by the American image quality has a lower resolution than that of CT scans;
BT Society (ABS) and the American Society for Radiation (iii) the pre-plan cannot be entirely followed as the ranges
Oncology (ASTRO) . The National Comprehensive of post-plan D90 doses are significantly varied, resulting
[26]
Cancer Network (NCCN) guideline supports the use of in non-assurance of the quality control according to the
LDR-BT as first-line therapy for low-intermediate risk designed pre-plan; (iv) the ultrasound images cannot
groups of prostate carcinoma, both as monotherapy and in be obtained if the air is in the field or there is boney
combination with EBRT . obstruction, resulting in limited applications; (v) the
[27]
ultrasound probe often interferes with needle placement
3.2. Ultrasound-guided I-125 RSI-BT for rHNC or advancement; and (vi) there is no specially designed
The ultrasound probe should have end-fire scanning template for assisting ultrasound guidance except for
capabilities and Doppler function, which can identify prostate carcinoma.
arterial or venous blood vessels. The criteria for the study There are many issues that need to be tackled or
were limited to the patients (i) who previously received techniques that need to be further improved on for
surgery or EBRT and were diagnosed with pathology and improvement in ultrasound guidance, for example, the
image diagnosis; (ii) with a diameter of the lesion less than development of a compatible template connected with the

Volume 1 Issue 1 (2023) 3 https://doi.org/10.36922/arnm.0907