Conformal 3D planned radiotherapy for pelvic lymphoceles following surgery for urological cancer: A case study

Introduction

Lymphoceles are an abnormal collection of lymphatic fluid occurring following surgery. They can cause abdominal pain, deep vein thrombosis or lower urinary tract problems (1). Incidence, for example following open radical prostatectomy with pelvic lymph node dissection, varies in the literature between 3 and 14% (2). While treatment options encompass percutaneous aspiration with or without instillation of sclerosing agents and laparoscopic marsupialization, no standard is defined (1,3). Very few papers have focussed on radiotherapy (RT) as an alternative treatment option using different doses and techniques (4–7). The aim of the present analysis was to evaluate outcome and toxicity of a homogenous treatment schedule and modern technique for patients with postoperative persistent lymphoceles in the setting of malignant urological disease.

Case study

Following radical prostatectomy/cystectomy with lymphadenectomy, 6 patients developed a pelvic lymphocele, which persisted after percutaneous drainage. Each patient (seven treatment volumes in total) was treated with external beam RT using 3D planned treatment with virtual simulation after planning CT. Clinical target volume (CTV) was contoured, including the entire lymphocele with a margin of 1–2 cm, creating the planning target volume (PTV). Photons of 6 and 18MV energy were selected and 3–5 coplanar fields were used (Fig. 1). Of the patients, 1 patient was simultaneously irradiated to the prostate bed (66 Gy; 2 Gy single dose). Patient and treatment-associated parameters are summarized in Table I.

Figure 1. 3D conformal treatment plan for right inguinal lymphocele. Color-wash illustration showing dose distribution.

Table I. Patient and treatment-related factors.

Table I.

Patient and treatment-related factors.

Factor	Patient 1	Patient 2	Patient 3	Patient 4	Patient 5	Patient 6
Location	Left inguinal	Left inguinal	Left iliacal	Left and righ iliacal	Right iliacal	Left inguinal
Gender	Male	Male	Male	Male	Male	Male
Age at RT	61	75	71	79	70	69
Tumor site	Prostate	Bladder	Prostate	Prostate	Prostate	Prostate
Interval surgery-RT	26 days	4 months	18 days	25 days	5 months	3 months
Previous treatment for lymphocele	Percutaneous drainage	Percutaneous drainage and slerotic agents	Percutaneous drainage and doxicyclin	Percutaneous drainage and slerotic agents	No previous therapy	Percutaneous drainage
Total/single dose	12/1 Gy	12/1 Gy	12/1 Gy	10/1 Gy	10/1 Gy	10/1 Gy
					In addition to RT to prostate bed (66 Gy)
PTV (ml)	69 ml	172 ml	57 ml	119 and 88 ml	114 ml	76 ml
Toxicity	None	None	None	None	None	None
Follow up	16 months	20 months	14 months	24 months	5 months	47 months
Early response	150 ml residuum (no initial value), drainage drawn	600 to 300 ml	1,000 to 300 ml	800 to 300 ml	150 to 0 ml	Persistent (500 ml)
Late response	Resolved	Resolved	Resolved		Resolved	Secondary marsupialization, now no symptoms

[i] RT, radiotherapy; PTV, planning target volume.

No acute toxicities or chronic side effects were observed. Of the 6 patients, 5 patients exhibited secretion of lymph fluid, which was resolved after RT (Table I). In 4 patients, secretion was already reduced during RT, while 1 patient responded time-delayed without further therapy (8 weeks after RT) (Table I). In 1 patient, RT caused no effect, making a marsupialization necessary. Following a mean follow-up of 21 months (range, 5–47 months), no patient suffered from any symptoms concerning his former lymphoceles. All drainages could be removed.

Discussion

Persistent lymphoceles are a common problem following pelvic surgery, particularly when lymphadenectomy is performed (3). Different approaches exist for the treatment of persistent lymphoceles but no standard is defined.

In previous literature, there are four studies exclusively focusing on RT for persistent lymphoceles (4–6,8). From 1989–1998, Neu et al (4) treated 29 patients after vascular surgery with a single daily dose of 1 Gy up to 3–12 Gy. The majority of patients were treated with electrons (7–18 MeV) (4). Also, following vascular surgery, Dietl et al (6) treated 28 patients for inguinal lymphorrhea with single doses of 2–3 Gy up to 8–15 Gy. An orthovoltage of 120–300 KV energy was used (6). The study group of Mayer et al (5) treated patients with fistulas after different, mostly vascular surgeries in different localizations with orthovoltage or electrons in majority. The single doses ranged from 0.3–2.0 Gy with total doses of 1–12 Gy (5). Previously, Jereczek-Fossa et al (8) showed RT after prostatectomy in the presence of asymptomatic lymphoceles to be feasible for integrating the lymphocele into the treatment plan of the prostate fossa with maximum doses to the lymphoceles of 5.7–73.3 Gy (8). Taken together, patient collectives of the above mentioned retrospective studies are heterogenous in localization, treatment technique, single and total doses, and primary surgery.

In the present study patients with urological cancer, primarily prostate cancer, were treated for inguinal/iliacal lymphoceles with a homogenous treatment schedule. Contrasting to the other study groups, a more precise RT technique was applied. Prior to the initiation of the treatment, a planning CT was performed, on which the planning target volume (lymphocele) was contoured. Afterwards a 3D treatment plan was generated. This allowed a more precise and conformal dose coverage of the target volume and sparing of the organs at risk compared with clinical approaches. In line with this, no acute or late side effects were observed.

The response rates (suspended secretion or removal of drains) varied between 76 and 93% in the literature, and compare well with the present findings (83%).

A limitation of the present retrospective case series is without any doubt the small number of patients. Nevertheless, in the absence of prospective studies, the present case series is the first, to the best of our knowledge, to show the effectiveness and safety of modern RT to persistent lymphoceles in patients with urological cancer.

In conclusion, 3D conformal RT for persistent pelvic lymphoceles in patients with urological cancer is effective and very well-tolerated. Urological surgeons must be aware of this treatment option, particularly following the failure of other treatment modalities.

References